Our home planet, making a spectacle of itself. Photographed by a human living and working on the International Space Station. Credit: NASA
Prometheus creating Saturn ring streamers
What’s causing those strange dark streaks in the rings of Saturn? Prometheus. Specifically, an orbital dance involving Saturn’s moon Prometheus keeps creating unusual light and dark streamers in the F-Ring of Saturn. Now Prometheus orbits Saturn just inside the thin F-ring, but ventures into its inner edge about every 15 hours. Prometheus’ gravity then pulls the closest ring particles toward the 100-km moon. The result is not only a stream of bright ring particles but also a dark ribbon where ring particles used to be. Since Prometheus orbits faster than the ring particles, the icy moon pulls out a new streamer every pass. Sometimes, several streamers or kinks are visible at once.
Image credit: Cassini Imaging Team, ISS, JPL, ESA, NASA
Filaments in the Cygnus Loop
Subtle and delicate in appearance, these are filaments of shocked interstellar gas — part of the expanding blast wave from a violent stellar explosion. Recorded in November 1997 with the Wide Field and Planetary Camera 2 onboard the Hubble Space Telescope, the picture is a closeup of a supernova remnant known as the Cygnus Loop. The nearly edge-on view shows a small portion of the immense shock front moving toward the top of the frame at about 170 kilometers per second while glowing in light emitted by atoms of excited Hydrogen gas. Situated at over 1,440 light-years away, the Cygnus Loop is thought to have been expanding for 5 - 10 thousand years.
Image credit: William P. Blair and Ravi Sankrit (Johns Hopkins University), NASA
Stunning shots from the 2013 ATCC Photo Contest:
1. Mouse muscle cell (myoblast) 8 days after differentiation - The University of Iowa
2. Human cervix epithelial cells under multiphoton fluorescence - National Center for Microscopy and Imaging Research @ UCSD