Mars sees near daily eclipses of the sun

WASHINGTON — If you think solar eclipses on Earth are cool, wait till you get a load of an eclipse on Mars.

Earth typically experiences anywhere from four to seven eclipses in a year, counting partial solar eclipses (when the moon doesn’t fully obscure the sun) and lunar eclipses (when the Earth’s shadow partially obscures the moon).

On Mars, however, solar eclipses are practically a daily event. Mars has two moons — tiny, potato-shaped satellites named Phobos and Deimos, after the Greek deities of fear and dread, respectively.

Mars’ moons orbit at a much closer distance than our own moon orbits. While the moon is about 238,000 miles away from Earth (give or take), Phobos is only about 6,000 miles away from the surface of Mars.

Among other things, that proximity causes it to orbit incredibly fast, circling Mars in under eight hours.

A person standing on Mars would see it cross the sky twice in one day. Because of its small size, it appears smaller than our own moon does to us.

Phobos’ close, fast orbit makes it cross paths with the sun fairly often — near-daily.

But because the moon is so small it never fully occludes the sun to create a total eclipse.

The Mars Curiosity rover captured real-time video of this happening on Aug. 20, 2013.

“Because this eclipse occurred near midday at Curiosity’s location on Mars,” NASA explained in a statement accompanying the vidoe, “Phobos was nearly overhead, closer to the rover than it would have been earlier in the morning or later in the afternoon. This timing made Phobos’ silhouette larger against the sun — as close to a total eclipse of the sun as is possible from Mars.”

What about the other Martian moon? Deimos orbits more than twice as far away from Mars and is smaller to boot, making it much less visible in the Martian sky. When Deimos crosses paths with the sun, it’s more properly called a transit, rather than an eclipse.

Other planets eclipses, too.

Because of the similarity between the apparent sizes of the moon and sun when viewed from Earth, our total eclipses block out the entirety of the sun’s disc while leaving the luminous corona plainly visible.

That event happens nowhere else in the solar system — not even on Mars. experience