planetesimal

Largest Batch of Earth-size, Habitable Zone Planets

Our Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in an area called the habitable zone, where liquid water is most likely to exist on a rocky planet.

This exoplanet system is called TRAPPIST-1, named for The Transiting Planets and Planetesimals Small Telescope (TRAPPIST) in Chile. In May 2016, researchers using TRAPPIST announced they had discovered three planets in the system.

Assisted by several ground-based telescopes, Spitzer confirmed the existence of two of these planets and discovered five additional ones, increasing the number of known planets in the system to seven.

This is the FIRST time three terrestrial planets have been found in the habitable zone of a star, and this is the FIRST time we have been able to measure both the masses and the radius for habitable zone Earth-sized planets.

All of these seven planets could have liquid water, key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.

At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets. To clarify, exoplanets are planets outside our solar system that orbit a sun-like star.

In this animation, you can see the planets orbiting the star, with the green area representing the famous habitable zone, defined as the range of distance to the star for which an Earth-like planet is the most likely to harbor abundant liquid water on its surface. Planets e, f and g fall in the habitable zone of the star.

Using Spitzer data, the team precisely measured the sizes of the seven planets and developed first estimates of the masses of six of them. The mass of the seventh and farthest exoplanet has not yet been estimated.

For comparison…if our sun was the size of a basketball, the TRAPPIST-1 star would be the size of a golf ball.

Based on their densities, all of the TRAPPIST-1 planets are likely to be rocky. Further observations will not only help determine whether they are rich in water, but also possibly reveal whether any could have liquid water on their surfaces.

The sun at the center of this system is classified as an ultra-cool dwarf and is so cool that liquid water could survive on planets orbiting very close to it, closer than is possible on planets in our solar system. All seven of the TRAPPIST-1 planetary orbits are closer to their host star than Mercury is to our sun.

 The planets also are very close to each other. How close? Well, if a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.

The planets may also be tidally-locked to their star, which means the same side of the planet is always facing the star, therefore each side is either perpetual day or night. This could mean they have weather patterns totally unlike those on Earth, such as strong wind blowing from the day side to the night side, and extreme temperature changes.

Because most TRAPPIST-1 planets are likely to be rocky, and they are very close to one another, scientists view the Galilean moons of Jupiter – lo, Europa, Callisto, Ganymede – as good comparisons in our solar system. All of these moons are also tidally locked to Jupiter. The TRAPPIST-1 star is only slightly wider than Jupiter, yet much warmer. 

How Did the Spitzer Space Telescope Detect this System?

Spitzer, an infrared telescope that trails Earth as it orbits the sun, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light, whose wavelengths are longer than the eye can see. Spitzer is uniquely positioned in its orbit to observe enough crossing (aka transits) of the planets in front of the host star to reveal the complex architecture of the system. 

Every time a planet passes by, or transits, a star, it blocks out some light. Spitzer measured the dips in light and based on how big the dip, you can determine the size of the planet. The timing of the transits tells you how long it takes for the planet to orbit the star.

The TRAPPIST-1 system provides one of the best opportunities in the next decade to study the atmospheres around Earth-size planets. Spitzer, Hubble and Kepler will help astronomers plan for follow-up studies using our upcoming James Webb Space Telescope, launching in 2018. With much greater sensitivity, Webb will be able to detect the chemical fingerprints of water, methane, oxygen, ozone and other components of a planet’s atmosphere.

At 40 light-years away, humans won’t be visiting this system in person anytime soon…that said…this poster can help us imagine what it would be like: 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

Seven Worlds for TRAPPIST 1 : Seven worlds orbit the ultracool dwarf star TRAPPIST-1, a mere 40 light-years away. In May 2016 astronomers using the Transiting Planets and Planetesimals Small Telescope announced the discovery of three planets in the TRAPPIST-1 system. Just announced, additional confirmations and discoveries by the Spitzer Space Telescope and supporting ESO ground-based telescopes have increased the number of known planets to seven. The TRAPPIST-1 planets are likely all rocky and similar in size to Earth, the largest treasure trove of terrestrial planets ever detected around a single star. Because they orbit very close to their faint, tiny star they could also have regions where surface temperatures allow for the presence of liquid water, a key ingredient for life. Their tantalizing proximity to Earth makes them prime candidates for future telescopic explorations of the atmospheres of potentially habitable planets. All seven worlds appear in this artists illustration, an imagined view from a fictionally powerful telescope near planet Earth. Planet sizes and relative positions are drawn to scale for the Spitzer observations. The systems inner planets are transiting their dim, red, nearly Jupiter-sized parent star. via NASA

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NASA’s Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. 

Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.


The TRAPPIST-1 system contains a total of seven planets, all around the size of Earth. Three of them around the parent star TRAPPIST-1: e, f and g – dwell in their star’s so-called “habitable zone.” The habitable zone, or Goldilocks zone, is a band around every star (shown in last pic in green) where astronomers have calculated that temperatures are just right – not too hot, not too cold – for liquid water to pool on the surface of an Earth-like world.


The system has been revealed through observations from NASA’s Spitzer Space Telescope and the ground-based TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope) telescope, as well as other ground-based observatories. The system was named for the TRAPPIST telescope.


At about 40 light-years (235 trillion miles) from Earth, the system of planets is relatively close to us, in the constellation Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets.

Click on the photos to view their captions for more information.

Peer Pressure keeps young planets growing

External image

Why don’t young planets get pushed into their companion stars before they have a chance to grow? Astronomers believe that planets form in a disk of gas and dust surrounding a young star. The first step towards planet formation is the planetesimal – a small rocky body with radius of roughly 1–10 km. As the dust condenses into planetesimals during the first few million years of a star’s life, larger rocks begin to emerge that grow much more rapidly than the rest. These bodies, termed oligarchs, are on their way to young planethood, using their gravitational pull to attract and pack on more planetesimals.

