Can you feel the heat? NASA’s Mars Odyssey can see it! This is an image of Mars’ smaller moon Deimos, captured with Odyssey’s THEMIS (Thermal Emission Imaging System) instrument on Feb. 15, 2018. Part of the 7-mile-wide Moon was in shadow, but the sunlit surface area reached temperatures up to 200 K (that’s still pretty cold for us, though… –100ºF / -73ºC!)
It’s finally happened—after over 14 years on Mars (14!!!) NASA’s Opportunity rover has turned its arm-mounted camera around to take a look at itself, giving us the very first true “selfie” of the Mars Exploration Rover mission! Hello Opportunity!
That’s here; that’s home; that’s us—the two bright objects in this picture are Earth and the Moon, imaged by NASA’s OSIRIS-REx spacecraft on January 17, 2018 from a distance of 39.5 million miles (63.5 million km).
This is about the distance between Earth and Mars at their closest points to each other (give or take about 6 million miles) or about 165 times farther away from us than the Moon.
Voyager 2 may have been the second of NASA’s famous twin exploration spacecraft but it actually launched first, on August 20, 1977. Eight and a half years later it became the first (and, to date, last) spacecraft to visit Uranus, at 31,500 miles across the third largest planet in the Solar System. Voyager 2 made its closest pass by Uranus 32 years ago, giving us our best views ever of the enormous ice giant planet and its moons.
On this night in 1610 the Pisan astronomer Galileo Galilei looked up at a bright Jupiter at opposition through his handmade telescope and noted three little “stars” next to it, piquing his natural scientific curiosity. Further observations over the next few nights showed that the planet wasn’t moving relative to the little “stars” as it would have if they were indeed background stars. In fact the smaller objects (of which he soon saw four) were moving along with Jupiter, each in its own little path. He realized that the little objects weren’t stars at all but rather moons orbiting the giant planet—and, most importantly, not the Earth. This revelation helped change our entire view of the Solar System… and caused no end of trouble for Galileo as the Church didn’t appreciate a restructuring of their conveniently Earth-centered Universe. But it also opened the door for later discoveries of many more moons around other planets.