24
May 11

Black holes spin faster and faster

Source: Royal Astronomical Society


Artist’s impression of  jets emerging from a supermassive black hole.
Credit: Dana Berry / STScI

Two UK astronomers have found that the giant black holes in the centre of galaxies are on average spinning faster than at any time in the history of the Universe. Dr Alejo Martinez-Sansigre of the University of Portsmouth and Prof. Steve Rawlings of the University of Oxford made the new discovery by using radio, optical and X-ray data. They publish their findings in the journal Monthly Notices of the Royal Astronomical Society.(read more)

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24
May 11

Kepler’s Astounding Haul of Multiple Planet Systems

Source: Kepler@NASA


Kepler's discoveries. Image credit: NASA/Wendy Stenzel.

NASA’s Kepler spacecraft is proving itself to be a prolific planet hunter. Within just the first four months of data, astronomers have found evidence for more than 1,200 planetary candidates. Of those, 408 reside in systems containing two or more planets, and most of those look very different than our solar system.

In particular, the Kepler systems with multiple planets are much flatter than our solar system. They have to be for Kepler to spot them. Kepler watches for a planet to cross in front of its star, blocking a tiny fraction of the star’s light. By measuring how much the star dims during such a transit, astronomers can calculate the planet’s size, and by observing the time between successive events they can derive the orbital period – how long it takes the planet to revolve around its star.

To see a transit, the planet’s orbit must be edge-on to our line of sight. To see multiple transiting planets, they all must be edge-on (or nearly so).(read more)

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24
May 11

Satellites monitor Icelandic ash plume

Source: ESA News

 

As Iceland's Grímsvötn volcano spews ash high into the atmosphere, satellite observations are providing essential information to advisory centres assessing the possible hazards to aviation.(read more)

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