Per­plex­ing “blobs” of gas seen in the far­away uni­verse are a bit more com­pre­hen­si­ble thanks to a new study.
 Glow­ing with an eerie bright­ness, the mas­sive blobs seem to sur­round very young galax­ies. NASA’s Chan­dra X-ray Obser­va­tory and other tele­scopes exam­ined the dis­tant gas balls and found that their lumi­nos­ity is likely due to energy released by black holes and star for­ma­tion inside the galaxies.

“For ten years the secrets of the blobs had been buried from view, but now we’ve uncov­ered their power source,” said James Geach of Durham Uni­ver­sity in the United King­dom, who led the study. “Now we can settle some impor­tant argu­ments about what role they played in the orig­i­nal con­struc­tion of galax­ies and black holes.”

Astronomers first spot­ted the blobs about a decade ago, but couldn’t figure out much about them, such as how they formed or why they were glow­ing (hence the vague name “blob”).

Recently Chan­dra, the Spitzer Space Tele­scope and other obser­va­to­ries pointed their lenses at a patch of space dubbed “SSA22” where 29 of these huge reser­voirs of hydro­gen gas can be seen. The blobs in this field date from when the uni­verse was only about 2 bil­lion years old, or roughly 15 per­cent of its cur­rent age.

The obser­va­tions revealed point-like sources of bright X-ray light — tell­tale signs of super­mas­sive black holes – within many of the blobs. They also showed that sev­eral of the baby galax­ies within the gas clouds were dom­i­nated by robust star formation.

Astronomers say the radi­a­tion from the black holes and star for­ma­tion could be pro­vid­ing the energy to light up the blobs.

It’s pos­si­ble that all mas­sive galax­ies go through a phase when they are sur­rounded by glow­ing clouds like this, Geach said. How­ever, since that phase is rel­a­tively short-lived – per­haps only a few hun­dred mil­lion years – and occurs when the galaxy is very young, astronomers will have a hard time catch­ing most galax­ies at the right moment.

“Prob­a­bly all galax­ies go through this phase, but to start off with the gas is hard to detect ’cause there’s noth­ing there to light it up,” said Sir Martin Rees, an astronomer at the Uni­ver­sity of Cam­bridge who did not work on the new study. Once star for­ma­tion gets going and the black holes begin emit­ting strong radi­a­tion, the blobs glow for a short period of time. “Then later the gas is either all con­verted into stars or blown away,” he said.

The hydro­gen gas making up the blobs is likely left­over mate­r­ial from when the galaxy formed that did not get pulled in to become stars. In fact, the galax­ies prob­a­bly exist in a sea of this left­over pri­mor­dial gas, but only a small cocoon around them is lit up and vis­i­ble to us, Geach said.

“There’s still a lot to learn about these objects,” said coau­thor Bret Lehmer, also at Durham. “In the future we’ll con­duct wide-area hunts for these blobs.”

Geach and team will report their find­ings in the July 10 issue of The Astro­phys­i­cal Journal.

By Clara Moskowitz, Staff Writer for LiveScience.com