arcminutes

Would there be a scientific way to determine how far Team Rocket would need to blast off to disappear into the sky? – Requested by @jc-75

Prepare for trouble, and make it double! If you are part of the pokémon fandom, you probably know Jessie, James, and Meowth’s motto by heart. Equally famous, however, is the fact that Team Rocket “blasts off” a lot. Nearly once every episode, Team Rocket is hurled into the sky, disappearing in a tiny sparkle.

Things look smaller the farther away they are: that much everyone knows. The relationship is not linear, however: something that is twice as far away does not necessarily appear twice as small. The numbers are actually related through angles and trigonometry: sines, cosines, and tangents.

Because of that, for this problem we want to use angular distances. Angular distance is a measurement of how much of your field of vision something covers. A full circle is 360 degrees. A full moon, for example, has an angular diameter of about 0.5 degrees: it covers half a degree in the sky.

Angles can be divided up into smaller units. There are 60 arcminutes in one degree, and 60 arcseconds in one arcminute. The human eye has an angular resolution of 1 arcminute (0.02 degrees). That is the smallest thing we can see in the sky: If something covers less than 1 arcminute, or eye can no longer detect it and it effectively disappears from view, like Team Rocket fading into the sky.

So: how far away does Team Rocket have to be to cover less than 1 arcminute in angular distance? I can’t find any official heights for Jessie and James, so I will estimate 6′0″ (1.8 meters) as an upper limit. After that, it’s just about drawing triangles.

Using 1 arcminute as the angular distance and 1.8 m as the height, you can easily solve for distance. Team Rocket effectively disappears at a distance of 6188 meters (3.84 miles).

Angular resolution is dependent on the size of the eyeball, so pokémon with large eyes like Claydol or Froakie would be able to see Team Rocket farther away than that. But for humans, that’s how far Team Rocket needs to blast off to disappear.

Team Rocket blasts off at least 6188 meters (3.84 miles) away in order to disappear from view.

flickr

M101_April2017_HomCavObservatory by homcavobservatory
Via Flickr:
M101 is a face-on, grand design spiral galaxy lying approximately 21 million light-years from Earth. Containing the equivilant of 1 trillion solar masses, it spans about 170,000 light-years from edge-to-edge. Fairly large, it appears over 28 arcminutes in diameter in our sky (i.e. approximately the size of the full moon), and can be found in the constellation of Ursa Major. Often referred to as the Pinwheel galaxy, it shares that moniker with the galaxy M33 in Triangulum. The attached image is via our wide-field imaging system and covers over 3 degrees (i.e. 6 full moons) in width, with North at left. Several other smaller and fainter galaxies can found near M101’s; to it’s lower right is the round galaxy NGC 5474, to it’s upper left the edge-on spiral galaxy NGC 5422 and to it’s lower left and just discernible in this image are NGC 5473, 5485 & 5486. Taken by Jay Edwards at the HomCav Observatory in Maine, NY while out shooting the most recent comets on the morning of April 19th using an Orion ED80T CF Triplet Apochromatic Refractor connected to a 0.8x Televue field flattener & focal reducer, CamRanger, IPad and Canon 700D DSLR; and guided by an Orion StarShoot autoguider connected to a Celestron 80MM short tube refractor; all riding on an Orion SkyView Pro goto mount guided by PHD, this image is nearly full frame and has been resized down here to HD resolution and the bit depth lowered from 16 to 8 bits per channel to reduce the file size.

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Say hello to my alien species, the Serrn.

The Serrn are a bipedal aquatic species that hail from a planet of the same name. Their world is roughly 98% covered in water, with aqueous mineral streams that traverse the oceanic currents. The mineral streams of their homeworld not only give the water an illustrious appearance, and are responsible for the development of some of the species’ distinctive traits.

