2017/12/16

A Wintry Shower


Four Geminids flash through northern skies in this wintry night skyscape. The bright fireball and 3 fainter meteors were captured in a single 10 second exposure, near the peak of December's Geminid meteor shower. Reflecting the fireball's greenish light, a partially frozen Lake Edith in Alberta Canada's Jasper National Park lies in the foreground, with the Canadian Rocky Mountains ranging along the northern horizon. Of course, the glacial lake is cold even in summer. But photographer Jack Fusco reports that he experienced -9 degree C temperatures that night while enjoying one of the most active meteor showers he's ever seen. via NASA http://ift.tt/2CyewHQ

2017/12/15

New Research Launches to Space Station Aboard SpaceX Resupply Mission


The two-stage Falcon 9 launch vehicle lifts off from Space Launch Complex 40 at Cape Canaveral Air Force Station carrying the Dragon resupply spacecraft to the International Space Station. Dragon will bring supplies, equipment and new science experiments for technology research to the orbiting laboratory. via NASA http://ift.tt/2BfDjA6

Geminids of the North


Earth's annual Geminid meteor shower did not disappoint as our fair planet plowed through dust from active asteroid 3200 Phaethon. Captured in this northern hemisphere nightscape, the meteors stream away from the shower's radiant in Gemini. To create the image, 37 individual frames recording meteor streaks were taken over period of 8.5 hours during the night of December 12/13. In the final composite they were selected and registered against the starry sky above a radio telescope dish of MUSER, a solar-dedicated radio telescope array at astronomically-named Mingantu Station in Inner Mongolia, China, about 400 kilometers from Beijing. Sirius, alpha star of Canis Major, shines brightly just above the radio dish and the Milky Way stretches toward the zenith. Yellowish Betelgeuse is a standout in Orion to the right of the northen Milky Way. The shower's radiant is at top left, high above the horizon near Castor and Pollux the twin stars of Gemini. The radiant effect is due to perspective as the parallel meteor tracks appear to converge in the distance. Gemini's meteors enter Earth's atmosphere traveling at about 22 kilometers per second. via NASA http://ift.tt/2BkhPVp

2017/12/14

Soyuz Carrying Expedition 53 Crew Lands in Kazakhstan


The Soyuz MS-05 spacecraft is seen as it lands with Expedition 53 Commander Randy Bresnik of NASA and Flight Engineers Paolo Nespoli of ESA (European Space Agency) and Sergey Ryazanskiy of the Russian space agency Roscosmos near the town of Zhezkazgan, Kazakhstan on Thursday, Dec. 14, 2017. via NASA http://ift.tt/2ytt3kN

2017/12/13

The Fault in Our Mars


This image from NASA's Mars Reconnaissance Orbiter (MRO) of northern Meridiani Planum shows faults that have disrupted layered deposits. via NASA http://ift.tt/2iXZy5j

2017/12/12

Chandra Reveals the Elementary Nature of Cassiopeia A


Due to its unique evolutionary status, Cassiopeia A (Cas A) is one of the most intensely studied of these supernova remnants. via NASA http://ift.tt/2C6ofVz

2017/12/11

Science From the Moon’s Shadow


The Aug. 21, 2017, total solar eclipse was rare in its long, uninterrupted path over land, which provided scientists with a rare chance to investigate the Sun and its influence on Earth in ways that aren’t usually possible. On Dec. 11, researchers discussed initial findings based on observations gathered during the eclipse. via NASA http://ift.tt/2AszyKt

2017/12/10

In Green Company: Aurora over Norway


Raise your arms if you see an aurora. With those instructions, two nights went by with, well, clouds -- mostly. On the third night of returning to same peaks, though, the sky not only cleared up but lit up with a spectacular auroral display. Arms went high in the air, patience and experience paid off, and the creative featured image was captured as a composite from three separate exposures. The setting is a summit of the Austnesfjorden fjord close to the town of Svolvear on the Lofoten islands in northern Norway. The time was early 2014. Although our Sun is nearing Solar Minimum and hence showing relatively little surface activity, holes in the upper corona have provided some nice auroral displays over the last few months. via NASA http://ift.tt/2nI8JvT

