2017/11/17

Jovian Tempest


This color-enhanced image of a massive, raging storm in Jupiter’s northern hemisphere was captured by NASA’s Juno spacecraft. via NASA http://ift.tt/2A7ToKr

2017/11/16

Visibility of naked-eye stars from other planets

Would it be possible to be unable to see stars from a planet somewhere in the Milky Way? - Tina (London, UK)


This is a very good question actually, and a hard one to answer quickly in short for most places in the milky way no - for some extreme cases maybe you could see very few stars (or maybe none). It depends on quite a lot of things, for instance, what you consider a "star". There are many things we can see in the night sky that one might see from Earth or indeed another planet. I'll run through the list of objects and then try to see where in the Milky way we can be to possibly not see them. Below when I say "planetary system" I mean the solar system for your planet.

  1. Other planets in the planetary system (but not all of them): From Earth we can see Mercury, Venus, Mars, Jupiter and Saturn quite easily, so if your "planetary system" had other planets they may be visible in the night sky from your planets (depending on the brightness of the "planetary systems" star and on where the other planets were compared to your planet. You would also see a moon if your planet had one if it were large enough (some moons cannot be seen). Planets don't look exactly like "stars" as they wander across the sky due to your planets motion and the other planets motion (however if you are far enough away from your sun this motion would be very small and they could basically look like bright stars - but your planet would probably be very very cold for this to be true).

  2. Asteroids comets meteors (think shooting stars) - even if there are no other planets in your "planetary" systems an observer would be able to see comets and asteroids like we do on Earth if your planet was close enough to its sun - but these don't really look like "normal" stars and wouldn't be seen every night and move a lot

  3. Stars - most of the sky you see in the sky are stars that are pretty close by, the brightest ones could be either the ones that are the closest or the ones that are the most massive so from looking it is quite hard to tell how far away stars that you can see, some of the most massive stars can be a few thousand light years away (As in this article here) but the milky way is huge (100,000 light years across) so we definitely cannot see all the stars in the milky way (as individual "points" in the sky) even with a powerful telescope.

  4. The Milky way itself - on a clear night (maybe not in areas with light pollution like most of the UK these days) you can see a faint "haze" running across the sky this is the milky way itself (looking towards the center) it is absolutely huge (the milky way is a disk with a bulge at the center and we are in that disk) - the center is too far away to see individual stars but we see the combined light from many of the stars and the lighting of gas and dust by those stars. With a telescope or good camera it looks like this:

  5. Nebulae and Galaxies - as well as "the whole milky way" depending where you are in the galaxy you may be able to see areas of dust and gas (eliminated by the stars) from Earth you need a telescope to really see these but they are there, the same is true for galaxies (other milky ways) of which a few can be seen with only your eyes (Andromeda in the northern hemisphere) and some small galaxies that orbit our own milky way - these mostly look like blobs in the sky but could be mistaken for stars.


So now to try to answer your question, is there anywhere in the milky way we could go (i.e. where you could put a planet) where we wouldn't see any "stars".
  1. For other planets - this is easy - if your planetary system had no other planets or they were really close to "your sun" or really far away from "your sun" you might not see them.

  2. For asteroids etc - chances are if you have a planet in your planetary system (that you are standing on) you will probably have asteroids and comets but seeing these events could be very rare - Halley's comet, for example, may be seen once every 75 years.. so these certainty wouldn't be "normal" "stars".

  3. For stars - This is a hard one, as I said above we can only see stars that are pretty close to the sun from Earth (even the massive ones we see, which are the most distant are pretty close compared to the size of the galaxy). The way to imagine this is that we see a small "bubble" of our milky way as individual stars and the rest form the "haze" of the milky way. The galaxy itself it a spiral galaxy (looks like this: https://www.universetoday.com/.../Milky-Way-artist-ESO...) so you could imagine areas in the galaxy where a planet would see fewer stars than we see on Earth or more stars than we see on Earth - and actually the more towards the center you go the more stars you can see (on average) so being near the edge of the milky way would definitely let you see fewer stars. There may be some areas on the very outskirts of the milky way that you could see very few stars.

