TNRTB Archive – Retained for reference information
An international team of astronomers has proven the viability of a new technique for measuring solar system design. Until now, astronomers had been limited to studying only large extrasolar planets in their quest to determine how fine-tuned our solar system must be for life. Now, gravitational microlensing has been shown capable of detecting extrasolar planets as small as Earth. A foreground star perfectly aligned with a distant star and with the astronomers’ telescope will act as a powerful gravitational lens, making the astronomers’ telescope up to 1,000 times more powerful. The team found a foreground star that magnified the light of a distant star by 500 times. Then, by carefully searching for distortions in the lensing effect of the foreground star the team was able to rule out the existence of certain-sized planets orbiting the foreground star. For the star under observation, for varying ranges of distances from the star, any planet ranging from 1.3 times the mass of Earth to planets many times the mass of Jupiter would be detected. None were. Future exploitation of this technique will determine just how rare are Earth-sized planets orbiting in systems nearly identical to the solar system.
- F. Abe et al., “Search for Low-Mass Exoplanets by Gravitational Microlensing at High Magnification,” Science 305 (2004): 1264-66.
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