A High Cliff on Comet Churyumov Gerasimenko

This high cliff occurs not on a planet, not on a moon, but on a comet. It was discovered to be part of the dark nucleus of Comet Churyumov-Gerasimenko (CG) by Rosetta, a robotic spacecraft launched by ESA that rendezvoused with the Sun-orbiting comet in 2014. The ragged cliff, as featured here, was imaged by Rosetta in 2014. Although towering about one kilometer high, the low surface gravity of Comet CG would likely make it an accessible climb -- and even a jump from the cliff survivable. At the foot of the cliff is relatively smooth terrain dotted with boulders as large as 20 meters across. Data from Rosetta indicates that the ice in Comet CG has a significantly different deuterium fraction -- and hence likely a different origin -- than the water in Earth's oceans. Rosetta ended its mission with a controlled impact onto Comet CG in 2016. Comet CG has just completed another close approach to Earth and remains visible through a small telescope.

from NASA https://ift.tt/3FO2dXu

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A Spiral Aurora over Iceland

What's happened to the sky? Aurora ! Captured in 2015, this aurora was noted by Iceland ers for its great brightness and quick development. The aurora resulted from a solar storm, with high energy particles bursting out from the Sun and through a crack in Earth's protective magnetosphere a few days later. Although a spiral pattern can be discerned, creative human s might imagine the complex glow as an atmospheric apparition of any number of common icons . In the foreground of the featured image is the Ã–lfusÃ¡ River while the lights illuminate a bridge in Selfoss City . Just beyond the low clouds is a nearly full Moon. The liveliness of the Sun -- and likely the resulting auroras on Earth -- is slowly increasing as the Sun emerges from a Solar minimum , a historically quiet period in its 11-year cycle. from NASA https://ift.tt/2XgnyIE

NGC 2419: Intergalactic Wanderer

Stars of the globular cluster NGC 2419 are packed into this Hubble Space Telescope field of view toward the mostly stealthy constellation Lynx . The two brighter spiky stars near the edge of the frame are within our own galaxy. NGC 2419 itself is remote though, some 300,000 light-years away. In comparison, the Milky Way's satellite galaxy, the Large Magellanic Cloud , is only about 160,000 light-years distant. Roughly similar to other large globular star clusters like Omega Centauri , NGC 2419 is intrinsically bright, but appears faint because it is so far away. Its extreme distance makes it difficult to study and compare its properties with other globular clusters that roam the halo of our Milky Way galaxy. Sometimes called "the Intergalactic Wanderer", NGC 2419 really does seem to have come from beyond the Milky Way. Measurements of the cluster's motion through space suggest it once belonged to the Sagittarius dwarf spheroidal galaxy , another small satellite...

The Gator Back Rocks of Mars

Wind-sharpened rocks known as ventifacts, cover this broad sloping plain in the foot hills of Mount Sharp, Gale crater, Mars. Dubbed gator-back rocks their rugged, scaly appearance is captured in these digitally stitched Mastcam frames from the Curiosity rover on mission sol 3,415 (March 15, 2022). Driving over gator-back rocks before has resulted in damage to the rover's wheels, so Curiosity team members decided to turn around and take another path to continue the rover's climb. Curiosity has been on an ascent of Gale crater's central 5.5 kilometer high mountain since 2014. As it climbs, it's been able to study layers shaped by water on Mars billions of years ago . from NASA https://ift.tt/IGon5ra

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