Sunday, October 8, 2017

Dark Molecular Cloud Barnard

Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud. Here, a high concentration of dust and molecular gasabsorb practically all the visible light emitted from background stars. The eerily dark surroundings help make the interiors ofmolecular clouds some of the coldest and mostisolated places in the universe. One of the most notable of these dark absorption nebulae is a cloud toward the constellation Ophiuchusknown as Barnard 68pictured here. That no stars are visible in the center indicates thatBarnard 68 is relatively nearby, with measurements placing it about 500 light-years away and half a light-year across. It is not known exactly how molecular clouds likeBarnard 68 form, but it is known that these clouds are themselves likely places for new stars to form. In fact, Barnard 68 itself has been found likely to collapse and form a new star system. It is possible to look right through the cloud in infrared light.
Image Credit: FORS Team8.2-meter VLT Antu,ESO

Thursday, October 5, 2017

Pluto's Bladed Terrain

Imaged during the New Horizons spacecraft flyby in July 2015, Pluto's bladed terrain is captured in this close-up of the distant world.The bizarre texture belongs to fields of skyscraper-sized, jagged landforms made almost entirely of methane ice, found at extreme altitudes near Pluto's equator. Casting dramatic shadows, the tall, knife-like ridges seem to have been formed by sublimation. By that process, condensed methane ice turns directly to methane gas without passing through a liquid phase during Pluto's warmer geological periods. On planet Earth, sublimation can also produce standing fields of knife-like ice sheets, found along the high plateau of the Andes mountain range. Known as penitentes, those bladed structures are made of water ice and at most a few meters tall.

New Horizons

Wednesday, October 4, 2017

95 Minutes Over Jupiter

This sequence of color-enhanced images shows how quickly the viewing geometry changes for NASA’s Juno spacecraft as it swoops by Jupiter. The images were obtained by JunoCam.

Once every 53 days, Juno swings close to Jupiter, speeding over its clouds. In just two hours, the spacecraft travels from a perch over Jupiter’s north pole through its closest approach (perijove), then passes over the south pole on its way back out. This sequence shows 11 color-enhanced images from Perijove 8 (Sept. 1, 2017) with the south pole on the left (11th image in the sequence) and the north pole on the right (first image in the sequence).

The first image on the right shows a half-lit globe of Jupiter, with the north pole approximately at the upper center of the image close to the terminator -- the dividing line between night and day. As the spacecraft gets closer to Jupiter, the horizon moves in and the range of visible latitudes shrinks. The second and third images in this sequence show the north polar region rotating away from the spacecraft's field of view while the first of Jupiter's lighter-colored bands comes into view. The fourth through the eighth images display a blue-colored vortex in the mid-southern latitudes near Points of Interest "Collision of Colours," "Sharp Edge," "Caltech, by Halka," and "Structure01." The Points of Interest are locations in Jupiter’s atmosphere that were identified and named by members of the general public. Additionally, a darker, dynamic band can be seen just south of the vortex. In the ninth and tenth images, the south polar region rotates into view. The final image on the left displays Jupiter's south pole in the center.

From the start of this sequence of images to the end, roughly 1 hour and 35 minutes elapsed.

JunoCam's raw images are available for the public to peruse and process into image products at:

www.missionjuno.swri.edu/junocam      

Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill

Larger view

Juno

Wednesday, August 2, 2017

The Dust Monster in IC 1396

Is there a monster in IC 1396? Known to some as the Elephant's Trunk Nebula, parts of gas and dust clouds of this star formation regionmay appear to take on foreboding forms, somenearly human. The only real monster here, however, is a bright young star too far fromEarth to hurt us. Energetic light from this star is eating away the dust of the dark cometary globule near the top of the featured imageJetsand winds of particles emitted from this star are also pushing away ambient gas and dust. Nearly 3,000 light-years distant, the relatively faint IC 1396 complex covers a much larger region on the sky than shown here, with an apparent width of more than 10 full moons.
For image credit and copyright guidance, please visit the image websitehttp://antwrp.gsfc.nasa.gov/apod/ap170802.html

Monday, July 31, 2017

Perseid Meteors Over Turkey

The Perseid Meteor Shower, usually the best meteor shower of the year, will peak late next week. A person watching a clear sky from a dark location might see a bright meteor every minute. These meteors are actually specks of rock that have broken off Comet Swift-Tuttleand continued to orbit the Sun until they vaporize in Earth's atmosphere. The featured composite image shows a outburst of Perseids as they appeared over Turkey during last year'smeteor shower. Enough meteors were captured to trace the shower's radiant back to theconstellation of Perseus on the far left. The tail-end of the Perseids will still be going during thetotal solar eclipse on August 21, creating a rare opportunity for some lucky astrophotographers to image a Perseid meteor during the day.
Image Credit & CopyrightTunç Tezel (TWAN)

Hubble's Cosmic Atlas

This beautiful clump of glowing gas, dark dust and glittering stars is the spiral galaxy NGC 4248, located about 24 million light-years away in the constellation of Canes Venatici (The Hunting Dogs).

This image was produced by the NASA/ESA Hubble Space Telescope as it embarked upon compiling the first Hubble ultraviolet 'atlas,'� for which the telescope targeted 50 nearby star-forming galaxies. The collection spans all kinds of different morphologies, masses, and structures. Studying this sample can help us to piece together the star-formation history of the universe.