2017/12/09

Stardust in Aries


This composition in stardust covers over 8 degrees on the northern sky. The mosaicked field of view is west of the familiar Pleiades star cluster, toward the zodiacal constellation Aries and the plane of our Milky Way Galaxy. At right in the deep skyscape is bluish Epsilon Arietis, a star visible to the naked-eye and about 330 light-years away. Reflecting starlight in the region, dusty nebulae LBN762, LBN753, and LBN743 sprawl left to right across the field, but are likely some 1,000 light-years away. At that estimated distance, the cosmic canvas is over 140 light-years across. Near the edge of a large molecular cloud, their dark interiors can hide newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form around dense cores embedded in the molecular cloud. via NASA http://ift.tt/2A1Zfx4

2017/12/08

Retrospective: Moon


This false-color image is composed of 15 images taken through three color filters by NASA's Galileo spacecraft as it passed through the Earth-Moon system on Dec. 8, 1992. via NASA http://ift.tt/2A4N6I1

Alpine Superga Moonset


December's Full Moon phase occurred near perigee, the closest point in its orbit around our fair planet. Big and bright, the fully illuminated lunar disk sets over rugged mountains in this early morningscape from Turin, Italy. Captured just before sunrise on the opposite horizon, scattered sunlight near the edge of Earth's shadow provides the beautiful reddish glow of the alpine peaks. Hills in the foreground are still in shadow. But the scattered sunlight just illuminates the dome and towers of Turin's historic Basilica of Superga on a hilltop near the lower right in the telephoto frame. via NASA http://ift.tt/2BGwGG3

2017/12/07

NASA's Science Aircraft Flies Over Thomas Fire in California


During an engineering flight test of the Cloud-Aerosol Multi-Angle Lidar (CAMAL) instrument, a view from NASA Armstrong Flight Research Center’s ER-2 aircraft shows smoke plumes, from roughly 65,000 feet, produced by the Thomas Fire in Ventura County, California, around 1 p.m. PST on Dec. 5th, 2017. via NASA http://ift.tt/2j3XCf5

All the Eclipses of 2017


As seen from planet Earth, all the lunar and solar eclipses of 2017 are represented at the same scale in these four panels. The year's celestial shadow play was followed through four different countries by one adventurous eclipse chaser. To kick off the eclipse season, at top left February's Full Moon was captured from the Czech Republic. Its subtle shading, a penumbral lunar eclipse, is due to Earth's lighter outer shadow. Later that month the New Moon at top right was surrounded by a ring of fire, recorded on film from Argentina near the midpoint of striking annular solar eclipse. The August eclipse pairing below finds the Earth's dark umbral shadow in a partial eclipse from Germany at left, and the vibrant solar corona surrounding a totally eclipsed Sun from the western USA. If you're keeping score, the Saros numbers (eclipse cycles) for all the 2017 eclipses are at bottom left in each panel. via NASA http://ift.tt/2AAbJ0j

2017/12/06

Cygnus Cargo Spacecraft at Sunrise


NASA astronaut Randy Bresnik photographed Orbital ATK's Cygnus cargo spacecraft at sunrise, prior to its departure from the International Space Station at 8:11 a.m., Dec. 6, 2017. Expedition 53 Flight Engineers Mark Vande Hei and Joe Acaba of NASA gave the station's Canadarm2 robotic arm the command to release Cygnus. via NASA http://ift.tt/2k27en9

HH 666: Carina Dust Pillar with Jet


To some, it may look like a beehive harboring an evil bee. In reality, the featured Hubble image captures a cosmic pillar of dust, two-light years long, inside of which is Herbig-Haro 666 -- a young star emitting powerful jets. The structure lies within one of our galaxy's largest star forming regions, the Carina Nebula, shining in southern skies at a distance of about 7,500 light-years. The pillar's layered outline are shaped by the winds and radiation of Carina's young, hot, massive stars, some of which are still forming inside the nebula. A dust-penetrating view in infrared light better shows the two, narrow, energetic jets blasting outward from a still hidden infant star. via NASA http://ift.tt/2Bzxqww

