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A host of factors have enabled
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the emergence of life on
our beautiful blue world.
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None of which exist on our moon.
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Indeed, to describe the lunar environment
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as inhospitable would be an understatement.
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So what will it take for us to live there?
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(dramatic music)
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Planet Earth is astonishingly well suited
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to supporting life.
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It is large enough to
maintain an atmosphere,
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which, in turn, means that it can support
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liquid water on it's surface.
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And thanks to that atmosphere,
global temperatures
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have never exceeded 60 degrees celsius.
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Nor have they ever fallen
below minus 90 degrees celsius.
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The annual average is a
comfy 15 degrees celsius.
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Fortunately, the Earth has managed
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to hang on to that atmosphere
for over 3.8 billion years.
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Thanks to it's swirling molten iron core.
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That turns it into one huge magnet,
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generating a massive magnetic field
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that extends far out into space.
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Without that magnetic field,
the Earth's atmosphere
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would have been stripped away long ago.
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That, in turn, would have meant that
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the surface of the Earth
would have been exposed
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to the full force of the sun's
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blistering ultraviolet radiation.
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And a constant stream of charged particles,
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known as the solar wind.
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The emergence of life as we know it
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would have been impossible.
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But our little sister moon enjoys
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none of the benefits of earth.
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It has no atmosphere.
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It has almost no magnetic field.
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And it's tiny.
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In short, the moon is about as inhospitable
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as it's possible to be.
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On the moon, the sky is always jet black,
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both by day and by night.
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The lunar surface is subject to
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dramatic extremes of temperature.
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By day the temperature in direct sunlight
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can reach over 120 degrees celsius.
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By night the temperature can drop
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to a distinctly frosty minus 153 celsius.
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Even the concepts of day and night
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are different on the moon.
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A lunar day, and a lunar night, are both
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a little over 14 and a
half earth days long.
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And for reasons that have to do with
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the interaction of the
earth's and the moon's
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uneven gravity fields, that is almost
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the same length of time that it takes
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for the moon to orbit the earth.
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They are locked together, which is why
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we only ever see this,
the near side of the moon,
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and we never see the far side.
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This was important when
planning the Apollo missions.
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{\an8}The reason why Apollo
missions were so short
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{\an8}was because they landed in the sunlight
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{\an8}and they took off while
the sun was still there.
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Should they have stayed past
14 days into the night time,
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the temperatures plummet drastically.
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On earth, you know,
the air around us allows us
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to cool machinery,
whereas in space you don't have that.
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So now I'm designing hardware
that may have to operate
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under conditions that would make the Arctic
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look like a summer day.
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And then turn around and have that
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maybe operate in the sunlight,
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where you're now at 100 degrees Fahrenheit,
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during lunar daytime.
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But the earth's atmosphere doesn't just
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help to regulate
temperatures at ground level,
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it also protects us from
the estimated 200 tons
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of interplanetary dust and rocks
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that plow into it's upper layers every day.
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Fortunately most of these
objects are very small.
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And because of their extremely high speed,
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they burn up in the atmosphere
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long before they reach the ground.
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It's a very different story on the moon.
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With no atmosphere to slow them down,
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meteorites of all shapes and sizes
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are smashing into the
lunar surface every day,
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and have been doing so
for 4.5 billion years.
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The scars of these impacts are plain to see
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in any image of the moon's face.
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But look more closely, and the reality
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becomes even more worrying.
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Imagine taking a glass and smashing it.
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You don't get nice rounded pieces.
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You get these shards
with very jagged edges.
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And that's what the soil, or lunar regolith
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is like on the moon.
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It's extremely abrasive.
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Also, it's been pummeled
for millions of years
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through asteroids and such.
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So these small abrasive particles can
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get into space suits and
moving machinery and such,
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and cause a lot of damage.
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There's been anecdotal stories about
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the Apollo astronauts' suits, the joints,
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being highly abraded,
such that if the Apollo missions
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had actually gone more than three days,
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that it might have been very difficult
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for the suits to survive
in that environment.
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{\an8}Mechanically it's very
difficult to deal with.
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{\an8}It's very abrasive.
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{\an8}It's all broken up in small angular pieces.
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The glass is very sharp,
they have sharp little edges.
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And that can cause moving parts to stop.
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You can get silicosis of the lungs,
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there's all kinds of problems
you could have with that.
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Currently, one solution to the problem
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is to never let the dust get inside
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the living quarters or the vehicles.
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On this lunar rover, the space suits
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are fixed to the shell of
the cabin in such a way
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that the astronaut enters and exits
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their suit from the rear.
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The backpack is, in effect,
also the access hatch
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into and out of the interior.
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The suit, and more
importantly, the dust on it,
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never enters the cabin.
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But not all of the hazards of lunar living
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can be mitigated as simply.
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The lack of an atmosphere, combined
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with the moon's almost
nonexistent magnetic field,
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means that the lunar surface is also
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bombarded with high energy particles
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coming from all directions.
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It's called cosmic background radiation.
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These come from deep space.
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You can't stop them.
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They're gonna penetrate almost anything.
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Right now the only way to deal with them
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is to accept that hit, and hope
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that you don't get a
really bad hit from one.
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A more difficult problem, but one that
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you can deal with,
are solar particle events.
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These are the coronal mass ejections, CMEs,
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where you have the sun
throws out huge quantities
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of highly energetic charged particles
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that travel through space and will kill ya.
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Effectively they're
extremely high radiation.
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The earth's magnetic field and atmosphere
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shield humans from that.
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But in space that's not
there, so the radiation
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from both our own sun as well as
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this cosmic background radiation,
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are significantly challenging
aspects of designing hardware.
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But, there's one potential health hazard
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that can never be overcome.
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Compared to earth, the moon is tiny.
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It's diameter is only
27 percent of earth's.
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It would fit neatly into
the North Atlantic Basin.
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And it's mass is just a little
over one percent of earth's.
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All of which leads to the fact that
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the pull of gravity on the moon
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is just under 17 percent of the gravity
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on earth, about a sixth.
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To date, 12 humans,
all of them Apollo astronauts,
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have spent an accumulated total
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of just 80 hours on the moon's surface.
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Long enough to collect some rocks,
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drive around a bit in the
world's most expensive car,
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and plant a few flags.
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But not long enough to assess
the biological consequences
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of living and working in one sixth g.
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It's already clear that
microgravity, or zero g,
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takes a heavy toll on
even short term visitors
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to the space station.
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From bone loss to impaired vision,
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from red blood cell loss,
to cardiovascular changes,
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from fluid redistribution,
to changes in coordination,
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these are just a few of the
physiological degradations
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that astronauts have to
endure, and try to counteract.
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We know that there are
physiological deterioration
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in microgravity, and they have to
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adopt countermeasures for that.
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What we don't know is how the human body
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responds to long periods of time
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in one sixth gravity of the moon.
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And that's a big question.
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It may turn out to be
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the biggest question of them all.
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And it won't only apply to the moon.
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Although bigger than the
moon, gravity on Mars
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is still only one third of earth's.
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And no one yet knows
whether future colonists
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will be able to have children
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in the fractional gravity
of the moon or Mars.
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What is known, is that during
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the first few hours and
days of development,
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most animal embryos, including humans,
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are exquisitely sensitive
to the force of gravity.
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But for the billions of years
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that life has been evolving here on earth,
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that gravity has been constant.
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The future of mankind in space may depend
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on whether our human biology will permit us
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to survive, thrive, and colonize worlds
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{\an8}that are very different from our own.
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