Each Serrn is born with a distinctive set of colored markings across their bodies, the pattern of which varies between individual. These markings are generally colored based on the dominant mineral present in the water during gestation Individuals use these bioluminescent markings in order to communicate with others of their species, particularly by controlling the luminosity of their markings and “flashing” in specific sequences to impart meaning. Skin tones vary across a small spectrum, mostly between a light and a dark tone. Lighter skin tones are normally found amongst Serrn who live at shallower depths, whereas darker skin tones are normally found in those living in the darker recesses of the oceans and seas. It is largely believed this is an evolved form of camouflage. 

Because they spend their entire lives in the water, the Serrn did not evolve a set of lungs common is most mammalian species. Instead, the Serrn absorb dissolved oxygen directly across their skin into their bloodstream. This means the species has two distinctive traits that generally make them different from other species on the galactic stage:

Because they lack lungs, they are a mute species. This generally makes communication between species somewhat difficult without translation. Serrn marking-flash tends to be rapid and is quite nuanced, making it one of the most difficult galactic languages to understand, though the adoption of specialized text-to-speech translators and standard language classes among individuals traveling off their homeworld means that most are able to communicate on par with other species.

Furthermore, because they rely on a dissolved form of oxygen in order to breathe, then require a steady supply of water. For this reason, all Serrn wear specialized environment suits that keeps a thin layer of water over their entire bodies, while an aerator keeps the water sufficiently “breathable.”

While a standard suit is provided through a subsidized venture between the Serrn government and the ArcMinute ITG, customization is celebrated amongst individuals to add not only functionality, but personality as well. Suit colors are generally set to match an individual’s marking color, and each Serrn takes pride in choosing a voice modulation setting for their translation program that is “sufficiently them.”


Art graciously provided by the-chibster.

NASA’s SWIFT has made the largest ever ultraviolet image of the Andromeda Galaxy. The image shows a region 200,000 light-years wide and 100,000 light-years high (100 arcminutes by 50 arcminutes). Credit: NASA/Swift/Stefan Immler (GSFC) and Erin Grand (UMCP) [4412x1939]

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VISTA’s infrared view of the Lagoon Nebula (Messier 8)
This new infrared view of the star formation region Messier 8, often called the Lagoon Nebula, was captured by the VISTA telescope at ESO’s Paranal Observatory in Chile. This colour picture was created from images taken through J, H and Ks near-infrared filters, and which were acquired as part of a huge survey of the central parts of the Milky Way. The field of view is about 34 by 15 arcminutes.

Credit:ESO/VVV
Acknowledgment: Cambridge Astronomical Surv

Astronomy Photo of the Day: 18/12/15 — Dusty NGC 3190

NGC 3190, today’s featured image, is certainly a personal favorite of mine. It lurks approximately 60 million light-years away from Earth toward the constellation of Leo. This image, taken using the ESO’s Very Large Telescope, highlights the galaxy’s best features, and puts the galaxy as a whole in a rather dusty light.

From this nearly edge-on vantage point, NGC 3190’s asymmetric spiral arms are clear, as is the central region of the galaxy, with additional focus placed on its slightly-warped disk. It seems like a foregone conclusion, that this particular oddity should be chalked up to gravitational encounters, since NGC 3190 is not alone. It, along with a neighboring galaxy, are often included as members of the Hickson 44 galaxy group.

Not included in this stunning image is SN 2002bo: a supernova remnant that was forged within the V-shaped dust lanes of a southwestern section of NGC 3190. Of course, it is obscured almost entirely by the large volume of dust the galaxy boasts.

The ESO notes: “This colour composite is based on images obtained on 26 March 2003 with FORS1 on UT2 (Kueyen) in four filters (B, V, R and I) for a total exposure time of 14 minutes. The observations were done in the framework of a programme aiming at studying the physics of Type Ia supernovae. The field of view is 6.15 x 5 arcminutes. North is up and East is to the left. The data extraction from the archive, data reduction and final colour processing of the image was done by Henri Boffin (ESO).”

This dazzling image shows the globular cluster Messier 69, or M 69 for short, as viewed through the NASA/ESA Hubble Space Telescope. Globular clusters are dense collections of old stars. In this picture, foreground stars look big and golden when set against the backdrop of the thousands of white, silvery stars that make up M 69.

