New telescope to shed light on 'Dark Ages'
For astronomers the Dark Ages represent the far-flung corners of the universe about which precious little is known, and which could yet hold the key to how planets were first formed. NASA hopes a "next generation" telescope slated for launch in 2013 will shed light on the question.
The James Webb Space Telescope, named after a former NASA administrator, is a joint project with the European and Canadian space agencies and a collection of private defence contractors.
Three key officials involved in the project offered an update on Thursday under a life-size model of the telescope, displayed outside the National Air and Space Museum in Washington.
Scientists hope the Webb observatory will help answer two of the biggest questions we have about space - how did it all start? And could there be life on other planets?
Its predecessor, the Hubble telescope, delivered some of the first major insights into the universe's formation after it was launched in 1990. Yet its findings surprised astronomers: faraway galaxies that were expected to offer a glimpse of the very early universe turned out to be much more developed, meaning even they were formed long after the Big Bang, when astronomers believe the universe originated.
In other words, to really get to the heart of the universe - to spot those distant galaxies that were formed first - NASA was going to need an even better set of binoculars.
"We needed a new telescope to see the very birth ... to see the first light of the universe," said Edward Weiler, director of NASA's Goddard Space Flight Centre in Greenbelt, Maryland, and formerly the chief scientist on Hubble.
And so while Hubble got things started, astronomers hope the Webb telescope will offer the "first view into this strange period we call the Dark Ages," said Matt Mountain, director of the Space Telescope Science Institute in Baltimore, Maryland. Mountain headed scientific operations on Hubble and now on Webb.
The Webb telescope, Mountain said, could examine the planet's atmosphere more closely for signs of the water, oxygen and carbon that are crucial for the existence of life.
The new telescope will have one large mirror about 6.5 metres wide - double the size yet half the weight of Hubble's - and a secondary, smaller mirror in front of it.
The Webb telescope will be placed in orbit on the other side of the moon, at one of the few spots in space where the earth and sun remain in line, known to astronomers as the second Lagrange point. That will allow the mirror to block rays from the earth, moon and sun.
The project has been in the works since 1994 - four years after Hubble went into space - and, unlike when Hubble was first due to launch, most of the groundwork has already been completed. The technology has been developed.
Hubble was a different story. NASA had been so confident about the earlier telescope's potential that by the time it was first projected to launch in 1983, some of the device's components had not yet been invented. The task of keeping the project going "at full speed" for another seven years meant major cost overruns, said Weiler.
At $4.5 billion, Webb is nearly half as costly as Hubble would have been at today's rates - it cost $1.6 billion two decades ago - but many times more powerful.