Other Worlds on Earth: Preparing for Space from Home

Other Worlds on Earth: Preparing for Space from Home


This episode is sponsored by The Ridge. Go to ridge.com/space and use promo code “SCISHOW” to get 10% off your next order. [♪ INTRO] As much as space inspires us to imagine and
explore, it doesn’t exactly welcome that exploration. You’ve got deadly radiation, extreme cold,
lack of oxygen, and those are just the start. Some of the most tempting destinations in
our solar system are home to the most
hostile environments you can imagine. But Earth also has its fair share of hostile
places. And we can use them to prepare space probes and even astronauts for some of the most
unwelcoming places in our solar system. And that includes our nearest neighbor, the Moon. Even though it’s the one other world humans
have walked on, the idea of something like a lunar colony is still a major challenge. Any long-term explorers would need protection from radiation and the constant shower of micrometeorites, because unlike on Earth,
there’s no atmosphere to burn them up. But the Moon itself might have the perfect
hideaway. Back in 2012, NASA’s GRAIL spacecraft created
a high-resolution map of the moon’s gravity, which reflected differences in density under
the surface. The map revealed huge underground voids on
the near side of the moon. They seemed to be in shape of tunnels, some of them dozens of kilometers long and hundreds of meters wide. Astronomers think these voids are massive
lava tubes. Lava tubes can form when cool air solidifies
the outer layer of a lava flow. When the molten rock inside drains away,
it forms a natural tunnel. And these giant lunar lava tubes could be
the perfect refuge for humans. Not only could they house a whole city, they could provide shelter from radiation, micrometeorites, and the Moon’s extreme temperatures. So, scientists like those at JAXA, the Japan
Aerospace Exploration Agency, are considering building our first lunar cities
inside lava tubes. It’s a pretty dramatic idea, but fortunately,
we can do a practice run. Here at home, we also have lava tubes in volcanically active places like Hawai’i, Iceland, and the Canary Islands. The tubes are smaller because Earth’s stronger gravity collapses any that get too big, but they still make
a pretty great laboratory. In Lanzarote, one of the Canary Islands, lava
tubes stretch more than 8 kilometers in length. They go from openings in the surface
to more than 50 meters below sea level. And inside, the European Space Agency has been training future astronauts and mission specialists since 2016. The trainees work alongside robots inside
these volcanic caverns, and practice using pioneering technology to do things like map the cave systems and look for signs of water and life. These are techniques that will keep them alive
and help them scope out the alien environments they might one day encounter on the Moon. As barren as it is, the volcanic landscape
of Lanzarote is charming compared to some of the more hostile environments in the solar system, like Mars. Even though it’s our most-visited planet, we still struggle to answer the one basic question that keeps drawing us back: Has it
ever had life? Mars’s surface is unbelievably dry and cold, and its thin atmosphere means that its soil can’t catch a break from radiation. So if it has life at all, it’s probably microscopic and buried beneath the surface for protection. And NASA is developing a rover that they hope
will be able to detect life like this. And luckily we have just the place on Earth to
test it out. The Atacama Desert in Chile is one of the
driest places on Earth. Some areas get just 1 to 3 millimeters of rain a year. Between this and the chemical makeup of its soil, it’s about as close to a Martian environment
as you can get on our muggy planet. The microscopic Atacaman life is forced to
live underground, where the last drops of water might persist. Now, scientists are using a rover to look
for these buried microbes, just like we would on Mars. The Atacama Rover Astrobiology Drilling Studies
project, or ARADS, has designed a rover that can drill down as much as 2 meters, through soil, salt, and rock, and return samples to its onboard lab. NASA hopes to be able to detect signs of life
from these samples, and this test run will tell us if a rover like this could pull off the same stunt on Mars. Much deeper in the solar system, scientists
are eyeing Jupiter’s icy moon Europa as another target for robotic explorers. Astronomers believe the moon has a liquid
ocean, and, as far as we can tell, liquid water is the number-one requirement for life. The thing is, that water and any life it contains are buried beneath a 20 kilometer-thick crust of ice. Which is kind of inconvenient, but maybe not
impossible. Right now, scientists are training robots
using our own ice-covered ocean, the Antarctic. A team at Georgia Tech has developed a long-range,
underwater rover called Icefin. It’s about 3.5 meters long
but just 23 centimetres wide, which lets it slide into narrow boreholes that the scientists drilled in the ice. This robotic explorer can then dive beneath
the Antarctic ice shelf and navigate on its own, all the while surviving freezing temperatures,
crushing pressure, and unpredictable currents. But it can do much more than just survive. Instruments onboard Icefin can take high-resolution measurements of the environment. And that’s exactly what we’ll need any
Europan explorer to do, if we want to get a picture of this alien ocean and figure out if it’s habitable, or even inhabited. Of course it’ll take more research before
we’re ready to launch an underwater drone to an icy moon more than 600 million kilometers
from home. So Icefin itself won’t make it to Europa. But its great-grandchild might. In the meantime, Icefin’s measurements are helping us understand and document the melting of Antarctic glaciers. It turns out that in reaching for space, we’re also learning about some of the most amazing places on Earth. And preparing for hostile worlds gives us even more reason to appreciate the one world in this solar system that actually does welcome
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