The Cosmic Rambler

Written by: Fatima Saleem (SS-07)

Hi! I am Hubble, and if you are a space enthusiast, you might have heard about me. In case you haven’t, you can google for me later. For now, let us focus on the story of a hot planet I visited in 2015.   

It is called “WASP-121 b”, which is 880 light-years from Earth. This alien world is known as a “hot Jupiter,” a class of gas giants that have physical similarities to Jupiter but orbit their stars much closer (hence, their “hot” nature). This exoplanet is tidally locked, meaning it has one side that is always facing its star and another side that faces away.

On the star-facing dayside, metals and minerals evaporate. The dayside’s upper atmosphere gets as hot as about 5,400 degrees Fahrenheit (3,000 degrees Celsius), so hot that water in the atmosphere glows and molecules break down.

But on the planet’s nightside, the atmospheric temperature is essentially cut in half. This difference in temperature causes strong winds to blow from west to east around the planet, pulling water through the atmosphere from the dayside to the nightside. As water molecules are pulled apart into hydrogen and oxygen atoms by the heat on the dayside, the cool temperatures on the nightside then recombine the atoms into water vapour. That water is pulled back to the dayside by the winds and pulled apart in a continuous cycle.

The temperatures on the nightside are never low enough for water clouds to form during this cycle, but that doesn’t mean that clouds don’t form at all. While water clouds don’t form, metal clouds do.

And, just as the strong winds pull water vapour and atoms around the planet to break apart and recombine, metal clouds will blow to the planet’s dayside and evaporate, condense back on the nightside, and so on. 

But metal clouds aren’t the only strange phenomenon I spotted on this hot Jupiter. I also found evidence of possible rain in the form of liquid gems. 

It’s exciting to study and visit planets like WASP-121 b that are very different from those in our solar system because they allow us to see how atmospheres behave under extreme conditions. I told everyone about it, and my younger brother James Webb will visit the Hot Planet real soon…

For more details refer to
https://www.mpg.de/18278975/MPIA-PR_WASP-121b_Mikal-Evans_2022_Article.pdf