Hubble Finds Oldest Galaxy JWST Needed to Probe Further Back in Time

Hubble Finds Oldest Galaxy JWST Needed to Probe Further Back in Time

Scientists using NASA’s Hubble space telescope announced yesterday the discovery of what may be the oldest observed object in the universe: a galaxy that existed around 500 million years after the Big Bang. They also argued that while observations with Hubble would continue, only its successor, the James Webb Space Telescope (JWST), would allow them to observe even further back in time.

In 2009, during Hubble’s last servicing mission, astronauts fitted the telescope with the Wide Field Camera 3, which provided scientists with new opportunities for studying the universe. Garth Illingworth, from the University of California-Santa Cruz, explained that WFC-3 allowed researchers to look back 96% of the 13.7 billion years of the age of the universe. With observations taken over one and a half years, an international team of researchers took the farthest infrared image ever of the universe and found a faint object believed to be a galaxy. Rychard Bouwens, University of Leiden (Netherlands), explained that using the new capabilities researchers found the compact galaxy of blue stars because they were looking for it: “this [was] not a blind search,” he said.

Their search revealed something else: missing galaxies. It was “the dog that didn’t bark,” said Rachel Somerville, an astronomer at the Space Telescope Science Institute, which operates Hubble. She explained that observations taken at later time periods led researchers to expect to find many young, blue stars when glimpsing this earlier period. Instead they found at least ten times fewer the number of galaxies expected, which would only account for 12% of the level of radiation at that stage of galaxy evolution. It is a “mystery” that she said the JWST would hopefully help solve once it is launched. Because the number of galaxies found at later periods – at 650 million and 800 million years after the Big Bang, for example- is considerably higher, the Hubble finding suggests that galaxy population was “evolving very rapidly” and that the rate of star birth must have increased dramatically between 500 and 650 million years after the Big Bang, a relatively “short” period.

“[We’re] pushing Hubble to its limits here,” explained Illingworth, who added that Hubble would be unable to observe the universe at any earlier time. JWST, however, is designed to do just that. He added that the findings announced today were “striking and wonderful,” and would be a powerful source for JWST to look at.

An independent review of the JWST program in 2010 revealed that “budgeting and program management” issues had led to significant cost and schedule growth, delaying JWST’s launch until at least 2015. NASA is currently performing a more detailed internal analysis of the program to determine what resources are needed to fix the program. Whether JWST will receive those resources and maintain a 2015 launch date remains to be seen. Some astronomers are concerned that money may be diverted from other NASA astrophysics projects in order to pay for the JWST cost growth.

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