In addition to providing a means for growth, planetesimals can also push an oligarch towards its doom in the central star. A lone oligarch orbiting through the disk of planetesimals clears a path much like a stick being dragged through sand. The planetesimals on either side of the trench press on the oligarch, and as the outer ring has more mass, the planetesimals deliver a net inward push.

In the past, magnetic fields, turbulence and thermodynamics have been used to explain how rocky planets are prevented from falling into their stars. However, a new study by Bromley and Kenyon say that the wake patterns created by multiple oligarchs circling a star are enough to prevent structures from forming in the planetesimal disk that would push the young planets in.

Once the oligarchs account for about half of the material in the disk, a few tens of millions of years after the birth of the star, they begin making even more material gains by combining with one another. Rather than hollowing out a series of trenches, the oligarchs are now randomly scrawling in the planetesimal “sand”, which also prevents the planetesimals from settling into patterns that would feed the oligarchs to the star.

To the boy who likes to call me by my second name:
There are days when the sun dips the skyline and in those moments I think of you
And how you radiate all the colors of the visible spectrum
Maybe even more, of various frequencies that our eyes cannot see
But you remind me of lemon dew and honeysuckle
Of strawberry colored popsicle sticks on a hot Tuesday afternoon
You embody the classical music that I like to hum in the mornings
Not because you are soft nor gentle, but because you spark on every note
And dont even get me started on astrophysics
I fly past, accelerating without a moment’s notice
Because even gravity cannot handle my own momentum
Like the Planetesimal Theory, only this time the collision ignites me;
Only this time, instead of drifting far apart -
Your gravity pulls all my pieces together
And just like that you make me whole.
You always do.
—  e. // To the boy who I call ‘Marius’ (You remind me of all my favorite Les Mis songs)
cosmic witchcraft 101: jovian magick ♃

Jupiter is the fifth planet from the Sun. Due to its massive size, there are multiple ways the planet could have formed. Regardless of its formation process, some scientists believe that Jupiter migrated inward right up to the orbit of Mars after its initial formation. This is referred to as the Grand Tack Hypothesis. In the early solar system, Neptune and the other outer planets may have begun interacting with icy planetesimals, sending comets from one planet to the next, causing Uranus, Neptune, and Saturn to move outwards as the comets moved inwards. When the comets reached Jupiter, the planet’s massive gravity flung the comets into highly elliptical orbits or out of the solar system entirely and Jupiter migrated inwards to conserve angular momentum.

As it made its way towards the Sun, Jupiter’s gravity would have prevented the asteroid belt material from forming into planets and swept away large amounts of material that may have made Mars more massive. Thanks to Saturn, Jupiter stopped its inward migration and turned around, settling approximately where we see it today. As Jupiter moved inward and Saturn moved outward, it’s theorized that they became locked in a 3:2 orbital resonance, with Saturn finishing 3 orbits around the Sun for Jupiter’s 2. Jupiter’s migration may have also brought icy and gaseous material into the inner solar system, helping the inner planets form their atmospheres and perhaps even providing those vital life-giving compounds we can thank for our existence today.

Facts:

  • Jupiter produces more heat than it receives from the Sun.
  • Jupiter is more than twice as massive as all the other planets combined.
  • The planet has at least 67 moons.
  • Jupiter is NOT a failed star. The smallest stars in the observable universe have about 1/12 of the Sun’s mass, and Jupiter has about 1/1000th of the Sun’s mass. Jupiter is simply a colossal planet.
  • The Great Red Spot is larger than Earth. It’s a colossal hurricane that’s been going on since the 17th century, maybe even before that.
  • Jupiter rotates faster than any of the other planets; a Jovian day is only about 10 Earth hours. It takes 11.86 years to orbit around the Sun.
  • Lighter stripes along the planet are called zones and darker stripes are called belts. They flow in opposite directions and turbulence between regions causes the Jupiter’s storms.

Magickal Correspondences*

Colors: red, white, yellow, brown, purple

Intents: growth, expansion, prosperity, justice, exploration, freedom, protection, spiritual evolution, success, meditation, psychic development, confidence, storm magick

Herbs: frankincense, rosemary, oak, cedar, nutmeg, sage, anise, catnip, sandalwood, rosehips, dandelion, fennel, tansy

Crystals: tin, amethyst, lepidolite, sugilite, lapis lazuli, sapphire, diamond, agate, antimony, rhodocrosite, aragonite, jasper, onyx, amber

*some of these correspondences are based on traditional associations and some are based on my personal associations

A Denied stardom status - Jupiter

Of all the planets in our solar system, Jupiter seems to stand out as this massive giants.

When scientists started uncovering the secrets of this mysterious planet, they discovered that Jupiter was probably a ‘star in the making’ during the early years of the solar system.


Jupiter and the sun

Jupiter has a lot in common with the sun than you think.

It is made of the same elements such as Hydrogen and Helium that are found in the sun and other stars!

But it is not massive enough and does not have have the pressure and temperature to fuse the existing Hydrogen atoms to form helium, which is the power source of stars.


How do stars form ?

Stars form directly from the collapse of dense clouds of interstellar gas and dust. Because of rotation, these clouds form flattened disks that surround the central, growing stars.

After the star has nearly reached its final mass, by accreting gas from the disk, the leftover matter in the disk is free to form planets. 


How was Jupiter formed ?

Jupiter is generally believed to have formed in a two-step process:

First, a vast swarm of ice and rock ‘planetesimals’ formed. These comet-sized bodies collided and accumulated into ever-larger planetary embryos.

Once an embryo became about as massive as ten Earths, its self-gravity became strong enough to pull in gas directly from the disk. 

During this second step, the proto-Jupiter gained most of its present mass (a total of 318 times the mass of the Earth).