  4. For the Milky Way - It would be very hard to be somewhere where you cannot see the milky way unless you were very far away from its center (the sun is 30,000 light years from the center) so with a diameter of 100,000 light years (radius of 50,000 light years) you could only go about 1.5 times as far from the center as we are before you reach the "edge" of the milky way... so you would still see** "something" of the milky way from your planet (as we can see the Andromeda galaxy that is about 2.5 MILLION light years away (albeit VERY faintly) you would have to be very far away to not see the milky way at all!)

  5. For other galaxies - If you were in the milky way you would always** be able to see galaxy such as Andromeda from the milky way
** There are a couple of ways you could see no "stars" in the sky even if there were actually objects at the right brightnesses to see them. I'll list them below:
  1. Being in a very dusty/gas-rich part of the milky way: dust basically blocks light, when you look at the milky way those dark areas in the middle do have stars there is just lots of gas and dust in the way, enough to block out the light from the stars behind - I'm not sure how possible it would be to find an area in the milky way with enough dust between you and all other stars that you see no stars though, but it is possible (you would have to combine being very dusty with being far enough away from other bright stars) - this occurs in areas in the milky way where stars are being born, or even if your planet was very young you may have enough dust in your own solar system to block out the light from other stars

  2. If you were on a planet that was "tidally locked" (this means one side faces its sun at all times) and you only lived on the day side and couldn't/didn't travel to the night side you may not see any stars (but it would also never be night time) - it would probably also be unpleasantly warm unless you were far enough away from the star but then it is difficult to make a planet "tidally locked".

  3. Light pollution or thick atmosphere (cloudy atmosphere) - if there was significant light pollution on your planet (i.e. like living in the centre of a city) you may not see any stars at all and just a "haze" from all the light pollution around! Equally if you had a thicker atmosphere it could almost seem like it was cloudy all the time or maybe your planet could be cloudy the whole time (but the planet might then not be very habitable and who wants to live on a planet with 100% cloud cover all the time) - you'd still get day and night but never see the star unless you went up into space/away from all the light pollution. Also, light pollution could occur naturally certain chemistry and biology can produce fluorescence in the atmosphere that could block out any light from stars.

Sunrise Flight to the Space Station


Orbital ATK's Cygnus resupply ship with its cymbal-ike UltraFlex solar arrays approaches the International Space Station on Nov. 14, 2017. via NASA http://ift.tt/2z9ouRN

The Tarantula Nebula is more than a thousand light-years in diameter, a giant star forming region within nearby satellite galaxy the Large Magellanic Cloud, about 180 thousand light-years away. The largest, most violent star forming region known in the whole Local Group of galaxies, the cosmic arachnid sprawls across this spectacular view composed with narrowband data centered on emission from ionized hydrogen and oxygen atoms. Within the Tarantula (NGC 2070), intense radiation, stellar winds and supernova shocks from the central young cluster of massive stars, cataloged as R136, energize the nebular glow and shape the spidery filaments. Around the Tarantula are other star forming regions with young star clusters, filaments, and blown-out bubble-shaped clouds. In fact, the frame includes the site of the closest supernova in modern times, SN 1987A, right of center. The rich field of view spans about 1 degree or 2 full moons, in the southern constellation Dorado. But were the Tarantula Nebula closer, say 1,500 light-years distant like the local star forming Orion Nebula, it would take up half the sky. via NASA http://ift.tt/2AJQWqN

2017/11/15

How to See the Atmosphere


How can you see the atmosphere? The answer is blowing in the wind. via NASA http://ift.tt/2z3kqCD

