Discovering the source of life on Mars
Scientists suggest liquid water is forming on
contemporary Mars and renew search for signs of life:
by Ali Younes
NASA announced on Monday (28) that liquid saltwater exists on the
surface of Mars – a discovery that scientists say indicates the
"potential" for life on the planet.
Lujendra Ojha |
The historic findings by scientists from NASA and several US
universities are based on research on dark, narrow and elongated streaks
that appear on the surface of the Red Planet and which are known as
‘recurring slope lineae’ (RSL).
Research shows the streaks "appear and grow incrementally in the down
slope direction during warm seasons."
NASA scientists suggest the streaks were formed as a result of salty
"flows" or "seeps" because they bear a striking resemblance to the
shapes and curves that water on Earth makes as it flows along the
surface of the ground.
The theory that water exists on Mars was first proposed by scientist
Lujendra Ojha, who as an undergraduate student at the University of
Arizona in 2011, studied dark, finger-shaped images on Mars.
Ojha, now a PhD candidate at the Georgia Institute of Technology and
the lead author of the study, told Al Jazeera that "water does exist on
Mars."
Ojha added that chemical signatures of water were found in the
crystals of salt samples.
"We found evidence of water activity in hydrated salts on Mars," he
said.
Step one discovery
The authors of the research paper – ‘Spectral Evidence for Hydrated
Salts in Recurring Slope Linea on Mars’ – published in the scientific
journal Nature Geoscience identified four key hydrated salts that
indicated the presence of water: magnesium perchlorate, magnesium,
chlorate, and sodium perchlorate as present in the dark streaks.
"Our findings strongly support the hypothesis that recurring slope
lineae form as a result of contemporary water activity on Mars," the
paper, which will be the topic of NASA's announcement, said.
Alfred McEwen – planetary geology professor at the University of
Arizona, who co-authored the paper – had previously done extensive
research on ravines to see if water existed on the dry and frigid
planet.
"Water [in a liquid state] is essential to life as we know it, so
finding water is a big step. On Earth, anywhere there's water in nature,
there is life, but that isn't necessarily true on the surface of Mars,"
McEwen told Al Jazeera when asked what the discovery meant for the
possibility of life on Mars.
"The water may be such a dense brine that life can't flourish, and
the radiation environment of Mars' surface is detrimental. However,
finding the water is step one, and we need future investigations to look
for life at these locations."
Science fiction enthusiasts and Hollywood executives may be
disappointed to learn there will be no alien creatures, or even large
organisms, as far as science is concerned.
Life on Mars, if it exists, will most likely be microbes, McEwen
said.
The dark streaks were originally seen by NASA's Mars Reconnaissance
Orbiter travelling at low and middle latitudes in the southern
hemisphere, but as temperatures spiked during summer months, the streaks
appeared to be seeping down slope and faded in cold seasons. They
appeared again and in the same spot year after year.
Observing this, scientists reasoned that, since Mars is about 80.5
million km further from the sun than Earth and its surface temperature
rarely rises above freezing point, it was the rise in temperature during
summer months that triggered the shapes to appear again.
Scientists say this suggests that trapped ice inside salty particles
melted and flowed down the steep slopes of Mars, creating the dark
river-shaped streaks on the surface.
"These results strongly support the hypothesis that seasonal warm
slops are forming liquid water on contemporary Mars," the paper said.
"If water on Mars proves to be real, it would not look or feel like
water on Earth. Mars water would most likely be 'briny rather than pure'
not free flowing."
"This is a wet soil, not standing water," McEwen said.
-Al Jazeera
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