Previous: 3 Mysteries Solved by Extraterrestrial Tsunamis
Next: How Does Titan Still Have an Atmosphere?



View count:1,233
Last sync:
Astrophysicists have discovered an exoplanet that lost its atmosphere, but then, somehow, grew it back! Also, astronomers used satellite data to find a magnetic hurricane above the north pole that we almost missed!

Hosted by: Hank Green

SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at
Support SciShow by becoming a patron on Patreon:
Huge thanks go to the following Patreon supporters for helping us keep SciShow free for everyone forever:

Silas Emrys, Charles Copley, Drew Hart, Jeffrey Mckishen, James Knight, Christoph Schwanke, Jacob, Matt Curls, Christopher R Boucher, Eric Jensen, Lehel Kovacs, Adam Brainard, Greg, GrowingViolet, Ash, Laura Sanborn, Sam Lutfi, Piya Shedden, KatieMarie Magnone, Scott Satovsky Jr, charles george, Alex Hackman, Chris Peters, Kevin Bealer

Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:
Looking for SciShow elsewhere on the internet?

Image Sources:

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. {♫Outro♫}.