This artist’s illustration depicts the possible inner dynamics of the super-Earth’s exoplanet [+]
Universität Bern / University of Bern, illustration: Thibaut Roge
We know very little about exoplanets. Despite there being thousands that have been confirmed by astronomers, little is known about whether they have atmospheres, water, or anything else that can make them habitable.
We only occasionally know their size and even how far they orbit their host star.
So the claim that a planet has been found around a star with volcanoes illuminating the night sky is a big one. So far, researchers have found no evidence of global tectonic activity on planets outside of our solar system.
The seminal work, published this week in The Astrophysical Journal Letters, is an exoplanet called LHS 3844b, orbiting a red dwarf star – the most common type of star in the Milky Way – about 49 light-years away in the constellation Indus.
What We Know About This Volcanic Planet
Here’s everything you need to know about LHS 3844b:
- It is a “super Earth”, but only – its radius is 1.3 times larger than our planet and 2.25 times the mass.
- A year on LHS 3844b lasts just 11 hours – that’s how fast it takes to orbit its star.
- Day and night on LHS 3844b last forever. That’s because the LHS 3844b is neatly connected to its star, showing one side of it – just like the moon does to Earth.
- It’s a bare, rocky basalt planet that makes it dark – much the same as Mercury and the dark mares on the moon.
- It probably has no atmosphere, so it is not habitable – and at least it is 1410 ° F / 770 ° C on the day side and -418 ° F / -250 ° C on the night side.
- Its host star is a red dwarf star that is about one fifth the size of our sun.
- Its discovery was announced in September 2018 using data from the Transiting Exoplanet Survey Satellite (TESS).
This artist’s illustration shows the exoplanet LHS 3844b, which is 1.3 times heavier than Earth and [+]
NASA / JPL-Caltech / R. Pain (IPAC)
What’s so bizarre about LHS 3844b
The surface may be largely covered with dark lava rock, according to 2019 observations by NASA’s Spitzer Space Telescope. It also found that very little heat is dissipated from the star-facing day side of the planet to the space-facing night side. That indicates a lack of wind and weather – and therefore no atmosphere.
Now scientists at the University of Bern and the National Center of Competence in Research NCCR PlanetS in Switzerland have discovered that the material in LHS 3844b flows from one hemisphere to another. It could be responsible for countless volcanic eruptions on one side of the planet.
How tectonic activity works on LHS 3844b
“Observing signs of tectonic activity is very difficult because they are usually hidden under an atmosphere,” said Tobias Meier of the Center for Space and Habitability (CSH) at the University of Bern. “We thought that the strong temperature contrast could affect the material flow inside the planet.”
To test that theory, the team performed computer simulations of varying strengths of material and internal heat sources, such as heat from the planet’s core and the decay of radioactive elements.
LHS 3844b orbits so closely around its star that one side of the planet is in constant daylight and [+]
Getty
“Based on what we are used to from Earth, you would expect the material to be lighter on hot days and therefore flow upwards, and vice versa,” said study co-author Dan Bower of the University of Bern and NCCR PlanetS. However, some simulations showed the opposite direction of flow. “This initially counter-intuitive result is due to the change in viscosity with temperature – cold material is stiffer and therefore will not bend, break or submerge in the interior,” said Bower. “Warm material is less viscous, so even solid rock becomes more mobile when heated – and can easily flow into the interior of the planet.”
It seems clear that LHS 3844b works in a very different way than Earth, where plate tectonics brings material from the interior of the planet to the surface and the atmosphere and then transports it back under the Earth’s crust – making Earth habitable.
Volcanoes light up the night on LHS 3844b
The strange material flow in LHS 3844b has bizarre consequences. “Whichever side of the planet the material is flowing upward, you’d expect a great deal of volcanism on that side,” Bower said. “Comparable deep upwelling currents on Earth create volcanic activity in Hawaii and Iceland”
The bottom line is that LHS 3844b likely has a hemisphere riddled with volcanoes and one with almost none.
LHS 3844b may have similar deep upwelling currents to those on Earth that power volcanic [+]
AFP via Getty Images
What comes next for LHS 3844b
These conclusions are drawn from computer simulations, so more detailed observations are needed from LHS 3844b – such as a higher-resolution map of the surface temperature that could reveal volcanic outgassing.
How long would it take to get to LHS 3844b
Not good news here / Although 49 light years puts it firmly in our cosmic backyard, the LHS 3844b is far too far away to reach.
If you were to travel at a light speed, it would take 49 years. Take it a step further to humanity’s fastest moving space probe, New Horizons – traveling at about 33,000 mph / 53,100 – and it would take 987,026 years to reach LHS 3844b.
I wish you a clear sky and wide eyes