NASA's images of the week

Image Credit: ESA/NASA/SOHO

After 20 years in space, ESA and NASA’s Solar and Heliospheric Observatory, or SOHO, is still going strong. Originally launched in 1995 to study the sun and its influence out to the very edges of the solar system, SOHO revolutionized this field of science, known as heliophysics, providing the basis for nearly 5,000 scientific papers. SOHO discovered dynamic solar phenomena such as coronal waves, solar tsunamis and sun quakes, and found an unexpected role as the greatest comet hunter of all time—reaching 3,000 comet discoveries in September 2015.
This “Best of SOHO” image by the observatory’s LASCO C2 coronograph from Nov. 8, 2000, shows what appears to be two coronal mass ejections (CMEs) heading in symmetrically opposite directions from the sun. A 304Å image from SOHO’s Extreme ultraviolet Imaging Telescope (EIT) taken on the same day has been superimposed over the dark disk which blocks the sun so that the LASCO instrument can observe the structures of the corona in visible light.




Image Credit: NASA/JPL-Caltech/Space Science Institute


Although Enceladus and Saturn’s rings are largely made up of water ice, they show very different characteristics. The small ring particles are too tiny to retain internal heat and have no way to get warm, so they are frozen and geologically dead. Enceladus, on the other hand, is subject to forces that heat its interior to this very day. This results in its famous south polar water jets, which are just visible above the moon’s dark, southern limb, along with a sub-surface ocean.




Image Credit: M. Helfenbein, Yale University / OPAC


In July 2015, researchers announced the discovery of a black hole, shown in the above illustration, that grew much more quickly than its host galaxy. The discovery calls into question previous assumptions on the development of galaxies. The black hole was originally discovered using NASA’s Hubble Space Telescope, and was then detected in the Sloan Digital Sky Survey and by ESA’s XMM-Newton and NASA’s Chandra X-ray Observatory.