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The mystery of why the Earth has so much water, allowing our "blue
marble "to support an incredible number of lives, is clearer with the new
research on comets. Comets are like snowballs of rock, dust, ice and more
frozen chemicals that vaporize as they get closer to the Sun, producing the
tails seen in the pictures. New study reveals that
Water in many comets can share a common origin with the Earth's oceans, reinforcing
the idea that comets have played a key role in bringing water to our planet, billions
from years ago.
The stratospheric observatory for infrared astronomy, SOFIA, the largest airborne observatory in the world, observed
Comet Wirtanen as it got closer to EarthDecember
2018. Data collected from the top flight observatory
found that this comet contains water "similar to the ocean". comparing
this with information on other comets, suggest scientists in a new study
that many more comets than previously thought could have provided water to
Earth. The results have been published in Astronomy and
Letters of astrophysics.
"We have identified a vast
Earth-like water reservoir in the confines of the solar system, "
said Darek Lis, a scientist at NASA's Jet Propulsion Laboratory in Pasadena,
California and lead author of the study. "Water was crucial for the
development of life as we know it. We not only want to understand how the Earth
water was delivered, but also if this process could work in other planetary
systems. "
Dirty snowballs
planets
form of debris in orbit in a disk shape around a
star; small debris can clump and grow with time.
The remains of debris remain in areas of our own solar system, such as the Kuiper Belt,
beyond Neptune or the Oort Cloud,
far after Pluto. Comets come from these areas, but we can only see them
their orbits bring them closer to the sun The heat of the sun causes a part of
the dirty snow to spray, creating the hazy halo or "coma" of
water vapor, dust and grains of ice seen in comet images.
Scientists predict that water in the Earth
the oceans came from bodies carrying water in the primitive solar system that collided
with our planet, similar to asteroids or ice – rich comets of today. But
Scientists do not know where these objects come from in the formative disc.
Water
Types
Water is also known by its chemical name H2O
because it is composed of two atoms of hydrogen and one atom of oxygen. But using special
instruments, scientists can detect two types: ordinary water, H2O
and heavy water, HDO, which has an extra neutrally charged particle called
neutron inside one of the atoms of hydrogen. Scientists compare the amount of
heavy in regular water in comets. If comets have the same ratio of these waters
like the oceans of the Earth, this indicates that the water of both can share a same
origin.
But measuring this relationship is difficult. Ground
and space telescopes can study this level of detail in comets only when they
pass near the Earth, and missions to visit comets, like Rosetta, are rare. Scientists have only been able to study this report in about
a dozen comets since the 1980s. Moreover, it is difficult
study the water of a comet from the ground because the water in the atmosphere is blocking
his signatures.
New observations
Observing at high altitude over most of the
The atmospheric water of the Earth has allowed SOFIA to accurately measure the ratio of
ordinary to heavy water in the comet Wirtanen. The data showed that the comet Wirtanen
the ratio of water is the same as the oceans of the Earth.
When the team compared the new SOFIA data to the previous ones
comet studies, they found a surprising similarity. The report from regular to
Heavy water was not related to the origin of comets – they come from
the Oort cloud or the Kuiper belt. Instead, it was related to the amount of water
was released from ice grains in the coma of the comet as compared to directly from the
snowy surface. This could imply that all comets could have a heavy to regular
report of water similar to the oceans of the Earth, and that they could have provided a
large fraction of water to the Earth.
"It's the first
time we could relate the ratio of heavy water to regular of all comets to a single
factor, "said Dominique Bockelée-Morvan, scientist at the
The Observatory and the National Center for Scientific Research and second
author of the article. "We may need to rethink our way of studying comets because
the water released by the grains of ice seems to be a better indicator of the
global ratio of water that the water released from the surface ice. "
More studies are needed to see if these results
true for other comets. The next time a comet should fly close
enough for this type of study will be in November 2021.
SOFIA, the stratospheric observatory
for infrared astronomy, is a Boeing 747SP airliner modified to carry a
diameter of the telescope. It is a joint project of NASA and the German aerospace company.
Center, DLR. NASA's Ames Research Center in California's Silicon Valley manages
SOFIA program, science and mission operations in cooperation with the
Universities Space Research Association, headquartered in Columbia, Maryland,
and the German SOFIA Institute (DSI) of the University of Stuttgart. the
the aircraft is serviced and operated from NASA's Armstrong Flight Research
Center Building 703, Palmdale, California.
Media contact
Nicholas Veronico
SOFIA Science Center
Ames Research Center, Silicon Valley, California
650-604-4589 / 650-224-8726
[email protected]
Elizabeth Landau
NASA Headquarters, Washington
818-359-3241
[email protected]
Calla Cofield
Jet Propulsion Laboratory, Pasadena, California
626-808-2469
[email protected]
2019-097
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