Just like teenagers, black holes undergo an adolescent growth spurt, astronomers have found.

Observations from the Gemini North telescope on Mauna Kea have helped confirm the rapid growth of black holes when the universe was relatively young.

The research results, announced yesterday and soon to appear in the Astrophysical Journal, show that black holes began to swell rapidly in size when the universe was about 1.2 billion years old, less than 10 percent of its current age.

Most mature galaxies in the universe, including the Milky Way, harbor super-massive black holes, varying in mass from about 1 million to about 10 billion times the size of the sun. To find them, astronomers look for the enormous amount of radiation emitted when gas falls into them.

Using data from Gemini and another observatory in Chile, scientists at Tel Aviv University calculate that the black holes began growing fast when they were only 100 to 1,000 times the mass of the sun. The growth spurt lasted 100 to 200 million years.