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August 2, 2010 - Shining a Light on Dark Matter

Shining a Light on Dark Matter Dark matter makes up most of the material in the universe, while ordinary matter, which makes up stars and planets, comprises only a few percent of the material in the universe. Although dark matter itself cannot be observed directly, its existence in a galaxy cluster can be inferred by observing how its gravity bends the light of more distant background galaxies. The Hubble Space Telescope observed galaxy cluster CI 0024+17, some 5 billion light-years away, and discovered not only dark matter, but also its unexpected distribution in a ghostly ring shape, most likely caused by the long-ago collision of two clusters of galaxies. Nearly every object in the above image is a galaxy, with blue representing the distribution of the dark matter that distorts those background galaxies.

Image credit: NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

Weekly Calendar

August 2-8, 2010

Holidays - Sky Events - Space History

Moon phase Monday 2

1971: Apollo 15 lunar module Falcon leaves Moon in first televised lunar liftoff
1991: STS-43 Atlantis launched

Moon phase Tuesday 3

Last Quarter Moon 12:59 AM ET

2004: MESSENGER spacecraft launched to Mercury
2005: First in-flight space shuttle repair

Moon phase Wednesday 4

1967: NASA announces sixth astronaut class
1984: First Ariane 3 launched
2007: Phoenix Mars Lander launched

Moon phase Thursday 5

1930: Neil Armstrong born
1966: Final M2-F1 lifting body glide test
1969: Mariner 7 flies by Mars

Moon phase Friday 6

Mercury at greatest elongation (27° E)

1961: Vostok 2 launched, first full-day human space mission, Gherman Titov first person to sleep in space

Moon phase Saturday 7

1959: Explorer 6 launched
1969: Zond 7 launched
1980: Viking 1 orbiter ceases operation
1997: STS-85 Discovery launched

Moon phase Sunday 8

Ceres appears stationary

1978: Pioneer-Venus 2 launched
1989: Hipparcos observatory launched
1989: STS-28 Columbia launched
2001: Genesis spacecraft launched
2007: STS-118 Endeavour launched

Suggestions for new history dates or better links? Corrections for errors on this page? Please e-mail me.