It’s been pretty warm in New York City this week, with temperatures reaching the mid-90s. The South Pole is currently at -89 degrees Fahrenheit. It’s incredible that one planet can have such a temperature difference, but consider WASP-39b, a distant exoplanet: One side is permanently bathed in light, while the other side is always dark, and the dark side is somehow 300 degrees hotter.
The exoplanet is 1.3 times larger than Jupiter and is located 700 light-years away. As it orbits its star, it doesn’t spin like Earth does. Instead, one side is always pointed toward the stars. You might think that the side with permanent daylight would be boiling, while the side with permanent nighttime light would be freezing, but it turns out the opposite is true. New data from the Webb Space Telescope shows that when gas on the side with permanent daylight is heated, it creates powerful winds that reach thousands of miles per hour and rush toward the dark side, while winds coming the other way push cold gas toward the bright side. The result is a permanent night that is heated to 1,450 degrees Fahrenheit, enough to instantly melt the skin on your body. The side with the permanent morning light has more clouds than the side with the evening light, meaning that in addition to being a relatively chilly 1,150 degrees, it is also consistently cloudier than an adjacent area on the other side of the barrier that separates the two sides. It is unclear how much influence those clouds have on the temperature, but scientists from the Space Telescope Science Institute, who published their findings in Nature, I hope I can find out with more analysis.
The researchers were able to gather their information using the Webb Space Telescope’s near-infrared spectrograph, which allowed them to compare the light that passed through the exoplanet’s atmosphere as it passed in front of the star with the light that the star emitted when it was unobstructed.
Previous glimpses of WASP-39b have revealed the presence of materials such as carbon dioxide, sulfur dioxide, water vapor, and sodium in its atmosphere. With this new knowledge about one exoplanet, STSI Webb now hopes to turn to other tidally locked exoplanets to study their atmospheres and see if there are similar oddities in their weather patterns.