Mars isn’t a planet well-known for its natural satellites but it actually does have two small moons. The larger, Phobos, is an irregularly-shaped, heavily grooved and cratered world only about 17 miles (27 km) across at its widest. It orbits Mars so closely that it completes 3 orbits every day, and isn’t even visible from some parts of the planet. But Phobos has an even smaller companion in orbit: Deimos, which at the most 7.5 miles across is half Phobos’ size. Deimos orbits Mars much further away as well, taking about 30 hours to complete one orbit.
Saturn’s “yin-yang” moon Iapetus (pronounced eye-AH-pe-tus) is seen in this image, a color composite made from raw images acquired by Cassini’s narrow-angle camera on March 11, 2017.
The color difference on Iapetus is due to a fine coating of dark material that falls onto its leading hemisphere, sent its way by the distant moon Phoebe traveling within the recently-discovered giant diffuse ring. This dark coating of dust causes that half of Iapetus’ surface to warm up ever-so-slightly-more than the other, making the underlying water ice evaporate and redeposit on the other side. This in turn reinforces the cycle…a positive feedback loop.
NASA’s OSIRIS-REx may be designed to study asteroids close up but recently it’s captured a view of something farther away and much, much larger: the giant planet Jupiter and three of its largest moons at a distance of over 400 million miles!
The image was taken on Feb. 12, 2017, when the spacecraft was 76 million miles (122 million km) away from Earth—near the Earth-Sun L4 point—and 418 million miles (673 million km) from Jupiter. It’s a combination of two images taken with the PolyCam instrument, OSIRIS-REx’s longest range camera, which will capture images of the asteroid Bennu from a distance of over a million miles.
Read the full article here: NASA’s OSIRIS-REx Takes Closer Image of Jupiter
Even if you’re feeling inundated by Valentine-themed everything at the moment, if you love space and you’re at all creative you’re definitely going to adore this. With Cassini in the final months of its 13 years at Saturn, NASA wants you to share your love of the spacecraft, its discoveries, and the ringed planet and its fascinating family of moons.
“We’re so gratified that Cassini’s images have inspired people to work with the pictures themselves to produce such beautiful creations,” said Linda Spilker, Cassini project scientist at NASA’s Jet Propulsion Laboratory. “It’s been truly wonderful for us to feel the love for Cassini from the public. The feeling from those of us on the mission is mutual.”
In honor of Cassini’s last year in orbit (as well as its last Valentine’s Day!) the mission team is inviting all the Saturn lovers out there to share their Cassini-inspired creations through the “Cassini Inspires” outreach program. Digital art, processed images, paintings, drawings, songs, poems…if it drew any inspiration at all from something Cassini made possible, share it with the world!
The HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter (MRO) is specifically designed to take super high-resolution images of the surface of Mars but it also does a pretty darn good job capturing pictures of other objects too—like Jupiter and its Galilean moons, several hundred million miles away! The image above was captured in expanded color (that is, it includes wavelengths in infrared) by HiRISE on January 11, 2007, and shows the giant planet from Mars orbit.
Mars and Jupiter were at opposition at the time, only about 345 million miles apart.