2017/12/05

Cloud Streets in the Sea of Okhotsk


Frigid air blowing from Eastern Russia created dramatic cloud formations over the Sea of Okhotsk in late November, 2017. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite acquired a true-color image of the stunning scene on November 25. via NASA http://ift.tt/2At1dK0

A Horizon with Blue and Red


What's happening on the horizon? The horizon itself, past a spinach field in Guatemala, shows not only trees but a large volcano: the Volcán de Fuego (Volcano of Fire). The red glow at the top of the volcano is hot lava. But your eye may also be drawn to the blue circle above the horizon on the left. This circle surrounds the Moon and, together with other colors, is called a corona. A corona is caused by diffraction of light -- here moonlight -- by small water droplets in the Earth's intervening atmosphere. A break in the clouds on the right shows stars and even the planet Saturn far beyond the volcano. Although Volcán de Fuego frequently undergoes low-level activity, the astrophotographer considered himself lucky to capture the scene just during an explosive eruption in late September. via NASA http://ift.tt/2klfuTd

2017/12/04

Space Station Transits the Moon


The International Space Station is seen in silhouette as it transits the Moon at roughly five miles per second, Dec. 2, 2017, in Manchester Township, York County, Pennsylvania. Onboard are NASA astronauts Joe Acaba, Mark Vande Hei, and Randy Bresnik; Russian cosmonauts Alexander Misurkin and Sergey Ryanzansky; and ESA astronaut Paolo Nespoli. via NASA http://ift.tt/2kkVEaq

2017/12/01

Hubble Sees Galaxy Cluster Warping Space and Time


The Hubble Space Telescope peers into the distant universe to reveal a galaxy cluster called Abell 2537. via NASA http://ift.tt/2BtpnkK

North America and the Pelican


Fans of our fair planet might recognize the outlines of these cosmic clouds. On the left, bright emission outlined by dark, obscuring dust lanes seems to trace a continental shape, lending the popular name North America Nebula to the emission region cataloged as NGC 7000. To the right, just off the North America Nebula's east coast, is IC 5070, whose profile suggests the Pelican Nebula. The two bright nebulae are about 1,500 light-years away, part of the same large and complex star forming region, almost as nearby as the better-known Orion Nebula. At that distance, the 6 degree wide field of view would span 150 light-years. This careful cosmic portrait uses narrow band images to highlight the bright ionization fronts and the characteristic red glow from atomic hydrogen gas. These nebulae can be seen with binoculars from a dark location. Look northeast of bright star Deneb in the constellation of Cygnus the Swan. via NASA http://ift.tt/2jysEbh

2017/11/30

Space Station in the Sky Over Washington D.C.


The International Space Station is seen in this twenty-second exposure as it flies over the Washington National Cathedral, Wednesday, Nov. 29, 2017. Onboard are: NASA astronauts Joe Acaba, Mark Vande Hei, and Randy Bresnik; Russian cosmonauts Alexander Misurkin and Sergey Ryanzansky; and ESA astronaut Paolo Nespoli. via NASA http://ift.tt/2Ai5EYb

M33: Triangulum Galaxy


The small, northern constellation Triangulum harbors this magnificent face-on spiral galaxy, M33. Its popular names include the Pinwheel Galaxy or just the Triangulum Galaxy. M33 is over 50,000 light-years in diameter, third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. About 3 million light-years from the Milky Way, M33 is itself thought to be a satellite of the Andromeda Galaxy and astronomers in these two galaxies would likely have spectacular views of each other's grand spiral star systems. As for the view from planet Earth, this sharp composite image nicely shows off M33's blue star clusters and pinkish star forming regions along the galaxy's loosely wound spiral arms. In fact, the cavernous NGC 604 is the brightest star forming region, seen here at about the 7 o'clock position from the galaxy center. Like M31, M33's population of well-measured variable stars have helped make this nearby spiral a cosmic yardstick for establishing the distance scale of the Universe. via NASA http://ift.tt/2zzRm20

