cosmic rays and radiation

“If there is energy within the substance it can only come from without. This truth was so manifest to me that I expressed it in the following axiom: ‘There is no energy in matter except that absorbed from the medium…’ If all energy is supplied to matter from without then this all important function must be performed by the medium.”

“When radio-active rays were discovered their investigators believed them to be due to liberation of atomic energy in the form of waves. This being impossible in the light of the preceding I concluded that they were produced by some external disturbance and composed of electrified particles. My theory was not seriously taken although it appeared simple and plausible. Suppose that bullets are fired against a wall. Where a missile strikes the material is crushed and spatters in all directions radial from the place of impact. In this example it is perfectly clear that the energy of the flying pieces can only be derived from that of the bullets. But in manifestation of radio-activity no such proof could be advanced and it was, therefore, of the first importance to demonstrate experimentally the existence of this miraculous disturbance in the medium. I was rewarded in these efforts with quick success largely because of the efficient method I adopted which consisted in deriving from a great mass of air, ionized by the disturbance, a current, storing its energy in a condenser and discharging the same through an indicating device. This plan did away with the limitations and incertitude of the electroscope first employed and was described by me in articles and patents from 1900 to 1905. It was logical to expect, judging from the behavior of known radiations, that the chief source of the new rays would be the sun, but this supposition was contradicted by observations and theoretical considerations which disclosed some surprising facts in this connection.

“Light and heat rays are absorbed in their passage through a medium in a certain proportion to its density. The ether, although the most tenuous of all substances, is no exception to this rule.  Its density has been first estimated by Lord Kelvin and conformably to his finding a column of one square centimeter cross section and of a length such that light, traveling at a rate of three hundred thousands kilometers per second, would require one year to traverse it, should weigh 4.8 grams. This is just about the weight of a prism of ordinary glass of the same cross section and two centimeters length which, therefore, may be assumed as the equivalent of the ether column in absorption. A column of the ether one thousand times longer would thus absorb as much light as twenty meters of glass.  However, there are suns at distances of many thousands of light years and it is evident that virtually no light from them can reach the earth. But if these suns emit rays immensely more penetrative than those of light they will be slightly dimmed and so the aggregate amount of radiations pouring upon the earth from all sides will be overwhelmingly greater than that supplied to it by our luminary. If light and heat rays would be as penetrative as the cosmic, so fierce would be the perpetual glare and so scorching the heat that life on this and other planets could not exist.

“Rays in every respect similar to the cosmic are produced by my vacuum tubes when operated at pressures of ten millions of volts or more, but even if it were not confirmed by experiment, the theory I advanced in 1897 would afford the simplest and most probable explanation of the phenomena. Is not the universe with its infinite and impenetrable boundary a perfect vacuum tube of dimensions and power inconceivable? Are not its fiery suns electrodes at temperatures far beyond any we can apply in the puny and crude contrivances of our making? Is it not a fact that the suns and stars are under immense electrical pressures transcending any that man can ever produce and is this not equally true of the vacuum in celestial space? Finally, can there be any doubt that cosmic dust and meteoric matter present an infinitude of targets acting as reflectors and transformers of energy? If under ideal working conditions, and with apparatus on a scale beyond the grasp of the human mind, rays of surpassing intensity and penetrative power would not be generated, then, indeed, nature has made an unique exception to its laws.

"It has been suggested that the cosmic rays are electrons or that they are the result of creation of new matter in the interstellar deserts. These views are too fantastic to be even for a moment seriously considered. They are natural outcroppings of this age of deep but unrational thinking, of impossible theories, the latest of which might, perhaps, deal with the curvature of time. What this world of ours would be if time were curved…“

–Nikola Tesla

“The Eternal Source of Energy of the Universe, Origin and Intensity of Cosmic Rays.” October 13, 1932.
Cosmic Rays: Space Messengers

We only know 4% of what the universe is made up of. Can we also know what lies beyond our galaxy … and if there are undiscovered forms of matter? Luckily, we have space messengers — cosmic rays — that bring us physical data from parts of the cosmos beyond our reach. 

Cosmic rays were first discovered in 1912 by Victor Hess when he set out to explore variations in the atmosphere’s level of radiation, which had been thought to emanate from the Earth’s crust. By taking measurements on board a flying balloon during an eclipse, Hess demonstrated both that the radiation actually increased at greater altitudes and that the sun could not be its source. The startling conclusion was that it wasn’t coming from anywhere within the Earth’s atmosphere but from outer space. Our universe is composed of many astronomical objects. Billions of stars of all sizes, black holes, active galactic nuclei, astroids, planets and more. 

During violent disturbances, such as a large star exploding into a supernova, billions of particles are emitted into space. Although they are called rays, cosmic rays consist of these high energy particles rather than the photons that make up light rays. What makes cosmic rays useful as messengers is that they carry the traces of their origins. By studying the frequency with which different particles occur, scientists are able to determine the relative abundance of elements, such as hydrogen and helium, within the universe. But cosmic rays may provide even more fascinating information about the fabric of the universe itself. 

An experiment called the Alpha Magnetic Spectrometer, A.M.S., has recently been installed on board the International Space Station, containing several detectors that can separately measure a cosmic ray particle’s velocity, trajectory, radiation, mass and energy, as well as whether the particle is matter or antimatter. While the two are normally indistinguishable, their opposite charges enable them to be detected with the help of a magnet. The Alpha Magnetic Spectrometer is currently measuring 50 million particles per day with information about each particle being sent in real time from the space station to the A.M.S. control room at CERN. Over the upcoming months and years, it’s expected to yield both amazing and useful information about antimatter, the possible existence of dark matter, and even possible ways to mitigate the effects of cosmic radiation on space travel.

As we stay tuned for new discoveries, look to the sky on a clear night, and you may see the International Space Station, where the Alpha Magnetic Spectrometer receives the tiny messengers that carry cosmic secrets.

From the TED-Ed Lesson How cosmic rays help us understand the universe - Veronica Bindi

Animation by TED-Ed / Jeremiah Dickey



US Patent No. 685,957: Apparatus for the Utilization of Radiant Energy

To all whom it may concern:

Be it known that I, NIKOLA TESLA, a citizen of the United States… have invented certain new and useful Improvements in Apparatus for the Utilization of Radiant Energy…

It is well known that certain radiations–such as those of ultra-violet light, cathodic, Roentgen rays, or the like–possess the property of charging and discharging conductors of electricity, the discharge being particularly noticeable when the conductor upon which the rays impinge is negatively electrified. These radiations are generally considered to be ether vibrations of extremely small wave lengths, and in explanation of the phenomena noted it has been assumed by some authorities that they ionize or render conducting the atmosphere through which they are propagated. My own experiments and observations, however, lead me to conclusions more in accord with the theory heretofore advanced by me that sources of such radiant energy throw off with great velocity minute particles of matter which are strongly electrified, and therefore capable of charging an electrical conductor, or, even if not so, may at any rate discharge an electrified conductor either by carrying off bodily its charge or otherwise.

My present application is based upon a discovery which I have made that when rays, or, radiations of the above kind are permitted to fall upon an insulated conducting-body connected to one of the terminals of a condenser while the other terminal of the same is made by independent means to receive or to carry away electricity a current flows into the condenser so long as the insulated body is exposed to the rays, and under the conditions hereinafter specified an indefinite accumulation of electrical energy in the condenser takes place. This energy after a suitable time interval, during which the rays are allowed to act, may manifest itself in a powerful discharge, which may be utilized for the operation or control of mechanical or electrical devices or rendered useful in many other ways.

Figure 1 is a diagram showing the general arrangement of apparatus as usually employed.

Fig. 2 is a similar diagram illustrating more in detail typical forms of the devices or elements used in practice.

Figs. 3 and 4 are diagrammatical representations of modified arrangements suitable for special purposes.

