Using NASA’s Hubble Space Telescope, astronomers captured this striking image of Mars, when the planet was 50 million miles from Earth. The photo reveals details as small as 20 miles to 30 miles across. On May 30th, Mars will be the closest it has been to Earth in 11 years, at a distance of 46.8 million miles. Mars is especially photogenic during opposition because it can be seen fully illuminated by the sun as viewed from Earth.
During May 2016 the Earth and Mars get closer to each other than at any time in the last ten years. The NASA/ESA Hubble Space Telescope has exploited this special configuration to catch a new image of our red neighbor, showing some of its famous surface features. This image supplements previous Hubble observations of Mars and allows astronomers to study large-scale changes on its surface.
On May 22nd Mars came into opposition, the point at which the planet is located directly opposite the Sun in the sky. This means that the Sun, Earth and Mars line up, with Earth sitting in between the Sun and the red planet.
Opposition also marks the planet’s closest approach to Earth, so that Mars appears bigger and brighter in the sky than usual. This event allows astronomers using telescopes in space and on the ground to see more details on the Martian surface. For observers using ground-based instruments the opposing planet is visible throughout the night and is also fully illuminated, making it a great opportunity for detailed studies.
On May 12th Hubble took advantage of this favorable alignment and turned its gaze towards Mars to take an image of our rusty-hued neighbor, adding it to the collection of previous images. From this distance the telescope could see Martian features as small as 30 kilometers across.
Hubble observed Mars using its Wide Field Camera 3 (WFC3). The final image shows a sharp, natural-color view of Mars and reveals several prominent geological features, from smaller mountains and erosion channels to immense canyons and volcanoes.
The large, dark region to the far right is Syrtis Major Planitia, one of the first features identified on the surface of the planet by seventeenth century observers. Syrtis Major is an ancient, inactive shield volcano. Late-afternoon clouds surround its summit in this view. The oval feature south of Syrtis Major is the bright Hellas Planitia basin, the largest crater on Mars. About 1,800 kilometers across and eight kilometers 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. The landscape is densely cratered and heavily eroded, indicating that it could be among the oldest features on the planet.
South of Arabia Terra, running east to west along the equator, are the long dark features known as Sinus Sabaeous (to the east) and Sinus Meridiani (to the west). These darker regions are covered by bedrock from ancient lava flows and other volcanic features.
An extended blanket of clouds can be seen over the southern polar cap. The icy northern polar cap has receded to a comparatively small size because it is now late summer in the northern hemisphere.
For Mars, the average time between successive oppositions — known as the planet’s synodic period — is 780 days — so the previous time that the planet was in opposition was April 2014. Hubble has observed Mars at (or near) opposition many times, including in 1995, 1999 (twice), 2001, 2003 (twice), 2005, and 2007.