Astronomy Picture

[aspundir]

[aspundir]

[aspundir]

[aspundir]

Few cosmic vistas excite the imagination like the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This stunning false-color view spans about 40 light-years across the region, constructed using infrared data from the Spitzer Space Telescope. Compared to its visual wavelength appearance, the brightest portion of the nebula is likewise centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But the infrared image also detects the nebula's many protostars, still in the process of formation, seen here in red hues. In fact, red spots along the dark dusty filament to the left of the bright cluster include the protostar cataloged as HOPS 68, recently found to have crystals of the silicate mineral olivine within its protostellar envelope.

[aspundir]

This image, taken on Dec. 31, 2013 by the AIA instrument on NASA's Solar Dynamics Observatory at 171 Angstrom, shows the current conditions of the quiet corona and upper transition region of the Sun.

[aspundir]

Located some 25 million light-years away, this new Hubble image shows spiral galaxy ESO 373-8. Together with at least seven of its galactic neighbors, this galaxy is a member of the NGC 2997 group. We see it side-on as a thin, glittering streak across the sky, with all its contents neatly aligned in the same plane. We see so many galaxies like this — flat, stretched-out pancakes — that our brains barely process their shape. But let us stop and ask: Why are galaxies stretched out and aligned like this? Try spinning around in your chair with your legs and arms out. Slowly pull your legs and arms inwards, and tuck them in against your body. Notice anything? You should have started spinning faster. This effect is due to conservation of angular momentum, and it’s true for galaxies, too. This galaxy began life as a humungous ball of slowly rotating gas. Collapsing in upon itself, it spun faster and faster until, like pizza dough spinning and stretching in the air, a disc started to form. Anything that bobbed up and down through this disk was pulled back in line with this motion, creating a streamlined shape. Angular momentum is always conserved — from a spinning galactic disk 25 million light-years away from us, to any astronomer, or astronomer-wannabe, spinning in an office chair.

[aspundir]

Saturn's moons create art on the canvas of Saturn's rings with gravity as their tool. Here Prometheus is seen sculpting the F ring while Daphnis (too small to discern in this image) raises waves on the edges of the Keeler gap. Prometheus (53 miles, or 86 kilometers across) is just above image center while Daphnis (5 miles, or 8 kilometers across), although too small to see in its location in the Keeler gap just to the right of center, can be located by the waves it creates on the edges of the gap. Prometheus and stars have been brightened by a factor of 2 relative to the rest of the image to enhance their visibility. There are 20 stars visible in this image. This view looks toward the unilluminated side of the rings from about 53 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Aug. 25, 2013. The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 111 degrees. Image scale is 7 miles (11 kilometers) per pixel. The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

[aspundir]

A team of astronomers has discovered enormous arms of hot gas in the Coma cluster of galaxies by usingNASA’s Chandra X-ray Observatory and ESA’s XMM-Newton. These features, which span at least half a million light years, provide insight into how the Coma cluster has grown through mergers of smaller groups and clusters of galaxies to become one of the largest structures in the universe held together by gravity. A new composite image, with Chandra data in pink and optical data from the Sloan Digital Sky Survey appearing in white and blue, features these spectacular arms. In this image, the Chandra data have been processed so extra detail can be seen. The X-ray emission is from multimillion-degree gas and the optical data shows galaxies in the Coma Cluster, which contain only about one-sixth the mass in hot gas. Only the brightest X-ray emission is shown here, to emphasize the arms, but the hot gas is present over the entire field of view. Researchers think that these arms were most likely formed when smaller galaxy clusters had their gas stripped away by the head wind created by the motion of the cluster through the hot gas, in much the same way that the headwind created by a roller coaster blows the hats off riders. Coma is an unusual galaxy cluster because it contains not one, but two giant elliptical galaxies near its center. These two giant elliptical galaxies are probably the vestiges from each of the two largest clusters that merged with Coma in the past. The researchers also uncovered other signs of past collisions and mergers in the data. From their length, and the speed of sound in the hot gas (about four million km/hr), the newly discovered X-ray arms are estimated to be about 300 million years old, and they appear to have a rather smooth shape. This gives researchers some clues about the conditions of the hot gas in Coma. Most theoretical models expect that mergers between clusters like those in Coma will produce strong turbulence, like ocean water that has been churned by many passing ships. Instead, the smooth shape of these lengthy arms points to a rather calm setting for the hot gas in the Coma cluster, even after many mergers. Large-scale magnetic fields are likely responsible for the small amount of turbulence that is present in Coma. Estimating the amount of turbulence in a galaxy cluster has been a challenging problem for astrophysicists. Researchers have found a range of answers, some of them conflicting, and so observations of other clusters are needed. Two of the arms appear to be connected to a group of galaxies located about two million light years from the center of Coma. One or both of these arms connects to a larger structure seen in the XMM-Newton data, and spans a distance or at least 1.5 million light years. A very thin tail also appears behind one of the galaxies in Coma. This is probably evidence of gas being stripped from a single galaxy, in addition to the groups or clusters that have merged there. These new results on the Coma cluster, which incorporate over six days worth of Chandra observing time, will appear in the September 20, 2013, issue of the journal Science. The first author of the paper is Jeremy Sanders from the Max Planck Institute for Extraterrestrial Physics in Garching, Germany. The co-authors are Andy Fabian from Cambridge University in the UK; Eugene Churazov from the Max Planck Institute for Astrophysics in Garching, Germany; Alexander Schekochihin from University of Oxford in the UK; Aurora Simionescu from Stanford University in Stanford, CA; Stephen Walker from Cambridge University in the UK and Norbert Werner from Stanford University in Stanford, CA. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Chandra Program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge,

[aspundir]

[aspundir]

Antares Rocket With Cygnus Spacecraft Launches

The Orbital Sciences Corporation Antares rocket, with the Cygnus cargo spacecraft aboard, is seen in this false color infrared image, as it launches from Pad-0A of the Mid-Atlantic Regional Spaceport (MARS), Wednesday, Sept. 18, 2013, NASA Wallops Flight Facility, Virginia. Cygnus is on its way to rendezvous with the space station. The spacecraft will deliver about 1,300 pounds (589 kilograms) of cargo, including food and clothing, to the Expedition 37 crew.