NASA recently released images of comet C/2013 A1 that will pass within 84,000 miles of Mars — less than half the distance between Earth and our moon – on October 19, 2014.
The image on the left, captured March 11 by NASA’s Hubble Space Telescope, shows the comet at a distance of 353 million miles from Earth.
Hubble can’t see C/2013 A1’s icy nucleus because of its small size, and the nucleus is surrounded by a glowing dust cloud that measures roughly 12,000 miles across. The left image is the comet as it appears to Hubble, and the right image has been processed to show see through the comet’s coma, revealing two jets of dust being blasted off the surface.
The comet was observed as Earth was crossing through it’s path around the Sun. This positioning of the two bodies allowed astronomers to determine the speed of the dust coming off the nucleus.
“This is critical information that we need to determine whether, and to what degree, dust grains in the coma of the comet will impact Mars and spacecraft in the vicinity of Mars,” said Jian-Yang Li of the Planetary Science Institute in Tucson, Arizona.
Discovered in January 2013 by Robert H. McNaught at Siding Spring Observatory, the comet is falling toward the sun along a roughly 1 million year orbit and is now within the radius of Jupiter’s orbit. The comet will make its closest approach to our sun on Oct. 25, at a distance of 130 million miles – well outside of Earth’s orbit. The comet is not expected to become bright enough to be seen by the naked eye.
More: National Geographic