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Naked-eye gamma-ray burst aimed straight
for Earth

...six months ago the brightest gamma-ray burst ever seen from Earth was picked up by the SWIFT telescope, giving astronomers the most detailed portrait yet of a stellar explosion...

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Dark matter disc in Milky Way

...using the results of a supercomputer simulation, an international team of scientists predict that our Milky Way Galaxy contains a disc of dark matter that could be detected and identified by direct observations...

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Eta Carinae’s eruptions a multi-stage process

...the outbursts of Eta Carinae, could be driven by an entirely new type of stellar explosion that is fainter than a typical supernova...

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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 captures rare alignment

Posted: September 17, 2008

Just weeks before Hubble is due for an upgrade, the Hubble team have released this image of a rare alignment between two spiral galaxies, bringing to life the normally invisible tentacles of dust that extend further beyond the visible disc than previously thought.

Hubble captured this image of a small galaxy silhouetted in front of a larger galaxy on 19 September 2006. Lanes of dust extend from the small galaxy's visible edge. Image: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

The snap shot was captured purely by chance; astronomers were using Hubble to study galaxy NGC 253, to which most of the stars scattered across the foreground of the image belong. The two galaxies looked like a single ‘blob’ from ground based telescopes, but the Advanced Camera on Hubble resolved the nucleus into two separate galaxies that although appear close together, are not close enough to interact with each other. The background galaxy is now known to be about the size of the Milky Way Galaxy and is about 10 times larger than the foreground galaxy. Together they are classified as 2MASX J00482185-2507365 and are estimated to lie 780 million light-years away.

The chance arrangement of a small galaxy silhouetted against a larger background galaxy will greatly improve astronomers’ understanding of the structure of galaxies, since they have never before seen dust extend so far out from the visible edge of a galaxy. Moreover, the tracks of dust extending from the smaller galaxy appear to be completely devoid of stars.

Given the vast cavern of space there is usually nothing positioned so fortunately to allow the right illumination conditions, so it is not yet known if these dusty structures are common features in all galaxies. Astronomers will have to play the waiting game to find out.

The fourth and final Hubble servicing mission is now due for launch on 10 October; you can read more about the mission and the planned upgrades in the October issue of Astronomy Now.