Good morning and happy Monday!

This week's topic is on tholins! A very weird word to say in the planetary community, but what in the world is it? Let's explore!

What is the definition of tholin?

Tholin are "abiotic complex organic gunk." That's right…gunk. Methane, carbon dioxide, nitrogen and other gaseous mixtures are irradiated, or rather mixed then energized by solar radiation. What happens is that this "gunk" becomes a discolored solid mass. The key words here are abiotic and complex. Petroleum, asphalt, tar- these are complex solids, but all from "biotic" backgrounds. Tholins did not come from any earth biology, but rather from clumps of gases and dust, which makes the complexity of this substance very fascinating in the planetary formation and evolution community. 

What did it come about in research?

Carl Sagan and his colleague, Bishun Khare published a paper in 1979 that simulated UV radiation of space onto mixtures of gas compounds, and the result- named "tholin"- was born!

What's the future outlook on studying tholins?

We've had hints of dark colored surfaces on otherwise ice-covered bodies and thought the possibility of tholin production. Some of the dark streaks on Europa, some darker atmospheric layers on Titan, and certainly the reddish-brown region on Pluto might all be various degrees of tholin production. There is still much to learn about these compounds and radiation. 

Possible tholin-covered region on Pluto. The mystery continues! Could we find more on other far away rocky bodies? Image credit: New Horizons/ NASA.

Possible tholin-covered region on Pluto. The mystery continues! Could we find more on other far away rocky bodies? Image credit: New Horizons/ NASA.

Thank you for reading and have a Happy Holiday! Come back on January 2nd for a section on ice and lava!