A Star with a Comet’s Tail
Astronomers using a NASA space telescope, the Galaxy Evolution Explorer, have spotted an amazingly long comet-like tail behind a star streaking through space. The star, named Mira after the Latin word for “wonderful,” has been a favorite of astronomers for about 400 years, yet this is the first time the tail has been seen.
Galaxy Evolution Explorer—“GALEX” for short—scanned the popular star during its ongoing survey of the entire sky in ultraviolet light. Astronomers then noticed what looked like a comet with a gargantuan tail. In fact, material blowing off Mira is forming a wake 13 light-years long, or about 20,000 times the average distance of Pluto from the sun. Nothing like this has ever been seen before around a star.
Researchers have used new lunar satellite images to pinpoint exactly where the Apollo 17 astronauts took their iconic photographs of the moon’s surface. That data has in turn allowed planetary scientists to build the most precise 3-D maps yet of the Apollo 17 mission site.
“We’re making these images more valuable by giving them incredibly accurate coordinates,” said planetary scientist Mark Robinson of Arizona State University. “The 3-D models of areas explored by astronauts may enable future exploration of these sites and allow us to better understand the observations they made at the time.”
Robinson and his team’s study of the Apollo 17 site was published online April 1 in the Journal of Geophysical Research.
2004: Launched in 1997, Cassini-Huygens eneters the orbit of Saturn in 2004 returning stunning images of the planet, its rings and its satellites.
Apollo 16 command and service module above the Moon.
M82: ”Survivor” Black Holes May Be Mid-Sized
This composite image of the nearby starburst galaxy M82 shows Chandra X-ray Observatory data in blue, optical data from the Hubble Space Telescope in green and orange, and infrared data from the Spitzer Space Telescope in red. The pullout is a Chandra image that shows the central region of the galaxy and contains two bright X-ray sources.
New studies with Chandra and ESA’s XMM-Newton show that these two sources may be intermediate-mass black holes, with masses in between those of the stellar-mass and supermassive variety. These “survivor” black holes avoided falling into the center of the galaxy and could be examples of the seeds required for the growth of supermassive black holes in galaxies, including the one in the Milky Way.
This is the first case where good evidence for more than one mid-sized black hole exists in a single galaxy. The evidence comes from how their X-ray emission varies over time and analysis of their X-ray brightness and spectra, i.e., the distribution of X-rays with energy.
One of the black holes (called “X42.3+59”) is located at a projected distance of 290 light years from the center of M82 (labeled with an “x”) and its mass is estimated to be between 12,000 and 43,000 times the mass of the Sun. At this close distance, if the black hole was born at the same time as the galaxy and its mass was more than about 30,000 solar masses, it likely would have been pulled into the center of the galaxy. That is, it may have just escaped falling into the supermassive black hole that is presumably located in the center of M82.
The second black hole (called “X41.4+60”) is located 600 light years in projection away from the center of M82. The best model for this M82 black hole has a mass between 200 and 800 times that of the Sun, and tilted at an angle between 60 and 80 degrees, meaning that the disk is viewed almost side-on. However, because of relativistic effects for a rapidly spinning black hole with this mass, a disk viewed at a high inclination is almost as bright as one viewed at a low inclination (i.e., face-on).
These results are interesting because they may help address the mystery of how supermassive black holes in the centers of galaxies form. M82 is located about 12 million light years from Earth and is the nearest place to us where the conditions are similar to those in the early Universe, with lots of stars forming.
Multiple observations of M82 have been made with Chandra beginning soon after launch. The Chandra data shown here were not used in the new research because the X-ray sources are so bright that some distortion is introduced into the X-ray spectra. To combat this, the pointing of Chandra is changed so that images of the sources are deliberately blurred, producing fewer counts in each pixel.
Susitna Glacier, Alaska by NASA Goddard Photo and Video
NASA image acquired August 27, 2009
Content below by NASA Goddard Photo and Video’s Flickr
“Like rivers of liquid water, glaciers flow downhill, with tributaries joining to form larger rivers. But where water rushes, ice crawls. As a result, glaciers gather dust and dirt, and bear long-lasting evidence of past movements.”
“Alaska’s Susitna Glacier revealed some of its long, grinding journey when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite passed overhead on August 27, 2009. This satellite image combines infrared, red, and green wavelengths to form a false-color image. Vegetation is red and the glacier’s surface is marbled with dirt-free blue ice and dirt-coated brown ice. Infusions of relatively clean ice push in from tributaries in the north. The glacier surface appears especially complex near the center of the image, where a tributary has pushed the ice in the main glacier slightly southward.”
“A photograph taken by researchers from the U.S. Geological Survey (archived by the National Snow and Ice Data Center) shows an equally complicated Susitna Glacier in 1970, with dirt-free and dirt-encrusted surfaces forming stripes, curves, and U-turns.”
“Susitna flows over a seismically active area. In fact, a 7.9-magnitude quake struck the region in November 2002, along a previously unknown fault. Geologists surmised that earthquakes had created the steep cliffs and slopes in the glacier surface, but in fact most of the jumble is the result of surges in tributary glaciers.”
“Glacier surges—typically short-lived events where a glacier moves many times its normal rate—can occur when melt water accumulates at the base and lubricates the flow. This water may be supplied by meltwater lakes that accumulate on top of the glacier; some are visible in the lower left corner of this image. The underlying bedrock can also contribute to glacier surges, with soft, easily deformed rock leading to more frequent surges.”
NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Michon Scott.
Instrument: Terra - ASTER
Credit: NASA Earth Observatory
Look closely and you’ll see two moving objects in this footage. The most obvious one is a meteor however, more subtly in the middle towards the top right, there’s a small object moving slowly up and that is a fuselage of a Russian rocket breaking up in the upper atmosphere.
1998: Few would recognise this as a part of the International Space Station (ISS), however this satellite was the first module of the ISS, from which the rest of it grew.