Water Is Flowing on Mars
In a major
scientific finding, researchers confirm briny water flows seasonally on
the Red Planet.
ADRIENNE LAFRANCE, SEP 28, 2015
Right now, 140 million miles
away, somewhere on the frigid surface of Mars, there is water forming.
Scientists announced they have strong evidence that briny water flows on the planet, a critical
step toward identifying possible life on Mars.
“Water is essential to life as
we know it,” wrote Lujendra Ojha, Mary Beth Wilhelm, and their co-authors in a
paper published Monday in Nature Geoscience. “The presence of liquid water
on Mars today has astrobiological, geologic, and hydrologic implications and
may affect future human exploration.”
If this announcement, which
NASA billed as “major” in the days leading
up to it, sounds not altogether new, it’s because scientists have
been obsessing over the water on
Mars for decades. (The sight of ice volcanoes on Pluto this
summer had scientists similarly elated.) Astrobiologists have long
suspected that Mars was at least partially covered in water at one
time—markings on the planet indicate the presence of ancient streambeds.
A billion years ago, scientists believe the planet may have had a roiling,
primitive ocean. Meandering formations on the surface of Mars suggested
water flowed on the planet for a geologically significant period of time. Long
enough, perhaps, to have sustained bacteria or other simple life forms.
In recent years, it became
increasingly clear that water in some form was still present on Mars—in vast near-surface
deposits of ice, in massive glaciers near the poles, and in large sheets in
crater and gullies. The knowledge that water existed at all on Mars
“completely shifted the paradigm of Mars today from a static, arid world
to a planet still being shaped by water. If life evolved there, conceivably it
may still survive,” as the Mars Exploration Program Analysis Group put it.
In 2013, scientists identified
geographic features suggesting “surprisingly abundant” briny water near Mars’s
equator, according to a paper that appeared inNature Geoscience two years ago. Monday’s
announcement builds on that finding.
“Mars is not the dry, arid
planet that we thought of in the past,” said Jim Green, director of planetary
science at NASA Headquarters, in a press conference on Monday. Previously,
evidence of flowing water on Mars was still considered circumstantial.
Scientists used spectral
data to more closely analyze those geographic features and found
hydrated salts that suggested a seasonal pattern of water flow. “The hydrated salts most
consistent with the spectral absorption features we detect are magnesium
perchlorate, magnesium chlorate, and sodium perchlorate,” the authors wrote in
Monday’s paper. “Our findings strongly support the hypothesis that recurring slope
lineae form as a result of contemporary water activity on Mars.”
That the water is believed to be briny—not fresh—is another exciting
finding. It makes it more likely that the water could support life. Fresh water
would freeze on Mars, and likely kill any organisms with it.
“The detection described here warrants
further astrobiological characterization and exploration of these unique
regions on Mars,” the authors wrote. So this finding answers one huge question
about the nature of Mars, but it raises many more.
Mars once had clouds, snowy mountaintops,
fresh lakes, and a deep ocean. All that water dissipated over time as Mars’s
atmosphere thinned. But scientists still don’t know why that
happened.
They also want to investigate
how cold and concentrated the brine is—not just to see whether the water
supports life on Mars today, but to determine whether it might be a resource
for humans visiting the planet in the future.
“Mars is looking more and
more—it’s a potential habitat, extant from Earth,” said the physicist John Mace
Grunsfeld in a press conference Monday. “The resources are there.”
1)
Word bank: search for:
Frigid: ………………
Briny/brine: ………………
To flow: ………………
Toward: ………………
To bill: ………………
Altogether: ………………
Decade: ………………
Sight: ………………
Elated: ………………
Streambed: ………………
Roiling: ………………
Gully/ies: ………………
To shift: ………………
Spectral: ………………
Feature: ………………
Slope: ………………
Warrant: ………………
To raise: ………………
Mountaintop: …………
2) Answer the WH_ questions. (on your copybook) Who (writer,
discoverer)? What? Where? When? Why is it important, what are the consequences?
3) Analyser la phrase the water is
believed l36. (sujet, verbe complément) de quelle forme verbale
s’agit-il? A quel temps est le verbe ?
4) Examiner
les verbes l 3/6/8, à quoi servent ces
particules ?
5) Identify the important elements in each paragraph.
6) Write a summary of the text (10lines).
7) Translate from l42 to 50.
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