NGC 7789: Caroline's Rose


Found among the rich starfields of the Milky Way, star cluster NGC 7789 lies about 8,000 light-years away toward the constellation Cassiopeia. A late 18th century deep sky discovery of astronomer Caroline Lucretia Herschel, the cluster is also known as Caroline's Rose. Its flowery visual appearance in small telescopes is created by the cluster's nestled complex of stars and voids. Now estimated to be 1.6 billion years young, the galactic or open cluster of stars also shows its age. All the stars in the cluster were likely born at the same time, but the brighter and more massive ones have more rapidly exhausted the hydrogen fuel in their cores. These have evolved from main sequence stars like the Sun into the many red giant stars shown with a yellowish cast in this lovely color composite. Using measured color and brightness, astronomers can model the mass and hence the age of the cluster stars just starting to "turn off" the main sequence and become red giants. Over 50 light-years across, Caroline's Rose spans about half a degree (the angular size of the Moon) near the center of the wide-field telescopic image. via NASA http://ift.tt/2zzTXMu

2017/11/14

Mariner 9 Sees Shield Volcano on Mars


On November 14, 1971, Mariner ( took this image of a shield volcano on Mars. via NASA http://ift.tt/2zW0Sjy

The Pleiades Deep and Dusty


The well-known Pleiades star cluster is slowly destroying part of a passing cloud of gas and dust. The Pleiades is the brightest open cluster of stars on Earth's sky and can be seen from almost any northerly location with the unaided eye. The passing young dust cloud is thought to be part of Gould's Belt, an unusual ring of young star formation surrounding the Sun in the local Milky Way Galaxy. Over the past 100,000 years, part of Gould's Belt is by chance moving right through the older Pleiades and is causing a strong reaction between stars and dust. Pressure from the stars' light significantly repels the dust in the surrounding blue reflection nebula, with smaller dust particles being repelled more strongly. A short-term result is that parts of the dust cloud have become filamentary and stratified. The featured deep image also captured Comet C/2015 ER61 (PanSTARRS) on the lower left. via NASA http://ift.tt/2iPV9kg

2017/11/13

Our Living Earth ... From Space


Can you identify this river? via NASA http://ift.tt/2hp8xvp

Comet Machholz Approaches the Sun


Why is Comet Maccholz so depleted of carbon-containing chemicals? Comet 96P/Machholz's original fame derives from its getting closer to the Sun than any other short period comet -- half as close as Mercury -- and doing so every five years. To better understand this unusual comet, NASA's Sun-monitoring SOHO spacecraft tracked the comet during its latest approach to the Sun in October. The featured image composite shows the tail-enhanced comet swooping past the Sun. The Sun's bright surface is hidden from view behind a dark occulter, although parts of the Sun's extended corona are visible. Neighboring stars dot the background. One hypothesis holds that these close solar approaches somehow cause Comet Machholz to shed its carbon, while another hypothesis posits that the comet formed with this composition far away -- possibly even in another star system. via NASA http://ift.tt/2iOfVAW

2017/11/12

Liftoff! Orbital Antares Rocket Launches From Wallops Flight Facility


The Orbital ATK Antares rocket, with the Cygnus spacecraft onboard, launches from Pad-0A, Sunday, Nov. 12, 2017 via NASA http://ift.tt/2ji3l0C

A Happy Sky over Los Angeles


Sometimes, the sky may seem to smile over much of planet Earth. On this day in 2008, visible the world over, was an unusual superposition of our Moon and the planets Venus and Jupiter. Pictures taken at the right time show a crescent Moon that appears to be a smile when paired with the planetary conjunction of seemingly nearby Jupiter and Venus. Pictured here is the scene as it appeared from Mt. Wilson Observatory overlooking Los Angeles, California, USA after sunset on 2008 November 30. Highest in the sky and farthest in the distance is the planet Jupiter. Significantly closer and visible to Jupiter's lower left is Venus, appearing through Earth's atmospheric clouds as unusually blue. On the far right, above the horizon, is our Moon, in a waxing crescent phase. Thin clouds illuminated by the Moon appear unusually orange. Sprawling across the bottom of the image are the hills of Los Angeles, many covered by a thin haze, while LA skyscrapers are visible on the far left. Hours after the taking of this image, the Moon approached the distant duo, briefly eclipsed Venus, and then moved on. This week, another conjunction of Venus and Jupiter is occurring and is visible to much of planet Earth to the east just before sunrise. via NASA http://ift.tt/2yQsEy2

