Discovering New Planets

by Lisa Cardy

PLANETARY science has been rocked by the discovery of something that shouldn't exist. A gargantuan 'planet' has frightened experts who thought that they had Mother Nature all worked out and sent them back to the drawing board on how planets are formed.

The scientists from the University of California, Berkeley, USA, say two objects, one of which may be the biggest planet ever found, 17 times larger than Jupiter, are circling a star 123 light-years from Earth.

The surprises don't stop there: in another system, two planets are orbiting a star in a gravitationally synchronised 'dance'. The planets are gravitationally locked to each other in what is termed a resonate orbit. One circles the star every 30 days, and the other takes 60. Experts admit that they have no idea how the planets came to be moving together in this way.

These discoveries were announced at a meeting of the American Astronomical Society in San Diego recently and have sent shock waves through the science community. 'We thought we had our labels straight, but Mother Nature seems to have other ideas,' said Alan Boss, a Carnegie Institution astronomer.

The natural world occasionally throws up surprises, such as the discovery of fish, thought to have been extinct for millions of years, on sale in a market. But such discoveries, and their localised impact, pale into relative insignificance in the light of this announcement with its galactic implications.

Stars form when a cloud of dust and gas collapses under its own weight. A planet is created from the debris and fallout, or so astronomers think. It's doubtful that the enormous 'planet' could have amassed enough material to become so large so quickly. It suggests that there is at least one more way of creating a planet than astronomers know about. This also leads to the possibility that there may be lots more planets than scientists think there are.