A few nice University of Colorado images I found:
Starting for big trees near Santa Cruz
Image by SMU Central University Libraries
Title: Starting for big trees near Santa Cruz
Place: Santa Cruz, Santa Cruz County, California
Description: This is one of 287 photographs in an album entitled, ‘Tourist Album: Mexico, Arizona, California, Colorado and Utah.’
Physical Description: 1 photographic print: gelatin silver, part of 1 album (287 gelatin silver prints); 10 x 13 cm on 28 x 35 cm mount
Rights: Please cite DeGolyer Library, Southern Methodist University when using this file. A high-resolution version of this file may be obtained for a fee. For details see the sites.smu.edu/cul/degolyer/research/permissions/ web page. For other information, contact email@example.com.
For more information and to view in high resolution, see: digitalcollections.smu.edu/cdm/ref/collection/wes/id/2349
MAVEN Ultraviolet Image of Comet Siding Spring’s Hydrogen Coma
Image by NASA Goddard Photo and Video
NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft obtained this ultraviolet image of hydrogen surrounding comet Siding Spring on Friday, Oct. 17, two days before the comet’s closest approach to Mars. The Imaging Ultraviolet Spectrograph (IUVS) instrument imaged the comet at a distance of 5.3 million miles (8.5 million kilometers).
The image shows sunlight that has been scattered by atomic hydrogen, and is shown as blue in this false-color representation. Comets are surrounded by a huge cloud of atomic hydrogen because water (H2O) vaporizes from the icy nucleus, and solar ultraviolet light breaks it apart into hydrogen and oxygen. Hydrogen atoms scatter solar ultraviolet light, and it was this light that was imaged by the IUVS. Two observations were combined to create this image, after removing the foreground signal that results from sunlight being scattered from hydrogen surrounding Mars.
The bulk of the scattered sunlight shows a cloud that was about a half degree across on the “sky” background, comparable in size to Earth’s moon as seen from Earth. Hydrogen was detected to as far as 93,000 miles (150,000 kilometers) away from the comet’s nucleus. The distance is comparable to the distance of the comet from Mars at its closest approach. Gas from the comet is likely to have hit Mars, and would have done so at a speed of 125,000 mph (56 kilometers/second. This gas may have disturbed the Mars atmosphere.
Credit: Laboratory for Atmospheric and Space Physics, University of Colorado; NASA
NASA image use policy.
NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission.
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