2017/11/29

M42: The Great Orion Nebula


Few astronomical sights excite the imagination like the nearby stellar nursery known as the Orion Nebula. The Nebula's glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud. Many of the filamentary structures visible in the featured image are actually shock waves - fronts where fast moving material encounters slow moving gas. The Orion Nebula spans about 40 light years and is located about 1500 light years away in the same spiral arm of our Galaxy as the Sun. The Great Nebula in Orion can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. The featured image, taken last month, shows a two-hour exposure of the nebula in three colors. The whole Orion Nebula cloud complex, which includes the Horsehead Nebula, will slowly disperse over the next 100,000 years. via NASA http://ift.tt/2ibgKYp

2017/11/28

A Proving Ground in Space


Dellingr is a shoebox-sized spacecraft built to show that CubeSat platforms could be cost-effective, reliable and capable of gathering highly robust science. via NASA http://ift.tt/2zNsgko

2017/11/27

Alpha and Omega


These two images illustrate just how far Cassini traveled to get to Saturn. via NASA http://ift.tt/2BgsfBr

2017/11/25

Crossing Horizons


Follow this vertical panoramic view from horizon to horizon and your gaze will sweep through the zenith of a dark night sky over Pic du Midi mountaintop observatory. To make the journey above a sea of clouds, 19 single exposures were taken near the end of night on October 31 and assembled in a mercator projection that renders the two horizons flat. Begin at the top and you're looking east toward the upsidedown dome of the observatory's 1 meter telescope. It's easy to follow the plane of our Milky Way galaxy as it appears to emerge from the dome and angle down toward the far horizon. Just to its right, the sky holds a remarkable diffuse glow of zodiacal light along our Solar System's ecliptic plane. Zodiacal light and Milky Way with star clusters, cosmic dust clouds and faint nebulae, cross near the zenith. Both continue down toward the airglow in the west. They disappear near the western horizon at the bottom, beyond more Pic du Midi observatory domes and a tall communications relay antenna. via NASA http://ift.tt/2iNjjwX

2017/11/24

Star Wanders Too Close to a Black Hole


This artist's rendering shows the tidal disruption event named ASASSN-14li, where a star wandering too close to a 3-million-solar-mass black hole was torn apart. The debris gathered into an accretion disk around the black hole. via NASA http://ift.tt/2hS1Q5y

Apollo 17 at Shorty Crater


In December of 1972, Apollo 17 astronauts Eugene Cernan and Harrison Schmitt spent about 75 hours on the Moon in the Taurus-Littrow valley, while colleague Ronald Evans orbited overhead. This sharp image was taken by Cernan as he and Schmitt roamed the valley floor. The image shows Schmitt on the left with the lunar rover at the edge of Shorty Crater, near the spot where geologist Schmitt discovered orange lunar soil. The Apollo 17 crew returned with 110 kilograms of rock and soil samples, more than was returned from any of the other lunar landing sites. Forty five years later, Cernan and Schmitt are still the last to walk on the Moon. via NASA http://ift.tt/2iHLwoC

2017/11/23

Alnitak, Alnilam, Mintaka


Alnitak, Alnilam, and Mintaka, are the bright bluish stars from east to west (lower right to upper left) along the diagonal in this cosmic vista. Otherwise known as the Belt of Orion, these three blue supergiant stars are hotter and much more massive than the Sun. They lie from 800 to 1,500 light-years away, born of Orion's well-studied interstellar clouds. In fact, clouds of gas and dust adrift in this region have some surprisingly familiar shapes, including the dark Horsehead Nebula and Flame Nebula near Alnitak at the lower right. The famous Orion Nebula itself is off the right edge of this colorful starfield. This well-framed, 2-panel telescopic mosaic spans about 4 degrees on the sky. via NASA http://ift.tt/2A3km2Q

