Hubble uncovers universe in infancy

In feeble light of cosmos, stars form after big bang

March 10, 2004|By Michael Stroh | Michael Stroh,SUN STAFF

In an effort compared to photographing a firefly on the moon, the Hubble Space Telescope has gathered enough feeble light from the fringes of the cosmos to create a stunning portrait of the universe as it existed less than 800 million years after the big bang.

The photograph, dubbed the Hubble Ultra Deep Field, reveals a chaotic, strange and often savage environment of dueling galaxies and infant stars - most of which are invisible to telescopes on the ground.

"The image you see is full of superlatives," Steven V.W. Beckwith, director of the Space Telescope Science Institute in Baltimore, said yesterday morning at a news conference to unveil the image. "For the first time, we're looking back at stars that are forming out of the depths of the big bang."

Astronomers said the image would help them piece together the puzzling story of how the infant universe went from a cold, dark void, mostly filled with hydrogen and helium, to the dazzling display of celestial eye candy we see today.

In the wake of NASA's recent decision to retire the telescope early, astronomers said the new Ultra Deep Field might be one of Hubble's last big contributions to astronomy.

This week, retired Adm. Harold W. Gehman Jr. is expected to issue a highly anticipated review of Administrator Sean O'Keefe's Jan. 16 decision to scrub the final space shuttle flight to the telescope. Without a mission to swap out failing batteries, gyroscopes and other components, the 14-year-old Hubble might not last beyond 2007, Beckwith said.

A storm of protest from the scientific community and politicians who back Hubble led NASA Administrator Sean O'Keefe to call for the review Jan. 29.

"The future of Hubble should not be made by one man in a NASA backroom," Maryland Sen. Barbara A. Mikulski told applauding astronomers at yesterday's unveiling. Mikulski, a senior member of the committee that oversees NASA's budget, called the new Ultra Deep Field photo a perfect example of "why the world loves Hubble."

This isn't the first time Hubble has made such an intense study of a single sliver of space. In 1995 and 1998, astronomers photographed different regions to create the Hubble Deep Fields. The pair of images, showing the universe 1 billion years after the big bang, led scientists to a variety of stellar discoveries.

Astronomers have equally high hopes for the Ultra Deep Field, which could contain relics of ancient stars shining just 400 million years after the big bang. (In astronomy, the more distant an object is from Hubble, the longer its light takes to reach the telescope and therefore the greater its age.)

The light from such distant objects is 10 billion times fainter than the eye can see. Creating the image required Hubble to patiently gather photons trickling in from the same slice of the southern sky for 1 million seconds - the longest single exposure Hubble has ever made of one region. The exposure took 400 orbits and nearly four months to complete.

Because no individual scientist is ever granted so much precious telescope time on Hubble - estimated to run $10 a second - institute director Beckwith gave scientists his entire annual allocation of "discretionary time" to complete the project.

"These images will be in astronomy textbooks for years," said Beckwith.

Located in the constellation Fornax, the Ultra Deep Field shows the universe when it was a much smaller and less populated place - which isn't to say it was empty.

Astronomers estimate that the Ultra Deep Field, which shows a slice of sky just one-tenth the diameter of the full moon, contains roughly 10,000 galaxies. Furthermore, it would take nearly 13 million Ultra Deep Field-sized snapshots to cover the entire sky.

The image was taken by Hubble's Advanced Camera for Surveys and the Near Infrared Camera and Multi-object Spectrometer, or NICMOS, instruments that were either installed or improved by Shuttle astronauts in the last few years.

The objects in the Ultra Deep Field are so old and so distant that a ground-based telescope staring at the same patch of sky would find mostly darkness, said Beckwith. He added that the light emanating from some of these distant objects is ten billion times fainter than what the human eye can see.

As he pointed out some of the more eye-catching wisps of gas recorded in the new photograph, Massimo Stiavelli, the Space Telescope Science Institute astronomer who led the project, said the image will keep astronomers busy for years.

"I have no idea what this is," he said, jabbing his finger toward a blob of blue gas. "But I'm sure somebody will soon write papers on it."

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