The image took more than 500 hours to build
The Hubble Space Telescope (HST) has produced one of its 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.
But this was no simple point and snap - some of the objects in this image are too distant and too faint for that.
Rather, this view required Hubble to stare at a tiny patch of sky for more than 500 hours to detect all the light.
The XDF will become an invaluable tool for astronomy. The objects embedded in it will now be followed up by other telescopes. It will keep scientists busy for years, enabling them to study the full history of galaxy formation and evolution.
The new vista is actually an updating of a previous HST product - the Hubble Ultra Deep Field.
That was built from data acquired in 2003 and 2004, and 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.
But XDF goes further; it dials down into an even smaller fraction of the UDF.
It incorporates more than 2,000 separate exposures over 10 years using Hubble's 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.
Beyond the visible
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 is seen as it existed just 450 million years after the Universe's birth in the Big Bang. Scientists time that event to be 13.7 billion years ago.
This remarkable image will be updated again when Hubble's successor gets into orbit. The James Webb Space Telescope is scheduled to launch in 2018.
This next-generation observatory's larger mirror and more sensitive infrared instruments will allow it to go deeper still, to witness the very first starlight in the Universe.
No comments:
Post a Comment