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Page history last edited by ar.fisk@... 13 years, 5 months ago

p 413

Mesosphere: "We ought to know the answer in a few years"..."We'll know when the Han finally launch that big interferometer of theirs. Until then talk is pointless."

They had been disputing whether any nearby stellar systems might have earth-like planets...


Stan shrugged "The Euro-Russian and American telescopes are quite old now, Elena. Yes, they've detected planets around nearby stars, but only giants like Jupiter and Saturn. Little rocky worlds like Earth are harder to find... like picking out the reflected glint of a needle next to a burning haystack, I should think."

Status: Disproved



While detecting the light of earth-like planets would be impossible with current technology, and the perturbation of a star by such specks would be imperceptible, there remains the fact that planets cast shadows.


An earth-like planet passing in front of its sun would cause a brief and very small drop in apparent brightness. This dip is detectable to current instruments.


This technique was used to detect the presence of Gliese 581c in 2007. It is 20 light years away, is estimated to be about 50% larger than Earth, and orbits at a distance that would allow the presence of  liquid water on the surface. I don't any has actually been detected, however.


A similar technique can be used to detect atmospheric compounds (from the absoprtion patterns imprinted on the sunlight as it passes through the atmosphere at the planet's limb. It has been used to detect sodium


On March 5, 2009, the Kepler observatory was launched. It is intended to hunt for other earth-like planets.


So, there is at least one earth like planet out there, and we probably won't have to wait for the Han to detect others.

As a consolation, however, David does predict the detection of Jupiter mass exoplanets. The first of these was discovered at PSR1257 in 1991, two years after publication.




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