Astronomy Picture of the Day
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 September 19 
Posted on 09/19/2003 1:36:25 PM PDT by petuniasevan
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2003 September 19
Explanation: Launched in 1989 and looping through the jovian system since late 1995, the voyage of NASA's Galileo spacecraft will soon come to an end. The spacecraft has been targeted to plunge directly into Jupiter this Sunday, September 21st, at about 30 miles per second. Its components will be vaporized in the gas giant's outer atmosphere. While Galileo's long voyage of exploration has resulted in a spectacular scientific legacy, the spacecraft's ultimate fate is related to perhaps its most tantalizing discovery -- strong evidence for a liquid ocean beneath the frozen surface of Jupiter's moon Europa. Galileo is now almost completely out of fuel for maneuvers, so this intentional collision with Jupiter will prevent any unintentional future collision with Europa and the possibility of contaminating the jovian moon with microbes from Earth hardy enough to survive in interplanetary space. Color image data from the Galileo mission recorded between 1995 and 1998 was used to create this depiction of Europa's cracked and icy surface. The inset shows dark reddish, disrupted regions dubbed Thera and Thrace.
Yes, it's time to say goodbye to the Galileo spacecraft. From its valuable images while enroute to Jupiter (Shoemaker-Levy 9 comet fragment impacts) to its encounters with asteroids to its detailed data on Europa, this craft has paid its way.
Original Caption Released with Image: These four images of Jupiter and the luminous night-side impact of fragment W of Comet Shoemaker-Levy 9 are different versions of an average of 8 images taken by the Galileo spacecraft of July 22, 1994. The frames that were averaged span about 30 seconds near 8:06 UT.
These four "averaged" images show the scene without and with (top and bottom) spatial filtering and contrast enhancement, and without and with (left and right) a latitude/longitude grid. Grid spacing is 30 degrees, with 230 degrees longitude centered. The terminator is at about 265 degrees. The impact location is about 43 degrees south, as predicted, and at 280 degrees longitude. The dark spots to the right of the flash are from previous impacts.
The Deep Sleep
The Surveyor probes were the first U.S. spacecraft to land safely on the Moon. In November, 1969, the Surveyor 3 spacecraft's microorganisms were recovered from inside its camera that was brought back to Earth under sterile conditions by the Apollo 12 crew.
The 50-100 Streptococcus mitis organisms survived launch, space vacuum, 3 years of radiation exposure, deep-freeze at an average temperature of only 20 degrees above absolute zero, and no nutrient, water or energy source. (The United States landed 5 Surveyors on the Moon; Surveyor 3 was the only one of the Surveyors visited by any of the six Apollo landings. No other life forms were found in soil samples retrieved by the Apollo missions or by two Soviet unmanned sampling missions, although amino acids - not necessarily of biological origin - were found in soil retrieved by the Apollo astronauts.)
Ever have "strep throat"? I have. Nasty infection. This bug or a variant strain (S. oralis, S. pneumoniae) is the guilty party. To think it survived 3 years of the above harsh conditions...ooh.
See also reactor-dwelling Deinococcus radiodurans. That weird name is even weirder in English: "Strange berry which withstands radiation".
Berry? Its appearance suggests one:
Read more about it at this link page:
Case Western Reserve University astronomers have announced the discovery of a new galaxy, termed Andromeda VIII. The new galaxy is so widespread and transparent that astronomers did not suspect its existence until they mapped the velocity of stars thought to belong to the well-known and nearby large Andromeda spiral galaxy and found them to move independently of Andromeda.
 An image of Andromeda with the position of Andromeda VIII marked in graphics by Case student Nancy Lin over a photo by Robert Gensler. |
"This is particularly exciting because it allows us to watch the ongoing growth of the nearby Andromeda galaxy from smaller galaxies," says Morrison.
The astronomers used Case's Burrell Schmidt telescope and the 3.5m WIYN telescope to identify the galaxy. Both telescopes are located at Kitt Peak National Observatory near Tucson, Ariz. NOAO is operated by the Association of Universities for Research in Astronomy (AURA) Inc., under a cooperative agreement with the National Science Foundation.
The newly found galaxy is being torn apart into streams of stars, which leaves a trail of stars that are strung out along the new galaxy's orbit around the Andromeda galaxy in the way a jet's contrail shows its route. Andromeda is the nearest large spiral galaxy to our own Milky Way galaxy two million light years away. It is visible as a hazy glowing object to the naked eye in a dark sky in the northern hemisphere and is found in the constellation of Andromeda.
Discovered over 1,000 years ago by the Persian astronomer Azophi Al-Sufi, Andromeda is a member of the Local Group of approximately 30 galaxies in the Milky Way's celestial backyard.
In early August, Morrison finished analyzing the data of these stars from the Andromeda celestial neighborhood. "I was amazed to find a new dwarf galaxy orbiting Andromeda. It is a 'see-thru' galaxy, which was only discovered once we obtained velocity measurements for some of its stars, said Morrison.
She adds that the reason Andromeda VIII escaped detection was the fact that it is located in front of the bright regions of Andromeda's galaxy disk.
Andromeda VIII's total brightness is comparable to that of Andromeda's well-known companion M32, a small nearby galaxy, but Andromeda VIII is spread over an area of the sky as much as ten times or more larger than M32. Its elongated shape is caused by Andromeda's gravitational pull, which has stretched it out due to the stronger gravity on the side nearest Andromeda.
Morrison and her collaborators also suggested that a very faint stream of stars, detected near the large Andromeda galaxy in 2001 by the Italian Astronmer R. A. Ibata and colleagues, was pulled off Andromeda VIII in an earlier passage around the parent galaxy. "Future research in this area should provide rich and fruitful results," stated Morrison.
Theory has predicted for decades that galaxies are assembled in a "bottom-up" process, forming first as small galaxies that later merge to form large ones.
"Since 1994, when Ibata and colleagues announced the discovery of a new satellite in the process of being swallowed by the Milky Way, we have been able to see the process taking place in our own galaxy," stated Morrison. "Now we find the same process in our nearest large neighbor."
She adds that now it looks like Andromeda is even more inundated by small galaxies than the Milky Way. Ibata and colleagues have taken deep images of Andromeda which show a rich collection of star streams wreathed about the galaxy. Morrison and her colleagues have now identified the source of one of these star streams. They plan future observations to connect the different star streams with their progenitors, and thus learn more about the properties of the companion galaxy, the Andromeda galaxy and its elusive dark matter halo, the unseen matter that is suspected to be present in the universe.
The galaxy research was supported by a five-year National Science Foundation Early Career Development Award.
The Burrell Schmidt telescope is part of Case's Warner and Swasey Observatory. The WIYN 3.5-meter telescope is a partnership of the University of Wisconsin, Indiana University, Yale University and the National Optical Astronomy Observatory (NOAO). NOAO is operated by the Association of Universities for Research in Astronomy (AURA) Inc., under a cooperative agreement with the National Science Foundation.
About Case Western Reserve University:
Founded in 1826 and shaped by the unique merger of an institute of technology and a liberal arts college. Case is distinguished by its strengths in education, research and service. Located in Cleveland and offering top programs in the Arts and Sciences, Dentistry, Engineering, Law, Management, Medicine, Nursing and Social Sciences, Case is among the world's leading research institutions.
Case Western Reserve University
The other half's alma mater.
I had no idea they did this kind of research.
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