Saturn’s moon Enceladus has fascinated scientists for decades.
I mean, it’s one of the shiniest objects in the solar system, thanks to its ice-covered surface.
And scientists love shiny objects, just like all the rest of us!
Geysers at its south pole launch water and organic molecules from its global subsurface
ocean into Saturn’s beautiful ring system.
Now, a paper in the journal Nature Astronomy claims that there are spots on the surface
with an awful lot of heat coming from the ocean below.
And if Earth’s any guide, that’s a pretty good starter pack for life.
In the paper, an international group of researchers looked at measurements that the Cassini probe’s
RADAR instrument made back in 2011.
Radar usually shines microwaves on something and learns about its surface features based
on how the microwaves bounce back.
But Cassini’s RADAR instrument is designed so that if you turn the transmitter off, it
can still detect the light given off by the surface itself.
And that can tell you about its temperature -- like how seeing that metal is glowing red
tells you it’s hot.
As it flew over Enceladus’s south pole, Cassini measured a stripey pattern of temperature
changes near the pole right next to a bunch of fractures in the surface.
Scientists have thought for a while that Enceladus’s ice might be broken up into big sections that
act like icy versions of Earth’s tectonic plates.
And these stripey temperature measurements seem to confirm that idea.
Most of Enceladus’s heat comes from tidal effects, where Enceladus gets stretched and
flexed by Saturn’s gravity as it orbits.
Thin ice flexes and heats more than thick ice, and it also lets more underground heat
through to the surface.
So higher surface temperatures probably mean thinner ice.
And plates with different thicknesses would make patterns of warmer and cooler areas on
the surface -- just like Cassini measured.
Icy plates would also make something like volcanoes and faults that we see at Earth’s
plate boundaries -- again, just like the geysers and fractures Cassini saw a few years ago.
So between the higher temperatures and active geysers, the ice near the south pole could
be way thinner than we used to think.
Based on the evidence they’d collected before this, astronomers estimated that the ice on
Enceladus might be 30 or 40 km thick in some places, and maybe 5 km thick at the south pole.
But now, it seems like ice right near the pole might be as little as 2 km thick!
All this makes the south pole a prime target if we ever want to send something to check
out the oceans under the ice.
And we might actually do that, because heat bubbling up from the bottom of a huge, salty
ocean of liquid water and organic molecules sounds a lot like the conditions where life
first evolved here on Earth.
If there’s life anywhere else in our solar system, Enceladus is one of the best places
to look for it.
Meanwhile, other researchers are looking into how our entire universe came to be in the
first place.
In a recent video over on the main SciShow channel, we talked about five big mysteries
that poke holes in our understanding of the universe.
But if a recent paper in The Astrophysical Journal has anything to say about it, that
number could drop down to four.
A few minutes after the Big Bang, the universe was filled with a hot plasma of particles
that sometimes fused together to form the first few elements on the periodic table.
So hydrogen fused into helium, and then helium combined into different types of lithium and beryllium.
And our current model of this process does a great job of predicting how much of each
element was produced.
Except lithium-7, a type of lithium with four neutrons.
There was about a third as much lithium-7 in the early universe as the model predicts,
and there’s no accepted explanation for why.
But the authors of this paper are proposing a pretty simple way around this frustrating problem.
Cosmologists generally assume that that plasma throughout the early universe acted like what’s
called an ideal gas.
Ideal gases are in equilibrium: They look pretty much the same everywhere.
And assuming the plasma stayed in equilibrium leads to those great predictions of the amounts
of elements — besides for lithium-7.
But by the time lithium was forming, that plasma was really quickly cooling down to
where new elements couldn’t fuse together anymore.
And as the authors point out, there aren’t great reasons to assume this happened at the
same time everywhere.
So the plasma might not have been in equilibrium as it cooled.
By changing that one assumption, the researchers were able to create a model that predicts
the right amounts of every early element -- including lithium!
If they’re right, it’s a beautifully simple way to explain a problem that had a lot of
physicists thinking we needed whole new laws of physics.
But we’ll have to wait and see if it gets accepted by the scientific community.
The researchers don’t really have strong reasons to think that the plasma wouldn’t
be in equilibrium; they just say that it’s plausible.
And their model also doesn’t predict anything new; it just matches what we already know,
which makes it hard to test.
We should just keep running the Big Bang over again...take some measurements...just...you
know...more Big Bangs!
The authors end the paper by encouraging more research into this new model to see if it
predicts anything else that we haven’t seen yet about the universe’s first few minutes.
They also point out that the insides of stars might be out of equilibrium in a similar way,
so research into those types of plasmas could lead to other predictions that scientists
can go out and test.
And if it does, maybe we’ll have an update to that list of mysteries about the universe
sooner than we thought.
Thanks for watching this episode of SciShow Space News.
One of our favorite parts of space is the Earth!
It’s a really great planet and April 22 is Earth Day this year.
And on Earth Day, the March for Science is taking place in Washington, D.C. and all over the US.
To show our support for scientists and their work making the world a better place and understanding
it better, we made these “Knowledge is Power” shirts and posters that we think are great
for any day, but if you want one before April 22, make sure you order yours today!
There’s a link in the description.
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