3 million years to planet formation: astronomers

Earth-like planets may form around the cosmic dust swirling around a distant newborn star far more quickly than thought, astronomers say.

New telescope observations looked at the dusty disks that form around young stars. The cosmic dust and gas can either be absorbed into the star or collect into dense blocks and become planets.

Astronomers Elizabeth Lada of the University of Florida in Gainesville, and Karl Haisch of the University of Michigan in Ann Arbor concluded the beginnings of planets might form about three million years after the birth of stars three times faster than many scientists believe.

• FROM NOV. 28, 2002: Astronomers simulate formation of giant gas planets

Studies of giant gas planets like Jupiter suggest it takes at least 10 million years to form from the "protoplanetary disks" of dust and gas.

Lada and Haisch found many disks clustered together around stars about one million years old, but relatively few were found by the time stars were three million years old and none by six million years.

The pair used radio telescopes to examine dozens of young stars in the constellations Orion and Perseus about 1,000 light-years from Earth. (A light-year is about 10 trillion kilometres, the distance light travels in a year.) The researchers presumed the presence of a dust disk based on changes in infrared light coming from the stars.

Astronomer David Weintraub and his colleagues at Vanderbilt University in Nashville also reported X-ray mesurements of molecular hydrogen around young stars that may also support early planet formation. Protoplanetary disks are largely made of hydrogen.

The findings were reported on Monday and Tuesday at a meeting of the American Astronomical Society.