December 5, 2011
X-Treme Astronomy!
Dr Darren Baskill
Report by: Chris Sutcliffe
The main event of the Flamsteed Christmas evening was a lecture by Dr Darren Baskill who is well known to us as an Astronomy Learning Officer at Greenwich where he gives many planetarium shows and runs various short courses. His main role away from Greenwich is Outreach Officer at the Department of Physics and Astronomy for the University of Sussex, Brighton.
The subject of Darren’s lecture was ‘X-treme Astronomy’ and in opening his talk he mentioned that today was his birthday, and that his age was 19 years! After inviting suggestions as to why this should be, he revealed that he would be 19 if he lived on Mars (it takes Mars 687 of our days to orbit the sun).
The focus of his lecture was violent processes in the Universe.
We depend on ‘light’ (electro-magnetic radiation) to observe the Universe. Light is emitted by astronomical phenomena in various forms depending on the temperature of the phenomenon —
> -273C: microwaves
> up to 10,000 degrees C: visible light
> 100 million degrees C: X rays
> 10 billion degrees C: gamma rays
Telescopes, including orbiting space scopes, are built to observe different kinds (wavelengths) of electro-magnetic radiation. An X ray telescope shows hot gas at a temperature of over one million degrees.
ESA’s XMM-Newton spacecraft was launched in 1999 and the EPIC MOS camera on XMM-Newton was looked after by Darren before he came to Greenwich.
He showed a view of the Orion nebula M42 seen through a conventional telescope (visible light), a photo he had taken as a keen astro-photographer of this favourite object in the night sky. X-ray photography from XMM-Newton shows this to be a huge area of high temperature gas with new stars being formed (some only 1 million years old) giving massive bursts of X rays.
X-ray photography of Sirius from XMM-Newton is dominated by Sirius-B which it shows to be a white dwarf and very hot.
In 1999, NASA’s Chandra X ray observatory found the left-over core of a collapsed star, Cassiopeia A. In fact this may have been observed as a supernova in 1680 by John Flamsteed. The star collapsed into a neutron star which is still expanding today.
The Crab Nebula is the remains of a supernova which died in 1054 when a star collapsed and a neutron star came into existence.
Darren advised that he was searching for Black Holes. On one occasion during 8 hours of observing, he observed a flare for a period of 20 minutes, evidence of remains getting closer to a black hole and the temperature increasing very significantly. In 2007, he discovered 12 new black holes.
Seen through X-ray astronomy the Universe is a violent place!
Darren then moved on to a different kind of X-treme astronomy — his experience of observing at Hawaii, 27 hours travel from the UK. It’s hard work! At a height of 4.200 metres, there is no light pollution but whilst we are accustomed to a pressure of about 1,050 millibars at sea level, at the observatory in Hawaii, it is only 600 millibars. The observatory has the 8 metre Gemini telescope, and Darren was taking typically 30 minute exposures enabling him to have the opportunity of doing a number of 30 second exposures outside on his own camera.
After a Christmas refreshment interval, Dr Darren concluded the evening with a Planetarium show with a Christmas theme. He first showed the night sky in December, and then the Royal Observatory with animated snow, reindeer, and Father Christmas flying across the night sky. He concluded with the 12 days of Christmas (astronomy version!).
A great evening, with a great lecture, and a festive Planetarium show.
Posted under: Flamsteed, Flamsteed Lecture, Meeting Report
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