We have been
exploring the surface of Mars for a good few decades now, and in the process
have discovered evidence for water and an ancient habitable environment. One
thing remained elusive though – any signs of the building blocks of life.
exploring the surface of Mars for a good few decades now, and in the process
have discovered evidence for water and an ancient habitable environment. One
thing remained elusive though – any signs of the building blocks of life.
Now that
looming problem has been solved by the Curiosity rover.
looming problem has been solved by the Curiosity rover.
Reporting in the
journal Science, researchers have announced that the rover’s Sample Analysis at
Mars (SAM) instrument has successfully detected organics on Mars, a major
breakthrough in our search for life on the Red Planet. A second paper also
reports some interesting findings about methane.
journal Science, researchers have announced that the rover’s Sample Analysis at
Mars (SAM) instrument has successfully detected organics on Mars, a major
breakthrough in our search for life on the Red Planet. A second paper also
reports some interesting findings about methane.
“It’s a
really, really big stepping stone,” Sanjeev Gupta from Imperial College London
in the UK, one of the co-authors on the study, told IFLScience. “It gives us
great confidence that future missions have the potential to discover life.”
really, really big stepping stone,” Sanjeev Gupta from Imperial College London
in the UK, one of the co-authors on the study, told IFLScience. “It gives us
great confidence that future missions have the potential to discover life.”
Using the
SAM instrument, the team led by Jennifer Eigenbrode from NASA’s Goddard Space
Flight Center examined samples of Martian soil about three years ago from
mudstone in Gale Crater. It was collected by Curiosity’s drill from 5
centimeters (2 inches) beneath the surface, preserved in sulfur and dating back
in time between 3.2 and 3.8 billion years, when water was once present here.
SAM instrument, the team led by Jennifer Eigenbrode from NASA’s Goddard Space
Flight Center examined samples of Martian soil about three years ago from
mudstone in Gale Crater. It was collected by Curiosity’s drill from 5
centimeters (2 inches) beneath the surface, preserved in sulfur and dating back
in time between 3.2 and 3.8 billion years, when water was once present here.
While we
have seen organics on Mars before, this is the first time they have been linked
to larger molecules that could be indicative of life.
have seen organics on Mars before, this is the first time they have been linked
to larger molecules that could be indicative of life.
Gale Crater
on Mars, pictured, is thought to have once hosted a lake. NASA/JPL-Caltech
on Mars, pictured, is thought to have once hosted a lake. NASA/JPL-Caltech
Heating the
sample in the instrument, the team found evidence for several organic
materials, including thiophene, methanethiol, and dimethyl sulfide. These are not
compounds directly related to life, but they are signatures of larger molecules
that could have been produced by life.
sample in the instrument, the team found evidence for several organic
materials, including thiophene, methanethiol, and dimethyl sulfide. These are not
compounds directly related to life, but they are signatures of larger molecules
that could have been produced by life.
Organic
molecules are ones that contain carbon and hydrogen. They can come from
non-life sources, such as meteorites, and also from interactions with rocks and
water. However, they also come from living matter. So we needed to find some on
Mars to prove we were heading in the right direction.
molecules are ones that contain carbon and hydrogen. They can come from
non-life sources, such as meteorites, and also from interactions with rocks and
water. However, they also come from living matter. So we needed to find some on
Mars to prove we were heading in the right direction.
“The
detection of organic matter on Mars is the next step in the search for life on
Mars,” Eigenbrode told IFLScience. “If the organic matter we discovered was
derived from life, then it could contain signatures of that ancient life.”
detection of organic matter on Mars is the next step in the search for life on
Mars,” Eigenbrode told IFLScience. “If the organic matter we discovered was
derived from life, then it could contain signatures of that ancient life.”
Previous
attempts to find organics on Mars, including the Viking missions in 1976 and
the Phoenix lander in 2008, had been inconclusive. Curiosity’s discovery marks
the first time we have truly known about organic compounds on the surface of
Mars.
attempts to find organics on Mars, including the Viking missions in 1976 and
the Phoenix lander in 2008, had been inconclusive. Curiosity’s discovery marks
the first time we have truly known about organic compounds on the surface of
Mars.
It’s
important to stress that this is not a detection of life, nor is it proof that
past or present life exists on Mars. It instead gives us ever-growing evidence
that parts of Mars, such as Gale Crater in which Curiosity now resides, was
capable of supporting life as we know it.
important to stress that this is not a detection of life, nor is it proof that
past or present life exists on Mars. It instead gives us ever-growing evidence
that parts of Mars, such as Gale Crater in which Curiosity now resides, was
capable of supporting life as we know it.
Thanks to
this discovery, we now know that Mars once had all of the basic ingredients we
know life needs. This will give scientists planning future missions confidence
that they are on the right track in the search for life.
this discovery, we now know that Mars once had all of the basic ingredients we
know life needs. This will give scientists planning future missions confidence
that they are on the right track in the search for life.
It poses
another question though, specifically if life did not arise. If Mars had all
the same conditions as Earth, including water and organics, then why did life
spring up on our planet but not on our neighbor?
another question though, specifically if life did not arise. If Mars had all
the same conditions as Earth, including water and organics, then why did life
spring up on our planet but not on our neighbor?