…It will be found that when the radiations of the sun or of any other source capable of producing the effects before described fall upon the plate P an accumulation of electrical energy in the condenser C will result. This phenomenon, I believe, is best explained as follows: The sun, as well as other sources of radiant energy, throws off minute particles of matter positively electrified, which, impinging upon the plate P, communicate continuously an electrical charge to the same. The opposite terminal of the condenser being connected to the ground, which may be considered as a vast reservoir of negative electricity, a feeble current flows continuously into the condenser, and inasmuch as these supposed particles are of an inconceivably small radius or curvature, and consequently charged to a relatively very high potential, this charging of the condenser may continue, as I have actually observed, almost indefinitely, even to the point of rupturing the dielectric. If the device d be of such character that it will operate to close the circuit in which it is included when the potential in the condenser has reached a certain magnitude, the accumulated charge will pass through the circuit, which also includes the receiver R, and operate the latter…



Megastructures 8 Bernal Sphere

The original Bernal Sphere (proposed by John Desmond Bernal in 1929) is a space colony that would serve as a residential area for a space manufacturing plant. The residents would be found within the spherical portion of the hollow orbiting space station. The outside of the shell would be dense enough to shield the people from cosmic rays and other sources of radiation. The inner sphere rotates to provide gravity via centrifugal force, with dwellings built on the inside surface. The poles of the sphere would have far less gravity than the equator, and hence would be the location of spaceship docking ports and zero gravity manufacturing. Recreational activities such as low-gravity swimming could also be held in this area. Farms could be placed in stacked rings on the outside of the sphere, or could be scattered in with the residential areas as part of a mixed-use development program.


Close Views Show Saturn’s Rings in Unprecedented Detail

Newly released images showcase the incredible closeness with which NASA’s Cassini spacecraft, now in its “Ring-Grazing” orbits phase, is observing Saturn’s dazzling rings of icy debris.

The views are some of the closest-ever images of the outer parts of the main rings, giving scientists an eagerly awaited opportunity to observe features with names like “straw” and “propellers.” Although Cassini saw these features earlier in the mission, the spacecraft’s current, special orbits are now providing opportunities to see them in greater detail. The new images resolve details as small as 0.3 miles (550 meters), which is on the scale of Earth’s tallest buildings.

Cassini is now about halfway through its penultimate mission phase – 20 orbits that dive past the outer edge of the main ring system. The ring-grazing orbits began last November, and will continue until late April, when Cassini begins its grand finale. During the 22 finale orbits, Cassini will repeatedly plunge through the gap between the rings and Saturn. The first finale plunge is scheduled for April 26.

For now, the veteran spacecraft is shooting past the outer edges of the rings every week, gathering some of its best images of the rings and moons. Already Cassini has sent back the closest-ever views of small moons Daphnis and Pandora.

Some of the structures seen in recent Cassini images have not been visible at this level of detail since the spacecraft arrived at Saturn in mid-2004. At that time, fine details like straw and propellers – which are caused by clumping ring particles and small, embedded moonlets, respectively – had never been seen before. (Although propellers were present in Cassini’s arrival images, they were actually discovered in later analysis, the following year.)

Cassini came a bit closer to the rings during its arrival at Saturn, but the quality of those arrival images (examples: 1, 2, 3) was not as high as in the new views. Those precious few observations only looked out on the backlit side of the rings, and the team chose short exposure times to minimize smearing due to Cassini’s fast motion as it vaulted over the ring plane. This resulted in images that were scientifically stunning, but somewhat dark and noisy.

In contrast, the close views Cassini has begun capturing in its ring-grazing orbits (and soon will capture in its Grand Finale phase) are taking in both the backlit and sunlit side of the rings. Instead of just one brief pass lasting a few hours, Cassini is making several dozen passes during these final months.

“As the person who planned those initial orbit-insertion ring images – which remained our most detailed views of the rings for the past 13 years – I am taken aback by how vastly improved are the details in this new collection,” said Cassini Imaging Team Lead Carolyn Porco, of Space Science Institute, Boulder, Colorado. “How fitting it is that we should go out with the best views of Saturn’s rings we’ve ever collected.”

After nearly 13 years studying Saturn’s rings from orbit, the Cassini team has a deeper, richer understanding of what they’re seeing, but they still anticipate new surprises.

“These close views represent the opening of an entirely new window onto Saturn’s rings, and over the next few months we look forward to even more exciting data as we train our cameras on other parts of the rings closer to the planet,” said Matthew Tiscareno, a Cassini scientist who studies Saturn’s rings at the SETI Institute, Mountain View, California. Tiscareno planned the new images for the camera team.

Launched in 1997, Cassini has been touring the Saturn system since arriving in 2004 for an up-close study of the planet, its rings and moons, and its vast magnetosphere. Cassini has made numerous dramatic discoveries, including a global ocean with indications of hydrothermal activity within the moon Enceladus, and liquid methane seas on another moon, Titan.

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA’s Jet Propulsion Laboratory in Pasadena, California, manages the mission for the agency’s Science Mission Directorate in Washington. JPL is a division of Caltech in Pasadena. The Cassini imaging operations center is based at Space Science Institute in Boulder, Colorado.

TOP IMAGE….Moon Waves and Moon Wakes This Cassini image features a density wave in Saturn’s A ring (at left) that lies around 134,500 km from Saturn. Density waves are accumulations of particles at certain distances from the planet. This feature is filled with clumpy perturbations, which researchers informally refer to as “straw.” The wave itself is created by the gravity of the moons Janus and Epimetheus, which share the same orbit around Saturn. Elsewhere, the scene is dominated by “wakes” from a recent pass of the ring moon Pan.

Two versions of this image are available. This is a lightly processed version, with minimal enhancement, preserving all original details present in the image. The other version (Figure 1) has been processed to remove the small bright blemishes caused by cosmic rays and charged particle radiation near the planet – a more aesthetically pleasing image, but with a slight softening of the finest details.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 34,000 miles (56,000 kilometers) from the rings and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (340 meters) per pixel.

CENTRE IMAGE….The Propeller Belts in Saturn’s A Ring This image from NASA’s Cassini mission shows a region in Saturn’s A ring. The level of detail is twice as high as this part of the rings has ever been seen before. The view contains many small, bright blemishes due to cosmic rays and charged particle radiation near the planet.

The view shows a section of the A ring known to researchers for hosting belts of propellers – bright, narrow, propeller-shaped disturbances in the ring produced by the gravity of unseen embedded moonlets. Several small propellers are visible in this view. These are on the order of 10 times smaller than the large, bright propellers whose orbits scientists have routinely tracked (and which are given nicknames for famous aviators).

The prominent feature at left is a density wave created by the ring’s gravitational interaction with the moon Prometheus (the 12:11 resonance). Density waves are spiral-shaped disturbances (similar to the spiral arms of galaxies) that propagate through the rings at certain distances from the planet. (For more about density waves, see PIA09894)

Three versions of this image are available. This image is a lightly processed version, with minimal enhancement, preserving all original details present in the image. A second version has circles to indicate the locations of many of the small propellers in the image (Figure 1). The third version has been processed to remove the bright blemishes due to cosmic rays and charged particle radiation – a more aesthetically pleasing image, but with a slight softening of the finest details (Figure 2).

The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 33,000 miles (54,000 kilometers) from the rings and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (330 meters) per pixel.

LOWER IMAGE….Saturn’s B Ring, Finer Than Ever This image shows a region in Saturn’s outer B ring. NASA’s Cassini spacecraft viewed this area at a level of detail twice as high as it had ever been observed before. And from this view, it is clear that there are still finer details to uncover.

Researchers have yet to determine what generated the rich structure seen in this view, but they hope detailed images like this will help them unravel the mystery.

In order to preserve the finest details, this image has not been processed to remove the many small bright blemishes, which are created by cosmic rays and charged particle radiation near the planet.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 32,000 miles (51,000 kilometers) from the rings, and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (360 meters) per pixel.

BOTTOM IMAGE….Straw in the B Ring’s Edge This image shows a region in Saturn’s outer B ring. NASA’s Cassini spacecraft viewed this area at a level of detail twice as high as it had ever been observed before.