2017/11/11

A Colourful Moon


The Moon is normally seen in subtle shades of grey. But small, measurable color differences have been greatly exaggerated in this mosaic of high-resolution images captured near the Moon's full phase, to construct a multicolored, central moonscape. The different colors are recognized to correspond to real differences in the mineral makeup of the lunar surface. Blue hues reveal titanium rich areas while more orange and purple colors show regions relatively poor in titanium and iron. The intriguing Sea of Vapors, or Mare Vaporum, is below center in the frame with the sweeping arc of the lunar Montes Apenninus (Apennine Mountains) above it. The dark floor of 83 kilometer diameter Archimedes crater within the Sea of Rains, or Mare Imbrium, is toward the top left. Near the gap at the top of the Apennine's arc is the Apollo 15 landing site. Calibrated by rock samples returned by the Apollo missions, similar multicolor images from spacecraft have been used to explore the Moon's global surface composition. via NASA http://ift.tt/2zrdKNZ

2017/11/10

Astronaut Jack Fischer With Honor Flight Veterans


NASA astronaut Jack Fischer talks with veterans at the World War II Memorial who traveled to Washington, DC with the Buffalo Niagara Honor Flight. Fischer, a colonel in the U.S. Air Force, wrote, "Few things can compare to the honor of meeting WWII, Korea and Vietnam vets today--thank you for your sacrifices to keep us all free." via NASA http://ift.tt/2iKZW6A

Williamina Fleming s Triangular Wisp


Chaotic in appearance, these tangled filaments of shocked, glowing gas are spread across planet Earth's sky toward the constellation of Cygnus as part of the Veil Nebula. The Veil Nebula itself is a large supernova remnant, an expanding cloud born of the death explosion of a massive star. Light from the original supernova explosion likely reached Earth over 5,000 years ago. Blasted out in the cataclysmic event, the interstellar shock waves plow through space sweeping up and exciting interstellar material. The glowing filaments are really more like long ripples in a sheet seen almost edge on, remarkably well separated into the glow of ionized hydrogen atoms shown in red and oxygen in blue hues. Also known as the Cygnus Loop, the Veil Nebula now spans nearly 3 degrees or about 6 times the diameter of the full Moon. While that translates to over 70 light-years at its estimated distance of 1,500 light-years, this field of view spans less than one third that distance. Often identified as Pickering's Triangle for a director of Harvard College Observatory, the the complex of filaments is cataloged as NGC 6979. It is also known for its discoverer, astronomer Williamina Fleming, as Fleming's Triangular Wisp. via NASA http://ift.tt/2zIS7cI

2017/11/09

Earth as Viewed From 10,000 Miles


On November 9, 1969, the uncrewed Apollo 4 test flight made a great ellipse around Earth as a test of the translunar motors and of the high speed entry required of a crewed flight returning from the Moon. via NASA http://ift.tt/2m8w1ua

NGC 1055 Close up


Big, beautiful spiral galaxy NGC 1055 is a dominant member of a small galaxy group a mere 60 million light-years away toward the aquatically intimidating constellation Cetus. Seen edge-on, the island universe spans over 100,000 light-years, a little larger than our own Milky Way. The colorful stars in this cosmic close-up of NGC 1055 are in the foreground, well within the Milky Way. But the telltale pinkish star forming regions are scattered through winding dust lanes along the distant galaxy's thin disk. With a smattering of even more distant background galaxies, the deep image also reveals a boxy halo that extends far above and below the central bluge and disk of NGC 1055. The halo itself is laced with faint, narrow structures, and could represent the mixed and spread out debris from a satellite galaxy disrupted by the larger spiral some 10 billion years ago. via NASA http://ift.tt/2AsB3oa

2017/11/08

Rare Encircling Filament


NASA's Solar Dynamics Observatory came across an oddity that the spacecraft has rarely observed before: a dark filament encircling an active region (Oct. 29-31, 2017). Solar filaments are clouds of charged particles that float above the sun, tethered to it by magnetic forces. via NASA http://ift.tt/2yhGPrr

