This July we're going to be celebrating the
50th anniversary of the Moon landing Apollo
11.
I was actually not alive for the moon landing.
And I have no memory of people being on the
Moon.
I was alive in the very early '70s, but as
a two or three-year-old, was never something
that I was aware of.
So I never had the chance to look up in the
sky at the Moon and think there are people
up there today.
So in the 1960s, of course, this was a part
of the Cold War.
It was some of our competition with the Soviet
Union.
We wanted to make sure that we were ahead
of them in terms of building big rockets and
missiles and that kind of thing.
But I think what's happened now is that we
have a much stronger scientific case for returning
to the Moon.
And this is something that I'm really excited
about as a scientist, not just as an American,
and not just as a human.
I'm also very much looking forward to having
the first woman on the moon, the first person
of color on the moon, I think that's very
important because so far, everybody who's
walked on the moon is somebody that doesn't
look a whole lot like me.
And I would like that to change in the very
near future.
But why do I want to go back to the Moon?
I mean, we were there before, 50 years ago.
We brought back hundreds of pounds of rocks.
So why would you want to go back?
And one of the things is that the samples
that we took from the moon the rocks, the
dust, the soil, from the moon that we took
completely revolutionized our view of how
the Earth formed, how the solar system formed,
and even things that we see as we look out
into other solar systems around other stars.
Now, why?
Well, what changed so much?
The moon rocks were entirely different than
what we expected.
Specifically, anything that could possibly
burn at all.
What we call volatiles was gone.
They were very, very dry.
There was almost no water, and by water, I
mean water that was actually dissolved into
the minerals.
I mean not liquid water, not even ice, but
water that's contained in the chemical structure
of the rock.
But in other ways they were almost identical
to the Earth.
They had the same type of isotopic ratios,
chemical markers about how old the rocks were.
And so how could you have something that has
such a similar composition to the Earth but
be so different?
Almost as if you had Earth rocks, but then
everything that could possibly burn was taken
away.
And we realized that the moon must really
be something special.
It seems that the moon is the product of a
giant collision, a collision between planets.
Something at least the size of Mars and maybe
even bigger, maybe the size of the Earth today,
actually hit the young Earth when it was forming.
This would have happened billions of years
ago.
And debris was thrown off during that explosion
that eventually came together under the force
of gravity and formed the moon.
So in the moon rocks there's records of this
giant collision.
There may even be records in some of the minerals
of what that other planet was like, the planet
that's no longer there, what actually hit
us to form the current Earth and Moon system.
There's also all kinds of wonderful records
on the Moon as to what happened to the Earth
over time.
Unlike the surface of the Earth, the moon
doesn't really change much.
I mean, yes, there are meteorites that hit
it from time to time, but there's no water,
no erosion, no wind, there's no chemical weathering
of the rocks.
So what you have is a preservation of what
the Earth has been through for the last billion,
hundreds of millions of years.
One of the amazing things we found in moon
rocks is evidence that the Earth probably
passed very close to an exploding star about
300 million years ago.
And there actually was kind of a radioactive
rain that came down on us from this exploding
star.
And we only see that record on the surface
of the moon in the rocks, and also at the
very bottom of the Earth's ocean.
In sediments that are that ancient, they preserved
that time.
So the moon is actually going to be able to
tell us, when we have more samples, what the
whole history of the Earth was like, how the
Earth formed, and what happened to the Earth
over time.
Recently, we actually found the oldest Earth
rock that we have on the moon.
It was actually in a lunar sample.
We found that there was a little bit of Earth
that had actually probably been thrown off
during a collision.
A big asteroid hit us.
Rocks flew up into space, some of them landed
on the moon.
And now, we actually have a sample of the
Earth three billion years ago when it was
hit by something very large.
The moon rocks are also telling us things
like where organic molecules, the building
blocks of our chemistry, came from, and maybe
even the origin of water.
We're finding tiny little bits were actually
formed during collisions and volcanism on
the surface of the moon.
Now, all of these things are things we've
just realized are there in the lunar samples.
Most of the samples have already been picked
over and chemically analyzed.
We've crushed things up.
We've changed them.
We're so much better now at being able to
do the chemical analysis, And we understand
so much more about what it's saying, That
we need better samples. and the exploration
is going to be really amazing.
One of the challenges is protecting the astronauts
from solar storms.
We realize we got pretty lucky with Apollo.
Had there been a very strong solar storm,
It could have damaged instruments, could even
have hurt the astronauts.
And so now, we know we need to protect people
when they're up there.
And we'll probably have them land very near
craters at the poles of the moon.
The poles are really important because there
are craters up there that never see sunlight.
They're actually permanently shadowed from
the sun.
And so, if there's a big solar storm, all
the astronauts need to do is go down one of
these craters, And they can be safe from that.
Also, when you're near the poles.
You're almost continuously illuminated by
the sunlight, and you have great contact with
Earth as well.
So I think probably the first place we're
going to go, we actually have chosen the South
Pole.
That's the goal for the place to send astronauts
next, South Pole of the moon.
So as a scientist, the moon has a much larger
context as well.
We see things happening in other solar systems
around other stars.
Occasionally, you see a giant flash of heat,
And a solar system many light-years away appears
to be full of molten metal All at once.
And probably what we've seen is an event like
the formation of the moon two planets have
collided.
I don't know if we'd really understand what
was going on if we didn't have the example
of the moon right there in front of us.
So it's been more than 50 years, I am really
looking forward to someday looking up there,
and I really hope I can see a little light,
You know something up there at the very base
of the moon that you can actually see that
there are people up there today.
And I think that will be an amazing feeling
to look up and feel humanity on the moon again.
