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Gravity-Bent Starlight Reveals a New Planet
dfab writes "The first experimental proof of Einstein's general theory has been revamped to discover planets around distant stars. Yesterday astronomers announced that a new technique called gravitational microlensing has found a star that hosts a roughly Jupiter-sized planet in a roughly Jupiter-sized orbit by observing its effect on the light from a bright star beyond that planetary system. See the NASA report or the gory details."
Space.com also had an article about this yesterday. It gives a little better timeline to when it will be available to check low mass stars in the future, as well as doing a comparision on other extrasolar planetary detection techniques.
For those who want a quick excerpt of the science:
Gravitational microlensing uses a distant star (or other massive object) to bend light the same way as a lens would. If that star is perfectly aligned with an even more distant star (from our perspective) then the lens will call the more distant star to brighten, at least for as long as the alignment lasts.
The brightening comes with a spike (from "caustics" which are like irregularities in the lens), as the alignment gets good and them bad again. If you see a second, smaller spike, or an unusual extra image, that's evidence of a planet.
I'm not sure how you distinguish planets from weird caustics.
Note: this technique is good for detecting planets with long-period orbits, whereas the doppler-shift techniques are lousy for that, because they only work if the planet's revolution period is small (like in days).