Etiqueta: #rs

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

What does Venus look like beneath its thick clouds? These clouds keep the planet’s surface hidden from even the powerful telescopic eyes of Earth-bound astronomers. In the early 1990s, though, using imaging radar, NASA’s Venus-orbiting Magellan spacecraft was able to lift the veil from the face of Venus and produced spectacular high resolution images of the planet’s surface. Colors used in this computer generated picture of Magellan radar data are based on color images from the surface of Venus transmitted by the Soviet Venera 13 and 14 landers. The bright area running roughly across the middle represents the largest highland region of Venus known as Aphrodite Terra. Venus, on the left, is about the same size as our Earth, shown to the right for comparison. [via NASA] https://go.nasa.gov/2tglHku

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

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

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

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

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

The silhouette of an intriguing dark nebula inhabits this cosmic scene. Lynds’ Dark Nebula (LDN) 1622 appears against a faint background of glowing hydrogen gas only easily seen in long telescopic exposures of the region. LDN 1622 lies near the plane of our Milky Way Galaxy, close on the sky to Barnard’s Loop, a large cloud surrounding the rich complex of emission nebulae found in the Belt and Sword of Orion. But the obscuring dust of LDN 1622 is thought to be much closer than Orion’s more famous nebulae, perhaps only 500 light-years away. At that distance, this 1 degree wide field of view would span less than 10 light-years. Its foreboding appearance lends this dark expanse a popular name, the Boogeyman Nebula. [via NASA] https://go.nasa.gov/2G6xF8R

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