By exploring how massive stars form and evolve within such galaxies, astronomers can learn more about how, when, and where star formation occurs, how star clusters change over time, and how the process of forming new stars is related to the properties of both the host galaxy and the surrounding interstellar medium (the gas and dust that fills the space between individual stars).

This galaxy was imaged with observations from Hubble's Wide Field Camera 3.

Image credit: ESA/Hubble andamp; NASA andnbsp;
Text credit: European Space Agency

Hubble Space Telescope

Monday, July 10, 2017

Composite Messier 20 and 21

The beautiful Trifid Nebula, also known as Messier 20, lies about 5,000 light-years away, a colorful study in cosmic contrasts. It shares this nearly 1 degree wide field with open star clusterMessier 21 (top left). Trisected by dust lanes the Trifid itself is about 40 light-years across and a mere 300,000 years old. That makes it one of the youngest star forming regions in our sky, with newborn and embryonic stars embedded in its natal dust and gas clouds. Estimates of the distance to open star cluster M21 are similar to M20's, but though they share this gorgeous telescopic skyscape there is no apparent connection between the two. M21's stars are much older, about 8 million years old. M20 and M21 are easy to find with even a small telescope in the nebula rich constellation Sagittarius. In fact, this well-composed scene is a composite from two different telescopes. Using narrowband data it blends a high resolution image of M20 with a wider field image extending to M21.
Image Credit & CopyrightMartin Pugh

M81 Galaxy Group through the Integrated Flux Nebula

Distant galaxies and nearby nebulas highlight this deep image of the M81 Group of galaxies. First and foremost in this 80-exposure mosaic is the grand design spiral galaxy M81, the largest galaxy in the image, visible on the lower right. M81 is gravitationally interacting with M82just above it, a large galaxy with an unusual halo of filamentary red-glowing gas. Around the image many other galaxies from the M81 Groupof galaxies can be seen, as well as many foreground Milky Way stars. This whole galaxy menagerie is seen through the glow of anIntegrated Flux Nebula (IFN), a vast and complex screen of diffuse gas and dust also in our Milky Way Galaxy. Details of the red and yellow IFN, digitally enhanced, were imaged by a new wide-field camera recently installed at theTeide Observatory in the Canary Islands ofSpain.
Image Credit & Copyright : D. Lopez & A. Rosenberg, IAC

Sunday, June 25, 2017

The N44 Superbubble

What created this gigantic hole? The vastemission nebula N44 in our neighboring galaxy the Large Magellanic Cloud has a large, 250light-year hole and astronomers are trying to figure out why. One possibility is particle windsexpelled by massive stars in the bubble's interior that are pushing out the glowing gas. This answer was found to be inconsistent with measured wind velocities, however. Another possibility is that the expanding shells of oldsupernovas have sculpted the unusual space cavern. An unexpected clue of hot X-rayemitting gas was recently been detected escaping the N44 superbubble. The featured image was taken in three very specific colors by the huge 8-meter Gemini South Telescope onCerro Pachon in Chile.
Image Credit & CopyrightGemini Obs.AURA,NSF

Hubble uses Gravitational Lens to Capture Disk Galaxy

Acting as a “natural telescope” in space, the gravity of the extremely massive foreground galaxy cluster MACS J2129-0741 magnifies, brightens, and distorts the far-distant background galaxy MACS2129-1 in the upper-right corner of this image. (View an annotated image highlighting the gravitationally-lensed galaxy.)

By combining the power of this "natural lens" in space with the capability of NASA's Hubble Space Telescope, astronomers made a surprising discovery—the first example of a compact yet massive, fast-spinning, disk-shaped galaxy that stopped making stars only a few billion years after the big bang.  Finding such a galaxy early in the history of the universe challenges the current understanding of how massive galaxies form and evolve, say researchers. This is the first direct observational evidence that at least some of the earliest so-called "dead" galaxies — where star formation stopped — somehow evolve from a Milky Way-shaped disk into the giant elliptical galaxies we see today.

Read more: Hubble Captures Massive Dead Disk Galaxy that Challenges Theories of Galaxy Evolution

Image Credit: NASA, ESA, M. Postman (STScI), and the CLASH team

Hubble Space Telescope

Markarian's Chain to Messier 64

Top to bottom, this colorful and broad telescopic mosaic links Markarian's Chain of galaxies across the core of the Virgo Cluster to dusty spiral galaxy Messier 64. Galaxies are scattered through the field of view that spans some 20 full moons across a gorgeous night sky. The cosmic frame is also filled with foreground stars from constellations Virgo and the well-groomed Coma Berenices, and faint, dusty nebulae drifting above the plane of the Milky Way. Look carefully for Markarian's eyes. The famous pair of interacting galaxies is near the top, not far from M87, the Virgo cluster's giant elliptical galaxy. At the bottom, you can stare down Messier 64, also known as the Black Eye Galaxy. The Virgo Cluster is the closest large galaxy cluster to our own local galaxy group. Virgo Cluster galaxies are about 50 million light-years distant, but M64 lies a mere 17 million light-years away.
Image Credit & CopyrightRogelio Bernal Andreo (Deep Sky Colors)