Blog Archives
An Asteroid’s Amazing Technicolor Dream Coat
Vesta — the asteroid that was almost a planet — has its complex surface composition revealed in this animation made from images acquired by NASA’s Dawn spacecraft.
The video reveals the dappled, variegated surface of the giant asteroid Vesta, the second most massive object in the main asteroid belt. The animation drapes high-resolution false color images over a 3-D model of the Vesta terrain constructed from Dawn’s observations. This visualization enables a detailed view of the variation in the material properties of Vesta in the context of its topography.
Mercury’s “Smooth” Plains
Mercury has a vast region of smooth volcanic plains surrounding its northern polar region, wrapping over a third of the way around the planet. But even though the plains are called smooth, they are still characteristically rugged – made obvious in this narrow-angle camera image from MESSEGER acquired December 13.
Being an area close to Mercury’s pole, the incidence angle of sunlight highlights every crater, ridge and rise… showing that “smooth” on Mercury is definitely a relative term!
This image shows an area about 43 miles (70 km) across. Read more on the MESSENGER website here.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Into The Darkness
The rugged terrain of Mercury’s north pole is made clear in this image from MESSENGER, taken on June 17, 2011. The shallow angle of sunlight striking the surface of our solar system’s innermost planet sends shadows across its landscape and highlights every rise and ridge.
This scene shows an area about 74 miles across.
MESSENGER launched from Cape Canaveral Air Force Station, Fla., on August 3, 2004. It established orbit around Mercury on March 18, 2011, the first spacecraft ever to do so.
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
Electric Blue
Yesterday’s Astronomy Picture of the Day was this fantastic image by the talented Alan Friedman, showing the sphere of our Sun taken in a special wavelength of light emitted by hydrogen gas and then inverted to look blue. Incredible details of the Sun’s surface – the chromosphere – become visible, most notably the texture caused by raised tubes of magnetically-contained plasma covering the surface called spicules.
From this distance the spicules create a carpet-like texture. But each one is a winding, magnetically-contained tube of hot gas traveling at 30,000 mph, hundreds of miles wide and half as long as the Earth. They constantly rise and fall across the surface of the sun, lasting about five minutes each. (Watch a video of them in action.)
In addition some bright solar prominences are visible along the edges of the Sun.
Alan Friedman’s photography features wonderful views of celestial objects both familiar and exotic, expertly composed with an eye for the inherent art only nature can create. Visit his website for more images: www.avertedimagination.com. (This will also have a permanent home in my sidebar.)
Image: Alan Friedman. Used with permission.












