It may be years before ordinary Earthlings get to see the surface of Mars in person, but we all got a sneak peek this week courtesy of the Hubble Space Telescope.
In a picture taken May 12, and transmitted on Thursday, Hubble shows the Red Planet in intricate detail, from the dark region known as Syrtis Major Planitia to an orange, lighter area called Arabia Terra.
Mars was just 50 million miles from Earth when the photo was taken, which sounds like a lot, but the picture actually gets relatively close up. Mars hasn’t been this close to Earth in eleven years.
Syrtis Major Planitia was first identified by Christiaan Huygens in the seventeenth century, who used it to measure Mars’ rotation rate. Syrtis Major is now known as an ancient, inactive shield volcano, a type of volcano made up almost entirely of cooled magma. Clouds glimmer and swirl above its peak.
Arabia Terra, because it has so many craters and is so heavily eroded, is thought to be one of the oldest landscapes on Mars’ surface. Although they can’t be seen in this image, Arabia Terra also contains dry river canyons.
If Mars looks unusually bright in this picture, it’s because the Red Planet is approaching "opposition" this month. That occurs when the orbits of Mars and Earth align, so that Mars and the sun are on "opposing" sides of Earth. "Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth," according to NASA.
How Mars’ surface was shaped, and in what form, are questions that scientists have been puzzling over for generations. Evidence released Thursday supports the hypothesis that ancient oceans on Mars’ surface may have given rise to the dusty red-orange fields so familiar today.
Over time, as Mars lost its atmosphere, those oceans receded. What water remains on Mars now is condensed and frozen at its poles. Scientists charted the change in Mars’ surface by looking at two Martian tsunami events that occurred millions of years apart but each had a similar impact. The tsunamis were giant enough to push and pull water across the surface of the Red Planet, such that when the water eventually receded, it left the channels that remain on Mars today.