Nation This exoplanet rains iron. And scientists say temperatures can hit a scorching 4,000 degrees October 6, 2021 Wyatte Grantham-Philips, USA TODAY Comments Off on This exoplanet rains iron. And scientists say temperatures can hit a scorching 4,000 degrees WASP-76b is a fiery gas giant exoplanet with iron rainfall. A new discovery of ionized calcium suggests its atmosphere may be even more extreme.