But sadly soon thereafter, the disk gas was removed by the intense early solar wind (from our sun) , before Jupiter could grow to a similar size.

This destroyed all hopes that Jupiter had on becoming a star


What if it had become a star ?

If Jupiter had become a star,our solar system would have become a binary star system.

A binary star system is those systems having two stars.they both revolve around themselves in their own orbits.

It is interesting to note that most of the solar systems in the universe are binary,triple or higher multiple star systems but our sun is rather unusual.

In other star systems the mass distribution of the stars is equitable, but in ours the sun decided to not let that happen


Why? We have no clue ! Scientists are still trying to fathom these mysterious details of the birth process. But the more we know, the more we learn we don’t know :D

Astronomers Confirm Orbital Details of TRAPPIST-1h

Scientists using NASA’s Kepler space telescope identified a regular pattern in the orbits of the planets in the TRAPPIST-1 system that confirmed suspected details about the orbit of its outermost and least understood planet, TRAPPIST-1h.

TRAPPIST-1 is only eight percent the mass of our sun, making it a cooler and less luminous star. It’s home to seven Earth-size planets, three of which orbit in their star’s habitable zone – the range of distances from a star where liquid water could pool on the surface of a rocky planet.

The system is located about 40 light-years away in the constellation of Aquarius. The star is estimated to be between 3 billion and 8 billion years old.

Scientists announced that the system has seven Earth-sized planets at a NASA press conference on Feb. 22. NASA’s Spitzer Space Telescope, the TRAPPIST (Transiting Planets and Planetesimals Small Telescope) in Chile and other ground-based telescopes were used to detect and characterize the planets. But the collaboration only had an estimate for the period of TRAPPIST-1h.

Astronomers from the University of Washington have used data from the Kepler spacecraft to confirm that TRAPPIST-1h orbits its star every 19 days. At six million miles from its cool dwarf star, TRAPPIST-1h is located beyond the outer edge of the habitable zone, and is likely too cold for life as we know it. The amount of energy (per unit area) planet h receives from its star is comparable to what the dwarf planet Ceres, located in the asteroid belt between Mars and Jupiter, gets from our sun.

“It’s incredibly exciting that we’re learning more about this planetary system elsewhere, especially about planet h, which we barely had information on until now,” said Thomas Zurbuchen, associate administrator of NASA’s Science Mission Directorate at Headquarters in Washington. “This finding is a great example of how the scientific community is unleashing the power of complementary data from our different missions to make such fascinating discoveries.”

“It really pleased me that TRAPPIST-1h was exactly where our team predicted it to be. It had me worried for a while that we were seeing what we wanted to see – after all, things are almost never exactly what you expect them to be in this field,” said Rodrigo Luger, doctoral student at UW in Seattle, and lead author of the study published in the journal Nature Astronomy. “Nature usually surprises us at every turn, but, in this case, theory and observation matched perfectly.”

Orbital Resonance - Harmony Among Celestial Bodies

Using the prior Spitzer data, the team recognized a mathematical pattern in the frequency at which each of the six innermost planets orbits their star. This complex but predictable pattern, called an orbital resonance, occurs when planets exert a regular, periodic gravitational tug on each other as they orbit their star.

To understand the concept of resonance, consider Jupiter’s moons Io, Europa and Ganymede, which is the farthest out of the three. For every time Ganymede orbits Jupiter, Europa orbits twice and Io makes four trips around the planet. This 1:2:4 resonance is considered stable and if one moon were nudged off course, it would self-correct and lock back into a stable orbit. It is this harmonious influence between the seven TRAPPIST-1 siblings that keeps the system stable.

These relationships, said Luger, suggested that by studying the orbital velocities of its neighboring planets, scientists could predict the exact orbital velocity, and hence also orbital period, of planet h, even before the Kepler observations. The team calculated six possible resonant periods for planet h that would not disrupt the stability of the system, but only one was not ruled out by additional data. The other five possibilities could have been observed in the Spitzer and ground-based data collected by the TRAPPIST team.

“All of this”, Luger said, “indicates that these orbital relationships were forged early in the life of the TRAPPIST-1 system, during the planet formation process.”

“The resonant structure is no coincidence, and points to an interesting dynamical history in which the planets likely migrated inward in lock-step,” said Luger. “This makes the system a great laboratory for planet formation and migration theories.”

Worldwide Real-time Collaboration

The Kepler spacecraft stared at the patch of sky home to the TRAPPIST-1 system from Dec. 15, 2016, to March 4, 2017. collecting data on the star’s minuscule changes in brightness due to transiting planets as part of its second mission, K2. On March 8, the raw, uncalibrated data was released to the scientific community to begin follow-up studies.

The work to confirm TRAPPIST-1h’s orbital period immediately began, and scientists from around the world took to social media to share in real-time the new information gleaned about the star’s behavior and its brood of planets. Within two hours of the data release, the team confirmed its prediction of a 19-day orbital period.

“Pulling results out of data is always stimulating, but it was a rare treat to watch scientists across the world collaborate and share their progress in near-real time on social media as they analyzed the data and identified the transits of TRAPPIST-1h,” said Jessie Dotson, project scientist for the K2 mission at NASA’s Ames Research Center in California’s Silicon Valley. “The creativity and expediency by which the data has been put to use has been a particularly thrilling aspect of K2’s community-focused approach.”

TRAPPIST-1’s seven-planet chain of resonances established a record among known planetary systems, the previous holders being the systems Kepler-80 and Kepler-223, each with four resonant planets.

The TRAPPIST-1 system was first discovered in 2016 by the TRAPPIST collaboration, and was thought to have just three planets at that time. Additional planets were found with Spitzer and ground-based telescopes. NASA’s Hubble Space Telescope is following up with atmospheric observations, and the James Webb Space Telescope will be able to probe potential atmospheres in further detail.

