On March 9, 2017, NASA’s Curiosity rover took this picture with its turret-mounted MAHLI camera of the calibration target installed near the “shoulder” of its robotic arm. In addition to color chips and a metric line graph, the target also includes a U.S. coin: a 1909 Lincoln penny, adhered heads-up.
Curiosity’s coin isn’t just for good luck though; it’s also a nod to geologists who typically use familiar objects in field photos to help determine scale. (Curiosity is, after all, one of only two working robot geologists on all of Mars!)
One of my all-time favorite space images is this little gem from the Clementine mission to the Moon, launched January 25, 1994. It features a view from beyond the far side of the Moon, illuminated by reflected light off the Earth off frame to the left. The Moon is blocking the disc of the Sun with the glow of the solar corona and an overexposed Venus shining brightly in front of a background of stars. It may have been taken on April 1 but this picture is no joke—it’s absolutely beautiful!
A field of spike-like structures rise up over two miles from the outer edge of Saturn’s B ring in the amazing image above, captured by Cassini during Saturn’s spring equinox in August 2009. These pointy perturbations are caused by the gravitational nudges of tiny (~1/2 mile) embedded moonlets traveling around Saturn within the B ring, causing fine icy particles to “splash” upwards from the otherwise relatively flat ring when they pass by them. The moonlets themselves are held in their orbits by the gravity of Mimas.
The spikes were made visible mainly because of the angle of illumination at the time of equinox, which on Saturn occurs every 15 years and in this instance was on Aug. 11, 2009.
Ever since the discovery of Pluto by Clyde Tombaugh in 1930 our Solar System was known to have nine planets orbiting the Sun. “My Very Eager Mother Just Served Us Nine Pizzas” was a popular mnemonic in my elementary school days to help remember the order of major planets from Mercury outward. But in 2006, a controversial decision by the International Astronomical Union—spurred in part by Caltech astronomer Mike Brown—changed the specifications on what officially classifies a planet in the Solar System, thereby stripping Pluto of its 76-year-old designation. The reclassification, done by an in-person vote at a meeting in Prague (at which only about 400 of over 9,000 IAU members were in attendance) has been a topic of debate—often fierce—in the astronomical community ever since, and now some scientists are demanding to have it redefined again.
Like some giant beast’s great blue eye Saturn’s north polar vortex appears to glare up at Cassini’s wide-angle camera in this image, a color-composite made from raw images acquired in red, green, and blue visible light wavelengths on February 13, 2017.