November 14, 2008
Extrasolar Planets Imaged for the First Time
No, this isn't political news. But it is one of the most significant scientific findings of the age.
Two different astronomers have, for the first time, been able to take a picture of alien planets circling a distant star:
Astronomers have taken what they say are the first-ever direct images of planets outside of our solar system, including a visible-light snapshot of a single-planet system and an infrared picture of a multiple-planet system.
Earth-like worlds might also exist in the three-planet system, but if so they are too dim to photograph. The other newfound planet orbits a star called Fomalhaut, which is visible without the aid of a telescope. It is the 18th brightest star in the sky.
The massive worlds, each much heftier than Jupiter (at least for the three-planet system), could change how astronomers define the term "planet," one planet-hunter said.
Previously, the 300 or so planets discovered have been found using a clever technique involving almost imperceptible changes in the mass of stars. As a planet goes around another star, there is a slight "wobble" in the orbit of that sun that can be measured thus indicating another body exerting gravitational influence on it. By measuring the size of the wobble, the mass of the planet can be determined.
To date, almost all the alien worlds discovered have been as large or larger than Jupiter, the largest planet in our own solar system. Finding worlds the size and composition of earth is a much more difficult undertaking given the extremely limited effect such a body would have on its parent star.
But this imaging of alien planets - made possible by a little gizmo placed on the Hubble Telescope by astronauts back in 2002 - is the first step toward viewing much smaller bodies, including earth-like planets. The James Webb Space Telescope, scheduled to be launched in 2013, is being designed to sniff out these earth like planets and could, before the next decade is out, discover planets where life is almost a certainty.