Ames manages the Kepler and K2 missions for NASA’s Science Mission Directorate. NASA’s Jet Propulsion Laboratory in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corp. operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

Quantum fluctuation. Inflation. Expansion. Strong nuclear interaction. Particle-antiparticle annihilation. Deuterium and helium production. Density perturbations. Recombination. Blackbody radiation. Local contraction. Cluster formation. Reionization? Violent relaxation. Virialization. Biased galaxy formation? Turbulent fragmentation. Contraction. Ionization. Compression. Opaque hydrogen. Massive star formation. Deuterium ignition. Hydrogen fusion. Hydrogen depletion. Core contraction. Envelope expansion. Helium fusion. Carbon, oxygen, and silicon fusion. Iron production. Implosion. Supernova explosion. Metals injection. Star formation. Supernova explosions. Star formation. Condensation. Planetesimal accretion. Planetary differentiation. Crust solidification. Volatile gas expulsion. Water condensation. Water dissociation. Ozone production. Ultraviolet absorption. Photosynthetic unicellular organisms. Oxidation. Mutation. Natural selection and evolution. Respiration. Cell differentiation. Sexual reproduction. Fossilization. Land exploration. Dinosaur extinction. Mammal expansion. Glaciation. Homo sapiens manifestation. Animal domestication. Food surplus production. Civilization! Innovation. Exploration. Religion. Warring nations. Empire creation and destruction. Exploration. Colonization. Taxation without representation. Revolution. Constitution. Election. Expansion. Industrialization. Rebellion. Emancipation Proclamation. Invention. Mass production. Urbanization. Immigration. World conflagration. League of Nations. Suffrage extension. Depression. World conflagration. Fission explosions. United Nations. Space exploration. Assassinations. Lunar excursions. Resignation. Computerization. World Trade Organization. Terrorism. Internet expansion. Reunification. Dissolution. World-Wide Web creation. Composition. Extrapolation?

anonymous asked:

what is moon

lets flashback 4.6 billion years:
baby sun is surrounded by a super dense disk of gas. “weeeeeee!!!!” - baby pre-planets (planetesimals) spinning around swallowing up gas and dust, growing and growing (accreting mass) until the gas gets blown out by solar winds

30-50 million years after 4.6 billion years ago:
at this point, the solar system was a crazy place. lots of planets, collisions and lots of change.

so here’s earth, just hanging out. then, some mars sized planet (theia, that ho) came along in a bad mood and crashed right into us. well honey didn’t realize she would go down too. now we got two disrupted masses. earth just kept spinning and spinning and gravity did its thing so we became bby earth surrounded by debris.

about 50 more million years pass:
the debris actually contained two satellites, our moon and a small lil blob moon. the moons crashed and the small moon literally just became splattered onto the big moon.

….and thats how baby moons are made

The key to forming a planet could be found in some of the tiniest pieces of space debris—glassy beads the size of grains of sand that are known as chondrules. According to simulations developed in part by researchers at the Museum, asteroid-like objects known as planetesimals sweep up these glassy grains, growing into planets as they accumulate more and more dusty particles. The results of the simulations, carried out with collaborators at Lund University in Sweden and elsewhere, were published today in the journal Science Advances

“The big question is, ‘How did the planets come to be?’” said Mordecai-Mark Mac Low, a curator in the American Museum of Natural History’s Department of Astrophysics and an author on the paper. “When the solar system first started forming, the largest solids were sub-micron dust. The challenge is to figure out how all of that dust was gathered up into planet-building objects that then formed the diversity of planets and other smaller bodies that we see today.”

Planets start out small, as dust particles in the disk of gas and dust surrounding a young star collide and stick together to form dust bunnies, then pebbles, then boulders. However, models show that when those boulders get larger than a person, they begin to orbit faster than the surrounding gas. The resulting headwind brakes them in their orbit, so that they drift into their parent star within about 100 orbits. In addition, fast-moving boulders break apart, rather than sticking together, when they collide. So how do some of these objects stick around long enough to grow into planets?

Learn more about this new research

Jupiter a "failed star"

   astronomy has developed a lot.scientists have studied almost all planets.they are trying to figure out the formation of the planets.by doing so the came to know that the formation of  jupiter, “the king of all planets” was a little bit different. jupiter’s  formation initially, likely to be a star but a very different manner than stars form.thus it was called a “failed star”.

formation of stars

  Stars form directly from the collapse of dense clouds of interstellar gas and dust. Because of rotation, these clouds form flattened disks that surround the central, growing stars. After the star has nearly reached its final mass, by accreting gas from the disk, the leftover matter in the disk is free to form planets.  

a different jupiter

Jupiter is generally believed to have formed in a two-step process. First, a vast swarm of ice and rock ‘planetesimals’ formed. These comet-sized bodies collided and accumulated into ever-larger planetary embryos. Once an embryo became about as massive as ten Earths, its self-gravity became strong enough to pull in gas directly from the disk. During this second step, the proto-Jupiter gained most of its present mass (a total of 318 times the mass of the Earth). Soon thereafter, the disk gas was removed by the intense early solar wind, before Saturn could grow to a similar size.          

brown dwarf      

 brown dwarfs may look like planets but they form like stars–that is, they collapse directly from a gas cloud, rather than building up in the disk around a star. Brown dwarfs lack sufficient mass to shine, so they might more fairly be described as “failed stars.“   

why jupiter?

                jupiter is formed  of same elements such as hydrogen,helium as of the sun,but it is not massive enough pressure and temperature to fuse hydrogens to form helium ,which is the power source of stars. 

binary star system

if jupiter had become a star,our solar system would have become a binary star system.a binary star system is those systems having two stars.they both revolve around themselves in their own orbits.it is interesting to note that most of the solar systems in the universe are binary,triple or higher multiple star systems but our sun is rather unusual.it is the sun which grabbed most of the mass during the formation of solar system.this made jupiter a failed star while in other systems the masses are more equitably distributed
thus its still mysterious, scientists are trying to fathom these mysterious details of the birth process.

source:scientific american

pc :nasa,wikipedia

#science#space#astronomy#nasa

So awhile ago I posted about a position I’ll be starting soon at my department. It’s to help building a new type of telescope detector (already 10/10 coolness) and will involve everything from programming to rigging cryogenics systems to the parts and freezing them to a temperature so cold that it doesn’t exist naturally (so unless there are aliens doing this stuff somewhere, it’ll be one of the coldest places in the universe inside this thing).

