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Fraser
2005-May-23, 04:21 PM
SUMMARY: Two amateur astronomers from New Zealand, working with a team of astronomers from around the world have helped to discover an extrasolar planet 15,000 light years from Earth. They used a technique known as gravitational microlensing, which occurs when a massive object (like a star or even a black hole) passes in front of a more distant star; its gravity bends and focuses light like a lens. The team noticed that the closer star had a strange pattern of distortion to its light that indicated a planet. This method could be used to find much smaller, even Earth-sized, planets.

View full article (http://www.universetoday.com/am/publish/amateurs_help_extrasolar.html)

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Greg
2005-May-24, 02:09 AM
This is fascinating stuff. I would like to know more details on how the procedure works, however. It sounds like a fair number of planets will be detected which will produce an abundance of information on planetary systems. Curiously this technique will not help us learn about the stars that we would be most interested about, those nearest us. BTW, we can thank Einstein for the original idea now being put into practice.

Nereid
2005-May-24, 12:07 PM
This website (http://www.nd.edu/~srhie/MPS/) gives some more details; a website with maths (http://www.physics.fsu.edu/Courses/spring98/AST3033/Micro/lensing.htm).

wstevenbrown
2005-May-24, 12:15 PM
It works pretty well in SF, also. In larry Niven's "Tales of Known Space" series of novels, the anti-hero Phthisspok uses a micro-BH for a lens. With a focal length of several hundreds of miles, he got pretty good magnification without having to mess with finicky glass optics. No central obstruction, either.

Best regards-- Steve

piersdad
2005-May-24, 08:04 PM
The two New Zealand astronomers were on N Z T V news this day
they both look as if they have many years of more brilliant work ahead of them.

the way it was described on how they found this 1 in a million chance was a sort of astigmatisim in the gravity lense.

It was the amount of distortion that determined the gravity infuence of the orbiting planet.