ON THIS PAGE
The Latest: It's the beginning of the end for the planet-encircling dust storm on Mars. But it could still be weeks, or even months, before skies are clear enough for NASA's Opportunity rover to recharge its batteries and phone home. The last signal received from the rover was on June 10.
Scientists observing the global event -- which is actually caused by a series of local and regional storms throwing dust into the Martian atmosphere -- say that, as of Monday, July 23, more dust is falling out than is being raised into the planet's thin air. That means the event has reached its decay phase, when dust-raising occurs in ever smaller areas, while others stop raising dust altogether.
Opportunity is part of an international fleet of spacecraft exploring Mars from all angles. The lineup: Mars Odyssey, Mars Reconnaissance Orbiter, Mars Orbiter Mission, Mars Express, MAVEN and the Curiosity rovers and ExoMars Trace Gas Orbiter. MarCo, the first CubeSats sent into Deep Space, are set to arrive at Mars in November with InSight. Explore Mars in Depth ›
If the Sun were as tall as a typical front door, Earth would be the size of a dime, and Mars would be about as big as an aspirin tablet. Mars orbits our Sun, a star. Mars is the fourth planet from the Sun at an average distance of about 228 million km (142 million miles) or 1.52 AU. One day on Mars takes a little over 24 hours. Mars makes a complete orbit around the Sun (a year in Martian time) in 687 Earth days. Mars is a rocky planet. Its solid surface has been altered by volcanoes, impacts, winds, crustal movement and chemical reactions. Mars has a thin atmosphere made up mostly of carbon dioxide (CO2), argon (Ar), nitrogen (N2), and a small amount of oxygen and water vapor. Mars has two moons named Phobos and Deimos. There are no rings around Mars. Several missions have visited this planet, from flybys and orbiters to rovers on the surface.The first true Mars mission success was the Mariner 4 flyby in 1965. At this time, Mars' surface cannot support life as we know it. Current missions are determining Mars' past and future potential for life. Mars is known as the Red Planet because iron minerals in the Martian soil oxidize, or rust, causing the soil and atmosphere to look red.
Ten Things to Know About Mars
Small Planet
Fourth Rock
Longer Days
Rugged Terrain
Bring a Spacesuit
Double Moons
Ringless
Many Missions
Tough Place for Life
Rusty Planet
Did You Know?
With about 1/3 the gravity of Earth, anyone on Mars could dunk a basketball in a regulation goal. But the required spacesuit might cut down on your edge.
Pop Culture
No other planet has captured our collective imagination quite like Mars. In the late 1800s when people first observed the canal-like features on Mars' surface, many speculated that an intelligent alien species resided there. This led to numerous stories about Martians, some of whom invade Earth, like in the 1938 radio drama, The War of the Worlds. According to an enduring urban legend, many listeners believed the story to be real news coverage of an invasion, causing widespread panic.
Countless stories since have taken place on Mars or explored the possibilities of its Martian inhabitants. Movies like Total Recall (1990 and 2012) take us to a terraformed Mars and a struggling colony running out of air. A Martian colony and Earth have a prickly relationship in The Expanse television series and novels.
And in the 2014 novel and and its 2015 movie adaptation, The Martian, botanist Mark Whatney is stranded alone on the planet and struggles to survive until a rescue mission can retrieve him.