The view here is of the outer edge of the B ring, at left, which is perturbed by the most powerful gravitational resonance in the rings: the “2:1 resonance” with the icy moon Mimas. This means that, for every single orbit of Mimas, the ring particles at this specific distance from Saturn orbit the planet twice. This results in a regular tugging force that perturbs the particles in this location.

A lot of structure is visible in the zone near the edge on the left. This is likely due to some combination of the gravity of embedded objects too small to see, or temporary clumping triggered by the action of the resonance itself. Scientists informally refer to this type of structure as “straw.”

This image was taken using a fairly long exposure, causing the embedded clumps to smear into streaks as they moved in their orbits. Later Cassini orbits will bring shorter exposures of the same region, which will give researchers a better idea of what these clumps look like. But in this case, the smearing does help provide a clearer idea of how the clumps are moving.

This image is a lightly processed version, with minimal enhancement; this version preserves all original details present in the image. Another other version (Figure 1) has been processed to remove the small bright blemishes due to cosmic rays and charged particle radiation near the planet – a more aesthetically pleasing image, but with a slight softening of the finest details.

The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 32,000 miles (52,000 kilometers) from the rings and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (360 meters) per pixel.

Nikola Tesla Won 8 Nobel Prizes For His Work And Discoveries. No He Didn’t. These People Did Instead.

  1. Wilhelm Conrad Röntgen, Physics, 1901: Wilhelm Roentgan was awarded the first Nobel Prize in physics for his discovery of X-Rays on November 8, 1895. Not many know this but Tesla was working with X-Rays prior to Roentgen in 1892, but used the term “radiant matter” instead. He conducted numerous experiments and some of the first imaging, which he called “shadowgraphs,” using these unknown rays in his laboratory before its destruction by fire on March 13, 1895. Tesla was also the first to warn the scientific world on the harms of these rays if not used properly.
  2. Marie Curie, Pierre Curie and Antoine Henri Becquerel, Physics/Chemistry, 1903/1911: The three shared the 1903 Nobel Prize in Physics for their discovery and work on radioactivity in 1898. Madame Curie won the 1911 Nobel Prize in Chemistry for her discovery of radium and polonium, also in 1898. Tesla discovered radioactivity in experiments with X-Rays in 1896, and published many articles on the subject in scientific periodicals prior to the three.
  3. Joseph John Thomson, Physics, 1906: Thomson was awarded the Nobel Prize for his discovery of the electron in 1897. Tesla originally called electrons “matter not further decomposable” in his experiments with radiant energy in 1896, but his finding of the electron goes back to when he and Thomson had a back and forth debate in 1891 about experiments with alternating currents of high frequency. Tesla claimed that his experiments proved the existence of charged particles, or “small charged balls.” Thomson denied Tesla’s claim of verifying these particles with his vacuum tubes until witnessing Tesla’s experiments and demonstrations given in a lecture before the Institute of Electrical Engineers at London in 1892. Thomson then adapted to Tesla’s methods and was able to create equipment which allowed him to produce the required high frequencies to investigate and establish his electron discovery. 
  4. Guglielmo Marconi and Karl Ferdinand Braun, Physics, 1909: Both shared the Nobel Prize for their work and development of radio. Marconi is known for proving radio transmission by sending a radio signal in Italy in 1895, but it is a fact that he used Tesla’s work to establish his discovery. Tesla invented the “Tesla Coil” in 1891, which radio relies on, and the inventor proved radio transmission in lectures given throughout 1893, sending electromagnetic waves to light wireless lamps. Tesla filed his own basic radio patent applications in 1897, and were granted in 1900. Marconi’s first patent application in the U.S. was filed on November 10, 1900, but was turned down. Marconi’s revised applications over the next three years were repeatedly rejected because of the priority of Tesla and other inventors. After Tesla’s death in 1943, the U.S. Supreme Court made Marconi’s patents invalid and recognized Tesla as the true inventor of radio.
  5. Charles Glover Barkla, Physics, 1917: Barkla was awarded the prize for his work with Rontgen radiation and the characteristics of these X-rays and their secondary elements and effects. He was educated by J. J. Thomson. Again, Tesla worked with and explained these radiations in full detail throughout the late 1890s, showing that the source of X-rays was the site of first impact of electrons within the bulbs. He even investigated reflected X-rays and their characteristics such as Barkla.
  6. Albert Einstein, Physics, 1921: Einstein was awarded the prize for his theoretical theories which are still praised today, and also his discovery of the law of the photoelectric effect (I have many other post that show Tesla’s fair arguments against Einstein’s theories so I will only dwell on the photoelectric effect). Einstein first postulated that light has a nature of both waves and particles in 1905. This lead to the development of “photons,” or photo electrons, which gave light a wave-particle duality. Now it must be noted that Nikola Tesla wasn’t just a theoretical physicist like Einstein, but was an experimental physicist as well. In 1896, Nikola Tesla was the first to promulgate that energy had both particle-like and wavelike properties in experiments with radiant energy. He set up targets to shoot his cathode rays at which upon reflection, projected particles, or vibrations of extremely high frequencies. Instead of taking the particle-wave duality route, he proposed that they were indeed vibrations, or basically sound waves in the ether. Nikola Tesla preceded by Einstein 4 years on the photoelectric effect publishing a patent titled “Apparatus of the Utilization of Radiant Energy.” filed in 1901, based off his experiments with radiant energy. He had a far better understanding on the matter than Einstein had, because he actually developed experimentations to prove his theories.
  7. James Chadwick, Physics, 1935: Awarded the prize for his discovery of the neutron in 1932. Tesla’s discovery of neutrons goes back to his work with cosmic rays, again in 1896, which are mentioned in the next bit. He investigated and discovered that cosmic rays shower down on us 24/7, and that they are small particles which carry so small a charge that we are justified in calling them neutrons. He measured some neutrons from distance stars, like Antares, which traveled at velocities exceeding that of light. Tesla succeeded in developing a motive device that operated off these cosmic rays
  8. Victor Franz Hess, Physics, 1936: Hess won the Prize for his discovery of the cosmic rays in 1919. Tesla predated him 23 years publishing a treatise in an electrical review on cosmic rays in 1896. Tesla’s knowledge on the matter surpasses even today’s understanding of cosmic rays.

If this isn’t proof enough that Nikola Tesla got shit on, then I will add that Tesla definitely should have won the Nobel Prize for being the first person to invent the commutatorless alternating current induction motor (a huge part of the electrical power system we still use today), for his inventions and work with light bulbs, radar, for his invention of remote control, and most importantly for demonstrating the transmission of electrical energy/power without wires. Ahead of his time is an understatement.

just-some-writer  asked:

I have a world in my novel that being investigated for terraformation. It's a large moon (slightly smaller than Earth) orbiting a gas giant. It's tidal-locked to its planet. Would the planet-facing hemisphere have a different climate than the non-planet-facing hemisphere? I currently have it written that the outward-facing side is more temperate, while the other is much warmer. But that just struck me as a fun idea and I don't actually want to use it if it's weird or implausible. Thanks!

Note: the following is for the moon to support life-as-we-know-it (carbon-based, some type of DNA or analogue, etc). Silicon-based life or other exotic life could live in very different environs..

A habitable moon orbiting a gas giant (which we will call the primary) would require both the gas giant primary and the habitable moon to have certain characteristics.

For analysis, lets assume the primary is a Jupiter-sized gas giant. We’d have to move it closer to it’s star than Jupiter is in our system, so there would be enough heat from the star to keep the planet habitable. The additional heat from the primary will help so we don’t have to move it as close to the star as we otherwise might.

This would make your primary a ‘hot Jupiter’ - a gas giant that orbits close to it’s star. We know of a lot of hot Jupiters in nearby systems.

Having an Earth-sized moon isn’t a stretch at all. The second largest moon in our Solar system is Titan, a moon of Saturn. It has a radius of 2575 km, about half the size of the Earth. It also has an atmosphere - one made of nitrogen, methane, and hydrogen. Ick, but this shows that a large moon with an atmosphere is possible.

