An interesting post from the Daily Galaxy.
Sent: 5/8/2013 6:36:41 P.M. Eastern Daylight Time
Subj: The Daily Galaxy: News from Planet Earth & Beyond
_The Daily Galaxy: News from Planet Earth & Beyond_
_"Life Bearing Alien Planets Will be Geologically Active with Volcanoes &
Posted: 08 May 2013 07:56 AM PDT
According to scientitsts at the _Harvard Smithsonian Center for
46,-71.12837&spn=0.01,0.01&q=42.38146,-71.12837 (Harvard–Smithsonian%20Center%20for%20Astrophysics)&t=h) ,
habitable worlds are most likely found on large, rocky planets that are up to
ten times the size of Earth and contain plate tectonics. Plate tectonics
play a critical role in determining the rate of cooling of a potentially
habitable planet by creating the optimum temperature ranges for the development
of intelligent animal life -as continents grow, planets cool."Super-Earths
would be more geologically active than our planet, experiencing more
vigorous plate tectonics due to thinner plates under more stress," according to
CfA." Earth itself was found to be a borderline case, not surprising since
the slightly smaller planet Venus is tectonically inactive."
Our planet is changing before our eyes, and as a result, many species are
living on the edge. Research by astronomers at the Harvard-Smithsonian
Center for Astrophysics has shown that if Earth had been slightly smaller and
less massive, it would not have plate tectonics - the forces that move
continents and build mountains. And without plate tectonics, life might never
have gained a foothold.
"Plate tectonics are essential to life as we know it," said Diana Valencia
of Harvard University. "Our calculations show that bigger is better when
it comes to the habitability of rocky planets."
Plate tectonics -the movement of huge chunks, or plates, of a planet's
surface- are crucial to a planet's habitability because they enable complex
chemistry and recycle substances like carbon dioxide, which acts as a
thermostat and keeps Earth balmy. Carbon dioxide that was locked into rocks is
released when those rocks melt, returning to the atmosphere from volcanoes and
"Recycling is important even on a planetary scale," Valencia explained.
Valencia and her colleagues, Richard O'Connell and _Dimitar Sasselov_
(Harvard University), have
examined the extremes to determine whether plate tectonics would be more or less
likely on different-sized rocky worlds. In particular, focusing on
"super-Earths"-planets more than twice the size of Earth and up to 10 times as
"It might not be a coincidence that Earth is the largest rocky planet in
our solar system, and also the only one with life," said Valencia.
Exoplanet searches have turned up five super-Earths already, although none
have life-friendly temperatures. If super-Earths are as common as new
Kepler data suggests, then it is inevitable that some will enjoy Earth-like
orbits, making them excellent havens for life.
"There are not only more potentially habitable planets, but MANY more,"
stated Sasselov, who is director of the Harvard Origins of Life Initiative.
In fact, a super-Earth could prove to be have volcanic "rings of fire"
that could span the globe while the equivalent of Yellowstone Park would
bubble with hot springs and burst with hundreds of geysers. An Earth-like
atmosphere would be possible, while the surface gravity would be up to three
times that of Earth on the biggest super-Earths.
Sasselov observed that although a super-Earth would be twice the size of
our home planet, it would have similar geography. Rapid plate tectonics
would provide less time for mountains and ocean trenches to form before the
surface was recycled, yielding mountains no taller and trenches no deeper than
those on Earth. Even the weather might be comparable for a world in an
"The landscape would be familiar. A super-Earth would feel very much like
home," said Sasselov.
Within our own Solar System, Mars has been found to be at a primitive
stage of plate tectonics. "It gives us a glimpse of how the early Earth may
have looked and may help us understand how plate tectonics began on Earth,"
said An Yin, a UCLA professor of Earth and space sciences. Yin made the
discovery during his analysis of satellite images from a NASA spacecraft known
as THEMIS (Time History of Events and Macroscale Interactions during
Substorms) and from the HIRISE (High Resolution Imaging Science Experiment) camera
on NASA's _Mars Reconnaissance Orbiter_
. He analyzed about 100 satellite images — approximately a dozen were
revealing of plate tectonics.
Yin has conducted geologic research in the Himalayas and Tibet, where two
of the Earth's seven major plates divide.* "When I studied the satellite
images from Mars, many of the features looked very much like fault systems I
have seen in the Himalayas and Tibet, and in California as well, including
the geomorphology," said Yin, a planetary geologist.
"You don't see these features anywhere else on other planets in our solar
system, other than Earth and Mars," said Yin.
The surface of Mars contains the longest and deepest system of canyons in
our solar system, known as _Valles Marineris_
below)-Latin for Mariner Valleys and named for the Mariner 9 Mars orbiter
of 1971, which discovered it. It is nearly 2,500 miles long — about nine
times longer than the Earth's Grand Canyon. Scientists have wondered for four
decades how it formed. Was it a big crack in Mars' shell that opened up?
