Thursday, October 4, 2012


Further to a previous Blog: after writing it I read about The Hubble Space Telescope producing the most extraordinary views of the Universe to date. Called the Extreme Deep Field, the picture captures a mass of galaxies stretching back almost to the time when the first stars began to shine. This view required Hubble to stare at a tiny patch of sky for more than 500 hours to detect all the light.
“It's a really spectacular image,” said Dr Michele Trenti, a science team member from the University of Cambridge. “We stared at a patch of sky the size of the moon for about 22 days, and obtained a very deep view of the distant Universe and how galaxies looked in their infancy."
The Extreme Deep Field will become a tool for astronomy. The objects embedded in it can be followed up by other telescopes. It should keep scientists busy for years, enabling them to study the full history of galaxy formation and evolution.
Data acquired in 2003 and 2004 saw the telescope burrow into a small area of space in the Constellation Fornax (The Furnace). Again, it necessitated many repeat observations, and revealed thousands of galaxies, both near and far, making it the deepest image of the cosmos ever taken at that time. Hubble helped astronomers calculate the age of the universe, about 13.7 billion years old. (Tell that to the creationists.) The Hubble telescope was carried into orbit aboard the Space Shuttle. It has taken more than 2,000 separate exposures over 10 years using its two main cameras - the Advanced Camera for Surveys, installed by astronauts in 2002, and the Wide Field Camera 3, which was added to the observatory during its final servicing in 2009. To see what it does, Hubble has to reach beyond the visible into the infrared. It is only at longer wavelengths of light that some of the most distant objects become detectable. Of the more than 5,000 galaxies in the XDF, one of them  is a candidate for the most distant galaxy yet discovered. If this is confirmed, it means it is being seen just 460 million years after the Universe's birth in the Big Bang. Scientists time that event to be 13.7 billion years ago.
Until that corroboration, another of the image objects probably holds the record. This galaxy is seen as it was 600 million years after the Big Bang.
But as remarkable as the XDF is, it is a prelude for an even deeper Hubble view. A team led from Caltech (US) and Edinburgh University (UK) has acquired more than 100 hours of additional observations, doubling the exposure time in the all-important near infrared wavebands made possible. The expectation is that it will contain galaxies even closer to the Big Bang. To see the first starlight in the Universe will most likely require Hubble's successor. The James Webb Space Telescope, which is scheduled to launch in 2018, will carry a much larger mirror and even more sensitive instruments.
It simply boggles the mind, doesn’t it?

1 comment:

lewis said...

Assiduous study of holy writ brought bishop Ussher to he conclusion that the universe began at 6 p.m. on Sunday, October 23, 4004 BC, in the proleptic Julian calendar.
Others, equally ;learned, claimed it was Thursday about 4 p.m., but they err, as Sunday is the first day of the week and God would, of course,have created the Beginning at the start. Some people !