The biggest danger to your habitable moon is the primary’s magnetosphere. This is the magnetic field generated by the primary. Although this magnetic field will help shield your moon from cosmic rays and radiation from its star, it also traps a lot of radiation particles and keeps them close to the primary - like Earth’s Van Allen Belts but much, much bigger and powerful. On moons close to the primary, that’s enough radiation to kill everything. Jupiter’s inner moons are orbiting inside a giant microwave oven.

To have a life-bearing moon, we need to do one of two things to it - preferably both to be on the safe side: move the moon outside of the radiation belts of the magnetosphere and/or give the moon it’s own magnetic field.

As your moon is about Earth-sized, it probably has a rotating iron core. It’ll have a magnetic field, but lets place it outside the primary’s radiation danger zone just to make sure.

For Jupiter, the safe distance is about 1.5 million km. So, lets put your moon at the orbit of Callisto at 1.8 million km. At this distance, what little radiation your moon gets from the primary’s belts is blocked by the moon’s magnetic field.

Good call on the moon being tidally-locked to its primary. Jupiter’s and Saturn’s largest, closest moons are tidally-locked to their primaries (including Callisto). What this situation will do is make your moon’s day-night cycle quite a bit more interesting than just sunlight and darkness.

As the above mages shows, your moon will have a varying amounts of illumination - a time where only the star is visible (true day), a time where both star and primary is visible (brighter day), a time where the primary only is visible (false day), and a dark time where neither primary nor star is visible (true night). The moon will have a day length equal to the time it takes to orbit it’s primary.

Putting your moon at the same, safe distance as Callisto, it will orbit it’s primary in about 16.5 Earth days, so the moon’s ‘day’ will be just under 400 hours. If your moon orbits in the same plane that the primary’s orbit is in (and it probably does, cause that’s how most orbits work), you’ll have a short eclipse of the star by the primary every day for a couple of hours. Indeed, it’ll happen at local noon.

The tidal-locking of your moon probably wont have much of an effect on the planet’s environment. The side pointing towards the star will get really hot, seeing 200 hours of daylight, but it’ll cool off at night. The heat from the star will have much more impact than the heat form the primary. 

A good atmosphere and oceans (like Earth’s) will do a lot to spread the heat across the planet more evenly. It’ll probably have more extreme days and nights than Earth, but probably not enough to make living there too difficult.

Of course, the view from your moon would be spectacular. The primary will hang in the same spot in the sky looking about nine times the diameter of Earth’s full moon. It’ll be dozens of times brighter than the full moon, as well.

tl;dr:  Your setup is quite plausible and believable, and you’ve got the basics pretty good.. There is nothing known that would make such a setup implausible.

Hey, if it’s good enough for the Rebels…

Nobel Prize in Physics 2017: Gravitational waves

The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2017 with one half to Rainer Weiss, LIGO/VIRGO Collaboration, and the other half jointly to Barry C. Barish, LIGO/VIRGO Collaboration and Kip S. Thorne, LIGO/VIRGO Collaboration “for decisive contributions to the LIGO detector and the observation of gravitational waves.”

Keep reading

thentheysaidburnher  asked:

Do you believe the universe is infinite? What's your favourite non-milky-way galaxy? Would you like to leave earth and explore space?

I believe the universe is infinite as it appears to go on and on…and on…..

As for my favorite non-milky way galaxy…I guess it would be Andromeda and M104, the Sombrero Galaxy

Would I leave earth….well, I would love to given that I don’t die from the insane levels of radiation and cosmic rays! Perhaps I can call my alien friends over and tell them I’m ready to leave this solar system…

Snk Read Through - Chapter 20 Page 16 and 24.

a.k.a The Read Through I Tried To Explain What Kruger Might Meant With Organic Material In Sciency Way.

It was so interesting to read that Titans do not need water, meat, flesh or any other needs that is necessary for a human. They need sunlight, like plants and some bacterias to gain energy. They need sunlight to work the organic material inside them.

Chapter 88.

My theory is that Ymir was able to connect with organic material somehow like Kruger said but like a car needs gas to work, this organic material needs sunlight to move. That is why Titans can’t move in midnight. I hear you all asking about moonlight Titans but hey, moonlight is just reflected sunlight!

But what about Titan shifters? Where do their energy come from?

Chapter 20 Page 24.

From themselves, of course. 

Get ready because you are in Ecology 101 with kyojinofbraveos!

All living energy above Earth originates from the Sun. While you are running, laughing, crying because of new chapter or reading this meta, the energy you use is actually converted energy that originates from Sun. 

Sunlights reaches to Earth, but it is not just nice and warm energy, there are also some damaging cosmic rays and radiation with it that is why Sun’s pure energy is just too much for living to handle. Sun is not that smiling yellow circle at the edge of your drawing, it is actually a fierce old lady ready to kill you anytime, anywhere with her rays. Some of this rays (%90) reverberate and spans to space thanks to our atmosphere. Remaining ones are going thorough our atmosphere’s natural filter, Ozone Layer. That is one of the main reasons why there is no life in other planets than Earth, because they don’t have the right atmosphere.

After that, sunlight finally reaches to Earth all clean and warm. Green plants are making photosynthesis and putting that energy in their fruit and stuff then they are being eaten by animals. The rest is the cruel circle of life, as you might guess.

So the energy that Titan Shifters and also all the other Titans are using is actually the energy of Sun as well.

Do you remember in Frankenstein novel, Victor gathered all the parts of human body together but he always failed to gave his monster life until he made lightnings hit that monster as he screamed: IT’S ALIVEE!!

Victor had the organic material, but his monster was not alive until he got enough energy.

I think Ymir the First was also able to make something similar as well. Not the scream part of course. She was able to connect with all organic material, somehow, and not just that, she was also able to control the energy that runs through Eldians. And maybe that is how she was able to create paths. 

She bond all Eldians with the same energy using their blood ties. Maybe that is why only Eldians, Subjects of Ymir, are able to turn Titans. 

Plants are only able to use visible light to make photosynthesis and fabricate aliment we are eating. Radiation kills them, or takes them in worser shapes. Other rays are not useful as well. Green plants are only making photosynthesis using visible light, purple light is where we see their max potential.

Only Eldians are able to turn into Titans because to Titan serums they are what visible light is to plants. If you inject it to a Marley or someone from a different nation, it doesn’t work like Gross said so. Because other nations are like radiation rays to Titan Serum, it is not effective and also deadly.

Chapter 87.

Only Eldians are connected with paths because they are all bonded with same energy that also makes them visible to Titan serum.  Shifters are able to reach this energy and see those paths.

Chapter 88.

With the help of shifting power, shifters are able to make the same connection with organic material and energy that runs through them and built themselves a Titan body. But after they got out from it, their energy lefts Titan’s body, that is why it disappears and recycles to nature as we seen many times. Like human body rotting after being buried, but in a much much faster way.

Also memories comes and goes through these energy paths as well. Since all Eldians are connected with the same paths, same energy bounds, they also are able to send it to elsewhere like our Sun sends her energy to us. But as this progress continues, like sunlights, I think memories are going through a filter, an Ozone Layer as well. That is why Eren is not able to remember other shifters’ lives. He can reach them by paths, but he also gets hooked to a filter because he might not able to handle them like our Earth can’t handle the actual pure Sunlight.

End of the class! Thank you all for reading!

