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Hubble Finds Ring of Dark Matter

hubblesite on 11/06/2007 at 10:52am (UTC)

Astronomers using NASA's Hubble Space Telescope have discovered a ghostly ring of dark matter that formed long ago during a titanic collision between two massive galaxy clusters. The ring's discovery is among the strongest evidence yet that dark matter exists. Astronomers have long suspected the existence of the invisible substance as the source of additional gravity that holds together galaxy clusters. Such clusters would fly apart if they relied only on the gravity from their visible stars. Although astronomers don't know what dark matter is made of, they hypothesize that it is a type of elementary particle that pervades the universe.

This Hubble composite image shows the ring of dark matter in the galaxy cluster Cl 0024+17. The ring-like structure is evident in the blue map of the cluster's dark matter distribution. The map was derived from Hubble observations of how the gravity of the cluster Cl 0024+17 distorts the light of more distant galaxies, an optical illusion called gravitational lensing. Although astronomers cannot see dark matter, they can infer its existence by mapping the distorted shapes of the background galaxies. The map is superimposed on a Hubble Advanced Camera for Surveys image of the cluster taken in November 2004.

Hubble Photographs Grand Design Spiral Galaxy M81

hubblesite on 11/06/2007 at 10:51am (UTC)

The sharpest image ever taken of the large "grand design" spiral galaxy M81 is being released today at the American Astronomical Society Meeting in Honolulu, Hawaii. A spiral-shaped system of stars, dust, and gas clouds, the galaxy's arms wind all the way down into the nucleus. Though the galaxy is located 11.6 million light-years away, the Hubble Space Telescope's view is so sharp that it can resolve individual stars, along with open star clusters, globular star clusters, and even glowing regions of fluorescent gas. The Hubble data was taken with the Advanced Camera for Surveys in 2004 through 2006. This color composite was assembled from images taken in blue, visible, and infrared light.

Hubble Photographs Grand Design Spiral Galaxy M81

hubblesite on 11/06/2007 at 10:51am (UTC)

STScI Appoints New Mission Head for the James Webb Space Telescope

hubblesite on 11/06/2007 at 10:50am (UTC)

	The Space Telescope Science Institute (STScI) has appointed Dr. Kathryn Flanagan as the James Webb Space Telescope (JWST) Mission Head. Dr. Flanagan will be responsible for the development and operations of the JWST Science and Operations Center at the STScI. The largest space observatory ever developed, the JWST is scheduled for launch in June 2013.

Astronomers Measure Mass of Largest Dwarf Planet

hubblesite on 11/06/2007 at 10:49am (UTC)

NASA's Hubble Space Telescope has teamed up with the W.M. Keck Observatory to precisely measure the mass of Eris, the largest member of a new class of dwarf planets in our solar system. Eris is 1.27 times the mass of Pluto, formerly the largest member of the Kuiper Belt of icy objects beyond Neptune.

Hubble observations in 2006 showed that Eris is slightly physically larger than Pluto. But the mass could only be calculated by observing the orbital motion of the moon Dysnomia around Eris. Multiple images of Dysnomia's movement along its orbit were taken by Hubble and Keck.

Hubble Images of Asteroids Help Astronomers Prepare for Spacecraft Visit

hubblesite on 11/06/2007 at 10:47am (UTC)

These Hubble Space Telescope images of Vesta and Ceres show two of the most massive asteroids in the asteroid belt, a region between Mars and Jupiter. The images are helping astronomers plan for the Dawn spacecraft’s tour of these hefty asteroids. On July 7, NASA is scheduled to launch the spacecraft on a four-year journey to the asteroid belt. Once there, Dawn will do some asteroid-hopping, going into orbit around Vesta in 2011 and Ceres in 2015. Dawn will be the first spacecraft to orbit two targets. At least 100,000 asteroids inhabit the asteroid belt, a reservoir of leftover material from the formation of our solar-system planets 4.6 billion years ago.

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