It’s been pretty hot in New York this week, with temperatures reaching the mid-90s. But in Antarctica, it’s currently at -89 degrees Fahrenheit. It’s hard to believe that such a temperature difference can exist on a single planet, but consider the example of a distant exoplanet called WASP-39b, which has a side that is always lit up and a side that is always dark, and for some reason the dark side is 300 degrees hotter.
This exoplanet is 1.3 times the size of Jupiter and 700 light-years away from Earth. As it orbits its star, instead of rotating like Earth, one side always faces the star. You might think that the day side would always be boiling and the night side would always be frigid, but it turns out that the opposite is actually true. According to new data from the Webb Space Telescope, as gas heats up on the side facing the star, powerful winds that can reach thousands of miles per hour form and flow into the dark side, while winds in the opposite direction push the cooler gas into the light side. As a result, the night side is always heated to 1,450 degrees Fahrenheit, enough to melt the skin on your body in an instant. The morning side is always cloudier than the evening side, and in addition to being a relatively chilly 1,150 degrees Fahrenheit, it is always more cloudy than the neighboring area across the wall that separates the two sides. It is unclear how much these clouds affect the temperature, but scientists from the Space Telescope Science Institute say that Nature, I think further analysis will reveal this.
The researchers were able to gather information thanks to the Webb Space Telescope’s near-infrared spectrograph, which allowed them to compare the light that passes through the exoplanet’s atmosphere as it moves in front of its star with the light that the star emits when it is undisturbed.
Previous observations of WASP-39b have shown the presence of substances such as carbon dioxide, sulfur dioxide, water vapor, and sodium in its atmosphere. Armed with new knowledge about this one exoplanet, STSI now hopes to point Webb at other tidally locked exoplanets to study their atmospheres and see if they have similar anomalies in their weather patterns.
