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Science Forum Index » Astro - Seti Forum » Telescopes can soon replace SETI, maybe
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| Matt Giwer |
 Posted: Mon Feb 04, 2008 8:14 am |
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Guest
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As I was saying a few months ago, if they have radio they have electricity.
It is a reasonable assumption that a diurnal species will have lights at
night. Images of planets will be available soon. A repeating pattern on the
dark side of a planet is a sign of intelligent life.
Yes, there is no reason to assume all intelligent life is daylight loving
but neither is we are the only daylight loving.
Yes, cities would not be necessary for an advanced civilization but one
expects there would be desirable places to live which would produce clusters
of living places and thus clusters of light sources.
And if not the generation discussed here then the next generation of
telescopes will be able to do it.
Which means we have been detectable from our light for around a century so
ETs interested in communicating are transmitting and listening is a very
good idea for now. Planets with lights on the dark side are those which
should be listened to.
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http://www.rawstory.com/news/mochila/Eyes_to_the_skies_getting_bigger_02032008.html
Eyes to the skies getting bigger
A Super-Sized Boom Coming for Telescopes: Large, Giant, Extremely Large,
OverWhelmingly Large
SETH BORENSTEIN
AP News
Feb 03, 2008 13:53 EST
A telescope arms race is taking shape around the world. Astronomers are
drawing up plans for the biggest, most powerful instruments ever
constructed, capable of peering far deeper into the universe — and further
back in time — than ever before.
The building boom, which is expected to play out over the next decade and
cost billions of dollars, is being driven by technological advances that
afford unprecedented clarity and magnification. Some scientists say it will
be much like switching from regular TV to high-definition.
In fact, the super-sized telescopes will yield even finer pictures than the
Hubble Space Telescope, which was put in orbit in 1990 and was long
considered superior because its view was freed from the distorting effects
of Earth's atmosphere. But now, land-based telescopes can correct for such
distortion.
Just the names of many of the proposed observatories suggest an arms race:
the Giant Magellan Telescope, the Thirty Meter Telescope and the European
Extremely Large Telescope, which was downsized from the OverWhelmingly Large
Telescope. Add to those three big ground observatories a new super eye in
the sky, NASA's James Webb Space Telescope, scheduled for launch in 2013.
With these proposed giant telescopes, astronomers hope to get the first
pictures of planets outside our solar system, watch stars and planets being
born, and catch a glimpse of what was happening near the birth of the universe.
"We know almost nothing about the universe in its early stages," said
Carnegie Observatories director Wendy Freedman, who chairs the board that is
building the Giant Magellan Telescope. "The GMT is going to see in action
the first stars, the first galaxies, the first supernovae, the first black
holes to form."
When scientists look at a faraway celestial object, they are seeing it as it
existed millions and millions of years ago, because it takes so long for
light from the object to reach Earth.
Current telescopes are able to look back only about 1 billion years in time.
But the new telescopes will be so powerful that they should be able to gaze
back to a couple of hundred million years after the Big Bang, which
scientists believe happened 13.7 billion years ago. That's where all the
action is.
"We hope to answer these questions: Are we alone in the universe? What is
the nature of dark matter and dark energy in the universe?" said astronomer
Henri Boffin, outreach scientist for the European Southern Observatory.
Two new technologies enable this extraordinary quest — one reliant on modern
lasers and computing power and the other inspired by ancient Greek and Roman
tilework.
The first is adaptive optics. It allows telescopes on the ground to get rid
of the distortion caused when looking through Earth's thick atmosphere into
space.
Adaptive optics relies on a laser to create an artificial star, or a
constellation of fake stars, in the sky. Astronomers then examine the fake
stars and use computers to calculate how much atmospheric distortion there
is at any given time. Then they adjust the mirrors to compensate like a pair
of eyeglasses. This adjustment happens automatically hundreds of times per
second.
Adaptive optics worked first for smaller telescopes. But getting it to work
for big observatories was a problem. The first successful use in large
telescopes was in 2003 at the twin-telescope Keck Observatory in Hawaii, an
effort that took nine years.
