- 3927 - WATER ON EARTH - how did it get here? A reserve of water the size of 140 trillion oceans is lurking in a faraway supermassive black hole, the universe's largest deposit of water and 4,000 times the amount found in the Milky Way.
------------ 3927 - WATER ON EARTH - how did it get here?
- Water makes
up 71% of Earth's surface, but no one knows how or when such massive quantities
of water arrived on Earth.
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- Researchers
are analyzing melted meteorites that had been floating around in space since
the solar system's formation 4.5 billion years ago. They found that these
meteorites had extremely low water content
They were among the driest extraterrestrial materials ever measured.
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- These
results, which let researchers rule them out as the primary source of Earth's
water, could have important implications for the search for water,and life, on
other planets. It helps researchers understand the unlikely conditions that
aligned to make Earth a habitable planet.
Getting water and having surface oceans on a planet that is small and
relatively near the sun is a challenge."
-
- The team of researchers analyzed seven
melted, or achondrite, meteorites that crashed into Earth billions of years
after splintering from at least five planetesimals. Planetesimals are objects that collided to
form the planets in our solar system.
-
- In a process known as melting, many of these
planetesimals were heated up by the decay of radioactive elements in the early
solar system's history, causing them to separate into layers with a crust,
mantle and core.
-
- Because
these meteorites fell to Earth only recently, this experiment was the first
time anyone had ever measured their volatiles.
They used an electron microprobe to measure their levels of magnesium,
iron, calcium and silicon and water contents measured with a secondary ion mass
spectrometry instrument.
-
- To reduce
contamination, researchers first baked their samples in a low-temperature
vacuum oven to remove any surface water. Before the samples could be analyzed
in the secondary ion mass spectrometer, the samples had to be dried out once
again. They had to leave the samples
under a turbo pump—a really high-quality vacuum—for more than a month to draw down
the terrestrial water enough.
-
- Some of
their meteorite samples came from the inner solar system, where Earth is
located and where conditions are generally assumed to have been warm and dry.
-
- Other rarer
samples came from the colder, icier outer reaches of our planetary system.
While it was generally thought that water came to Earth from the outer solar
system, it has yet to be determined what types of objects could have carried
that water across the solar system.
-
- After
analyzing the achondrite meteorite samples, researchers discovered that water
comprised less than two millionths of their mass. For comparison, the wettest
meteorites, carbonaceous chondrites, contain up to about 20% of water by
weight, or 100,000 times more than the meteorite samples.
-
- This means
that the heating and melting of planetesimals leads to near-total water loss,
regardless of where these planetesimals originated in the solar system and how
much water they started out with. Not all outer solar system objects are rich
in water. This led them to conclude that water was likely delivered to Earth
via unmelted, or chondritic, meteorites.
-
- Water is
considered to be an ingredient for life to be able to flourish, so as we're
looking out into the universe and finding all of these exoplanets, we're
starting to work out which of those planetary systems could be potential hosts
for life. In order to be able to
understand these other solar systems, we want to understand our own.
-
- A reserve of
water the size of 140 trillion oceans is lurking in a faraway supermassive
black hole, the universe's largest deposit of water and 4,000 times the amount
found in the Milky Way.
-
- This amount
of water was discovered by astronomers
12 billion light-years away, where it appears as vapor dispersed across
hundreds of light-years.
-
- The reservoir
was discovered in a quasar's gaseous area, which is a brilliant compact region
in the heart of a galaxy powered by a black hole. This demonstrates that water
may be present throughout the cosmos, even at the start.
-
- Water has
never been discovered this far out before. The light from the quasar
(specifically, the APM 08279+5255 quasar in the constellation Lynx) took 12
billion years to reach Earth, implying that this mass of water existed when the
universe was just 1.6 billion years old.
-
- One group
used the Z-Spec instrument at the Caltech Submillimeter Observatory in Hawaii,
while the other used the Plateau de Bure Interferometer in the French
Alps. These sensors detect millimeter
and submillimeter wavelengths, allowing the detection of trace gases (or vast
reservoirs of water vapor) in the early cosmos.
-
- The
discovery of many spectral fingerprints of water in the quasar provided
researchers with the data they needed to calculate the vast magnitude of the
reservoir.
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March 21, 2023 WATER ON
EARTH - how did it get here? 3927
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