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Subaru sees new light from Tycho’s 16th century supernova

...astronomers using the Subaru Telescope have observed light echoes from Tycho’s Supernova Remnant that provide new insight into the exploding star’s origin and type...

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A new class of comet?

...Lowell Observatory astronomer David Schleicher has uncovered a class of comet that bears extremely anomalous compositional characteristics, pinning its origin to just one of three places...

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New view of
Omega Centauri

...The European Southern Observatory has released a stunning new image of the “glittering giant of the southern skies”, Omega Centauri, the most massive of all our Galaxy’s globular clusters...

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Video archive

STS-120 day 2 highlights

Flight Day 2 of Discovery's mission focused on heat shield inspections. This movie shows the day's highlights.


STS-120 day 1 highlights

The highlights from shuttle Discovery's launch day are packaged into this movie.


STS-118: Highlights

The STS-118 crew, including Barbara Morgan, narrates its mission highlights film and answers questions in this post-flight presentation.

 Full presentation
 Mission film

STS-120: Rollout to pad

Space shuttle Discovery rolls out of the Vehicle Assembly Building and travels to launch pad 39A for its STS-120 mission.


Dawn leaves Earth

NASA's Dawn space probe launches aboard a Delta 2-Heavy rocket from Cape Canaveral to explore two worlds in the asteroid belt.

 Full coverage

Dawn: Launch preview

These briefings preview the launch and science objectives of NASA's Dawn asteroid orbiter.

 Launch | Science

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Hubble’s snow globe of stars

Posted: 05 December, 2008

Like a shaken snow globe of sparkling snow flakes frozen in time, Hubble has captured an instantaneous glimpse of the thousands of glittering stars moving about the globular cluster M13.

M13 is a densely packed globular cluster located 25,000 light years away. Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

M13 is one of the brightest and best-known globular clusters in the northern sky, and is easily located in the winter sky in the constellation Hercules. It is home to a metropolis of over 100,000 stars that are packed so closely together, especially in the central regions where the density of stars is about a hundred times greater than the density in the neighborhood of our Sun, that they occasionally slam into each other and form a new star, known as a blue straggler.

Blue stragglers are hotter and bluer than any other blue stars of the same luminosity in a given cluster, leading astronomers to believe that they underwent an unusual evolution. Since they are frequently observed in densely packed globular clusters, their genesis was attributed to stellar collisions. In contrast, the brightest red stars in the cluster are ancient red giants, aging stars that have expanded to many times their original diameters and subsequently cooled.

Globular clusters can be found in a vast halo around our Galaxy and M13 is one of nearly 150 known globular clusters surrounding our Milky Way. Globular clusters contain some of the oldest stars in the Universe. They likely formed before the disc of our Milky Way, so they are older than nearly all other stars in our galaxy. Studying globular clusters therefore tells us about the history of our Galaxy.

The newly released image is a composite of archival Hubble data taken with the Wide Field Planetary Camera 2 and the Advanced Camera for Surveys. Observations from four separate science proposals taken in November 1999, April 2000, August 2005, and April 2006 were used to construct the image, which includes broadband filters that isolate light from the blue, visible, and infrared portions of the spectrum.

Hubble has been in operation for over 18 years, and this week NASA officials announced that the delayed mission to repair and replace vital components on the troubled space telescope has been rescheduled for 12 May 2009.