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LUX dark matter detector

Detecting dark matter

The kind of matter and energy we can see and touch – whether it is in the form of atoms and molecules, or heat and light, only forms a tiny proportion of the content of the Universe, only about 5%. Over a quarter is dark matter, which is totally invisible but whose gravitational attraction can be detected; while over two thirds is dark energy, a force that pushes the Universe to expand ever faster.
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Comet ISON: full of surprises

29 November 2013

ISON/Sun from SDO
The Sun and Comet ISON seen by the Solar Dynamics Observatory this morning
Image credit: NASA/SDO

Lots of surprises from Comet ISON today!

UCL Physics & Astronomy's Francisco Diego spoke to the BBC last night about the comet, which seemed to have totally disappeared (presumably blasted to pieces) as it passed near the Sun, and was no longer visible to the Solar Dynamics Observatory (SDO).

But things have just got stranger. Francisco writes:

A few hours later, the SOHO spacecraft has detected ISON emerging on the other side of the sun, perhaps fainter than expected, but still following its predicted orbit and developing a new tail. A mystery why SDO failed to detect it.

This gives scientists a unique opportunity to study the interaction between the comet and the solar atmosphere. Whatever remains of the comet is still quite bright. My guess is that its nucleus has fragmented severely and this may produce a new very long tail of gas and dust. The coming hours and days will be full of interesting observations and speculations.

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Page last modified on 29 nov 13 16:33