WASHINGTON — Astronomers have found 32 new planets outside our solar system, adding evidence to the theory that the universe has many places where life could develop.

Scientists using European Southern Observatory telescopes didn’t find any planets quite the size of Earth or any that seemed habitable or even unusual. But their announcement increased the number of planets discovered outside the solar system to more than 400.

Six of the newly found planets are several times bigger than Earth, increasing the population of so-called SuperEarths by more than 30 percent. Most planets discovered so far are far bigger — Jupiter-sized or even larger.

Two of the newly discovered planets were as small as five times the size of Earth and one was up to five times larger than Jupiter.

Astronomer Stephane Udry of the University of Geneva said the results support the theory that planet-formation is common, especially with certain type of common stars.

“I’m pretty confident that there are Earth-like planets everywhere,” Udry said in a Web-based news conference from a conference in Portugal. “Nature doesn’t like a vacuum. If there is space to put a planet there, there will be a planet there.”

What astronomers said is especially exciting is the high percentage — about half — of a type of star systems with relatively light stars that had planets around them. This is more than planet-formation theory expected, astronomers said.

Two of the four planets found around these type stars were relatively close to Earth size, said astronomer Xavier Bonfils of Grenoble Observatory in France.

The discoveries were made by the High Accuracy Radial Velocity Planet Searcher, which looks for slight wobbles in a star’s movements, which would be made by the tug of a planet’s gravity on the star.

There are no photos of these planets.

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On the Net

European Southern Observatory: www.eso.org