5/19/2006

Neptune Times 3

Scientists from the Geneva Observatory have announced the discovery of a planetary system 41 lightyears away orbiting the star HD 69830 in the Puppis constellation. Announcements of the discovery of extrasolar planetary systems have become rather commonplace these days, but this one differs in several ways. Firstly, they've discovered three planets in this system. That in and of itself is not all that spectacular. These three planets however fall in a range of 10 to 18 times the mass of the Earth (about the size of Neptune). That places them amoungst the smallest extrasolar planets discovered thus far. Further, these three planets are not the ubiquitous gas giants most often discovered. they are all rocky bodies, terrestrial planets. The inner two orbit at a range that would indicate that their surface temperatures would be blisteringly hot. The third however orbits at a range that scientists call the "Goldilocks zone"... A distance not too far and yet not too close to preclude the existence of liquid water on the planet's surface. Thus far, scientists have not however proven the existence of liquid water on this planet. The scientists have also confirmed that this planetary system also has an asteroid belt like our sun.

Extrasolar planetary systems have been discovered by two methods. The first method detects the presence of planets by observing the wobble of the star as the planet's gravitational pull tugs at the star during the planet's orbit. The second method detects planetary bodies by detecting the occultation of the star's light when the planet moves between the star and an Earth-bound observer. This second method requires that the planet orbit on a plane perpendicular to the observer. Because of this, it is the less used of the two methods. These three planets were dicovered using the first method.

41 light years is relatively close in our stellar neighborhood, but it is none-the-less an insurmountable distance for us humans to traverse. To put things in perspective, the fastest spacecraft to date was the Helios 1 & 2 space probes which reached a blistering 252,800 km/h (158,000 mph). If it were possible to make the trip at this speed, it would still take about 173,757 years to reach the HD 69830 system.

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