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Κυριακή 16 Απριλίου 2017

Chemicals for Life Found on Enceladus

                

Chemicals for Life Found on Enceladus

Δημοσιεύτηκε στις 15 Απρ 2017
Did
you hear that NASA just announced an important discovery in the quest
to find life on other places in the Solar System? In this quick episode,
Fraser details what NASA found on Enceladus and Europa, and what it
means for the search for life.

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Team: Fraser Cain - @fcain / frasercain@gmail.com
Karla Thompson - @karlaii
Chad Weber - weber.chad@gmail.com

I know, I know, this is getting comically hilarious. Aliens, next episode.

Although maybe, aliens this episode?

Anyway,
NASA made a huge announcement today, and I thought it was important
enough to stop everything we were doing, call Chad and Karla back to
Universe Today headquarters to help me cover it.

Here’s the
announcement: NASA announced today that they’ve found an important
chemical for life - hydrogen gas - blasting out of Saturn’s icy moon
Enceladus. In addition to this, they confirmed that Jupiter’s Europa has
icy geysers too.

We’ve known about Enceladus’ plumes for a
while, so the discovery of hydrogen gas is pretty exciting. We’ve
suspected Europa has jets, but more confirmation of their existence is
great. We don’t know if there’s hydrogen gas in Europa’s plumes… yet,
but there’s a spacecraft in the works to help us find out.

Let’s get into the details.

Earlier
this week, NASA teased us that they were going to be announcing
something interesting about the ocean worlds of the Solar System. They
were vague on details, but Mike Brown confirmed what I’d always
expected: Europan Space Whales.

I was all ready to hear their mournful songs, muffled by kilometers of ice, but I was sadly disappointed.

Okay
fine, the reality turned out to be pretty cool too. NASA announced that
they’ve found evidence that there’s hydrogen gas pouring into the water
of one of Saturn’s icy moons: Enceladus. The source of this hydrogen is
probably some kind of hydrothermal activity down beneath the ocean.

The
tidal interactions between Enceladus and Saturn heat up the moon,
giving it vast oceans, which spews water into space from cracks at its
southern pole.

Here on Earth, remember, wherever we find water,
we find life. And one really interesting place that we find life is
surrounding volcanic hydrothermal vents at the bottom of the ocean.
These volcanic vents belch plumes of material into the ocean, and serve
as the energy source for a vast array of lifeforms.

Heat loving
thermophilic bacteria known as methanogens absorb the hydrogen coming
from these vents and use them as an energy source. Other creatures eat
this bacteria, and you’ve got a thriving ecosystem and food chain.

One
of the most interesting things about these hydrothermal vents is how
they provide a completely separate ecosystem from the rest of life on
Earth. They couldn’t care one bit if the Sun disappeared tomorrow, and
all life died. They’d keep slurping up their hydrogen gas, going and
going.

And that’s why this discovery about Enceladus is so
exciting. In their announcement, planetary scientists working with
Cassini described how the spacecraft detected this hydrogen gas in the
plumes blasting out of Enceladus.

On October 28, 2015, the
spacecraft made its deepest dive through the plumes coming out of
Enceladus. It sampled the icy material and found that 98% of the plumes
is water, 1% is hydrogen, and the rest is a mixture of ammonia, methane
and carbon dioxide.

Cassini isn’t equipped to search for life. It
just doesn’t have the instruments on board. Its Ion and Neutral Mass
Spectrometer instrument did the next best thing. It found food for
bacteria. When this environment is found on Earth, bacteria has a
feeding frenzy.

That’s pretty exciting. The discovery over on
Europa is different. Astronomers had suspected there were plumes on
Europa like Enceladus, based on images taken by the Hubble Space
Telescope back in 2014. But the results were inconclusive.

The
Hubble team took a second round of images in 2016, and detected plumes
coming from the same region of Europa, confirming their existence. Is
there hydrogen gas in those plumes too? We have no idea yet, but we soon
will.

In a second, I’m going to explain what we’re going to do
about this. What plans are in place to study this even further, but
first I’d like to thank Khaled Al Tal, Isaac Arthur, Lee Stuurmans,
Larry Johnson, Ryan Williams, and the rest of our 705 patrons for their
generous support. If you love what we’re doing and want to help out,
head over to patreon.com/universetoday.

Now we see another
tantalizing clue that there could be life in the oceans of Europa and
Enceladus, what are we doing to do about it? What plans are in place to
go back and study these worlds up close?
ANAΡΤΗΣΗ ΑΠΟ ΤΟ YOUTUBE 16/4/2017

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