Extra solar planets

 

Star gazing in Sinai

Artist’s view of planet passing in front of its sun causing a slight dimming of its light and a wobble in its motion.

A minor star, τ Bootis, in the constellation of Bootes, has emerged from relative obscurity to instant celebrity by having a planet detected in orbit around it.

Since 1995, over 300 stars have been identified with accompanying planets.

Planets around other stars are not easy to see, their tiny light swamped by the brilliance of their mother star.

Astronomers, however, can measure the velocity of a star’s motion towards or away from us by analysing their light spectra, and recent advances in technology have allowed them to detect slight periodic variations in these motions caused by the gravitational effect of planets orbiting these stars.

Our solar system is no longer alone! We have been joined by other planetary families. But how odd they are!

Most of them have planets the size of Jupiter, orbiting at distances to their stars closer than Mercury to our sun.

These “Jupiters” are extremely hot gassy balls with little that would endear them to a bacterium, never mind a worm or an ape. We are still a long way from discovering extraterrestrial life.

These families, however, are probably just exceptions, picked up by a technology that is still too clumsy to detect smaller planets.

The hunt is now on for other worlds more like ours. The European Space Agency has launched COROT, a French satellite that is able to detect the slight dimming of the light from a star caused by a planet, even a small rocky one, passing across its face. In Feburary 2009, the mission was crowned with success when a small rocky planet, less than twice the size of Earth was detected in orbit round a star.

Its surface temperature, however, is estimated to be a sizzling 1000°C, enough to annihilate any tentative life form. The search continues.

This blog first appeared in the Cairo BCA Magazine for May 2009 to promote star gazing in Sinai with Yallajabaleya and an 8″ Meade LX90 Telescope

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