NGC 2261: Hubble s Variable Nebula


What causes Hubble's Variable Nebula to vary? The unusual nebula featured here changes its appearance noticeably in just a few weeks. Discovered over 200 years ago and subsequently cataloged as NGC 2661, the remarkable nebula is named for Edwin Hubble, who studied it early last century. Fitting, perhaps, the featured image was taken by another namesake of Hubble: the Space Telescope. Hubble's Variable Nebula is a reflection nebula made of gas and fine dust fanning out from the star R Monocerotis. The faint nebula is about one light-year across and lies about 2500 light-years away towards the constellation of the Unicorn (Monocerotis). The leading variability explanation for Hubble's Variable Nebula holds that dense knots of opaque dust pass close to R Mon and cast moving shadows onto the reflecting dust seen in the rest of the nebula. via NASA http://ift.tt/2hNWlVH

2017/11/07

Space Station Crew Sees Lots of Clouds


Expedition 53 Flight Engineer Paolo Nespoli of the European Space Agency (ESA) photographed cloudy skies over Sudan during an International Space Station flyover on Oct. 22, 2017. Nespoli shared the image with his followers on social media on Nov. 6, writing, "#EarthFromSpace means also... Lots of clouds! How do they look from below?" via NASA http://ift.tt/2AhQv5K

The Prague Astronomical Clock


In the center of Prague there's a clock the size of a building. During the day, crowds gather to watch the show when it chimes in a new hour. The Prague Astronomical Clock's face is impressively complex, giving not only the expected time with respect to the Sun (solar time), but the time relative to the stars (sidereal time), the times of sunrise and sunset, the time at the equator, the phase of the Moon, and much more. The clock began operation in 1410, and even though much of its inner workings have been modernized several times, original parts remain. Below the clock is a nearly-equal sized, but static, solar calendar. Pictured, the Prague Astronomical Clock was photographed alone during an early morning in 2009 March. The Prague Astronomical Clock and the Old Town Tower behind it are currently being renovated once again, with the clock expected to be restarted in 2018 June. via NASA http://ift.tt/2ixnLyT

2017/11/06

Pandora, the Would-Be Perturber


As Cassini hurtled toward its fatal encounter with Saturn, the spacecraft turned to catch this final look at Saturn's moon Pandora next to the thin line of the F ring. via NASA http://ift.tt/2AdCOF7

A Dust Jet from the Surface of Comet 67P


Where do comet tails come from? There are no obvious places on the nuclei of comets from which the jets that create comet tails emanate. Last year, though, ESA's Rosetta spacecraft not only imaged a jet emerging from Comet 67P/Churyumov-Gerasimenko, but flew right through it. Featured is a telling picture showing a bright plume emerging from a small circular dip bounded on one side by a 10-meter high wall. Analyses of Rosetta data shows that the jet was composed of both dust and water-ice. The mundane terrain indicates that something likely happened far under the porous surface to create the plume. This image was taken last July, about two months before Rosetta's mission ended with a controlled impact onto Comet 67P's surface. via NASA http://ift.tt/2j1W7O4

A Year of Full Moons


Do all full moons look the same? No. To see the slight differences, consider this grid of twelve full moons. From upper left to lower right, the images represent every lunation from 2016 November through 2017 October, as imaged from Pakistan. The consecutive full moons are all shown at the same scale, so unlike the famous Moon Illusion, the change in apparent size seen here is real. The change is caused by the variation in lunar distance due to the Moon's significantly non-circular orbit. The dark notch at the bottom of the full moon of 2017 August is the shadow of the Earth -- making this a partial lunar eclipse. Besides the sometimes exaggerated coloring, a subtler change in appearance can also be noticed on close examination, as the Moon seems to wobble slightly from one full moon to the next. This effect, known as libration, is more dramatic and easier to see in this lunation video highlighting all of the ways that the Moon appears to change over a month (moon-th). via NASA http://ift.tt/2lPBaHp