What this thing will be able to do is scan the sky with incredible speed and power in addition to doing cool things like making observations through things (like clouds of dust and gas). Once we’re done there will be a telescope on Earth capable of staring into a protoplanetary disc, looking through the dust, and observing the planetesimals inside. We’ll be able to learn about comets by remotely sifting through the material in their tails. We’ll learn about how stars are born and how the universe has evolved. We’ll bring new things to the table and share them with the world.

The telescope we’ll be installing this on is in Mexico on top of a dormant volcano, Sierra Negra, four hours away from Mexico City:

(You can see the telescope at the summit on the left)

(Image credit: David Tuggy)

The telescope itself is known as the Large Millimeter Telescope, and it’s one of the largest single-aperture telescopes on Earth. From the top of Serra Negra you can see incredible amounts of stars and I look forward to seeing it in person when our lab work is finished.

(Image credit: Dr. James Lowenthall)

Needless to say, I’m psyched. The project is the first major opportunity I’ve had to do actual work in the field. I started studying astronomy when I started this blog and I’m sort of amazed there are still a bunch of you from back then who sticking around.

It’s been, is and will be an amazing adventure.

affectos  asked:

One part Pokemon, one part Steven Universe themed question: Is there any way to identify what mineral Minior is? I know we'll have to wait until the game comes out, could it be something to put on a 'to do' list?

Well, the fact that Minior is a meteorite gives us a big head start :)

Meteorites, of course, are bits of debris from an outer-space object, like a comet, asteroid, or meteoroid, that enters Earth’s atmosphere and survives long enough to land on the ground. There are three main types of meteors: each with different compositions and supposed origins. 

The first are called iron meteorites. Unsurprisingly, they are made out of iron and nickel. Specifically, the minerals kamacite and taenite. These meteorites are from the cores of planetesimals–the early building blocks of asteroids, comets, and planets like our own. And as a fun fact, these meteorites were the first sources of iron available to humans, before smelting was invented. King Tut had a dagger made from meteorite iron!

Second type of meteorite is called a chondrite. These are the most common type of meteorite, and also usually the oldest. Four and a half billion years ago, when our solar system was just starting to form, a lot of dust and particles were compressed to form the earliest asteroids. Chondrite meteorites are pieces of those asteroids: completely unchanged from how they formed that long ago. That’s why they look a bit like a sedimentary rock, with tons of different minerals all smushed together in clumps. The clumps are actually called chondrules – which is where they get their name. Chondrates are made of silicates and sulfates, just like most of the rocks on earth. The most common minerals in these are olivine and pyroxene. But they really have a wide variety of compositions. Some contain diamond or clays, and others can have water or even amino acids.

The last type of meteorite is an achondrite. These are typically from the crust of an astronomical body, such as the outer layers of the asteroid. Some have even been found to be from surface of the moon or Mars–knocked off from an impact there, and sent flying towards Earth which it inevitably landed on. Achondrites are typically made of basalts or similar igneous rocks.

Knowing what we know about Minior so far, it has two forms: its core and its outer crust:

Its crust is definitely most similar to an achondrite meteorite, so it is likely composed of igneous minerals. Its core is a little tricker to pin down, since it comes in a variety of colors in Minior’s forms. Because of this, I’d say it’s a chondrite. If Minior was an iron meteorite, it wouldn’t come in different colors and compositions. Chondrites can contain anything from green olivine, yellowish troilite, pink barite, blue celestite and more. 

I hope that helps!

-Professor Julie

anonymous asked:

How was planet Earth born tho?

Astronomers think the whole Solar System was born together, so to understand how Earth formed, you have to understand how the Sun formed. 

Stars like the Sun are born in enormous clouds of gas and dust called nebulae. The nebula that gave birth to our Sun and planets was 99% hydrogen and helium - the lightest and most abundant gases in the Universe - laced with 1% heavier elements like iron, silicon, oxygen, carbon and nitrogen. These elements, which make up most of our planet and our bodies, were made inside earlier generations of stars and released into space when they exploded, so we are quite literally made of stardust. This is still the pattern of elements we find in the Sun today.

About 4.57 billion years ago we think the shockwave from a nearby supernova (exploding star) rippled through our nebula, causing it to become unstable, and the nebula began to collapse under its own weight. It’s a bit like disturbing a house of cards. (This can also happen if nebulae collide, or due to spiral density waves rippling through the Galaxy’s disk. In our case we’re pretty sure it was a supernova because meteorites from the Solar System’s earliest days contain the leftover decay products of short-lived radioactive elements that are only produced in supernovae.) 

