Mercury's original crust was lost to sight, covered by lava from global volcanism. Since then, the little planet has cooled & shrunk, forming wrinkle ridges & other distinctive topographic features that run across pre-existing craters & lava plains. #gam2018 #RandomAstroFact

NASA's Curiosity Rover, operating on Mars since 2012, has recently been investigating the iron-bearing Vera Rubin Ridge. Rubin (1928-2016) was the distinguished astrophysicist whose observations confirmed the existence of dark matter in galaxies. #gam2018 #RandomAstroFact

Most gold in the universe is made in nuclear reactions triggered when neutron stars collide & merge, an event first observed last August by two gravitational wave observatories & the Fermi satellite. About 70 telescopes made follow-up measurements. #gam2018 #RandomAstroFact

Jupiter is known for colorful cloud belts parallel to the equator. Now its blue polar regions are seen in vivid form by the Juno space probe. Each has a huge central cyclone ringed by more cyclones, 8 at the north pole & 5 at the south pole. #gam2018 #RandomAstroFact

The red giant star Pi1 Gruis is 530 light-years from Earth & 350 times the size of the Sun. Infrared images from the Very Large Telescope in Chile reveal that the star has giant convection cells, about 75 million miles (120 million kilometers) wide. #gam2018 #RandomAstroFact