"In the beginning, I did not expect plate tectonics, but the more I
studied it, the more I realized Mars is so different from what other scientists
anticipated," Yin said. "I saw that the idea that it is just a big crack
that opened up is incorrect. It is really a plate boundary, with horizontal
motion. That is kind of shocking, but the evidence is quite clear.* "The
shell is broken and is moving horizontally over a long distance. It is very
similar to the Earth's Dead Sea fault system, which has also opened up and is
The two plates divided by Mars' Valles Marineris have moved approximately
93 miles horizontally relative to each other, Yin said. California's San
Andreas Fault, which is over the intersection of two plates, has moved about
twice as much — but the Earth is about twice the size of Mars, so Yin said
they are comparable.
"Earth has a very broken 'egg shell,' so its surface has many plates;
Mars' is slightly broken and may be on the way to becoming very broken, except
its pace is very slow due to its small size and, thus, less thermal energy
to drive it," Yin said. "This may be the reason Mars has fewer plates than
Earth endured a tectonic upheaval 1.1 billion years ago that saw the
world's continents collide and form a single supercontinent, accoring to Martin
Van Kranendonk of the University of New South Wales and Christopher
Kirkland of the Geological Survey of Western Australia, who set out to reconstruct
the history of plate tectonics to determine if Earth has been getting more
or less active over time.
It was the most active period of tectonic activity in Earth's history but
the globe has been getting calmer since, they said. Their analysis of 3,200
rock samples from around the world suggests tectonic activity increased
from 3 billion years ago, when the Earth was very young, to a peak around 1.1
billion years ago and then declined.
During the peak, all the continents collided and merged into a vast
supercontinent called Rodinia, the Austrailian researchers said, spanned by a
mountain range that dwarfed today's Himalayas.
The Daily Galaxy via UCLA and www.cfa.harvard.edu/
Image credit of Mars : With thanks to space artist, _Walter Myers_
Image Credit of Mars' Valles Marineris: from Google Mars, created by MOLA
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_"Space-Warp Galaxy" Explorers Wanted --Oxford University_
Posted: 08 May 2013 08:14 AM PDT
Online volunteers are being asked to search for 'space warps', very rare
massive galaxies that bend light around them so that they act rather like
giant lenses in space. By looking through data that has never been seen by
human eyes, citizen scientists can help astronomers discover some of the
rarest objects in the Universe.Visitors to www.spacewarps.org, which launches
today (8 May 2013), are being asked to spot these important astronomical
objects, more commonly called '_gravitational lenses_
', in hundreds of thousands of deep sky images.
Armchair astronomers could be the first humans to see these galaxies, each
one of which is several billion light years away. By spotting space warps,
they will help uncover the role _dark matter_
plays in how galaxies form.
'Not only do space warps act like lenses, magnifying the distant galaxies
behind them, but we can also use the light they distort to weigh them,
helping us to figure out how much dark matter they contain and how it’s
distributed,' said Dr Phil Marshall of _Oxford University_
(University%20of%20Oxford)&t=h) 's Department of Physics, who is one of the leaders of the
research team. 'Gravitational lenses help us to answer all kinds of questions
about galaxies, including how many very low mass stars such as brown dwarfs –
which aren't bright enough to detect directly in many observations – are
lurking in distant galaxies.'
'The Zooniverse has always been about connecting people with the biggest
questions and now, with Space Warps, we're taking our first trip to the
_early Universe_ (http://en.wikipedia.org/wiki/Chronology_of_the_universe)
We're excited to let participants and planetarium visitors be the first to see
some of the rarest astronomical objects of all,' said Dr Arfon Smith,
Director of Citizen Science at the _Adler Planetarium_
(Adler%20Planetarium%20&%20Astronomy%20Museum)&t=h) in Chicago home to the
team who built the Space Warps site.
The Space Warps project is a lens discovery engine. Joining the search is
easy: visitors to the website are given examples of what space warps look
like and are shown how to mark potential candidates on each image. The first
set of sky images to be inspected in this project is from the CFHT
Hawaii%20Telescope)&t=h) ) legacy survey.
'Computer algorithms have already scanned the images from the CFHT survey,
but there are likely to be many more space warps that the algorithms have
missed. Realistic simulated space warps are dropped into some images to
train the volunteers how to spot them, and reassure people that they are on
the right track,' said Dr Anupreeta More, project co-lead from Kavli IPMU,
Previous studies have shown that the human brain is better at identifying
complex lenses than computers are, and that members of the public can be at
least as good at spotting astronomical objects as experts. The team
describe the project as a collaboration between humans and computers, as data
from the human volunteers will help to train computers to become better space
'Even if individual visitors only spend a few minutes glancing over 40 or
so images each that's really helpful to our research – we only need a
handful of people to spot something in an image for us to say that it’s worth
investigating,' said Dr Aprajita Verma of Oxford University, space warps'
third principal investigator.
After identifying possible space warp candidates in images, people will be
able to discuss them on an online forum with other volunteers and experts,
and even create computer models of their discoveries. The final sample of
space warp candidates will be published for both amateur and professional
astronomers to investigate further.
The Daily Galaxy via
Image credit: NASA/ESA/Hubble Heritage Team (AURA/STScI)
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