“If there’s
no life on Mars, even though conditions are so similar, what made Earth so
special?” Inge Loes ten Kate from Utrecht University, who was not involved in
either study, told IFLScience.
no life on Mars, even though conditions are so similar, what made Earth so
special?” Inge Loes ten Kate from Utrecht University, who was not involved in
either study, told IFLScience.
Curiosity
will not be able to answer this question definitively. But future missions may
very well be able to give us a better picture, including ESA’s ExoMars rover in
2020. This will be able to drill up to 2 meters (6.5 feet) under the surface,
40 times further than Curiosity, to depths where material is more shielded from
radiation.
will not be able to answer this question definitively. But future missions may
very well be able to give us a better picture, including ESA’s ExoMars rover in
2020. This will be able to drill up to 2 meters (6.5 feet) under the surface,
40 times further than Curiosity, to depths where material is more shielded from
radiation.
At these
depths, it may be possible to find even more organic compounds like this. But
it will probably not be until we actually return Mars rocks to Earth, as NASA
is planning in the 2020s, that we will really be able to answer if life arose
on the Red Planet.
depths, it may be possible to find even more organic compounds like this. But
it will probably not be until we actually return Mars rocks to Earth, as NASA
is planning in the 2020s, that we will really be able to answer if life arose
on the Red Planet.
“This
discovery gives us confidence that we’re not wasting our time,” said Sanjeev.
discovery gives us confidence that we’re not wasting our time,” said Sanjeev.
NASA’s Mars
2020 rover will leave samples on Mars for an uncrewed mission to one day return
them to Earth. NASA/JPL-Caltech
2020 rover will leave samples on Mars for an uncrewed mission to one day return
them to Earth. NASA/JPL-Caltech
In the
second paper also released today, researchers led by Christopher Webster from
NASA’s Jet Propulsion Laboratory (JPL) measured methane levels on Mars. They
used an instrument on Curiosity called the Tunable Laser Spectrometer over five
years to make the discovery.
second paper also released today, researchers led by Christopher Webster from
NASA’s Jet Propulsion Laboratory (JPL) measured methane levels on Mars. They
used an instrument on Curiosity called the Tunable Laser Spectrometer over five
years to make the discovery.
The most
interesting finding is that methane levels on Mars seem to change with the
seasons. In the winter levels drop down to about 0.2 parts per billion, but in
the summer they raise three-fold to 0.6 parts per billion. It might sound
small, but this rise is hugely important.
interesting finding is that methane levels on Mars seem to change with the
seasons. In the winter levels drop down to about 0.2 parts per billion, but in
the summer they raise three-fold to 0.6 parts per billion. It might sound
small, but this rise is hugely important.
“Very few
gases on Earth change by a factor of three,” Webster told IFLScience. “So this
huge change allows us to rule out some things and causes.”
gases on Earth change by a factor of three,” Webster told IFLScience. “So this
huge change allows us to rule out some things and causes.”
This is
exciting for another ESA mission, one that’s currently in orbit around Mars,
called the Trace Gas Orbiter (TGO). Scientists are using this spacecraft to
study gases in the atmosphere of Mars and pinpoint some of the sources of them
on the surface.
exciting for another ESA mission, one that’s currently in orbit around Mars,
called the Trace Gas Orbiter (TGO). Scientists are using this spacecraft to
study gases in the atmosphere of Mars and pinpoint some of the sources of them
on the surface.
ESA’s Trace
Gas Orbiter (illustrated) will look more closely for methane. ESA/D. Ducros
Gas Orbiter (illustrated) will look more closely for methane. ESA/D. Ducros
It’s thought
this methane has been trapped in reservoirs underground, and over the summer as
temperatures increase, it is released from the surface into the air. Where this
methane came from isn’t clear, and it may simply be the result of geological
processes on Mars.
this methane has been trapped in reservoirs underground, and over the summer as
temperatures increase, it is released from the surface into the air. Where this
methane came from isn’t clear, and it may simply be the result of geological
processes on Mars.
But one
other source of methane is, of course, life. Coupled with the first paper, it
paints a tantalizing picture of what might be happening on Mars. And if you let
your mind wander, things certainly do get a bit interesting.
other source of methane is, of course, life. Coupled with the first paper, it
paints a tantalizing picture of what might be happening on Mars. And if you let
your mind wander, things certainly do get a bit interesting.
“You can
hypothesize that there might have been early life, and the organics might have
been the remnants from that, and those organics might have produced methane,
and that methane is being stored in the surface of Mars,” said Kate.
hypothesize that there might have been early life, and the organics might have
been the remnants from that, and those organics might have produced methane,
and that methane is being stored in the surface of Mars,” said Kate.
It will be
years before we truly know if that might have been the case. But this latest
discovery tells us that, for all the billions of dollars we’ve spent exploring
Mars, it just might be hiding the answer to the question we’ve wanted to know
all along: Are we alone, and if so, why?
years before we truly know if that might have been the case. But this latest
discovery tells us that, for all the billions of dollars we’ve spent exploring
Mars, it just might be hiding the answer to the question we’ve wanted to know
all along: Are we alone, and if so, why?
Via
IFLScience.
IFLScience.