2017/11/22

The Beauty of Ice


Ice can be stunningly beautiful and also quite varied in its appearance. via NASA http://ift.tt/2zssDk2

Nothing like it has ever been seen before. The unusual space rock 'Oumuamua is so intriguing mainly because it is the first asteroid ever detected from outside our Solar System -- although likely many more are to follow given modern computer-driven sky monitoring. Therefore humanity's telescopes -- of nearly every variety -- have put 'Oumuamua into their observing schedule to help better understand this unusual interstellar visitor. Pictured is an artist's illustration of what 'Oumuamua might look like up close. 'Oumuamua is also intriguing, however, because it has unexpected parallels to Rama, a famous fictional interstellar spaceship created by the late science fiction writer Arthur C. Clarke. Like Rama, 'Oumuamua is unusually elongated, should be made of strong material to avoid breaking apart, is only passing through our Solar System, and passed unusually close to the Sun for something gravitationally unbound. Unlike a visiting spaceship, though, 'Oumuamua's trajectory, speed, color, and even probability of detection are consistent with it forming naturally around a normal star many millions of years ago, being expelled after gravitationally encountering a normal planet, and subsequently orbiting in our Galaxy alone. Even given 'Oumuamua's likely conventional origin, perhaps humanity can hold hope that one day we will have the technology to engineer 'Oumuamua -- or another Solar System interloper -- into an interstellar Rama of our own. via NASA http://ift.tt/2jLMtjj

2017/11/21

Tending Your Garden ... In Space


If you plant it, will it grow (in space)? The answer is yes, at least for certain types of plants. via NASA http://ift.tt/2zpxa6R

2017/11/20

Behold! Observing the Sun


A broad hole in the corona was the Sun's dominant feature November 7-9, 2017. via NASA http://ift.tt/2jH94NM

Curiosity Rover Takes Selfie on Mars


Yes, but have you ever taken a selfie on Mars? The Curiosity rover on Mars has. This selfie was compiled from many smaller images -- which is why the mechanical arm holding the camera is not visible. (Although its shadow is!) Taken in mid-2015, the featured image shows not only the adventurous rover, but dark layered rocks, the light colored peak of Mount Sharp, and the rusting red sand that pervades Mars. If you look closely, you can even see that a small rock is stuck into one of Curiosity's aging wheels. Now nearing the end of 2017, Curiosity continues to explore the layers of sedimentary rocks it has discovered on Vera Rubin Ridge in order to better understand, generally, the ancient geologic history of Mars and, specifically, why these types of rocks exist there. via NASA http://ift.tt/2zQUhGy

2017/11/19

NGC 7822: Stars and Dust Pillars in Infrared


Young stars themselves are clearing out their nursery in NGC 7822. Within the nebula, bright edges and complex dust sculptures dominate this detailed skyscape taken in infrared light by NASA's Wide Field Infrared Survey Explorer (WISE) satellite. NGC 7822 lies at the edge of a giant molecular cloud toward the northern constellation Cepheus, a glowing star forming region that lies about 3,000 light-years away. The atomic emission of light by the nebula's gas is powered by energetic radiation from the hot stars, whose powerful winds and light also sculpt and erode the denser pillar shapes. Stars could still be forming inside the pillars by gravitational collapse, but as the pillars are eroded away, any forming stars will ultimately be cut off from their reservoir of star stuff. This field spans around 40 light-years at the estimated distance of NGC 7822. via NASA http://ift.tt/2yWIbIj

2017/11/18

Friday the Moon Smiled


Friday, an old Moon smiled for early morning risers. Its waning sunlit crescent is captured in this atmospheric scene from clear skies near Bursa, Turkey, planet Earth. In the subtle twilight hues nearby celestial lights are Jupiter (top) and Venus shining close to the eastern horizon. But today, Saturday, the Moon will be new and early next week its waxing crescent will follow the setting Sun as it sinks in the west. Then, a young Moon's smile will join Saturn and Mercury in early evening skies. via NASA http://ift.tt/2zKPtT8

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