The densest parts of the nebula began to collapse the fastest (as they had the strongest gravity) and so the nebula broke up into a cluster of small, collapsing globules of gas and dust. Our little globule was called the Solar Nebula because it would go on to form our Solar System. As the Solar Nebula shrunk as gravity pulled everything inwards, two things happened:

  1. The nebula began to heat up, as gas and dust was squeezed into a smaller and smaller space. Compressing a gas will heat it up.
  2. Nothing in space is still, and the nebula originally had a small amount of spin. Not enough to be noticeable at first, but it was spinning very, very slightly. The only way you wouldn’t get an overall spin is if all the random motions of gas and dust particles in the cloud exactly cancelled each other out - not very likely! As the nebula shrunk, however, that tiny spin got faster and faster as everything was drawn in towards the centre, like an ice skater drawing their arms in when they spin on the ice. As it spun faster and faster, it began to bulge out at the edges more and more, like pizza dough. The end result was that most of the material ended up falling towards the centre of the shrinking nebula, but a small amount was flung out into a flattened disk around it.


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Collisions between gas and dust particles also helped flatten out the disk, as particles above and below the disk tended to collide and either destroy each other or cancel each others’ motion out until everything stabilised in one flat plane, with everything spinning around in the same direction. So at this point the Solar Nebula looks like this:

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You’ve probably guessed that the big blob in the centre of the nebula is going to become the Sun, and the disk around it is going to form the planets. So how do we know this happened? One piece of evidence is that the planets, moons, asteroids, dwarf planets etc. mostly orbit the Sun in the same flat plane, the plane of the Sun’s equator, orbit around in the same direction the Sun spins, and spin around their axes in the same directions too, with moons orbiting planets in that direction and plane as well. This is what you would expect if the whole Solar System formed together out of a spinning flat disk. (There are exceptions, of course - the orbits of Mercury, Pluto and many small bodies are quite tilted, and Venus and Uranus spin backwards, but these exceptions have their own explanations which we’ll come to later. The overwhelming majority of everything in the Solar System orbits and rotates in the same plane and in the same direction, so that’s strong evidence we all came out of the same disk.)

The second big piece of evidence for this stage is that we can actually see it happening! When we look at other nebulae we can sometimes see dusty disks surrounding newly forming stars in them:

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This disk is sometimes called the protoplanetary disk, because the planets formed in it, and sometimes called the accretion disk because accretion is a later stage in planet formation.

As the Solar Nebula’s central bulge, now called a protostar, contracted, it got hotter and hotter, and began to glow. Hot things expand, so this hot gas pushed back against the force of gravity pulling it inwards. For now, gravity is winning, causing the proto-Sun to shrink and making it glow hotter and hotter…

The protoplanetary disk had grown hot during its collapse too, and only the toughest grains of interstellar dust (pre-solar grains) had survived without being vaporised. (More on these later!) As the disk settled down into a flat plane though, it stopped collapsing and began to cool down. As it cooled, solid grains of dust began to form again, condensing out of the gas molecule by molecule like raindrops or snowflakes in a cloud. Like the proto-Sun, the disk was made mostly of hydrogen and helium, with a tiny smattering of heavier elements. But hydrogen and helium remain gases down to fractions of a degree above Absolute Zero and are gases even in the coldest regions of space. The other elements, however - oxygen, carbon, nitrogen, iron, silicon, magnesium, sulfur - all condensed out to form microscopic grains of various solid substances. This condensation stage progressed slowly, and what kind of dust grains formed depended on where you were in the disk. 

Close to the proto-Sun, it was very hot. The cloud was denser there, with rings of gas and dust whirling round at high speed and rubbing against each other, and the blazing heat of the young proto-Sun intensifying. As a result, only high-temperature materials could condense out, stuff like metallic iron and grains of silicate minerals. Further out, the temperature was a little cooler. Conditions were right for iron to oxidise and form more minerals, so more rocky dust condensed out and less metallic iron. Even further out, organic materials began to condense out, and carbon-rich sooty material formed. Further out still, water ice could begin to form, and tiny snowflakes condensed out of the cloud just like the ones you see falling from the sky in winter. The distance from the proto-Sun at which this started to occur is called the frost line or snow line, and this was significant. Remember, hydrogen made up most of the disk, and oxygen was the third most abundant element in it after hydrogen and helium, so hydrogen oxide - water - was by far the most abundant compound in the disk and the biggest source of solid grains. There was probably about ten times more solid material just beyond the frost line than there was just inside it, because of the enormous amount of ice that formed there! Finally, even further out, gases like methane, ammonia, carbon monoxide, carbon dioxide and even nitrogen froze in the outermost regions of the disk, where the disk was thinnest, particles moved most slowly and were more spread out, and where the proto-Sun was little more than a distant twinkle in the sky.

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The next phase in planet formation was accretion - you’ve seen it yourself if you’ve ever stepped out on a snowy day and seen snowflakes clinging together on your scarf and gloves, or if you’ve ever seen dust bunnies form under your bed. Accretion simply means “clumping together.” Experiments done on board the International Space Station show that in zero gravity, dust particles will gently stick together through static electricity if given a slight shake. Fluffy aggregations of dust and ice particles began to form, sometimes glued together through localised melting and forming small glassy droplets called chondrules. Exactly why these chondrules formed is a bit of a mystery, although some think static discharge in the disk as rings of dust and gas rubbed against each other and caused small flashes of lightning in the disk. Whirlpools and eddies of gas also helped concentrate dust particles together in one place, causing more gentle clumping and bigger fluffballs to form. As fluffballs grew larger, they began to grow faster, because they had a larger surface area for more dust and fluff to stick to. 

