Scientists using NASA’s Swift satellite have detected a new kind of cosmic explosion. The event appears to be a precursor to a supernova, which is expected to reach peak brightness in about a week’s time. Astrophysicists around the world are watching closely as they have never seen an explosion of this kind before.

Satellites and the world’s largest telescopes are now trained on the sight, watching and waiting. The explosion has the trappings of a gamma-ray burst (GRB), the most distant and powerful type of explosion known. Yet this explosion, detected on February 18 2006, was very much closer and 100 times longer than the typical gamma-ray burst. And it possesses characteristics never seen before.

Dr Julian Osborne, lead investigator for Swift at the University of Leicester said “The bright X-ray source seen when Swift slewed to the burst varied rather slowly for about 40 minutes, quite different to the very rapid decline of more normal GRBs. It did later decline much more rapidly, like a normal GRB, so the challenge will be to find a physical description of the explosion expanding into the host galaxy gas which matches this new pattern”

“This is totally new and unexpected,” said Neil Gehrels, Swift principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Md. “This is the type of unscripted event in our nearby universe that we hoped Swift could catch.”

The explosion, called GRB 060218 after the date it was discovered, originated in a star-forming galaxy about 440 million light-years away toward the constellation Aries. This is the second-closest gamma-ray burst ever detected, if indeed it is a true burst.

The burst of gamma rays lasted for nearly 2,000 seconds; most bursts last a few milliseconds to tens of seconds. The explosion was surprisingly dim, however,given its relative closeness, suggesting that scientists might be viewing the event slightly off-axis. Yet this is just one explanation on the table. The standard theory for gamma-ray bursts is that the high-energy light is beamed in our direction.

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February 27th, 2006 | General Science | No comments

At the latest meeting of the European Space Agency’s Earth Observation Programme Board, which took place at ESA’s Headquarters in Paris on 23 and 24 February, ESA received the green light from its Member States to build and launch a CryoSat recovery mission, CryoSat-2.

The launch of the CryoSat spacecraft was unfortunately aborted on 8 October 2005 due to a malfunction of its Rockot launcher, which resulted in the total loss of the spacecraft.
“This decision is very important, as the scientific community in Europe and elsewhere is eagerly awaiting resumption of the CryoSat mission. We are happy to have obtained approval today”, said Volker Liebig, ESA Director of Earth observation programmes.

A CryoSat recovery plan was presented to the Programme Board by ESA’s Executive, which explained the status of ongoing activities and outlined the preparatory work leading to a CryoSat-2 mission, expected to be launched in March 2009.

CryoSat-2 will have the same mission objectives as the original CryoSat mission; it will monitor the thickness of land ice and sea ice and help explain the connection between the melting of the polar ice and the rise in sea levels and how this is contributing to climate change.

The positive decision on CryoSat-2 will allow rational use to be made of the technical and industrial competences for the original mission, as well as best use of the ground segment facilities and operational setup planned for that first mission. It means that the pre-launch scientific validation campaigns over land ice and sea ice can resume with the support of national institutes.

February 26th, 2006 | General Science | No comments