Sharpest Ultima Thule Sharpest Ultima Thule

On January 1, New Horizons swooped to within 3,500 kilometers of the Kuiper Belt world known as Ultima Thule. That's about 3 times closer than its July 2015 closest approach to Pluto. The spacecraft's unprecedented feat of navigational precision, supported by data from ground and space-based observing campaigns, was accomplished 6.6 billion kilometers (over 6 light-hours) from planet Earth. Six and a half minutes before closest approach to Ultima Thule it captured the nine frames used in this composite image. The most detailed picture possible of the farthest object ever explored, the image has a resolution of about 33 meters per pixel, revealing intriguing bright surface features and dark shadows near the terminator. A primitive Solar System object, Ultima Thule's two lobes combine to span just 30 kilometers. The larger lobe, referred to as Ultima, is recently understood to be flattened like a fluffy pancake, while the smaller, Thule, has a shape that resembles a dented walnut. via NASA https://ift.tt/2UjlMQ4

Simulation TNG50: A Galaxy Cluster Forms Simulation TNG50: A Galaxy Cluster Forms

How do clusters of galaxies form? Since our universe moves too slowly to watch, faster-moving computer simulations are created to help find out. A recent effort is TNG50 from IllustrisTNG, an upgrade of the famous Illustris Simulation. The first part of the featured video tracks cosmic gas (mostly hydrogen) as it evolves into galaxies and galaxy clusters from the early universe to today, with brighter colors marking faster moving gas. As the universe matures, gas falls into gravitational wells, galaxies forms, galaxies spin, galaxies collide and merge, all while black holes form in galaxy centers and expel surrounding gas at high speeds. The second half of the video switches to tracking stars, showing a galaxy cluster coming together complete with tidal tails and stellar streams. The outflow from black holes in TNG50 is surprisingly complex and details are being compared with our real universe. Studying how gas coalesced in the early universe helps humanity better understand how our Earth, Sun, and Solar System originally formed. via NASA https://ift.tt/2XxA5CW

Red Sprite Lightning over Kununurra Red Sprite Lightning over Kununurra

What are those red filaments in the sky? It is a rarely seen form of lightning confirmed only about 30 years ago: red sprites. Recent research has shown that following a powerful positive cloud-to-ground lightning strike, red sprites may start as 100-meter balls of ionized air that shoot down from about 80-km high at 10 percent the speed of light and are quickly followed by a group of upward streaking ionized balls. The featured image, taken just over a week ago in Kununurra, Western Australia, captured some red sprites while shooting a time-lapse sequence of a distant lightning storm. Pictured, green trees cover the foreground, dark mountains are seen on the horizon, ominous storm clouds hover over the distant land, while red sprites appear in front of stars far in the distance. Red sprites take only a fraction of a second to occur and are best seen when powerful thunderstorms are visible from the side. via NASA https://ift.tt/2T0DgV5

The Expanding Echoes of Supernova 1987A The Expanding Echoes of Supernova 1987A

Can you find supernova 1987A? It isn't hard -- it occurred at the center of the expanding bullseye pattern. Although this stellar detonation was first seen in 1987, light from SN 1987A continued to bounce off clumps of interstellar dust and be reflected to us even many years later. Light echoes recorded between 1988 and 1992 by the Anglo Australian Telescope (AAT) in Australia are shown moving out from the position of the supernova in the featured time-lapse sequence. These images were composed by subtracting an LMC image taken before the supernova light arrived from later LMC images that included the supernova echo. Other prominent light echo sequences include those taken by the EROS2 and SuperMACHO sky monitoring projects. Studies of expanding light echo rings around other supernovas have enabled more accurate determinations of the location, date, and symmetry of these tremendous stellar explosions. Yesterday marked the 32nd anniversary of SN 1987A: the last recoded supernova in or around our Milky Way Galaxy, and the last to be visible to the unaided eye. via NASA https://ift.tt/2VhAEPi

The Stars of the Triangulum Galaxy The Stars of the Triangulum Galaxy

Like grains of sand on a cosmic beach, stars of the Triangulum Galaxy are resolved in this sharp mosaic from the Hubble Space Telescope's Advanced Camera for Surveys (ACS). The inner region of the galaxy spanning over 17,000 light-years is covered at extreme resolution, the second largest image ever released by Hubble. At its center is the bright, densely packed galactic core surrounded by a loose array of dark dust lanes mixed with the stars in the galactic plane. Also known as M33, the face-on spiral galaxy lies 3 million light-years away in the small northern constellation Triangulum. Over 50,000 light-years in diameter, the Triangulum Galaxy is the third largest in the Local Group of galaxies after the Andromeda Galaxy (M31), and our own Milky Way. Of course, to fully appreciate the Triangulum's stars, star clusters, and bright nebulae captured in this Hubble mosaic, you'll need to use a zoom tool. via NASA https://ift.tt/2NnzwGV