Once fluffballs had grown to a few hundred metres or a few kilometres in size - something computer simulations suggest may have taken a few hundred thousand years - their gravity began to become quite significant. Their interiors were squeezed, compressing fluff into solid rock. Gravity pulled in more dust and fluff and rocks, and soon collisions turned from gentle clumping into violent cosmic traffic accidents. The rocks - now called planetesimals - began crashing into each other at high speeds. Some of them were destroyed and broke up into smaller rocks, but the biggest continued to grow faster and faster as they pulled in more and more material, their surfaces grew larger, and their gravity grew stronger…

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As planetesimals grew larger, they began to heat up - partly from gravitational compression (just like the Solar Nebula itself!), partly from radioactive decay of certain elements (the individual atoms released only a tiny amount of energy, but accretion formed lots of those atoms into one place, releasing a lot of energy together, and causing things to heat up quite a lot. This was especially true for planetesimals that accreted quickly in the early stages of planet formation, as the supernova explosion that had caused the nebula to collapse in the first place produced quite a few short-lived radioactive isotopes like aluminium-26, which are only highly radioactive for a few million years), and partly from the release of energy during collisions (not much when it was just tiny dust grains sticking together, but huge amounts of energy when it was asteroids colliding!) All this heat at first had a small but noticeable effect - melting ice and driving water out of certain water-rich minerals caused liquid water to flow through some of these planetesimals, precipitating out other minerals that cemented them together, or perhaps chemically altering some of the minerals and causing metamorphism. Some planetesimals however grew so hot they melted, and as they melted, the denser metals sank to the centre (forming cores) while the lighter rocks floated on top (forming mantles and crusts). So some planetesimals remained a relatively primitive mixture of rock and metal, some planetesimals were slightly altered by heat and pressure and fluids, and some got so hot they melted and differentiated into layers.

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Evidence for this era comes in the form of asteroids and meteorites. Asteroids are thought to be planetesimals that never made it past this stage (and why that happened, I’ll explain soon!), and they show the general pattern we’d expect from the condensation theory - more rocky asteroids on the inner edge of the asteroid belt, while those further out contain more dark, carbon-rich material and those on the outer edge of the belt even contain some ice. Meteorites are also known to be fragments of asteroids that have broken up in collisions and ended up on Earth, so examining them can tell us a lot about planetestimals. 

Some meteorites appear to be jumbled up mixtures of rock and iron, named chondrites. Chondrites consist of a matrix of grains of rock and metal all stuck together (sometimes cemented together by other minerals or the action of water, or sometimes quite crumbly and only weakly stuck together) - the grains seem to have formed from cooling and condensation of solid material in the Solar Nebula, and then clumped together during the accretion phase. Some chondrites have a relatively pristine matrix, while others seem to have been altered by heat, pressure or reactions with water and other fluids, so they show the accretion process in many different stages. Chondrites also contain chondrules - those small, glassy droplets I mentioned earlier - and many contain pre-solar grains (grains of substances like silicon carbide that have a REALLY high melting point and survived from the earliest solar nebula before it began to contract and heat up) and calcium-aluminium inclusions (fluffy aggregates of metal grains rich in calcium and aluminium that formed at high temperatures, showing the earliest stages in accretion). What’s more, several minerals in chondrites can be dated, showing them all to be a similar age - somewhere between 4.57 and 4.55 billion years old. This is strong evidence that they really are bits of leftover planetesimals from the earliest Solar System. Finally, if you ignore gases like hydrogen and helium and focus only on the elements that formed solid grains in the Solar Nebula, the matrices of most chondrites have pretty much the same chemical composition as the Sun - further evidence that they came fresh out of the Solar Nebula.

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Chondrites also come in three main types - enstatite, ordinary, and carbonaceous chondrites - with slightly different chemical make-ups. Carbonaceous chondrites, for example, contain more oxidised iron and less metallic iron than enstatite chondrites, and are much richer in water-containing minerals and carbon-rich material, giving them a dark colour. It seems that enstatite chondrites formed at a higher temperature than ordinary chondrites, which formed at a higher temperature than carbonaceous chondrites. We think these correspond to asteroids that formed in the inner, middle and outer regions of the asteroid belt respectively, where different grains condensed out.

Some meteorites are also much richer in silicate minerals (more “rocky”) than chondrites and are called stony achondrites. Some contain blobs of metal mixed in with rock, or blobs of rock mixed in with metal - these are stony-iron meteorites or pallasites. Finally, iron meteorites are made almost entirely of iron and nickel. We think these three groups come from the outer layers, middle layers, and core of differentiated planetesimals destroyed in huge collisions respectively.

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As the Solar Nebula aged, planetesimals and protoplanets continued to collide, growing larger and larger. Enormous collisions were now generating so much heat that all of the largest protoplanets melted and differentiated out into layers. Their gravity was strong enough to overcome the forces keeping their shape and pull equally in all directions, rounding them into roughly spherical shapes. Planets were forming - and they hit each other. It was highly unlikely these collisions would totally destroy any forming planets, though, as their gravity was so strong that after being shattered into pieces those pieces would most likely pull back together and re-form into a larger, combined planet under their own gravity. Slowly but surely, a recognisable Planet Earth appeared out of these collisions, taking about 30 million years to form - so Earth should be about 4.54 billion years old. No rocks on Earth have ever been found that are older than this, except meteorites, so we think this value for Earth’s age is correct. These major collisions, by the way, may explain some of the unusual spins and orbits mentioned earlier that don’t fit the pattern of the Solar Nebula. Everything formed spinning in the same plane and the same direction, and major collisions have wrecked a small minority of them and spoiled the nice neat pattern.

