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When we look at other planets, it can be easy to try and divide them into neat, orderly categories.
Like, you’ve got small rocky planets, and you’ve got big gas giants,
and beyond the solar system, there are some worlds in-between. But if you look closely enough,
those categories fall apart. Like, last week, one team announced that they found a planet that might have
started as a gas world, then lost its original atmosphere…
and is now a rocky planet trying to grow another atmosphere.
The exoplanet is GJ 1132 b, and we first spotted it in 2015.
It’s roughly the size and density of Earth, and is even roughly the same age. But it’s no Earth 2.0.
For one, it orbits its star so closely that its year is only 1.6 Earth days long.
Also, its star is a young red dwarf. And these stars are pretty temperamental,
shooting out a lot of high-energy particles that can strip away a planet’s atmosphere.
In fact, that might have had a huge effect on the place.
Based on their computer models, astronomers think this rocky exoplanet actually started out
as a mini-Neptune — a type of gaseous exoplanet smaller than the Neptune in our solar system.
Then, within 100 million years or so, it lost almost all of the hydrogen and helium
in its air to space, leaving behind a barren, rocky core.
Except… newer observations with the Hubble Space Telescope revealed that this planet
does have an atmosphere. It might even have a similar pressure to what we experience on Earth.
But it’s not hydrogen and helium.
Instead, with the help of more modeling, this team pieced together that this air is made of hydrogen,
hydrogen cyanide, methane, ammonia, and smog.
So, how does that work? If this planet’s atmosphere had
been stripped away by its star, where did this one come from?
Well, the team thinks that some of the original hydrogen gas went into hiding.
When this planet was still forming and the atmospheric pressure was high enough,
some of the hydrogen got dissolved into and stored inside the planet’s magma.
It would’ve been like how factories dissolve carbon
dioxide into pop. Just with hydrogen… and magma.
And now, that dissolved hydrogen is slowly getting released through some sort of volcanic process.
Based on their calculations about how hot the planet is and what it’s made of,
this team proposed that this world wouldn’t have actual, mountainous volcanoes.
But the crust would be so thin that it would be super easy for cracks to form, and the hydrogen
gas could escape through those — along with other gases made in chemical reactions down there.
Then, any remaining gases would have been made in reactions between the air and light from the star.
Now, the great thing is, we’ll be able to actually to test part of
this hypothesis when the James Webb Space Telescope launches — hopefully in October.
Despite being 41 light-years away, 1132 b is close enough
that NASA’s new-fangled telescope will be able to directly image this planet.
And if it can see down the surface,
it should be able to tell us if certain spots are warmer, indicating geologic activity.
Also, even if that’s not where this atmosphere is coming from,
this planet is still a big one because of how it overturns our previous expectations.
We used to think a small, rocky world super close to a red dwarf would just be a dead,
fried husk. But based on this, it looks like we might have been wrong.
Speaking of atmospheres, scientists have been making discoveries about Earth’s atmosphere, too.
Last month in the journal Nature Communications, a team published evidence of a cyclone made of
plasma in the atmosphere above the North Pole. And they’re calling it a space hurricane.
Space weather as a whole is nothing new.
The Sun regularly spits out light and charged particles that interact
with Earth’s magnetic field and upper atmosphere.
When these interactions are especially powerful,
we call them geomagnetic storms. And it turns out that some of these storms
can create a phenomenon that looks a lot like cyclones much closer to the ground.
This team found one of these structures in data collected in 2014
by the Defense Meteorological Satellite Program.
The storm was more than 100 kilometers up,
and the researchers used the data to map and model it in more detail.
They found that this thing had a central eye where everything was calm,
and several arms of ionized gas spinning around it.
The gas even spun counterclockwise, like hurricanes do in the northern hemisphere.
Just, instead of water, this one rained electrons.
It’s not clear if it was visible from the ground — this team only observed it
in ultraviolet light. But it was definitely big:
It stretched over 1000 kilometers across the sky and lasted for eight hours.
And finding it has big implications for research.
For one, if it weren’t for those satellites, this storm could have easily gone unnoticed.
Right now, much of the equipment scientists use to
monitor geomagnetic conditions around the planet doesn’t really register what’s going
at the poles. The equipment just isn’t far north or south enough.
So it read everything as perfectly calm, while a space hurricane was raging in the north.
This means scientists are going to have to adjust where they’ve been focusing their
observations to fully understand the intricacies of space weather.
But also, events like this are worth knowing about for the sake of our equipment.
Space hurricanes won’t hurt you on the ground,
but they can threaten the electronic equipment in orbit — disrupting communications with satellites,
and even causing drag that can mess with their trajectories.
So after this, scientists will likely keep an eye out for more of these storms — because
whether we’re studying space hurricanes close to home or planets light-years away,
there’s always more to learn.
Thanks for watching this episode of SciShow Space News! If you liked learning about how that rocky
exoplanet is breaking our expectations, we’ve got another episode you might enjoy.
It’s about three other planets that transformed our understanding of the universe,
and you can watch it after this.
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