Tag Archives: potd

Venus and the Triply Ultraviolet Sun

Venus and the Triple Ultraviolet Sun
Image Credit: NASA/SDO & the AIA, EVE, and HMI teams; Digital Composition: Peter L. Dove (http://www.flickr.com/photos/pldove/)

Explanation: An unusual type of solar eclipse occurred in 2012. Usually, it is the Earth’s Moon that eclipses the Sun. That year, most unusually, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Venus became a continually thinner crescent as Venus became increasingly better aligned with the Sun. Eventually, the alignment became perfect and the phase of Venus dropped to zero. The dark spot of Venus crossed our parent star. The situation could technically be labelled a Venusian annular eclipse with an extraordinarily large ring of fire. Pictured here during the occultation, the Sun was imaged in three colours of ultraviolet light by the Earth-orbiting Solar Dynamics Observatory, with the dark region toward the right corresponding to a coronal hole. Hours later, as Venus continued in its orbit, a slight crescent phase appeared again. The next Venusian transit across the Sun will occur in 2117. </center>

Sources and References:

https://www.nasa.gov/
https://apod.nasa.gov/apod/ap180204.html
https://en.wikipedia.org/wiki/22nd_century#Transits_and_occultations
http://sdo.gsfc.nasa.gov/

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Astronomy Picture of the Day – Eclipsosaurus Rex

See Explanation.  Clicking on the picture will download
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Eclipsosaurus Rex 
Image Credit & CopyrightFred Espenak (MrEclipse.com)Explanation: We live in an era where total solar eclipses are possible because at times the apparent size of the Moon can just cover the disk of the Sun. But the Moon is slowly moving away from planet Earth. Its distance is measured to increase about 1.5 inches (3.8 centimeters) per year due to tidal friction. So there will come a time, about 600 million years from now, when the Moon is far enough away that the lunar disk will be too small to ever completely cover the Sun. Then, at best only annular eclipses, a ring of fire surrounding the silhouetted disk of the too small Moon, will be seen from the surface of our fair planet. Of course the Moon was slightly closer and loomed a little larger 100 million years ago. So during the age of the dinosaurs there were more frequent total eclipses of the Sun. In front of the Tate Geological Museum at Casper College in Wyoming, this dinosaur statue posed with a modern total eclipse, though. An automated camera was placed under him to shoot his portrait during the Great American Eclipse of August 21.

 

From: https://apod.nasa.gov/apod/ap171007.html