2017/11/05

A Year of Full Moons


Do all full moons look the same? No. To see the slight differences, consider this grid of twelve full moons. From upper left to lower right, the images represent every lunation from 2016 November through 2017 October, as imaged from Pakistan. The consecutive full moons are all shown at the same scale, so unlike the famous Moon Illusion, the change in apparent size seen here is real. The change is caused by the variation in lunar distance due to the Moon's significantly non-circular orbit. The dark notch at the bottom of the full moon of 2017 August is the shadow of the Earth -- making this a partial lunar eclipse. Besides the sometimes exaggerated coloring, a subtler change in appearance can also be noticed on close examination, as the Moon seems to wobble slightly from one full moon to the next. This effect, known as libration, is more dramatic and easier to see in this lunation video highlighting all of the ways that the Moon appears to change over a month (moon-th). via NASA http://ift.tt/2lPBaHp

2017/11/03

Tests Ensure Astronaut, Ground Crew Safety Before Orion Launches


NASA is performing a series of tests to evaluate how astronauts and ground crew involved in final preparations before Orion missions will quickly get out of the spacecraft, if an emergency were to occur on the pad prior to launch. via NASA http://ift.tt/2zhQOR2

A 2017 U1: An Interstellar Visitor


Traveling at high velocity along an extreme hyperbolic orbit and making a hairpin turn as it swung past the Sun, the now designated A/2017 U1 is the first known small body from interstellar space. A point of light centered in this 5 minute exposure recorded with the William Herschel Telescope in the Canary Islands on October 28, the interstellar visitor is asteroid-like with no signs of cometary activity. Faint background stars appear streaked because the massive 4.2 meter diameter telescope is tracking the rapidly moving A/2017 U1 in the field of view. Astronomer Rob Weryk (IfA) first recognized the moving object in nightly Pan-STARRS sky survey data on October 19. A/2017 is presently outbound, never to return to the Solar System, and already only visible from planet Earth in large optical telescopes. Though an interstellar origin has been established based on its orbit, it is still unknown how long the object could have drifted among the stars of the Milky Way. But its interstellar cruise speed would be about 26 kilometers per second. By comparison humanity's Voyager 1 spacecraft travels about 17 kilometers per second through interstellar space. via NASA http://ift.tt/2A8SLNC

2017/11/02

Revealing What Lies Beneath


This false-color image demonstrates how use of special filters available on the Curiosity Mars rover's Mast Camera (Mastcam) can reveal the presence of certain minerals in target rocks. T via NASA http://ift.tt/2ioVgTK

NGC 891 vs Abell 347


Distant galaxies lie beyond a foreground of spiky Milky Way stars in this telescopic field of view. Centered on yellowish star HD 14771, the scene spans about 1 degree on the sky toward the northern constellation Andromeda. At top right is large spiral galaxy NGC 891, 100 thousand light-years across and seen almost exactly edge-on. About 30 million light-years distant, NGC 891 looks a lot like our own Milky Way with a flattened, thin, galactic disk. Its disk and central bulge are cut along the middle by dark, obscuring dust clouds. Scattered toward the lower left are members of galaxy cluster Abell 347. Nearly 240 million light-years away, Abell 347 shows off its own large galaxies in the sharp image. They are similar to NGC 891 in physical size but located almost 8 times farther away, so Abell 347 galaxies have roughly one eighth the apparent size of NGC 891. via NASA http://ift.tt/2z7NZBY

2017/11/01

From Hot to Hottest


This sequence of images shows the Sun from its surface to its upper atmosphere all taken at about the same time on Oct. 27, 2017. via NASA http://ift.tt/2iURKVn

