Astronomers Found a Brutal Hell Exoplanet Where It Rains Liquid Iron
At the moment, the COVID-19 virus is making life on Earth pretty unpleasant, but as the old parable says, "Things could always be worse." You could be living on the planet WASP-76b instead.
Located 640 light-years from Earth in the constellation Pisces, WASP-76b is an ultra-hot gas giant, having a diameter of 165,000 miles (266,000 km). That makes it almost twice the size of Jupiter, the largest of our solar system's planets. Jupiter's diameter is 88,695 miles (142,800 km), which is 11 times the size of Earth.
Despite its massive size, WASP-76b has less mass than Jupiter, possibly because it never has a chance to cool down. That's because WASP-76b revolves around a star that is almost twice as large as our Sun, and at a distance of only three times the radius of the star.
WASP-76b is its star's only planet, and it whips around the star once every 1.8 Earth days. That tight orbit causes the planet to be "tidally locked", much like our Moon. That means that the planet rotates on its axis and revolves around its star at the same rate. This causes one side of WASP-76b to always face its star, and one side to always face away.
Temperatures on the star facing, or "dayside", reach 4,350 ° Fahrenheit (2,400 ° Celsius), which is hot enough to vaporize any metals present on the planet. Temperatures on the side facing away from the star, or "nightside", reach 2,730 ° Fahrenheit (1,500 ° Celsius).
The exoplanet was discovered in 2013 by the Echelle Spectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO). This is an instrument installed on the European Southern Observatory's Very Large Telescope, located in Chile.
ESPRESSO detected iron vapor along the "evening" border that separates WASP-76 b's dayside from its nightside, however, they didn't detect it along the "morning" border. That meant that something was causing the iron to disappear.
Scientists concluded that winds on WASP-76b, having speeds in excess of 11,000 mph (18,000 km/h), were carrying the vaporized iron from the dayside to the nightside, where it was condensing into a molten iron rain.
Associate professor of astronomy at the University of Geneva in Switzerland, David Ehrenreich, described conditions on WASP-76b as, "These are likely the most extreme climates we could ever find on a planet."
The first exoplanet, or extrasolar planet, wasn't discovered until 1992. As of May 1, 2020, there are 4,260 exoplanets in 3,149 systems, and 696 systems have multiple planets.
"It was a world that could never know the meaning of night and day, of years or seasons. Six colored suns shared its sky, so that there came only a change of light, never darkness. ... Though the planet might be scorched by the central fires in one age, and frozen in the outer reaches in another, it was yet the home of intelligence. The great, many-faceted crystals stood grouped in intricate geometrical patterns, motionless in the eras of cold, growing slowly along the veins of mineral when the world was warm again. No matter if it took a thousand years for them to complete a thought. The universe was still young, and time stretched endlessly before them." -- Arthur C. Clarke, Childhood's End
NASA maintains a list of exoplanets in its NASA Exoplanet Archive, which is part of the Infrared Processing and Analysis Center located on the campus of the California Institute of Technology (Caltech) in Pasadena, CA.
So far, all known exoplanets are within our own Milky Way Galaxy. The least massive exoplanet is Draugr, which has about twice the mass of our Moon. The most massive exoplanet HR 2562 b, which is about 30 times the mass of Jupiter.
The time it takes for an exoplanet to orbit its star varies from a few hours to thousands of years. The nearest exoplanet to earth is Proxima Centauri b, which orbits the star located closest to our Sun, Proxima Centauri, and is just 4.2 light-years away.
The exoplanet most similar to Earth is Teegarden b, which orbits a red dwarf start located 12 light-years from our solar system. Teegarden b orbits its star in just 4.91 days, but it has a mass almost identical to that of Earth and is likely to be rocky. It may even have ocean water on its surface, and scientists estimate it to have a surface temperature between 0 ° and 50 ° C.
Whatever the conditions are on Teegarden b, they've got to be better than those on WASP-76b where it's always cloudy with a chance of molten iron rain.