It has come to my attention that it is very likely that our universe (and others beyond that, for that matter), are all simply a part of a computer simulation. Not only does this just make sense to me in its entirety, as I used to think this prior to finding the study, but physicists have also been able to somewhat prove it. Any civilization intelligent enough to create a simulation like the one that we’re likely living in, would. There would likely be many more simulations other than ours, simulations within simulations, within simulations. It is more likely than not that our world is artificial. The reason we believe this theory? Physicists created a computer stimulation of the universe. It looks sort of like us. Current simulations of the universe are small and weak, but not necessarily insignificant. They naturally put limits on physical laws. The issue that we have come across, though, is that “with all simulations is that the laws of physics, which appear continuous, have to be superimposed onto a discrete three dimensional lattice which advances in steps of time.” This means that just by being a simulation, there would be limits on things. For example, limits on the energy that particles can have within the program. These limits would be experienced by those living within the simulation - us. And guess what? Something that looks just like these limits do indeed exist. The GZK cut off is a boundary of the energy that cosmic ray particles can have. This is caused by interactions with cosmic background radiation. The pattern of this rule mirrors what you would expect from a computer simulation. I have conceived a few reasons as to why this is likely true:

  1. In order for humans to even exist, everything has to be perfect. The distance from the sun has to be perfect, the composition of the atmosphere has to be just right, gravity has to be strong enough to keep us from floating off, but weak enough as well, so we have the ability to move. Why is it so perfect? Because it was created that way. It was deliberately planned to sustain life. 
  2. Almost every problem relating to the universe and physics (and even beyond that) can be solved with math. Do you understand? Computers are coded with a series of 1’s and 0’s, in a system called binary code. Perhaps our entire world is created through binary code inside of a computer. Physicists are now examining the math that makes up our universe.
  3. God could be real. Not necessarily as a “bearded man up in the sky somewhere with a great sense of omniscience”, but as an entire race of something. A more intelligent something. Humans see themselves as the most intelligent species, which I suppose is true, but in truthfully we are just another animal in a series of “levels”, if you will, of animals. 
  4. Finally, as you may or may not know, Albert Einstein’s theory of gravity clashes with quantum physics. Guess what? The theory of a simulated environment solves the conflict. Our universe is just one big projection. The string theory was composed in the late 1990’s; basically, it’s a theory that everything in the universe, atoms and energy, are composed of little tiny vibrating “strings”. Each string makes up one fundamental particle. This theory is very mathematically intricate, but it creates a universe that is merely a hologram.

Think about it, if the beings that could possibly be conducting a simulation located within our universe are running other simulations as well, this would create (and therefore prove) parallel universes. 

We are merely Sims within a game of Sims.

“As I have searched the scientific records in more than half dozen languages for a long time without finding the least anticipation, I consider myself the original discoverer of this truth, which can be expressed by the statement: There is no energy in matter other than that received from the environment. On my 79th birthday I made a brief reference to it, but its meaning and significance have become clearer to me since then. I applies rigorously to molecules and atoms as well as the largest heavenly bodies, and to all matter in the universe in any phase of its existence from it: very formation to its ultimate disintegration.

“Being perfectly satisfied that all energy in matter is drawn from the environment, it was quite natural that when radioactivity was discovered in 1896 I immediately started a search for the external agent which caused it. The existence of radioactivity was positive proof of the existence of external rays. I had previously investigated various terrestrial disturbances affecting wireless circuits but none of them or any others emanating from the earth could produce a steady sustained action and I was driven to the conclusion that the activating rays were of cosmic origin. This fact I announced in my papers on Roentgenn rays and Radiations contributed to the Electrical Review of New York, in 1897. However, as radioactivity was observed equally well in other widely separated parts of the world, it was obvious that the rays must be impinging on the earth from all directions. Now, of all bodies in the Cosmos, our sun was most likely to furnish a clue as to their origin and character. Before the electron theory was advanced, I had established that radioactive rays consisted of particles of primary matter not further decomposable, and the first question to answer was whether the sun is charged to a sufficiently high potential to produce the effects noted. This called for a prolonged investigation which culminated in my finding that the sun’s potential was 216 billions of volts and that all such large and hot heavenly bodies emit cosmic rays. Through further solar research and observation of Novae this has been proved conclusively, and to deny it would be like denying the light and heat of the sun. Nevertheless, there are still some doubters who prefer to shroud the cosmic rays in deep mystery. I am sure that this is not true for there is no place where such a process occurs in this or any other universe beyond our ken.

“A few words will be sufficient in support of this contention. The kinetic and potential energy of a body is the result of motion and determined by the product of its mass and the square of velocity. Let the mass be reduced, the energy is diminished in the same proportion. If it be reduced to zero the energy is likewise zero for any finite velocity. In other words, it is absolutely impossible to convert mass into energy. It would be different if there were forces in nature capable of imparting to a mass infinite velocity. Then the product of zero mass with the square of infinite velocity would represent infinite energy. But we know that there are no such forces and the idea that mass is convertible into energy is rank nonsense.

–Nikola Tesla

“Dynamic Theory of Gravity.” July 10, 1937 (Prior to interviews with the press on his 81st birthday observance).

In 1895, Nikola Tesla began to notice a peculiar phenomena with electrical transformer systems when he added an extra or third coil. This would generate a very large non-linear amplification of electrical pressure over a modest linear amplification as seen with traditional transformers. He studied this phenomena in his Manhattan laboratory over the coming years, until he felt he needed to deploy this system to a larger testing ground. In Colorado Springs 1899, Tesla performed a series of experiments over nine months that led to his discoveries around a new kind of electrical transformer system that he called his Magnifying Transmitter. He soon received a patent for it thereafter (Patent #1,119,732) as well as several supportive auxiliary patents.

This system was capable of generating massive amounts of electrical pressure that would create electrical ripples along the surface of the earth. In a vibrational process known as constructive interference, Tesla was able to generate more wireless power received than transferred by creating a resonant boundary condition between the earth-atmosphere interface with the use of high frequency electrostatic shock waves. This is by no means electromagnetic radiation such as with visible light, cosmic rays, and radio waves. This was nothing like a radio antenna as many experts have proclaimed it is. Tesla’s goal was actually to minimize the electromagnetic radiation from the system as much as possible by containing it in a localized standing wave, the opposite notion of traditional radio antennas. This standing wave instead acts as a wave pump that generates surface waves. A simple analogy is a hand repetitively tapping the surface of the water in a bowl that is perfectly in time with the return wave of surface ripple.

Tesla measured these electrical ripples traveling around the entire circumference of the earth moving faster than the speed of light, specifically two times pi the speed of light (1.57c). When the linear velocity of the shock wave is the same as the angular velocity of the wave’s medium, and the wave and particle (the medium) are directly in phase with each other, the necessary conditions to create constructive interference with Tesla’s Magnifying Transmitter are possible.

In 1901, Nikola Tesla began the construction of Wardenclyff Tower on Long Island, New York. Tesla originally pitched the project to financier JP Morgan as a trans-Atlantic wireless communications platform. This system could not only transfer information faster than Marconi’s radio antennas, but energy as well, unbeknownst in detail to Morgan. When Tesla ran out of money for the project, Tesla revealed his true intent to Morgan of his visionary dream with the system involving the wireless transfer of energy. Not only did Morgan not give Tesla anymore money and withdraw entirely from the project, he supposedly managed to blacklist Tesla from the financial industry at large. JP Morgan had a major stake in the copper industry which was booming in demand due to electrical power distribution. The tower was eventually demolished in 1917 to pay a portion of Tesla’s debts.

Since then, his work has been buried continuously by corporate and political interests as other up and coming inventors rediscover Tesla’s principles and apply them to technology. History is continually repeating itself, and it takes only an open mind set of a free thinking intellectual to see the patterns.

Elon Musk’s company may honor the name, but they do not truly honor Tesla’s legacy. For there is great irony in Musk declaring that his role model is Thomas Edison.

Let us honor our history.
Let us honor our true visionaries.
Let us honor what solutions are available right now.
The clock is ticking.

For this is not an issue of science.
This is an issue of Man.


Do Black Holes Explode When They Die?

A new theory suggests that black holes might die by transforming into a ‘white hole,’ which theoretically behave in the exact opposite manner as a black hole - rather than sucking all matter in, a 'white hole’ spews it out.

The theory, as first reported by, is based on the speculative quantum theory of gravity. Scientists believe it may help determine the great debate over black holes about whether they destroy the things they consume.

According to the theory, a 'white hole’ would explosively expel all the material consumed by a black hole.

