Mysterious atmosphere of 'Rosetta Stone' exoplanet

A new study modeled the chemistry of TOI-270 d, an exoplanet between Earth and Neptune in size, finding evidence that it could be a giant rocky planet shrouded in a thick, hot atmosphere. TOI-270 d is only 73 light years from Earth and could serve as a 'Rosetta Stone' for understanding an entire class of new planets.