The Hubble Space Telescope has captured a stunning image of the full disk of Mars prior to the Red Planet's closest approach to Earth in 11 years. Mars has been the focal point of numerous unmanned missions, and, if NASA gets its way, will be the first planet beyond Earth to be visited by mankind.
Hubble snapped the Red Planet on May 12, 2016, at a distance of 50 million miles (80.5 million km) from Earth. Displaying features as small as 20 – 30 miles (32 – 48 km) across, the portrait of Mars stands as tribute to the versatility of a telescope that is often tasked with imaging some of the largest structures in the known universe.
The dull orange upland region of northern Mars known as Arabia Terra dominates the center of the portrait. Heavily cratered and eroded by the passage of time, this 2,800 mile (4,506 km) wide swathe of tortured terrain is believed to be among the oldest surface regions existing on the Red Planet today.
Younger geological features are easily discernible in the Hubble image. South of Arabia Terra, vast regions of land darkened by exposed bedrock and the ground-down remains of ancient lava flows stand as tribute to the volcanic history of Mars.
To the right of the image, partially obscured by bright cloud is a dark region known as Syrtis Major Planitia. We now know that the feature, which was previously believed to be a plain, is in reality a vast, low-relief shield volcano. To the south of the volcano is a 1,100 mile (1,770 km) wide oval impact crater known as the Hellas Planitia basin. It is thought that the basin formed roughly 3.5 billion years ago as a result of a powerful asteroid strike.
Mars is due to be in opposition on May 22. This is an orbital position in which two celestial bodies, in this case the Red Planet and the Sun, are on exact opposite sides of planet Earth. This period constitutes the ideal period for imaging Mars, which is fully illuminated by the Sun. While on average a Mars opposition occurs once every 26 months, this particular event will bring the Red Planet closer to Earth than at any point in the last 11 years, passing at a distance of 46.8 million miles.