Keep reading


New Ceres Views as Dawn Moves Higher

The brightest area on Ceres stands out amid shadowy, cratered terrain in a dramatic new view from NASA’s Dawn spacecraft, taken as it looked off to the side of the dwarf planet. Dawn snapped this image on Oct. 16, from its fifth science orbit, in which the angle of the sun was different from that in previous orbits. Dawn was about 920 miles (1,480 kilometers) above Ceres when this image was taken – an altitude the spacecraft had reached in early October.

Occator Crater, with its central bright region and secondary, less-reflective areas, appears quite prominent near the limb, or edge, of Ceres. At 57 miles (92 kilometers) wide and 2.5 miles (4 kilometers) deep, Occator displays evidence of recent geologic activity. The latest research suggests that the bright material in this crater is comprised of salts left behind after a briny liquid emerged from below, froze and then sublimated, meaning it turned from ice into vapor.

The impact that formed the crater millions of years ago unearthed material that blanketed the area outside the crater, and may have triggered the upwelling of salty liquid.

“This image captures the wonder of soaring above this fascinating, unique world that Dawn is the first to explore,” said Marc Rayman, Dawn’s chief engineer and mission director, based at NASA’s Jet Propulsion Laboratory, Pasadena, California.

Dawn scientists also have released an image of Ceres that approximates how the dwarf planet’s colors would appear to the human eye. This view, produced by the German Aerospace Center in Berlin, combines images taken from Dawn’s first science orbit in 2015, using the framing camera’s red, green and blue filters. The color was calculated based on the way Ceres reflects different wavelengths of light.

The spacecraft has gathered tens of thousands of images and other information from Ceres since arriving in orbit on March 6, 2015. After spending more than eight months studying Ceres at an altitude of about 240 miles (385 kilometers), closer than the International Space Station is to Earth, Dawn headed for a higher vantage point in August. In October, while the spacecraft was at its 920-mile altitude, it returned images and other valuable insights about Ceres.

On Nov. 4, Dawn began making its way to a sixth science orbit, which will be over 4,500 miles (7,200 kilometers) from Ceres. While Dawn needed to make several changes in its direction while spiraling between most previous orbits at Ceres, engineers have figured out a way for the spacecraft to arrive at this next orbit while the ion engine thrusts in the same direction that Dawn is already going. This uses less hydrazine and xenon fuel than Dawn’s normal spiral maneuvers. Dawn should reach this next orbit in early December.

One goal of Dawn’s sixth science orbit is to refine previously collected measurements. The spacecraft’s gamma ray and neutron spectrometer, which has been investigating the composition of Ceres’ surface, will characterize the radiation from cosmic rays unrelated to Ceres. This will allow scientists to subtract “noise” from measurements of Ceres, making the information more precise.

The spacecraft is healthy as it continues to operate in its extended mission phase, which began in July. During the primary mission, Dawn orbited and accomplished all of its original objectives at Ceres and protoplanet Vesta, which the spacecraft visited from July 2011 to September 2012.

Dawn’s mission is managed by NASA’s Jet Propulsion Laboratory for NASA’s Science Mission Directorate in Washington. Dawn is a project of the directorate’s Discovery Program, managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team.

TOP IMAGE….Occator on Ceres’ Limb This image of the limb of dwarf planet Ceres shows a section of the northern hemisphere. Prominently featured is Occator Crater, home of Ceres’ intriguing brightest areas.
At 57 miles (92 kilometers) wide and 2.5 miles (4 kilometers) deep, Occator displays evidence of recent geologic activity. The latest research suggests that the bright material in this crater is comprised of salts left behind after a briny liquid emerged from below, froze and then sublimated, meaning it turned from ice into vapor. Dawn took this image on Oct. 17 from its second extended-mission science orbit (XMO2), at a distance of about 920 miles (1,480 kilometers) above the surface. The image resolution is about 460 feet (140 meters) per pixel.

LOWER IMAGE….Ceres in Color This image of Ceres approximates how the dwarf planet’s colors would appear to the eye. This view of Ceres, produced by the German Aerospace Center in Berlin, combines images taken during Dawn’s first science orbit in 2015 using the framing camera’s red, green and blue spectral filters. The color was calculated using a reflectance spectrum, which is based on the way that Ceres reflects different wavelengths of light and the solar wavelengths that illuminate Ceres.

Earth's magnetic field is NOT about to flip

The weakening intensity of the Earth’s magnetic field may actually be coming down to normal rather than approaching a reversal, a new study says.

The intensity of the Earth’s magnetic field has been weakening for the last couple of hundred years, leading some scientists to think that its polarity might be about to flip.

Keep reading

artilleryvoodoo  asked:

Did Nikola Tesla believe that energy/elecrticity could be tapped from the air?

Yes he did. So Tesla was the first scientist to discover cosmic radiation, or “cosmic rays.” Not Victor Hess, like the internet will tell you. Tesla was 15 or 16 years ahead of Hess. He also understood them far better than Hess, and even our scientists today. But to answer your question, Tesla discovered that these cosmic rays shower down on us 24/7, and that they ionize the air, setting free many charges of ions and electrons. He invented and patented an apparatus that captures these charges in a condenser which was made to discharge through the circuit of his motor. He hoped to build a machine on a large scale but we all know he got blackballed by corporate interests. The important thing about Tesla’s invention is that this source of energy is unlimited–coming from our sun and all the stars in the universe, and could be tapped into anywhere on earth, night or day.

Thanks for the question! Hope I helped.


1) Packing lunches

Most of the meals are just-add-water, or come ready to eat in pouches. There are also packaged foods an ordinary person could buy from a store, like almonds or wrapped brownies. Hot and cold beverages come in bags with straws, similar to a Capri Sun. Food packets attach to the galley table with velcro patches so they don’t fly away.

2) Getting creative on Mars

NASA wants to load a vessel with food and send it to Mars before the astronauts set off. That means food scientists have to make meals that will stay good for five years.

3) The challenges

Some nutrients break down naturally over time; space radiation — cosmic rays and other forms of radiation that Earth’s atmosphere normally blocks — could be an added problem. Meals must take into account the special challenges to astronauts’ bodies in space, such as weightlessness, shrinking bones, and squashing eyeballs. 

4) Growing crops on the spaceship 

And even on the surface of another planet — could solve several of these problems at once. Astronauts wouldn’t need to lug as much food with them. They’d have fresh produce rich in vitamins. And they could mix up their menus with some of that texture they miss.

5) Keeping astronauts happy and healthy

NASA is studying how the senses of smell and taste change in microgravity and isolation, for example. In one study, researchers are supplying comfort foods and holiday treats to the space station, with astronauts filling out mood questionnaires before and after eating. The crew will also rate solo versus communal meals, as well as the experience of “cooking” the food themselves. 

“At the end of the day, we’re not worried about the muscle cells. We’re worried about the human.“

via Eater.

lesbianmooncolony  asked:

assuming a starship never has to travel through an atmosphere, and never has to worry about collisions with eg. asteroids or attackers' weapons (maybe some sort of forcefield, or a perfect interceptor weapon system), are there any compelling reasons for starships to be any particular shape? (let's also assume the starship can travel at relativistic speeds)

Aha! Excellent question! I love talking about spaceships.

So most of what I know comes off Atomic Rockets, which has far too much love of old whitedude science fiction novels, but also a lot of useful information, and more recently, lots of conversations with arborine, who has thought/knows a great deal about space habitats and is generally wonderful.

There are a few design considerations that constrain what shape your spaceship should have…

  1. it needs to bear the stresses of acceleration without breaking
  2. it needs to dissipate the heat generated by the crew, onboard machinery and direct sunlight into the highly insulating vacuum of space
  3. it needs to be able to manouvre correctly and, for example, not start spinning uncontrollably when the engine does a burn
  4. its rotation needs to be long-term stable in flight
  5. it needs to be able to withstand impacts with interplanetary/interstellar debris, which although consisting only of rarified gas and small particles, may (depending on the mission) may be approaching at extremely high, even relativistic speeds
  6. it needs to protect equipment and crew from space radiation (from stars or cosmic rays)
  7. it needs to protect the crew from any radiation produced by the ship’s engines, or its power source (a big issue if you use something scary like nuclear power or antimatter annihilation!)
  8. if humans are on board it needs to have pressurised compartments for them to live in, and enough space that they will be comfortable for the duration of the voyage
  9. it needs to minimise the extent of the damage if something goes wrong, e.g. part of the ship is depressurised
  10. it needs to survive for the entire length of the voyage, which probably means it needs to be self-sustaining
  11. it needs to carry enough propellant reaction mass to give it the \(\Delta v\) for whatever it’s out there to do
  12. it needs to be as light as possible, because every unit of mass of spaceship also adds a lot of units of reaction mass, depending on the mission \(\Delta v\)
  13. if you want the crew to experience artificial ‘gravity’, it either needs to be capable of accelerating near \(g\) for nearly the entire mission, or have sections of the spaceship capable of rotation to create a centrifugal force near \(g\)

I’m sure there are a lot more of them.

