View Full Version : Icy Extrasolar Planet Discovered

2006-Jan-26, 06:20 AM
SUMMARY: Astronomers have discovered an extrasolar planet only 5 times larger than the Earth orbiting a star in the Sagittarius constellation. They used a technique called microlensing, where a star briefly passes in front of a more distant star, acting as a lens that magnifies its brightness. In this case, the planet passed in front of the star as well and created a second brightening that allowed astronomers to measure its mass. The planet is likely very cold, as it orbits about three times the distance of the Earth to the Sun, and its parent star is a colder red dwarf.

View full article (http://www.universetoday.com/am/publish/icy_extrasolar_rocky.html)
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2006-Jan-29, 02:41 PM
This is a very exciting discovery. It's kind of neat how probably the smallest known exoplanet is also the farthest away; this apparent irony is explained by the nature of the discovery technique, microlensing. It's amazing that we have come from ten years ago not knowing if other planets exist around main sequence stars to now knowing of 150 planets orbiting main sequence stars, including the first terrestrial planet. The implications are enormous: the existence of this planet indicates that the most common type of planetary system in the galaxy is a red dwarf star with terrestrial planet(s). I think it's now beyond reasonable dispute that the Fp term in the Drake equation is not going to be the limiting factor in terms of how many civilizations there may be.

Although ten percent of G-type stars are now known to have gas giants, gas giants are more complex/larger bodies-- from an entropy point of view it makes sense that they are not as common as smaller rocky worlds and asteroids. Theorist's intuitions proved right: it is easier for nature to put together small rocky planets than it is for nature to build gas giants. I predict that in another ten years--that is, in time for the twenty year anniversary of the discovery of the first exoplanet, we will know of hundreds of rocky worlds.

2006-Jan-31, 03:18 AM
And we may yet find planet Aurelia. Home of "stinger fans"—animals that look like tall plants, and giraffe-like predators called gulphogs and tiny flesh-dissolving tadpoles known as hysteria.

Or maybe the Blue Moon, another world, actually a moon which has a 240-hour day and orbits a huge planet in a solar system with two suns. With an atmosphere three times denser than Earth's, the Blue Moon has giant whales gliding through its sky.

One can only hope, right?

The Incredible Bloke
2006-Jan-31, 05:12 AM
I find it amazing that we can see any planets that distant, let alone that we will probably one day be able to see Earth-size planets.