In May, skywatchers got a rare treat. The planet Mars was bigger and brighter than it has been in a decade. That's because Mars and the sun were aligned in "opposition." When that happens, the planet shines extra bright in the night sky.
(A bonus was the fact that Mars was nearing its closest approach to Earth, so it appeared larger than usual.)
In the weeks before and after opposition, Mars is easy to view with the naked eye. So what happens, then, when you point humanity's most famous telescope at it?
Behold Mars, the cheddar-colored marble.
This image was captured by Hubble a little more than a week before opposition, on May 12. It shows detail on the surface usually revealed by interplanetary probes, including clouds over the southern ice cap — "details as small as 20 to 30 miles across," NASA explains.
A large oval feature to the south of Syrtis Major is the bright Hellas Planitia basin. About 1,100 miles across and nearly five miles deep, it was formed about 3.5 billion years ago by an asteroid impact.
The orange area in the center of the image is Arabia Terra, a vast upland region in northern Mars that covers about 2,800 miles. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest terrains on the planet. Dried river canyons (too small to be seen here) wind through the region and empty into the large northern lowlands.
South of Arabia Terra, running east to west along the equator, are the long dark features known as Sinus Sabaeus (to the east) and Sinus Meridiani (to the west). These darker regions are covered by dark bedrock and fine-grained sand deposits ground down from ancient lava flows and other volcanic features. These sand grains are coarser and less reflective than the fine dust that gives the brighter regions of Mars their ruddy appearance.
Hubble is best known for its images of far-flung nebulae and galaxies, but it also conducts essential surveys of our solar system, NASA scientists explain in the following video.