Another aspect of M 69 lends itself to the bejewelled metaphor: As globular clusters go, M 69 is one of the most metal-rich on record. In astronomy, the term “metal” has a specialised meaning: it refers to any element heavier than the two most common elements in our Universe, hydrogen and helium. The nuclear fusion that powers stars created all of the metallic elements in nature, from the calcium in our bones to the carbon in diamonds. Successive generations of stars have built up the metallic abundances we see today.

Because the stars in globular clusters are ancient, their metallic abundances are much lower than more recently formed stars, such as the Sun. Studying the makeup of stars in globular clusters like M 69 has helped astronomers trace back the evolution of the cosmos.

M 69 is located 29 700 light-years away in the constellation Sagittarius (the Archer). The famed French comet hunter Charles Messier added M 69 to his catalogue in 1780. It is also known as NGC 6637.

The image is a combination of exposures taken in visible and near-infrared light by Hubble’s Advanced Camera for Surveys, and covers a field of view of approximately 3.4 by 3.4 arcminutes.

Object Names: M69

Image Type: Astronomical

Credit: ESA/Hubble & NASA

Time And Space

Majestic Star-Forming Region

Massive stars are born in tumultuous clouds of gas and dust. They lead a brief but intense life, blowing powerful winds of particles and radiation that strike their surroundings, before their explosive demise as supernovas.

The interplay between massive stars and their environment is revealed in this image of the star-forming region ON2. It combines X-ray coverage from ESA’s XMM-Newton X-ray observatory with an infrared view from NASA’s Spitzer Space Telescope. This stellar cradle is associated with the open cluster of stars named Berkeley 87, some 4000 light-years from Earth. The cluster is home to over 2000 stars, most of which are low-mass stars like our Sun or smaller, but some – a few dozen – are stellar monsters weighing 10–80 times more.

Two glowing clouds of gas and dust – the raw material from which stars form – dominate the centre of the image and are shown in red. Scattered across the image are a multitude of protostars – seeds of future stellar generations; these are shown in green. The bright yellow star in the upper part of the image is BC Cygni, a massive star that has puffed up enormously and will eventually explode as a supernova. Shown in blue is XMM-Newton’s X-ray view of ON2: it reveals individual sources – young, massive stars as well as protostars – and more diffuse regions of X-rays. Two ‘bubbles’ of X-rays can be seen in the upper and lower clouds, respectively, pink against the red background. These two bubbles conceal the cumulative emissions from many protostars, but also light radiated by very energetic particles – a signature of shockwaves triggered by massive stars and their winds.

The image combines observations performed in the X-ray energy range of 0.25–12 keV (blue) and at infrared wavelengths of 3.6 microns (green) and 8 microns (red). It spans about 15 arcminutes on each side; north is up and east is to the left. This image was first published in the paper “Hard X-Ray Emission in the Star-Forming Region ON 2: Discovery with XMM-Newton” by Oskinova et al. in April 2010.

Image Credit: L.M. OSKINOVA, R.A. GRUENDL, SPITZER SPACE TELESCOPE, JPL, NASA & ESA

A colourful star-forming region is featured in this stunning new NASA/ESA Hubble Space Telescope image of NGC 2467. Looking like a roiling cauldron of some exotic cosmic brew, huge clouds of gas and dust are sprinkled with bright blue, hot young stars.

Strangely shaped dust clouds, resembling spilled liquids, are silhouetted against a colourful background of glowing. Like the familiar Orion Nebula, NGC 2467 is a huge cloud of gas — mostly hydrogen — that serves as an incubator for new stars.

This picture was created from images taken with the Wide Field Channel of the Advanced Camera for Surveys through three different filters (F550M, F660N and F658N, shown in blue, green and red). These filters were selected to let through different colours of red and yellow light arising from different elements in the gas. The total aggregate exposure time was about 2000 seconds and the field of view is about 3.5 arcminutes across. These data were taken in 2004.

Credit: NASA, ESA and Orsola De Marco (Macquarie University)