? [music] ?
KIDS: Our World!
EVAN: Hey Globey, do you ever wonder if life exists on other planets?
I mean, after all, your surface is covered with life...
from people to animals to plants to bacteria that are
so small we canít even see them.
But what about other worlds like Mars? Does life exist there...
or did it exist in the past?
Today we are going to explore the possibility that life
exists on other worlds, but not in the form of the little
green men we call aliens that you often see in movies.
Have you heard of the term Extraterrestrial?
That term just means coming from some place other than Earth.
So when we talk about extraterrestrial life, weíre
talking about the potential life on other worlds.
But what would those life forms look like? Would they look like us?
Or would they look different?
And where would we look to find life outside our world?
Water is an essential ingredient for life as we know it.
Without water, there can be no life. Letís talk about Mars for a minute.
Two Mars orbiting space craft, Mars Global Surveyor
and Mars Oddyssey provided the first evidence that large
standing bodies of water once existing on Mars.
This made scientist believe in the presence of water on Mars
- not liquid water flowing across the surface of Mars,
but large subsurface deposits of water ice on the red planet.
These observations were then backed up when two Mars exploration Rovers,
Spirit and Opportunity , provided the first concrete
proof that large standing bodies of water once existed on Mars.
The Rover looked at the Rocks that were formed as the ancient seas dried up.
In 2007, NASA sent the Phoenix Lander to Mars to look for water.
The Phoenix Lander is a special craft that landed on the surface of Mars.
It has a robotic arm that could dig in the soil.
And it has a camera that can beam back photos of the surface of Mars.
The robotic arm dug just below the surface of Mars,
and do you know what it found? Water!
Frozen water in the form of ice found in the polar region of Mars.
It was the first time ever that a spacecraft actually touched water on Mars!
This was an incredible discovery!
CARLA BITTER: If we got there and there was no evidence of
liquid water in the past, of frozen water ice currently;
that would have dropped the odds that there was a habitable zone.
Liquid water is the key to life as we know it on Earth.
We wouldnít have the various life forms whether mammals,
or fish, or microbes.
Pretty much all of our species require some form of liquid water to survive.
EVAN: So when the Phoenix Lander discovered there was no liquid water on Mars,
did that automatically mean there was no life on Mars?
Not exactly. Let me explain.
You may have learned about a really cool discovery on Our
World that could teach us about life on other planets.
Did you know that NASA scientists found microscopic
bacteria buried in the ice in Alaska?
Do you know what the term microscopic means?
It means the object is so small you canít see it with the naked eye.
You need a microscope to see it.
The official name for the exact kind of bacteria the
scientists found in the ice is...
well, Iím not even going to try to pronounce it.
But it means ďancient red bacterium in ice.Ē
You can see its name right there...
This tiny bacterium had been buried in the ice for over 32,000 years.
And when the scientists melted the ice, the bacterium
started swimming in the liquid water! Something that
had been frozen for thousands and thousands of years was still alive!
Even though the bacteria seemed to prefer temperatures
that were near room-temperature, they were able
to adapt to the extreme cold and stay alive until the ice melted.
Scientists refer to these tough bacteria as
Extremeophiles, which means the bacteria can exist in
extremely harsh conditions, or at least conditions that are harsh to humans.
Such as the ice found at the North Pole...
Or the super heated waters of underwater volcanic vents and hot springs...
Or maybe even a place with no air like our Moon.
CARLA: An Extremeophile is something that lives in the extremes,
maybe a critter that inhabits a super hot thermal vent at
the bottom of the ocean under incredible pressure and heat.
That would be a thermophile. Or a Halophile. Halo is salt.
Something that can live in extremely desiccated dried
out, salty, absent of water environment.
EVAN: So when the Phoenix Lander found ice just below
the surface of Mars, did that also mean they found these incredible Extremeophiles? ?
CARLA: Phoenix found out that currently, no. There is not
currently any life form that we can detect on Mars based on our landing site.
But the potential for something in the past if we
go to another region of the planet, if we take different
instruments, has just gone up. Because we found the
secret ingredient, we found the evidence of possible past
liquid water and currently frozen water ice.
It would be very exciting to find some microbial form of
life out there in the solar system. And I have no doubt that,
itís out there in the solar system. What it would mean for us,
would mean that weíre just not so special. That we are
part of a much much larger, much more diverse community
within our solar system, within our galaxy,
within our universe than most people are willing to sit and imagine.
So I think that itís very exiting and very probable
that those are going to be discoveries that are going to be coming soon.
EVAN: So Globey, how exiting would that be if we found
life on another world. What do you think?
Is it only a matter of time before scientists discover
extraterrestrial life?
Will another NASA mission like the Phoenix Lander
discover the signs that life once lived on Mars?
Itís impossible to know for sure.
But it certainly is exciting to think about.
And who knows? Maybe all of these questions will be answered in your lifetime.
? [music] ?
KIDS: Our World!