Thors Helmet Emission Nebula


This helmet-shaped cosmic cloud with wing-like appendages is popularly called Thor's Helmet. Heroically sized even for a Norse god, Thor's Helmet spans about 30 light-years across. In fact, the helmet is more like an interstellar bubble, blown as a fast wind -- from the bright star near the center of the bubble's blue-hued region -- sweeps through a surrounding molecular cloud. This star, a Wolf-Rayet star, is a massive and extremely hot giant star thought to be in a brief, pre-supernova stage of evolution. Cataloged as NGC 2359, the emission nebula is located about 12,000 light-years away toward the constellation of the Big Dog (Canis Major). The sharp image, made using broadband and narrowband filters, captures striking details of the nebula's filamentary gas and dust structures. The blue color originates from strong emission from oxygen atoms in the nebula. via NASA http://ift.tt/2zS1WkA

2017/10/31

Learning to Walk Before Heading to Space


Canadian Space Agency astronaut Jeremy Hansen is suspended over a mock-up of the International Space Station during a microgravity simulation. via NASA http://ift.tt/2xGWGjb

2017/10/30

Viewing Australia's Great Sandy Desert From Space


Flying hundreds miles above, astronauts aboard the International Space Station photographed Lake Hazlett and Lake Willis in Western Australia's Great Sandy Desert. Hundreds of ephemeral salt lakes are peppered throughout the arid Australian Outback. via NASA http://ift.tt/2luBT0C

2017/10/27

Hubble Digs into Cosmic Archaeology


This Hubble infrared image is part of an observing program that imaged 41 massive galaxy clusters to find the brightest distant galaxies for theJames Webb Space Telescope to study. via NASA http://ift.tt/2zIrErL

Mirach s Ghost


As far as ghosts go, Mirach's Ghost isn't really that scary. Mirach's Ghost is just a faint, fuzzy galaxy, well known to astronomers, that happens to be seen nearly along the line-of-sight to Mirach, a bright star. Centered in this star field, Mirach is also called Beta Andromedae. About 200 light-years distant, Mirach is a red giant star, cooler than the Sun but much larger and so intrinsically much brighter than our parent star. In most telescopic views, glare and diffraction spikes tend to hide things that lie near Mirach and make the faint, fuzzy galaxy look like a ghostly internal reflection of the almost overwhelming starlight. Still, appearing in this sharp image just above and to the left of Mirach, Mirach's Ghost is cataloged as galaxy NGC 404 and is estimated to be some 10 million light-years away. via NASA http://ift.tt/2i7IzMS

2017/10/26

Studying the Genetics of Organisms in Space


At NASA's Kennedy Space Center, organisms in a Petri plate are exposed to blue excitation lighting in a Spectrum prototype unit. NASA scientists and engineers are developing experiments to determine how different organisms, such as plants, microbes or worms, develop under conditions of microgravity. via NASA http://ift.tt/2ySUIzn

NGC 7635: Bubble in a Cosmic Sea


Adrift in a cosmic sea of stars and glowing gas the delicate, floating apparition left of center in this widefield view is cataloged as NGC 7635, the Bubble Nebula. A mere 10 light-years wide, the tiny Bubble Nebula was blown by the winds of a massive star. It lies within a larger complex of interstellar gas and dust clouds found about 11,000 light-years distant, straddling the boundary between the parental constellations Cepheus and Cassiopeia. Included in the breathtaking vista is open star cluster M52 (lower left), some 5,000 light-years away. Above and right of the Bubble Nebula is an emission region identified as Sh2-157, also known as the Claw Nebula. Constructed from 47 hours of narrow-band and broad-band exposures, this image spans about 3 degrees on the sky. That corresponds to a width of 500 light-years at the estimated distance of the Bubble Nebula. via NASA http://ift.tt/2i2Uk7E

2017/10/25

NASA Astronauts on Third and Final Spacewalk in October Series


NASA astronauts Joe Acaba (left) and Randy Bresnik (right) at work outside the International Space Station on Oct. 20, 2017, in the third of a series of three planned spacewalks. The two astronauts successfully completed the 6 hour, 49 minute spacewalk at 2:36 p.m. EDT. via NASA http://ift.tt/2zFnj8q