So while there’s no reason for your ship to be streamlined, there are a bunch of constraints!

1. make it strong, and maybe put the engine at the front to save mass

The first one depends a lot on where you position your rockets. Most designs place the propulsion at the back of the ship, pushing the ship forwards.

If you put the propulsion system at the back of the ship, you need your ship to be sturdy against compressive strength, which adds to the mass of the mission - compressive strength usually requires massive beams and so on, and it’s hard to get around that. When you’re accelerating, it will feel as if gravity is pushing down on everything on board towards the back of the ship, and like a building, your ship has to be strong enough to stand up. Otherwise, your engine will punch straight through your ship, or crush it, or tear off, or something similarly bad.

A tiny number of designs, like the Valkyrie, and in fact some of the earliest rockets ever built, have the propulsion at the front of the ship, towing the rest of the ship behind it.

If you do that, your ship needs tensile strength to not snap against the propulsion. You generally don’t need as much mass to have tensile strength as compressive strength - but putting the engine at the front does mean your crew are directly in the path of the engine exhaust! (The radiation problem is a general one for nuclear and antimatter engines, but it’s particularly severe when you’re right in the engine beam…)

The Valkyrie gets around this by having a shadow shield between the engine and the crew compartment, which absorbs radiation from the engine and casts a shadow over the crew compartment.

Another option is to have your engines not point directly backwards, but have two or more engines angled slightly out to the sides in opposite directions - this is apparently what the ship in the film Avatar does (ship’s presumably a still from the film, annotations from Atomic Rockets).

Putting the engines at the front on a flexible tether does make it much harder to change direction, though.

2. make sure it has large flat surfaces, or sprays of recoverable droplets, to act as radiators

Although space is sometimes described as ‘cold’, especially in movies, that’s kind of misleading. Certainly, if not in direct sunlight, something in space without a heat source will eventually cool down until it’s incredibly cold… but for the same reason that we use vacuum flasks to keep tea or whatever warm, it takes a very long time.

If you’ve got something like a spaceship, which is generating a lot of heat, you need to do something to dissipate that heat. The only mechanism that heat can be lost in space, with no atmosphere to carry it away, is electromagnetic radiation. To lose heat through radiation, you need a large surface area (i.e. big flat surfaces called ‘radiators’), and to carry the heat from the rest of your ship to the radiators. You heat up the radiators and they radiate away your heat into the vacuum.

The Space Shuttle would apparently open its cargo bay doors in space to help it radiate away heat (labels once again from Atomic Rockets).

Your radiators should not have their surfaces facing each other, or else they will heat each other up, and won’t radiate heat as effectively.

Another trick to cool your ship down is to use a ‘Liquid Droplet Radiator’ (picture source - apparently the ‘ICAN-II’ design from Penn State University, no idea what that stands for). This involves using your waste heat to heat up a spray of hot liquid droplets, which travel through space, steadily cooling down. As your ship is accelerating, the droplets ‘fall’ towards the back/front of the ship (depending which way you go), and can be collected, heated up and sprayed back in the opposite direction, maintaining continuous circulation.

Atomic Rockets has some really weird-looking designs, including discs, triangles, and even one that looks like a spiral (using magnetic fields).

Have a look at Atomic Rockets - there are lots of radiator designs I haven’t covered, involving bubbles, nanotube filaments, all sorts of stuff.

3. make sure the thrust vector goes through the centre of mass

If it doesn’t - if your engine is off-centre - when you do an engine burn, it will also have a nonzero moment (torque). This means your ship will start to rotate around its centre of mass when you do an engine burn. Sometimes, this is what you want, but usually only by a small amount! And typically a large engine burn would set you spinning wildly. So you will probably have separate small thrusters for turning.

(This gets even more complicated if your ship has flexible elements!)

4. make sure that, if your ship is spinning, it is spinning around its major principal axis

Every rigid body has a thing called its moment of inertia tensor that can be calculated from its mass distribution. Its eigenvalues are called the principal moments of inertia, and its eigenvectors are called the principal axes of the body.  When the engine is not burning, the ship is undergoing free precession.

I remember a series of arguments about free precession in our classical mechanics lectures that say, since a not-quite-rigid body slowly loses energy to internal stresses but the angular momentum is conserved, it precesses (the angular velocity vector moves with respect to the body coordinates, if that means anything to you) so as to end up spinning around the principal axis with the largest moment of inertia.

If your plan is that your spaceship should spin around a different axis, you should be worried, because it will slowly precess to spin around the major axis.

At the time the USA launched their first ever satelite, Explorer 1, in 1958, this was not known. The pen-shaped (shh) satellite was set spinning around its minor axis, the long axis through the middle of the spaceship. To the scientists’ surprise, the axis of rotation changed in flight, until the satellite was flipping end over end. This led to the first development of Euler rotation (the kind of thing we’re talking about) in over 200 years. But we’ve done that now, so, make sure your spaceship is spinning around its major axis if it spins!

5. if you’re going too fast, the ship needs to be safe from relativistic dust

A tiny grain of dust, when raised to relativistic speeds, can have the kinetic energy of a bullet or bomb. And, if your ship is travelling through space at relativistic speeds, every grain of dust in space will be approaching your ship at those speeds! This is bad.

One solution is to put a shield at the front of your spaceship, which will be punched up by relativistic dust, but will disperse most of its energy before it smashes anything important.

I’m going to talk about the Valkyrie again. I am maybe a bit too into this design, but their solution is really cool.

The Valkyrie sprays fluid droplets ahead of the ship. Any incoming particles can detonate harmlessly among the droplets, without touching the engine. Because the ship is constantly accelerating, the fluid droplets will ‘fall’ back down and land relatively slowly on the front of the ship, where they can be recycled. This is also used for cooling - another ‘liquid drop radiator’.

During the deceleration phase of the mission, this doesn’t work - the droplets fly off ahead of the ship instead of being recaptured. The Valkyrie’s solution is to grind its spent fuel tanks into fine dust and release them ahead of the ship as it decelerates. Travelling at a constant relativistic speed, the ground up fuel tanks will punch their way through any interstellar dust particles ahead of the ship, clearing a path.

Some dust will still enter the path ahead of the ship, so in addition to that trick, the Valkyrie extends many layers of ‘blankets’ of extremely thin material (’similar to Mylar’) ahead of the ship. Because the ship is accelerating in the opposite direction, the blankets are stretched out in front of the ship.

Obviously, nothing remotely close to this has ever been tried! So who knows if it would actually work. I haven’t seen discussion of relativistic dust in other designs on Atomic Rockets, though.

6. you also need to be safe from the ordinary kind of space radiation

Even if you’re not travelling at relativistic speeds, you will (without the protection of an atmosphere) constantly be irradiated by cosmic rays and other ionising radiation from any nearby star. This is a problem even for current astronauts, who apparently hide behind water tanks during periods particularly intense radiation. And it’s often discussed as a major danger of a voyage to Mars.

To an extent, you are protected from this by the hull of your spaceship, which absorbs most kinds of radiation even if it’s quite thin. You apparently need two layers to deal with different kinds of radiation, since charged particles entering the e.g. lead you would use for gamma ray shields can create deadly X-rays. Everywhere where people will be living, long-term, needs to be protected this way.