What kind of planets formed depended on what kind of material had condensed out of the Solar Nebula. Close to the Sun where only rocky and metallic dust had formed, rocky and metallic planets formed - Mercury, Venus, Earth and Mars. Further out, the asteroid belt contains some carbon-rich material, and even ice-rich rocks on its outer edge. Just beyond the snow line, there was a LOT more solid material to build planets out of, causing enormous balls of rock and ice to form. These globes were so large they could hold on to the light hydrogen and helium gas that made up most of the Solar Nebula, and ballooned to enormous sizes, becoming the gas giants Jupiter and Saturn. (Jupiter is the reason the asteroid belt never formed into a planet - with lots of sticky snow and ice around to grow into a huge, fast-forming planet, Jupiter formed earlier than the other planets. Jupiter is huge, and its gravity stirred up the asteroid belt, flinging most of the asteroids out of it and leaving the belt mostly empty, and perturbing others into eccentric, inclined orbits that regularly collided with each other. So asteroids in the belt found themselves either too spread out from their neighbours to collide with them and grow any bigger, or forced into violent, high-speed collisions that were more likely to cause them to break up and shatter than stick together and grow. Thanks to Jupiter, collisions slow enough to facilitate planet growth just couldn’t happen!) Further out still, the ice giants Uranus and Neptune formed from more diverse and colder frozen gases like methane as well as just water, and they too grew large enough to hold on to thick atmospheres of hydrogen and helium. However, these planets formed from material that was more spread out and orbited the Sun more slowly, so it took longer for them to build up their icy cores. By the time they’d grown large enough to hold on to their gaseous envelopes, the Sun had blown most of the gas left in the nebula away into outer space, and so Uranus and Neptune contains more ice and less gas than Jupiter and Saturn. Even further out, where Pluto is, material was too widely spaced out and moving too slowly to accrete into large planets, and remained a bunch of frozen tiny comet nuclei and dwarf planets, made of rock, frozen gases, and water ice as hard as steel is on Earth. So the nebular theory explains the structure of the Solar System too - four small, rocky inner planets close to the Sun, an asteroid belt, four giant gassy and icy planets, and finally small icy comets and dwarf planets far out.

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So Earth was born from collisions, a molten ball of rock and iron constantly being bombarded by everything from dust to rocks to planetesimals to protoplanets. Earth even suffered a few collisions with small planets - the last big one happened after Earth had differentiated into a rocky outer mantle and iron inner core, stripping some Earth’s outer layers off. The Moon probably formed from the debris of this collision, which is why the Moon is chemically very similar to the outer layers of the Earth but doesn’t have a large iron core like Earth does.

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Our newborn molten Earth was a terrible place to live, but slowly, the debris of planet formation began to clear away. Planetesimals either collided with planets, were flung out of the Solar System altogether, or ended up safely stored in the asteroid belt or the deep outer Solar System beyond Neptune. Collisions slowed down, although they’ve never entirely stopped (ask anyone who’s ever seen a shooting star!), and the young Sun - now finally stabilising and stopping its contraction as nuclear reactions began in its core - blew away most of the remaining gas and dust with the solar wind, a stream of charged particles. The early Solar System was still more violent than it is today by a long way - we think the outer planets have moved since they first formed, due to gravitational tugs from each other and from planetesimals, leading to a second, much smaller round of collisions around 4 billion years ago. (This time it was a bombardment by asteroids and comets - no more major collisions of planets!) But in general, Earth had cooled and a solid outer crust had formed by 4.4 billion years ago, as this is the age of Earth’s oldest minerals. Earth would have had an atmosphere of carbon dioxide with some nitrogen and steam, and perhaps some methane and ammonia, belched out from volcanoes or directly from the previously-molten ground in a process called outgassing. Steam may have been driven out of minerals, or it may have arrived as ice from further out in the Solar System beyond the snow line from asteroids or comets. Either way, as Earth cooled further, steam in its atmosphere began to cool and condense, and millions of years’ worth of rain slowly began to form the first seas and oceans. Earth was slowly becoming the planet we know today.

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The hellish conditions on Earth at this time would have killed any human time traveller - intense heat, blasted by solar radiation with no ozone layer to protect them, heavy meteorite bombardment, a poisonous atmosphere and a total lack of breathable oxygen. But these conditions are similar to today’s hot springs and deep-sea volcanic vents, places where quite alien microbes thrive. Earth wouldn’t have been suitable for us - but it was the perfect place for some microbes. With liquid water, a source of energy, and abundant carbon, oxygen, nitrogen and other elements required for life on Earth’s surface, the stage was now set for life to begin. 

6

Mostly Mute Monday: The Glory of Saturn’s Rings

“Saturn is remarkable in a number of ways; among all the planets we know of, it’s the least dense, and also the only one with a spectacularly visible set of rings. Composed of icy, dust-like material, these rings are not solid at all, but made up of particles that pass each other, stick together briefly and then fly apart once again.

Snowballs and planetesimals coalesce, only to be torn apart by tidal forces exerted by Saturn and its passing moons. Gaps in the inner rings are caused by the gravitational presence of moons themselves, while many of the outer rings — like Saturn’s E-ring, below — are actually caused by the moons themselves.”

From their discovery in the 1600s, Saturn’s rings have been a source of wonder and puzzlement to skywatchers everywhere. The only ring system visible through most telescopes from Earth, Saturn’s main rings at more than 70,000 km long, yet no more than 1 km in thickness. Once thought to have only two gaps in them, the Cassini spacecraft has revealed over a thousand, teaching us that Saturn’s rings are likely as old as the planet itself, and will likely continue to exist for as long as our Sun shines.

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New views of giant asteroid Vesta revealed

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(This image released Monday, Dec. 5, 2011, by the Dawn spacecraft shows the surface of the massive asteroid Vesta. Credit: AP Photo/NASA)

“New views of the massive asteroid Vesta reveal it is more like a planet than an asteroid, scientists said Monday.”

“Since slipping into orbit around Vesta in July, NASA’s Dawn spacecraft has beamed back stunning images of the second largest object residing in the asteroid belt.”

“Vesta’s rugged surface is unique compared to the solar system’s much smaller and lightweight asteroids. Impact craters dot Vesta’s surface along with grooves, troughs and a variety of minerals.”

“‘Vesta is unlike any other asteroid,’ said mission co-scientist Vishnu Reddy of the Max Planck Institute for Solar System Research in Germany. The new findings were presented at a meeting of the American Geophysical Union in San Francisco.”