NGC 4565: Galaxy on Edge NGC 4565: Galaxy on Edge

Magnificent spiral galaxy NGC 4565 is viewed edge-on from planet Earth. Also known as the Needle Galaxy for its narrow profile, bright NGC 4565 is a stop on many telescopic tours of the northern sky, in the faint but well-groomed constellation Coma Berenices. This sharp, colorful image reveals the galaxy's bulging central core cut by obscuring dust lanes that lace NGC 4565's thin galactic plane. An assortment of other background galaxies is included in the pretty field of view, with neighboring galaxy NGC 4562 at the upper right. NGC 4565 itself lies about 40 million light-years distant and spans some 100,000 light-years. Easily spotted with small telescopes, sky enthusiasts consider NGC 4565 to be a prominent celestial masterpiece Messier missed. via NASA https://ift.tt/2It0o9C

Doomed Star Eta Carinae Doomed Star Eta Carinae

Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova. Historical records do show that about 170 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky. Eta Carinae, in the Keyhole Nebula, is the only star currently thought to emit natural LASER light. This featured image brings out details in the unusual nebula that surrounds this rogue star. Diffraction spikes, caused by the telescope, are visible as bright multi-colored streaks emanating from Eta Carinae's center. Two distinct lobes of the Homunculus Nebula encompass the hot central region, while some strange radial streaks are visible in red extending toward the image right. The lobes are filled with lanes of gas and dust which absorb the blue and ultraviolet light emitted near the center. The streaks, however, remain unexplained. via NASA https://ift.tt/2T0OfNw

Comet Iwamoto Before Spiral Galaxy NGC 2903 Comet Iwamoto Before Spiral Galaxy NGC 2903

It isn't every night that a comet passes a galaxy. Last Thursday, though, binocular comet C/2018 Y1 (Iwamoto) moved nearly in front of a spiral galaxy of approximately the same brightness: NGC 2903. Comet Iwamoto was discovered late last year and orbits the Sun in a long ellipse. It last visited the inner Solar System during the Middle Ages, around the year 648. The comet reached its closest point to the Sun -- between Earth and Mars -- on February 6, and its closest point to Earth a few days ago, on February 13. The featured time-lapse video condenses almost three hours into about ten seconds, and was captured last week from Switzerland. At that time Comet Iwamoto, sporting a green coma, was about 10 light minutes distant, while spiral galaxy NGC 2903 remained about 30 million light years away. Two satellites zip diagonally through the field about a third of the way through the video. Typically, a few comets each year become as bright as Comet Iwamoto. via NASA https://go.nasa.gov/2Egfnjp

Dragon Aurora over Iceland Dragon Aurora over Iceland

Have you ever seen a dragon in the sky? Although real flying dragons don't exist, a huge dragon-shaped aurora developed in the sky over Iceland earlier this month. The aurora was caused by a hole in the Sun's corona that expelled charged particles into a solar wind that followed a changing interplanetary magnetic field to Earth's magnetosphere. As some of those particles then struck Earth's atmosphere, they excited atoms which subsequently emitted light: aurora. This iconic display was so enthralling that the photographer's mother ran out to see it and was captured in the foreground. No sunspots have appeared on the Sun so far in February, making the multiple days of picturesque auroral activity this month somewhat surprising. via NASA https://go.nasa.gov/2V5BcHF

Shadow of a Martian Robot Shadow of a Martian Robot

What if you saw your shadow on Mars and it wasn't human? Then you might be the Opportunity rover currently exploring Mars. Opportunity explored the red planet from 2004 to 2018, finding evidence of ancient water, and sending breathtaking images across the inner Solar System. Pictured here in 2004, Opportunity looks opposite the Sun into Endurance Crater and sees its own shadow. Two wheels are visible on the lower left and right, while the floor and walls of the unusual crater are visible in the background. Caught in a dust storm in 2018, last week NASA stopped try contact Opportunity and declare the ground-breaking mission, originally planned for only 92 days, complete. via NASA https://go.nasa.gov/2NaXmWp

NGC 2359: Thor s Helmet NGC 2359: Thor s Helmet

NGC 2359 is a helmet-shaped cosmic cloud with wing-like appendages popularly called Thor's Helmet. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the helmet is more like an interstellar bubble, blown as a fast wind from the bright, massive star near the bubble's center inflates a region within the surrounding molecular cloud. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away in the constellation Canis Major. The remarkably detailed image is a mixed cocktail of data from broadband and narrowband filters that captures natural looking stars and the glow of the nebula's filamentary structures. It highlights a blue-green color from strong emission due to oxygen atoms in the glowing gas. via NASA https://go.nasa.gov/2toqgcs

