Rapid City, South Dakota, USA
June 1, 2015
Image Credit & Copyright: Mike Olbinski
March 4, 2017
Solar Eclipse seen by DSCOVR Observatory
On February 26, 2017, the skies above Argentina dimmed and the landscape darkened as the Moon moved in front of the Sun, partially blocking its rays. The same thing happened that day in Chile and Angola, as a “ring of fire” (annular eclipse) appeared over the South Atlantic.
An annular eclipse occurs when the Moon passes in front of the Sun but is too far from Earth to completely obscure it. This geometry leaves the Sun’s edges exposed in a red-orange ring. NASA satellites caught several earthly views of the event.
The animation above was assembled from three images acquired on February 26 by NASA’s Earth Polychromatic Imaging Camera (EPIC), a four-megapixel charge-coupled device (CCD) and Cassegrain telescope on the DSCOVR satellite. In that view, both the Earth and the lunar shadow move.
The animation below shows a static view of Earth and the progression of the eclipse shadow. It is composed from 13 separate images acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on NASA’s Aqua and Terra satellites, as well as the Visible Infrared Imaging Radiometer Suite (VIIRS) sensor on the Suomi NPP satellite. Each satellite follows the same orbital path but passes over points on Earth at slightly different times in a two-hour span. (Click here for a simple animation of the eclipse shadow path.)
But the February event will soon be eclipsed, so to speak, by another one. On August 21, 2017, a total solar eclipse will cross the entire continental United States for the first time in nearly four decades. The total eclipse will take about 90 minutes to cross from Oregon to South Carolina. During that time, 11 NASA-funded science teams will gather observations of the Sun’s tenuous atmosphere (corona)—which is too faint to see next to the bright solar disk—and of how the eclipse affects Earth and its atmosphere.
“When the Moon blocks out the Sun during a total eclipse, those regions of Earth that are in the direct path of totality become dark as night for almost three minutes,” said Steve Clarke, director of NASA’s Heliophysics Division, in an earlier interview. “This will be one of the best-observed eclipses to date, and we plan to take advantage of this unique opportunity to learn as much as we can about the Sun and its effects on Earth.”
Image Credit: NASA/JPL-CALTECH
Explanation from: http://earthobservatory.nasa.gov/IOTD/view.php?id=89748
The UGC 12591 Galaxy
This NASA/ESA Hubble Space Telescope image showcases the remarkable galaxy UGC 12591. Classified as an S0/Sa galaxy, UGC 12591 sits somewhere between a lenticular and a spiral. It lies just under 400 million light-years away from us in the westernmost region of the Pisces–Perseus Supercluster, a long chain of galaxy clusters that stretches out for 250 million light-years — one of the largest known structures in the cosmos.
The galaxy itself is also extraordinary: it is incredibly massive. The galaxy and its halo together contain several hundred billion times the mass of the Sun; four times the mass of the Milky Way. It also whirls round extremely quickly, rotating at speeds of up to 1.8 million kilometres per hour!
Observations with Hubble are helping astronomers to understand the mass of UGC 1259, and to determine whether the galaxy simply formed and grew slowly over time, or whether it might have grown unusually massive by colliding and merging with another large galaxy at some point in its past.
Image Credit: ESA/Hubble & NASA
Explanation from: https://www.spacetelescope.org/images/potw1709a/
