BERKELEY, California (AP) -- A startling image of a planet passing in front of a bright star has confirmed what scientists before only could deduce with math -- there are planets beyond our solar system.

"This is the first independent confirmation of a planet," said Geoffrey Marcy, a professor of astronomy at the University of California at Berkeley. "It also gives us the first-ever measure of the size of one of these planets."

Marcy's planet-hunting team had gathered mathematical evidence of 19 planets but could only infer their existence by measuring the wobble of nearby stars caused by the planets' gravity as they orbit.

That changed last week.

Marcy and his colleagues first detected a wobble in the star HD 209458, in the constellation Pegasus, on November 5 from the Keck Telescope atop Hawaii's Mauna Kea.

The team notified astronomer Greg Henry of Tennessee State University, who operates a cluster of remote-controlled telescopes in the Patagonia Mountains of Arizona.

Henry focused one automatic telescope on the star, and observed it dimming visibly as the planet crossed in front of it -- just as Marcy's scientists had predicted.

The star's radiance dimmed 1.7 percent on Nov. 7. On Thursday, it happened again, seemingly verifying the scientists' calculations that the planet orbits its star every 3.523 days. Henry is predicting the same dimming next Thursday and again November 22.

"We've essentially seen the shadow of the planet," Henry said.

Marcy's team determined the planet to be a "gas giant," similar to Jupiter, but its mass is just 63 percent of Jupiter's while it is 60 percent wider.

A gas giant could not have formed so close to a star, Henry said, which supports the theory that "extra-solar planets very near their star did not form where they are, but formed farther out and migrated inward."

The star HD 209458 lies 153 light-years from Earth -- almost a million billion miles. It is near the star 51 Pegasi, around which the first extra-solar planet was discovered in 1995.

"With this one, everything hangs together," Marcy said. "This is what we've been waiting for."