New planets discovered

     The researchers using the new Anglo-Australian telescope located in Australia have discovered the first new planets using the instrument. The planets, large jupiter like bodies, have been found in the neighborhood (in galatic terms) of our own solar system. Unlike Jupiter in our solar system, the planets orbit close to their suns, two, including one giant twice the size of Jupiter, are in a near earth orbit, another referred to as 'hot Jupiter' orbits at great speeds, circling its sun in an orbital year lasting only 3 days, and is located only a scorching 6 million kilometers from its sun (less than one twentieth of the distance from earth to the sun).

     At present astronomers are not able to detect objects much smaller than Jupiter. Current instruments are sensitive enough to be able to detect the wobbling caused in a star by the gravitational tug of such large objects as they circle the planet, and so far about 50 of these massive planets have recorded. Planets of this size, even when in near earth orbit in a temperate region around the star, are unlikely to be able to support life (no human being could survive the crushing gravitational pull that exists on the surface of a gas giant like Jupiter.) Most of these giants that have been detected are in closer orbits to their suns than Jupiter, Saturn, and the other gas giants in our system, which is bringing into question conventional theories about planet formation (which suggested, based only on the limited evidence available from our system, that gas is expelled outwards in newly forming system, creating gas giants on the outer edges of the system, while rocky planets form nearer the sun). Gas giants closer to their suns cause more wobbling in the star, and are easier to detect, so whether or not stars with gas giants in close orbit are the norm, or simply what we are able to detect using current technology is a matter yet to be established, but even so the discovery is causing some rethinking about previous theories of the formation of solar systems.

     According to the researchers, the planets are detected by using instruments sensitive enough to detect a doppler shift in the light of the star as small as 3 meters per second. If a star is being tugged in a direction towards the earth the light is doppler shifted to shorter blue wavelengths and towards longer, red wavelengths when the star is tugged in a direction away from the earth. A large enough planet orbiting a star will create this doppler shift and by measuring the time and the amount of the shift it is possible to calculate the size, orbital period and distance from the star or the orbiting object. A planet like Jupiter in our system causes a wobbling effect in the sun of about 12.5 meters per second over its 12 year orbital period. The method is not sensitive enough at present to detect object the size of earth, which produce no measurable doppler effects.