WASHINGTON: A new wide-angle view of the universe looks back to a mere billion years after the Big Bang, revealing secrets about the lives of galaxies and the black holes at their hearts, scientists reported on Thursday.
The new view is contained in one extraordinary image, compiled by astronomers using a super-high-resolution camera aboard NASA’s Hubble Space Telescope, along with a catalog of objects giving off strong X-rays from space, detected by the Chandra X-Ray Observatory, another NASA-affiliated instrument.
The image shows a section of sky about one-tenth the size of the full Moon viewed from Earth. Though this may seem narrow, it is about 30 times wider than the last deep look into the universe, the Hubble Deep Field observation released in 1996.
That earlier vision was described as a keyhole view; this one might reasonably be called a picture window.
Both images sought to peer far enough away from Earth to see back in time to when the light from some of the oldest galaxies headed toward our spot in the cosmos. They also captured cosmic objects from later periods.
As in that earlier path-breaking picture, the galaxies in the new image look like smudged jewels on black velvet, with distinct shapes and colours, their whirling arms and oval forms apparent.
But the new image, known as GOODS for Great Observatories Origins Deep Survey, managed to look back further — more than 12 billion years to when the universe was a billion years old. Astronomers put the age of the universe at 13.7 billion years.
“In terms of time, we go from when the universe was about 15 per cent of its current age to when it was 9 per cent of its age,” Mauro Giavalisco, a researcher who works with the Hubble data at the Space Telescope Science Institute, said in a telephone interview.
LEAP BACK IN TIME: Again, the difference between the older image and this new one sounds slight, but Giavalisco said the most rapid, dramatic changes occur early in a galaxy’s development, much as human development occurs most dramatically at the earliest stages. That means even a small-seeming leap back in time reveals worlds of detail on galactic development.
Starting about 1 billion years after the theoretical Big Bang — the giant explosion that many scientists believe gave birth to the universe — the galaxies grew in size and went through a “baby boom” period of furious star formation that lasted about 6 billion years.
At that point, star formation dropped to about one-tenth its earlier rate, and major galaxy building trailed off when the universe was about half its current age, preliminary findings from the new image show.
Many astronomers believe there are monstrous black holes lurking at the center of many galaxies, including the Milky Way that contains Earth. Black holes are thought to be matter-sucking drains in space, whose pull is so strong that nothing, not even light, can escape.
Black holes can be inferred by X-rays emitted from them or near them, and scientists want to know more about how supermassive black holes relate to the galaxies that swirl around them, said Niel Brandt, an astronomer at Pennsylvania State University who worked with the Chandra X-ray data.
The GOODS image is sharp enough at great distances to allow astronomers to try to match up hundreds of X-ray sources — thought to indicate black holes — with the galaxies they inhabit, Brandt said by telephone.—Reuters
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