2017/10/24

Remembering Astronaut Paul Weitz


In this June 1973 photo, astronaut Paul J. Weitz, Skylab 2 pilot, mans the control and display console of the Apollo Telescope Mount. Weitz, who also commanded the STS-6 shuttle mission and served as Deputy Director of Johnson Space Center, passed away this week at the age of 85. via NASA http://ift.tt/2z2GxbS

Where Your Elements Came From


The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe. The carbon in your body was made by nuclear fusion in the interior of stars, as was the oxygen. Much of the iron in your body was made during supernovas of stars that occurred long ago and far away. The gold in your jewelry was likely made from neutron stars during collisions that may have been visible as short-duration gamma-ray bursts or gravitational wave events. Elements like phosphorus and copper are present in our bodies in only small amounts but are essential to the functioning of all known life. The featured periodic table is color coded to indicate humanity's best guess as to the nuclear origin of all known elements. The sites of nuclear creation of some elements, such as copper, are not really well known and are continuing topics of observational and computational research. via NASA http://ift.tt/2zIV0GZ

2017/10/23

The Grace of Saturn


Saturn's graceful lanes of orbiting ice -- its iconic rings -- wind their way around the planet to pass beyond the horizon in this view from NASA's Cassini spacecraft. via NASA http://ift.tt/2xglHRL

NGC 4993: The Galactic Home of an Historic Explosion


That reddish dot -- it wasn't there before. It's the dot to the upper left of galaxy NGC 4993's center, do you see it? When scanning the large field of possible locations of an optical counterpart to the unprecedented gravitational wave event GW170817 in August, the appearance of this fading dot quickly became of historic importance. It pinpointed GW170817's exact location, thereby enabling humanity's major telescopes to examine the first ever electromagnetic wave counterpart to a gravitational wave event, an event giving strong evidence of being a short gamma-ray burst kilonova, the element-forming explosion that occurs after two neutron stars merge. The featured image of lenticular galaxy NGC 4993 by Hubble shows the fading dot several days after it was discovered. Analyses, continuing, include the physics of the explosion, what heavy elements formed, the similarity of the speeds of gravitational radiation and light, and calibrating a new method for determining the distance scale of our universe. via NASA http://ift.tt/2gXzCWG

2017/10/22

Two Black Holes Dancing in 3C 75


What's happening at the center of active galaxy 3C 75? The two bright sources at the center of this composite x-ray (blue)/ radio (pink) image are co-orbiting supermassive black holes powering the giant radio source 3C 75. Surrounded by multimillion degree x-ray emitting gas, and blasting out jets of relativistic particles the supermassive black holes are separated by 25,000 light-years. At the cores of two merging galaxies in the Abell 400 galaxy cluster they are some 300 million light-years away. Astronomers conclude that these two supermassive black holes are bound together by gravity in a binary system in part because the jets' consistent swept back appearance is most likely due to their common motion as they speed through the hot cluster gas at 1200 kilometers per second. Such spectacular cosmic mergers are thought to be common in crowded galaxy cluster environments in the distant universe. In their final stages the mergers are expected to be intense sources of gravitational waves. via NASA http://ift.tt/2gWCW4t

2017/10/21

Lynds Dark Nebula 183


Beverly Lynds Dark Nebula 183 lies a mere 325 light-years away, drifting high above the plane of our Milky Way Galaxy. Obscuring the starlight behind it when viewed at optical wavelengths, the dark, dusty molecular cloud itself seems starless. But far infrared explorations reveal dense clumps within, likely stars in the early stages of formation as enhanced regions of the cloud undergo gravitational collapse. One of the closest molecular clouds, it is seen toward the constellation Serpens Caput. This sharp cosmic cloud portrait spans about half a degree on the sky. That's about 3 light-years at the estimated distance of Lynds Dark Nebula 183. via NASA http://ift.tt/2x9BMbW

2017/10/20

Hubble Unravels a Twisted Cosmic Knot


This Hubble image shows what happens when two galaxies become one. The twisted cosmic knot seen here is NGC 2623 — or Arp 243 — and is located about 250 million light-years away in the constellation of Cancer (The Crab). via NASA http://ift.tt/2xTIy5i