During periods of major radiation, such as solar flares, this may not be enough. You need a particularly well-shielded part of your spaceship to hide in at these times. One method is to use the water (that you’re carrying anyway, for the crew to drink) to protect the crew at these times. You need a way for the crew to access this area, and take anything particularly vulnerable to radiation - such as food - in there with them.

Apparently people are also considering other methods, involving things like powerful electric or magnetic fields, or bubbles of plasma. I don’t know a lot about this.

7. you also need to be safe from the radiation from your ship’s propulsion and power plant

To travel long distances in space, chemical rockets tend not really to be enough - you need something with a very high \(\Delta v\). Many such propulsion systems have been designed, but they tend to have the side effect of producing lots of ionising radiation.

This isn’t necessarily a huge problem. You don’t necessarily need to shield your entire reactor (which would be very heavy), but can instead use a shadow shield, like we discussed on the Valkyrie, to keep just your ship safe from the radiation, and let the rest of the radiation radiate away into space. But it does imply that the rest of the ship, including your thermal radiators, needs to keep itself inside the cone of safety created your shadow shield. And your shadow shield is usually still quite massive, because the main way we attenuate radiation is to make a lump of very dense materials.

Here’s an example of a NASA design which uses a shadow shield, and has to keep its radiatiors inside the shadow:

8. it needs to have pressurised areas for humans to breathe in

The pressure outside the spaceship is nothing. The pressure inside the spaceship is probably about 1 atmosphere. Your ship needs to be strong enough to contain that.

You definitely don’t want to have too many parts of your ship that would be particularly vulnerable to rupturing, so the walls of your pressurised areas are probably going to be nice and curved with minimal sharp corners.

One way to build a pressure vessel, the way we currently do, is to use lots of strong metal. But that adds a lot to your payload mass. So another possibility is to have an inflatable spaceship.

NASA has one such design called the TransHab. Which I assume means it can’t be boarded by cis people. It looks like this (source)…

(all of those weird CGI people are trans. no arguing)

arborine has generally talked about much larger, long-term designs: a big sphere or torus, containing a much more comfortable landscape built for many people (I will have to ask her to help me recreate the details though!). Spheres and toruses are good for inflatable shapes, because the tension is nice and even across the surface (well, this is complicated by rotation, but basically).

The need to have a pressurised hull and radiation shielding does introduce some limitations. Windows in a pressurised compartment generally need to be quite small and rounded, like aeroplane cabin windows, but when you’re far from a planet, there’s not really anything to see anyway. (It seems that, with sufficient engineering, you can make bigger windows, such as in the ISS’s observation bubble thingy. Even then, the bubble’s pretty small, and there’s plenty of structural stuff keeping that together.)

9. you need to be able to deal with problems with mimimal damage

Despite all your best efforts, it seems inevitable that a pressurised compartment travelling through the vacuum of space might have something go terribly wrong. For example, something punches a hole in the hull. You need to have that not end the mission, and cause as little harm to the crew as possible.

This probably means, internally, that your ship needs to be divided into separate compartments, so that if one gets depressurised, the rest of the ship is still safe. If the walls of your ship can somehow be self-sealing, even better.

10. you need self-repair and a self-renewing ecosystem for a long voyage

If you’re travelling on a very long voyage, carrying supplies for the entire journey just takes too much mass. You need to carry with you a functional, lasting ecosystem of plants etc. that won’t die off during the voyage.

Making a closed ecosystem is very hard - as far as I know, we haven’t succeeded yet. I will defer to arborine on the details of one, as I can’t remember what she said or what was in her extremely practical space habitats book off the top of my head.

In addition, parts of your ship will slowly fail and go wrong. Atomic Rockets claims the best NASA probes can last 40 years in space, and that may well not be enough for your purposes (even taking as much advantage as possible of relativistic time dilation). For a very long voyage like a generation ship or something, everything can probably be assumed to go wrong your spaceship to an extent needs to have the capabilities on board to build itself, and apply its repairs outside the safety of crew compartments.

Needing to recreate them en route might constrain the materials you can use, and hence the shapes you can make.

( breathofzephyr made an interesting point that the total computing power, data storage etc. available to the crew of a generation ship will, unless they can build more computers, go down over the course of the mission. which could have interesting social effects…)

11. you will probably need to dedicate a lot of your spaceship to storing reaction mass in suitable containers

A consequence of the rocket equation is that, for every gram (or whatever mass unit) of payload - structural elements, people, food, computers, robots, whatever - you have, you will need a certain number of grams of reaction mass to throw out the back of your rocket.

(The exception is if you are using a propulsion system such as a solar sail or a laser sail where you are propelled by collisions with material that you’re not carrying with you. Or if you’ve figured out a way to get the Bussard Ramjet, or its variants, to be practical!)

The shape of your propellant tanks depends a great deal on what kind of engine you’d use, but basically, you need a lot of pressure vessels somewhere on your ship, likely held separate from the crew modules.

12. it needs to be really really light, as far as possible

The rocket equation is a very demanding thing, and unless you somehow have vast amounts of leftover \(\Delta v\), you want to take every possible opportunity to save on mass. (’loads of leftover \(\Delta v\) is like, you’re using Project Orion to travel through the solar system or something.)

This is why lots of spaceship designs are modules held together by a lightweight framework - you want to minimise heavy structural elements as much as possible.

We’ve talked quite a bit about this already, though!

13. if you provide gravity, you either need a lot of \(\Delta v\) or something has to spin

For a long voyage, your crew’s bones and muscle will atrophy unless they’re given an environment with a source of ‘gravity’ similar to Earth’s.

There are two ways you can do this, which amount to accelerating some or all of your spaceship. One way is to have your engine burning so as to provide \(1 g\) acceleration throughout your voyage. By contrast, current space missions usually involve very short rocket burns, with the spaceship flying freely for most of its mission. To burn throughout the mission, your ship will need vastly more \(\Delta v\), and hence vastly more propellant mass per unit payload mass.

Since that’s pretty demanding, the other option is to have part of your spaceship spinning. This could be for example a toroidal ring, or a cylinder, or a sphere, or a couple of rooms on the end of long arms.

Depending on how large your rotating section is, it will have to spin more or less fast in order to maintain the amount of gravity you need. The centrifugal acceleration in a rotating reference frame is given by \(r\omega^2\), where \(r\) is the distance from the centre, and \(\omega\) is the angular speed.

Note this means the artificial ‘gravity’ in a rotating section with multiple floors, or in a spherical habitat, will vary as you get closer or further away from the centre! The further out you are, the stronger gravity will be.

A rotating habitat section has some implications about the design of the inside. ‘Level’ surfaces will be curved instead of flat, and the Coriolis effect will apply to deflect trajectories from a straight line - particularly strongly in a small, fast-spinning section.

There are lots of difficulties to overcome if only part of your spaceship is spinning. A major one is the problem of the bearing between the rotating section and the rest of the ship - it needs to be near frictionless, or your spin section will slowly spin down (and your ship will slowly spin up.

Another problem comes from spinning up your spin section without setting the rest of your spaceship rotating in the opposite direction (with possible consequences of precession, and the like). One solution is to have a flywheel inside your ship, but this implies a large mass that’s generally useless. Another is to have multiple counter-rotating spin sections, such that the net angular momentum change can be 0 without spinning the entire ship.

Or, you can just let the entire spaceship spin at once, though this makes manouevring the ship somewhat complicated because of the way gyroscopes act (it becomes forced precession, and you need to push at \(90^\circ\) from the way you actually want to turn…)

A further problem comes from the fact that, when your spaceship is accelerating, the direction of ‘down’ will change. This can be accomodated by some very complicated-looking designs involving arms that swing in and out (source), or just ignored because most of the time your ship is not accelerating.

and more stuff, probably

So, yes, there are a lot of physical demands on the shape of a spaceship, even one that never visits an atmosphere!

Building a spaceship is a lot different from building on Earth, and of course nobody actually knows how to build a spaceship for an interstellar voyage. But this is what we think, based on the physical constraints we’ve imagined so far…