A Telescope Bigger than a Galaxy
 
March 7, 2014:  More than 400 years ago, Galileo turned a primitive spyglass
toward the sky, and in just a few nights learned more about the unseen heavens
than all of the scientists and philosophers before him, combined.
 
Since then astronomers have been guided by a simple imperative: Make Bigger
Telescopes. As the 21st century unfolds, the power of optics has grown a
million-fold.  Telescopes cap the highest mountains, sprawl across deserts,
fill valleys and even fly through space. These modern giants provide
crystal-clear views of stars and galaxies billions of light years farther away
than anything Galileo ever saw, each breakthrough in size bringing a new and
deeper understanding of the cosmos.
 
It makes you wonder, how big can a telescope get?
 
https://www.youtube.com/watch?v=3_iTofcXqfM
 
A new ScienceCast video peers through the biggest telescope in the history of
astronomy.  Play it!
 
Would you believe, bigger than an entire galaxy? At the January 2014 meeting
of the American Astronomical Society, researchers revealed a patch of sky seen
through a lens more than 500,000 light years wide.
 
The "lens" is actually a massive cluster of galaxies known as Abell 2744. As
predicted by Einstein's Theory of General Relativity, the mass of the cluster
warps the fabric of space around it.  Starlight passing by is bent and
magnified, much like an ordinary lens except on a vastly larger scale.
 
Lately, the Hubble Space Telescope, along with the Spitzer Space Telescope and
the Chandra X-ray Observatory, has been looking through this gravitational
lens as part of a program called "Frontier Fields."
 
"Frontier Fields is an experiment to explore the first billion years of the
Universe's history," says Matt Mountain from the Space Telescope Science
Institute in Baltimore, Maryland. The question is, "Can we use Hubble's
exquisite image quality and Einstein's theory of general relativity to search
for the first galaxies?"
 
The answer seems to be "yes."  At the AAS meeting, an international team led
by astronomers from the Instituto de Astrof¡sica de Canarias and La Laguna
University discussed Hubble and Spitzer observations of the Abell 2744
cluster. Among the results was the discovery of one of the most distant
galaxies ever seen-a star system 30 times smaller yet 10 times more active
than our own Milky Way.  Bursting with newborn stars, the firebrand is giving
astronomers a rare glimpse of a galaxy born not long after the Big Bang itself.
 
Overall, the Hubble exposure of Abell2744 revealed almost 3,000 distant
galaxies magnified as much as 10 to 20 times larger than they would normally
appear. Without the boost of gravitational lensing, almost all of those
background galaxies would be invisible.
 
Abell 2744 is just the beginning.  Frontier Fields is targeting six galaxy
clusters as gravitational lenses. Together, they form an array of mighty
telescopes capable of probing the heavens as never before.
 
For more news from Frontier Fields visit frontierfields.org
 
Credits:
Author: Dr. Tony Phillips | Production editor: Dr. Tony Phillips | Credit:
Science@NASA
 
 
Regards,
 
Roger

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 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)