Hubble, bubble, galactic toil and trouble

Debris in this rising geyser could eventually rain down on the galactic core.

By Richard Stenger
CNN

(CNN) -- Periodically blowing its top like a cosmic Old Faithful, a galactic geyser is spewing hot gas and glowing debris in a sensational burst captured by the Hubble Space Telescope.

Intense explosions heralding the birth and death of stars most likely generated winds that blew the boiling bubble of energy and matter "skyward" for thousands of light years from the heart of the galaxy, said Hubble astronomers.

Swirling around above the galactic disk, the glowing filaments will eventually rain down on the galaxy, where they could squeeze central gas clouds enough to kick-start more stellar formation, speculate the scientists, who released the image Thursday.

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But for now, the young tendrils are still rising, speeding from the galaxy at more than 4 million mph (6 million km/h), according to researchers.

"The bursts are sporadic because most of the galaxy gas is blown out of the nuclear region, essentially snuffing out the fire. Roughly 10 million years suffices for enough gas to dribble back to trigger another burst of star formation," said University of North Carolina physicist Gerald Cecil, who led the team.

The bubble erupts from the center of this galaxy, known as NGC 3079.

The galaxy, known as NGC 3079, unleashes the bursts about once every 10 million years. The current one began about one million years ago, astronomers theorize. NGC 3079 resides about 50 million light-years from Earth in the constellation Ursa Major, popularly known as the Big Dipper.

The four main filaments in the close-up image are about 75 light-years across and dissipate after rising about 2,000 light years, according to the astronomers, who published a report on the Hubble data in the July issue of Astrophysical Journal. In the photograph, the reds signal glowing gases. Blues and greens identify light from stars.

While difficult to observe, such bubble bursts might be common in the universe. There is evidence that the Milky Way experienced a similar outburst some time ago.

"Maybe if people around a few million years ago had had infrared or X-ray sensitive eyes, they'd have been able to see a huge shell looming over the constellation Sagittarius, almost 15 times the diameter of the moon," Cecil said.

Hubble, a powerful optical observatory managed by NASA and the European Space Agency, has taken more than 200,000 pictures since it was placed in orbit in 1990.