Dark Matter Distribution in the Abell 901/902 Supercluster
Astronomers assembled this photo by combining a visible-light image of the Abell 901/902 supercluster taken with the MPG/ESO 2.2-meter telescope in La Silla, Chile, with a dark matter map derived from observations with NASA’s Hubble Space Telescope. The magenta-tinted clumps represent a map of the dark matter in the cluster. Dark matter is an invisible form of matter that accounts for most of the universe’s mass. The image shows that the supercluster galaxies lie within the clumps of dark matter.
Hubble cannot see the dark matter directly. Astronomers inferred its location by analyzing the effect of so-called weak gravitational lensing, where light from more than 60,000 galaxies behind Abell 901/902 is distorted by intervening matter within the cluster. Researchers used the observed, subtle distortion of the galaxies’ shapes to reconstruct the dark matter distribution in the supercluster.
Americans spent about $7 billion on potato chips in 2012. We spent just under $18 million on NASA. That’s less than half of 1% of the national budget.
If this bothers you, you can and should write your Congressional representatives. penny4nasa.org
The Milky Way and Andromeda, From under a tree.
Source: OM3N1R (reddit)
I’d really like to organise a trip to Galloway forest park sometime during the next year, weather permitting. It’s just so difficult to organise observing trips in Scotland, the weather is so unpredictable!
Anyone on here been there before? Any advice?
I have my timetable for next year. During term 2 on Tuesdays I have a physics lecture on campus finishing at 11 and my astronomy labs, which are at the observatory 3 miles away, start at 11.
So I’m guessing that during term 1 we’ll be working on teleportation during the physics labs.
Heartening news of the day: Stanford’s Maryam Mirzakhani becomes the first woman to win the Fields Medal, the “Nobel Prize of mathematics.” In some distant galaxy, Maria Mitchell’s heart is bursting with joy.
Maria Mitchell - Scientist of the Day
Maria Mitchell, an American astronomer, was born Aug. 1, 1818, in Nantucket. Mitchell was the first professional woman astronomer in the United States and a role model for generations of aspiring women scientists. She was trained by her father, a school-teacher, and had the extreme good fortune to discover a comet in 1847. Not only was she the first to see the comet, she also had the mathematical skill to calculate its orbit. Her feat won her an international gold medal from the Danish government, the first such recognition for any American woman, and eventually, the professorship of astronomy at Vassar College, also the first such position for any woman. (It is probably of interest to some of this reading audience that, before she became famous, Mitchell spent 17 years as a librarian on Nantucket.) Mitchell was admitted to various male bastions, such as the American Academy of Arts and Sciences in Boston (the only woman so honored until the 20th century), but she decided early on that, instead of trying to show men that women could be good scientists, she would spend her life showing young women that they could be good scientists. She seems to have done a superb job at this task, becoming a legendary teacher at Vassar. Antonia Maury, a noted astronomer at Harvard, was one of her pupils. The lovely albumen print portrait of Maria above is at Harvard.
In 1863, Matthew Vassar, the founder of Vassar College, personally commissioned a telescope for Mitchell from Henry Fitz, a well-known New York telescope builder. With a lense 12 inches in diameter, it was second among American telescopes only to the great refractor at Harvard (see second image above). The telescope is now in the National Museum of American History in Washington. Vassar also built an observatory for Maria; a period photo can be seen above, just below the Fitz refractor.
The small telescope that Mitchell used to discover the Nantucket comet is now mounted in her childhood home on Vestal Street (see last photo above), across from the headquarters of the Maria Mitchell Association, the group her descendants founded in 1908 to continue Mitchell’s lifelong passion for the natural sciences and science education.
Dr. William B. Ashworth, Jr., Consultant for the History of Science, Linda Hall Library and Associate Professor, Department of History, University of Missouri-Kansas City
intrepid: Earthrise, photographed from Apollo 12, November 1969.
5 Hasselblad photographs, taken from lunar orbit, between 18th and 21st November.
Image credit: NASA/JSC, c/o LPI. Animation: AgeOfDestruction.