The Helix Nebula in Hydrogen and Oxygen The Helix Nebula in Hydrogen and Oxygen

Is the Helix Nebula looking at you? No, not in any biological sense, but it does look quite like an eye. The Helix Nebula is so named because it also appears that you are looking down the axis of a helix. In actuality, it is now understood to have a surprisingly complex geometry, including radial filaments and extended outer loops. The Helix Nebula (aka NGC 7293) is one of brightest and closest examples of a planetary nebula, a gas cloud created at the end of the life of a Sun-like star. The remnant central stellar core, destined to become a white dwarf star, glows in light so energetic it causes the previously expelled gas to fluoresce. The featured picture, taken in the light emitted by oxygen (shown in blue) and hydrogen (shown in red), was created from 74 hours of exposure over three months from a small telescope in a backyard of suburban Melbourne, Australia. A close-up of the inner edge of the Helix Nebula shows complex gas knots of unknown origin. via NASA https://go.nasa.gov/2tiiwZz

Plane Crossing a Crescent Moon Plane Crossing a Crescent Moon

No, this is not a good way to get to the Moon. What is pictured is a chance superposition of an airplane and the Moon. The contrail would normally appear white, but the large volume of air toward the setting Sun preferentially knocks away blue light, giving the reflected trail a bright red hue. Far in the distance, well behind the plane, is a crescent Moon, also slightly reddened. Captured a month ago above Valais, Switzerland, the featured image was taken so soon after sunset that planes in the sky were still in sunlight, as were their contrails. Within minutes, unfortunately, the impromptu sky show ended. The plane crossed the Moon and moved out of sight. The Moon set. The contrail became unilluminated and then dispersed. via NASA https://go.nasa.gov/2tqTvM1

New Data: Ultima Thule Surprisingly Flat New Data: Ultima Thule Surprisingly Flat

Ultima Thule is not the object humanity thought that it was last month. When the robotic New Horizons spacecraft zoomed past the distant asteroid Ultima Thule (officially 2014 MU69) in early January, early images showed two circular lobes that when most simply extrapolated to 3D were thought to be, roughly, spheres. However, analyses of newly beamed-back images -- including many taken soon after closest approach -- shows eclipsed stars re-appearing sooner than expected. The only explanation possible is that this 30-km long Kuiper belt object has a different 3D shape than believed only a few weeks ago. Specifically, as shown in the featured illustration, it now appears that the larger lobe -- Ultima -- is more similar to a fluffy pancake than a sphere, while the smaller lobe -- Thule -- resembles a dented walnut. The remaining uncertainty in the outlines are shown by the dashed blue lines. The new shape information indicates that gravity -- which contracts more massive bodies into spheres -- played perhaps less of a role in contouring the lobes of Ultima Thule than previously thought. The New Horizons spacecraft continued on to Ultima Thule after passing Pluto in mid-2015. New data and images are still being received. via NASA https://go.nasa.gov/2THETDp

Comet Iwamoto and the Sombrero Galaxy Comet Iwamoto and the Sombrero Galaxy

Comet Iwamoto (C/2018 Y1), shows off a pretty, greenish coma at the upper left in this telescopic field of view. Taken on February 4 from the Mount John Observatory, University of Canterbury, the 30 minute long total exposure time shows the comet sweeping quickly across a background of stars and distant galaxies in the constellation Virgo. The long exposure and Iwamoto's rapid motion relative to the stars and galaxies results in the noticeable blurred streak tracing the the comet's bright inner coma. In fact, the streaked coma gives the comet a remarkably similar appearance to Messier 104 at lower right, popularly known as the Sombrero Galaxy. The comet, a visitor to the inner Solar System, is a mere 4 light-minutes away though, while majestic Messier 104, a spiral galaxy posing edge-on, is 30 million light-years distant. The first binocular comet of 2019, Iwamoto will pass closest to Earth on February 12. This comet's highly elliptical orbit around the Sun stretches beyond the Kuiper belt with an estimated 1,371 year orbital period. That should bring it back to the inner Solar System in 3390 AD. via NASA https://go.nasa.gov/2GiHxfU

Moon, Four Planets, and Emu Moon, Four Planets, and Emu

A luminous Milky Way falls toward the horizon in this deep skyscape, starting at the top of the frame from the stars of the Southern Cross and the dark Coalsack Nebula. Captured in the dark predawn of February 2nd from Central Victoria, Australia, planet Earth, the 26 day old waning crescent Moon still shines brightly near the horizon. The second and third brightest celestial beacons are Venus and Jupiter along the lower part of the Milky Way's central bulge. Almost in line with the brighter planets and Moon, Saturn is the pinprick of light just visible below and right of the lunar glow. Australia's first astronomers saw the elongated, bulging shape of the familiar Milky Way as a great celestial Emu. The Moon and planets could almost be the Emu's eggs on this starry night. via NASA https://go.nasa.gov/2TEBll5

