3d Illustration of a volcanic planet

1249982508

3d Illustration of a volcanic planet

Photo by: Razvan25

Razvan25

Say Hello to a Planet So Hot that the Oceans are Lava and it Rains Rocks

Exoplanets are planets orbiting stars outside the solar system, and every month seems to bring in a new batch of weird, wild, and wonderful worlds.

December 23, 2020

Ah, I love exoplanets. Case in point: K2-141b, a planet so hot that the oceans are made of lava, it rains rocks, and the atmosphere is dirt.

It’s absolutely breathtaking. Too bad it’s a couple hundred light-years away.

No Pictures, Please

So check this out. We don’t actually have any pictures of this Nightmare Planet (as I prefer to call it). Instead, we know of its existence through a little trick of light. As K2-141b orbits its star, it occasionally passes in front of it, causing the light that we see here on Earth to dim just a tiny bit. Using a powerful instrument like the Kepler Space Telescope, we can monitor that dip in brightness and figure out that planet’s size, mass, and distance from its parent star.

We’ve done this thousands of times for systems all across the galaxy, but something about K2-141b just…stands out.

Maybe it’s the fact that K2-141b isn’t much different than the Earth–it’s only about 50% wider than our planet. But it’s much, much bulkier, stuffing in five times the mass of the Earth in that volume.

Flying Too Close

The sun, illustration.

1042136264

The sun, illustration.

Photo by: KTSDESIGN/SCIENCE PHOTO LIBRARY

KTSDESIGN/SCIENCE PHOTO LIBRARY

Oh, right, there’s also the fact that it orbits its parent star only about a million kilometers away from it. That’s just 0.74% percent of the distance that the Earth orbits the sun.

This makes for two interesting facts of life on K2-141b. One, it’s hot. Very hot. The dayside reaches a scorching 5,500 degrees Fahrenheit in the shade. Two, orbiting that close to the star, it’s highly likely to be tidally locked--meaning that one side of the planet always faces the star, just like one side of the Moon is always facing the Earth.

That means that while the side facing the star is super-duper-hot, the nightside is plunged in never-ending night, cooling down to 328 degrees below zero.

It’s a bit of a contrast, and scientists have taken these basic numbers to model what’s going on with the planet and its atmosphere. That’s how we know that the place is a nightmare. For example, at 5,500 degrees, rock turns into lava, so the dayside surface of K2-141b must be a molten mess.

Hot 'n Cold

Photo Taken In Milo, Italy

1097039820

Photo Taken In Milo, Italy

Photo by: Salvatore Virzi / EyeEm

Salvatore Virzi / EyeEm

Second, -328 degrees is cold enough for rock to…well, just be a rock, so the nightside has a “normal” surface. But because the planet is getting roasted on one side and iced on the other, there has to be a massive flow of heat, with giant currents of magma oceans running from one side of the planet to the other, cooling off, warming up, and repeating in a never-ending cycle.

It’s also hot enough to not only melt rock, but also vaporize it. That means on the dayside the atmosphere isn’t made of air (it’s way too hot for puny nitrogen or carbon dioxide), but of…vaporized rocks. Those tiny particles blast their way in multi-hundred-mph winds to the nightside, where they cool and condense, falling as a never-ending hailstorm of pebbles.

A wondrous place to see… from a safe distance.

Paul M. Sutter

Paul M. Sutter is an astrophysicist at Stony Brook University and the Flatiron Institute, host of Ask a Spaceman and Space Radio, and author of How to Die in Space.

Next Up

What We’ve Already Learned From James Webb? (Hint: it’s a lot)

That was worth the wait. Just a quick handful of months since its historic launch on Christmas Day, the James Webb Space Telescope has flown to its observing position, unfolded its delicate instruments and ultra-sized mirror, and run through a suite of checks and alignments and calibrations. The team at NASA behind the telescopes released their first batch of images from the science runs, and besides being gorgeous, they're powerful.

Why Astronomers Care About Super-Old Galaxies?

A long time ago, our universe was dark.It was just 380,000 years after the big bang. Up until that age, our entire observable cosmos was less than a millionth of its present size. All the material in the universe was compressed into that tiny volume, forcing it to heat up and become a plasma. But as the universe expanded and cooled, eventually the plasma changed into a neutral gas as the first atoms formed.

A Guide to this August’s Best Astronomy Attractions

Learn more about the exciting things happening in the night sky this month! From the rings of Saturn to the most popular meteor shower of the year, August 2022 has us stargazing all month.

How Astronomers Use a Trick of Gravity to See the Most Distant Objects in the Universe

Let’s say you’re an astronomer (work with me here) and you want to take a picture of something incredibly, deeply far away. You know, the typical business of astronomy.

How Exoplanets Became the Next Big Thing in Astronomy

To date, we know of over 5,000 planets outside the solar system. And astronomers suspect that there may be *checks notes* around a trillion more in our galaxy alone. The search for exoplanets is one of the hottest topics in astronomy, with expensive telescopes and giant collaborations all searching for the holy grail of the 21st century: an Earth 2.0, a habitable world like our own.

South Korea Joins Space Race by Sending its First Spacecraft to the Moon

South Korea is launching its first lunar probe to the moon on August 4th. The Korea Pathfinder Lunar Orbiter (KPLO) or Danuri, developed by the Korea Aerospace Research Institute (KARI) is being launched to study moon carters, magnetic fields, and surface weathering.

The Best Planets are Rogue Planets

We can debate the status of objects in the solar system all day long, arguing if little Pluto is a planet or not. But to tell you the truth, any planet in any solar system got the short end of the stick. The real winners of the galactic game are the travelers, the roamers, the rogue planets.

India’s Space Agency is Going Big… By Going Small

Astrophysicist Paul M. Sutter shares the latest in the world of rocket launches and what India’s SSLV is all about.

Jupiter Makes Its Closest Approach to Earth in Nearly 60 Years

The last time Jupiter appeared this large and bright in the sky was in October 1963.

The Perseid Meteor Shower Reaches its Peak

Stargazers rejoice! The annual Perseid meteor shower is upon us. Here's what you need to know...(updated August 11, 2022)

Related To: