ADVERTISEMENT
Related topics

Astronomers Witness Birth Of A Galaxy For The First Time

January 6, 1987 GMT

PASADENA, Calif. (AP) _ Astronomers say they have detected starlight from the birth of a galaxy 12 billion years ago, which would mean galaxies kept forming long after the universe emerged from the ″Big Bang.″

″It’s probably the first forming galaxy we’ve seen, and if that’s right, galaxy formation is a much more extended process than heretofore imagined,″ said Stanislav Djorgovski of the Harvard-Smithsonian Center for Astrophysics.

While some astronomers believe the universe is much younger, Djorgovski and others believe it is about 20 billion years old.

ADVERTISEMENT

To them, the discovery that a galaxy was born from a collapsing cloud of gas and dust 12 billion years ago means galaxies were not all created at the same time shortly after the universe is believed to have formed in a massive explosion known as the Big Bang.

″That’s something very new and changes our conception of how galaxies form,″ Djorgovski said.

The discovery was announced Monday at the American Astronomical Society’s annual meeting by Djorgovski, James Liebert of the University of Arizona and Patrick McCarthy, Hyron Spinrad, Wil van Breugel and Michael Strauss, all of the University of California, Berkeley.

The object is too far away for positive identification, but scientists detected evidence that perhaps 1 billion suns ignited as a huge gas cloud collapsed under its own gravity 71 billion trillion miles, or 12 billion light years, from Earth. A light year is the distance light travels in one year, so the birth of the galaxy actually happened 12 billion years ago.

″We’re talking about the turn-on of an entire galaxy, or at least that’s what we think,″ Spinrad said. Stars form when the collapsing gas ″heats up to the point where it can turn on thermonuclear reactions,″ he said.

The researchers focused on the possible ″proto-galaxy,″ known as radio wave source 3C 326.1, with the Very Large Array radio telescope in New Mexico and with optical telescopes at Lick Observatory near San Jose and at the Multiple Mirror Observatory and Kitt Peak National Observatory in Arizona.

Using special filters, they detected mostly extreme blue light from the object and some other colors. The blue light indicates most of the object is a huge cloud of electrically charged hydrogen gas about three times bigger than our own Milky Way galaxy.

ADVERTISEMENT

The cloud is about 100 times brighter than the starlight, suggesting that the cloud is in the earliest stages of galaxy formation and will continue to collapse to spawn many more stars.

″It’s on its way to becoming a giant galaxy and hasn’t quite got there yet,″ Spinrad said.

The galaxy eventually might contain 10 billion stars, McCarthy said.

Djorgovski said the number of stars was hard to measure because using telescopes to detect light from the proto-galaxy is like trying to detect a 25-watt lightbulb on the moon.

The fact that 3C 326.1 is a powerful source of radio wave energy poses a problem for the idea that it is a proto-galaxy, Spinrad acknowledged.

Prevailing theory holds that such radio signals are produced when vast amounts of material are sucked into a black hole, an older star so dense that its gravity pulls in even light. The astronomers cannot explain how a black hole might exist, if one really does, within a newborn galaxy.

But McCarthy and Spinrad said some scientists believe very dense matter like a black hole can exist at the centers of young galaxies.

Two years ago, van Breugel theorized that a new galaxy might be formed by a collision between a cosmic jet of energized gas from dying stars and gas in a strange, luminous region of space known as Minkowski’s Object, located 240 million light years from Earth, much closer than 3C 326.1

But Spinrad said Minkowski’s Object is much smaller and more completely formed than the possible proto-galaxy and really may be an older galaxy undergoing a burst of star formation.