The second breakthrough involves technology that makes bigger mirrors
possible. Instead of casting a giant mirror in one piece, which is difficult
and limits size, astronomers now make smaller mirror segments and piece them
together.
Keck scientist Jerry Nelson, now working on the Thirty Meter Telescope,
pioneered this technique and said he got the idea from looking at how the
Greeks and Romans tiled their baths. This technique is going from 36
segments in current telescopes to 492 segments with his new project.
In astronomy, the bigger the mirror, the greater the amount of light that
can be grabbed from the universe. For the past decade and a half, the Keck
has had the largest Earth-bound telescopes, with mirrors nearly 33 feet in
diameter.
However, three giant land observatories, proposed for construction within
the decade, are going to dwarf those:
_ The Giant Magellan Telescope. A partnership of six U.S. universities, an
Australian college, the Smithsonian Astrophysical Observatory and the
Carnegie Institution of Washington will place the telescope in Las Campanas,
Chile, around 2016. The plan is for an 80-foot mirror. The cost is around
$500 million.
_ The Thirty Meter Telescope. The California Institute of Technology, the
University of California and the Association of Canadian Universities for
Research in Astronomy are aiming for a telescope with about a 98-foot mirror
by 2018. No site has been chosen. The cost is about $780 million.
_ The European Extremely Large Telescope. A partnership of European
countries called the European Southern Observatory already has telescopes in
Chile and is aiming for a new one with a mirror of 138 feet, scaled back
from initial plans of 328 feet. The Europeans are aiming for a 2018
completion, but have not chosen a specific location yet. The cost would be
$1.17 billion.
The managers of these projects are fairly confident they will get the money
they need to complete their grand visions. However, some astronomers worry
that there may not be enough private or government money for all of them, so
they find themselves competing for funding, even as they cheer each other on.
If completed, ESO's European Extremely Large Telescope would be the biggest
of the new observatories and should be able to see 20 to 100 times more
sharply than the current best land-based telescopes. The Hubble, which set
the standard for stunning astronomical pictures, will seem less amazing.
"Oh, you ain't seen nothing yet," said 2006 Nobel Prize-winning physicist
John Mather, senior project scientist for NASA's James Webb Space Telescope.
The $4.5 billion Webb Telescope, designed to travel 900,000 miles beyond
Earth's orbit, is not faced with the atmospheric distortion of ground
telescopes. Still, it will use its own version of adaptive optics. Because
of temperature fluctuations in the cold of space, the telescope will have to
adjust the shape of its mirrors automatically. Webb's mirror, which is 2 1/2
times bigger than Hubble's, has 18 segments.
While places like Arizona and Hawaii have been successful sites for
high-quality space images, Chile is the focal point of the next-generation
building boom.
Both the Thirty Meter and European telescope are looking at several sites
there although the Thirty Meter team is also considering Baja Mexico and
Hawaii. What's needed is the right combination of atmospheric conditions,
weather, high altitude, prevailing winds and dark skies.
But there is more in the works than just the super-sized scopes. Smaller,
more specialized telescopes are in various stages of design and construction.
The $400 million Large Synoptic Survey Telescope to be built in Chile by
2014 would survey the sky, constantly shooting a movie of 20 billion objects
in the cosmos and spotting targets for bigger telescopes.
A planned project in Hawaii would be on the lookout for "killer asteroids."
And in Chile, dozens of high-precision antennas are being erected for a huge
radio astronomy observatory, called ALMA, that would look into the universe
in a different way.
It is the biggest observatories in the works, however, that will provide the
dramatic change in astronomical pictures. The pictures to come, Nelson said
of the Thirty Meter project, will "knock your socks off, faint stuff that
Hubble can't see."
___
On the Net:
Thirty Meter Telescope: http://www.tmt.org
Giant Magellan Telescope: http://www.gmto.org
European Extremely Large Telescope:
http://www.eso.org/public/astronomy/projects/e-elt.html
James Webb Space Telescope: http://www.jwst.nasa.gov
Source: AP News
--
Bush says he does not believe the National Intelligence Assessment on Iran.
He also says he follows his gut and that his god talks to him.
He is also commander in chief of the US military.
I can't add a thing to this.
-- The Iron Webmaster, 3926
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