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Comet provides new clues to the origins of the Earth's oceans

The mystery why the earth has so much water and allows our "blue"
Marble "to support an amazing variety of life is clearer with new
Exploration of comets. Comets are like snowballs of stone, dust, ice and more
frozen chemicals that evaporate as they approach the sun, and the
Tails seen in pictures. A new study shows that the
Water in many comets can have a common origin with the oceans of the earth and strengthen themselves
the idea that comets played a key role in supplying billions of dollars of our planet's water
years ago.

The Stratosphere Observatory for Infrared Astronomy, SOFIA, the world's largest observatory in the air, was observed
The comet Wirtanen came closest to Earth in December
. Data collected from the soaring observatory
found out that this comet contains "ocean-like" water. to compare
This with information about other comets, scientists suggest in a new study
that many more comets than previously thought could have supplied water
Earth. The results were published in Astronomy and
Astrophysics Letters.

"We have identified a big one
Reservoir of earth-like water in the outer area 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 to that
Development of life as we know it. We do not just want to understand what the earth is like
Water was delivered, but even if this process could work on other planets
Systems. "

Dirty snowballs

out of shape
which revolve around a in disc form
Star; Small debris can stick together and become larger over time.
Remains of debris remain in regions of our own solar system such as the Kuiper Belt .
beyond Neptune or the Oort cloud
far behind Pluto. Comets come from these areas, but we can only see them if
their orbits bring them closer to the sun. The heat from the sun causes some of it
The dirty snow evaporates and creates the blurred halo or "coma" of
Water vapor, dust and ice grains in comet pictures.

Scientists predict that the water is in the earth
The oceans came from aquatic bodies in the early solar system that collided
with our planet, much like today's ice-rich asteroids or comets. But
The scientists do not know where these objects come from in the formative disk.


Water is also known by the chemical name H 2 O
because it consists of two hydrogen atoms and one oxygen atom. But with special
Scientists can detect two types of instruments: normal water, H 2 O,
and heavy water, HDO, which has an extra neutrally charged particle called a
Neutron in one of the hydrogen atoms. Scientists compare the amount of
heavy to regular water in comets. If comets have the same ratio of these waters
Species like oceans of the earth, it indicates that the water in both can have one common

However, measuring this ratio is difficult. ground
and space telescopes can only investigate this degree of detail in comets when they are
Pass near Earth, and missions to visit comets, such as Rosetta are rare. Scientists could only roughly investigate this relationship
a dozen comets since the 1980s. In addition, it is difficult
to examine the water of a comet from the ground, because it blocks the water in the earth's atmosphere
his signatures.

New Observations

Observing at high altitudes above much of the
The atmospheric water of the earth allowed SOFIA to accurately measure the ratio
Regular to heavy water in the comet Wirtanen. The data showed that the comet is Wirtanen
Water content is the same as in the oceans of the earth.

When the team compared the new SOFIA data with the previous ones
Studies of comets found a surprising commonality. The ratio of regular to
heavy water was not associated with the origin of comets – whether they were from
the Oortenwolke or the Kuipergürtel. Instead, it was related to how much water there was
was released from grains of ice in comet coma compared to straight from the
snowy surface. This could mean that all comets could have a hard-to-rule
Water ratio similar to the oceans of the earth, and that they could have delivered a
big fraction of the water to the earth.

"This is the first one
For a long time, we were able to relate the ratio of heavy to normal water of all comets to a single one
Factor, "noted Dominique Bockelée-Morvan, a scientist at the University of Paris
Observatory and the French National Center for Scientific Research and secondly
Author of the paper. "We may need to reconsider how we examine comets because
Water released from the ice grains seems to be a better indicator of this
Total water ratio as the water released from surface ice.

Further studies are needed to determine if these results are correct
also applies to other comets. The next time a comet is supposed to fly nearby
enough for this type of study will be in November 2021.

SOFIA, the Stratospheric Observatory
for infrared astronomy is a Boeing 747SP jetliner that has been modified to carry a 106-inch jet
Diameter telescope. It is a joint project of NASA and German Aerospace
Center, DLR. Manages NASA's Ames Research Center in Silicon Valley, California
the SOFIA program, science and missionary operations in collaboration with the
Universities Space Research Association, headquartered in Columbia, Maryland,
and the German SOFIA-Institut (DSI) at the University of Stuttgart. The
Aircraft are maintained and operated by NASA's Armstrong Flight Research
Center Building 703 in Palmdale, California.

News 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
[email protected]

Calla Cofield
Jet Propulsion Laboratory, Pasadena, California
[email protected]


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