The question of whether there is intelligent life on other planets has been a dead one up until now for one simple reason -- there weren't any other planets.

But a University professor found the first evidence that other planets do exist -- outside our solar system -- and announced his findings Friday after they were reported in the journal Nature.

The evidence shows the existence of two planets orbiting a dense star, or pulsar, in the Milky Way Galaxy about 1,300 light-years away in the direction of the constellation Virgo. A light-year is the distance light travels in one year -- about 5.9 trillion miles.

"There's nothing magic about it," said Alexander Wolszczan, professor of astronomy and astrophysics, adding that observation of the pulsar's activity and mathematics led him to the discovery.

Wolszczan said his original detection of the planets in 1992 was not as publicized because he wanted more data to back up his find. But now, he said, "There is no more doubt about it."

The planets are located in a system designated PSR125712, which is the set of coordinates that shows where the pulsar is located in the sky. Although not visible, even with powerful telescopes, the pulsar can be observed through the radio waves it periodically emits.

Wolszczan used a huge radio telescope located in Puerto Rico to monitor the radio waves. By measuring the irregularities in the pulsar's transmissions -- created by the planets' gravitational pull on the star -- the existence of the two planets was proven.

One planet appears to have 2.8 times the Earth's mass and orbit the pulsar every 98.2 days at about half the distance between the Earth and sun. The other planet, with at least 3.4 times Earth's mass, appears to orbit every 66.6 days at just more than one-third the distance between the Earth and sun.

"The story of planetary discoveries has been dramatic," Wolszczan said. "There have been a lot of false alarms."

But this time, the evidence seems to be concrete.

"On one side of the scale, it's astounding," said Robin Ciardullo, assistant professor of astronomy and astrophysics. "It's one of the holy grails people have been looking for."

Ciardullo said the pulsar's radio emissions are extremely regular, more accurate than anything existing on Earth. This makes the data clear, proving that the pulsar -- about the size of State College and spinning about 1,000 times per second -- has at least two planets and perhaps more, he said.

Although the pulsar and planets are not visible, they may provide the basis for further study of other systems, because the planets may have been formed differently than the planets in our solar system, Ciardullo said.

"There's a huge amount of science accessible," he said.

The Associated Press contributed to this report.