Moon and Venus Appulse over a Tree Moon and Venus Appulse over a Tree

What's that bright spot near the Moon? Venus. About a week ago, Earth's Moon appeared unusually close to the distant planet Venus, an angular coincidence known as an appulse. Similar to a conjunction, which is a coordinate term, an appulse refers more generally to when two celestial objects appear close together. This Moon and Venus appulse -- once as close as 0.05 degrees -- was captured rising during the early morning behind Koko crater on the island of O'ahu in Hawaii, USA. The Moon was in a crescent phase with its lower left reflecting direct sunlight, while the rest of the Moon is seen because of Earthshine, sunlight first reflected from the Earth. Some leaves and branches of a foreground kiawe tree are seen in silhouette in front of the bright crescent, while others, in front of a darker background, appear white because of forward scattering. Appulses involving the Moon typically occur several times a year: for example the Moon is expected to pass within 0.20 degrees of distant Saturn on March 1. via NASA https://go.nasa.gov/2GqqUhu

Perijove 16: Passing Jupiter Perijove 16: Passing Jupiter

Watch Juno zoom past Jupiter again. NASA's robotic spacecraft Juno is continuing on its 53-day, highly-elongated orbits around our Solar System's largest planet. The featured video is from perijove 16, the sixteenth time that Juno has passed near Jupiter since it arrived in mid-2016. Each perijove passes near a slightly different part of Jupiter's cloud tops. This color-enhanced video has been digitally composed from 21 JunoCam still images, resulting in a 125-fold time-lapse. The video begins with Jupiter rising as Juno approaches from the north. As Juno reaches its closest view -- from about 3,500 kilometers over Jupiter's cloud tops -- the spacecraft captures the great planet in tremendous detail. Juno passes light zones and dark belt of clouds that circle the planet, as well as numerous swirling circular storms, many of which are larger than hurricanes on Earth. As Juno moves away, the remarkable dolphin-shaped cloud is visible. After the perijove, Jupiter recedes into the distance, now displaying the unusual clouds that appear over Jupiter's south. To get desired science data, Juno swoops so close to Jupiter that its instruments are exposed to very high levels of radiation. via NASA https://go.nasa.gov/2TwcwYL

Henize 70: A Superbubble in the LMC Henize 70: A Superbubble in the LMC

Massive stars profoundly affect their galactic environments. Churning and mixing interstellar clouds of gas and dust, stars -- most notably those upwards of tens of times the mass of our Sun -- leave their mark on the compositions and locations of future generations of stars. Dramatic evidence of this is illustrated in our neighboring galaxy, the Large Magellanic Cloud (LMC), by the featured nebula, Henize 70 (also known as N70 and DEM301). Henize 70 is actually a luminous superbubble of interstellar gas about 300 light-years in diameter, blown by winds from hot, massive stars and supernova explosions, with its interior filled with tenuous hot and expanding gas. Because superbubbles can expand through an entire galaxy, they offer humanity a chance to explore the connection between the lifecycles of stars and the evolution of galaxies. via NASA https://go.nasa.gov/2UJN0zx

An Airglow Fan from Lake to Sky An Airglow Fan from Lake to Sky

Why would the sky look like a giant fan? Airglow. The featured intermittent green glow appeared to rise from a lake through the arch of our Milky Way Galaxy, as captured during 2015 next to Bryce Canyon in Utah, USA. The unusual pattern was created by atmospheric gravity waves, ripples of alternating air pressure that can grow with height as the air thins, in this case about 90 kilometers up. Unlike auroras powered by collisions with energetic charged particles and seen at high latitudes, airglow is due to chemiluminescence, the production of light in a chemical reaction. More typically seen near the horizon, airglow keeps the night sky from ever being completely dark. via NASA https://go.nasa.gov/2GlQRP5

Twin Galaxies in Virgo Twin Galaxies in Virgo

Spiral galaxy pair NGC 4567 and NGC 4568 share this sharp cosmic vista with lonely elliptical galaxy NGC 4564. All are members of the large Virgo Galaxy Cluster. With their classic spiral arms, dust lanes, and star clusters, the eye-catching spiral pair is also known as the Butterfly Galaxies or the Siamese Twins. Very close together, the galaxy twins don't seem to be too distorted by gravitational tides. Their giant molecular clouds are known to be colliding though and are likely fueling the formation of massive star clusters. The galaxy twins are about 52 million light-years distant, while their bright cores appear separated by about 20,000 light-years. Of course, the spiky foreground stars lie within our own Milky Way. via NASA https://go.nasa.gov/2RXVF4a