March 5, 2013
Comet Siding Spring To Pass Close To Mars In 2014
Lee Rannals for redOrbit.com — Your Universe Online
We've had our fair share of close calls from asteroids recently, but a neighboring planet will soon have its day in the spotlight as a comet grazes past it.
Mars will have a front row ticket to comet 2013 A1 as it passes by the Red Planet in 2014, passing within 186,000 miles of Mars, according to NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, California. The office even said there is a strong possibility the comet could pass by the Red Planet within about 31,000 miles, which is just a little more than the distance between Earth and some of our communication satellites.
Comets are hard for astronomers to predict, and current estimates are based on October 2012 observations. NASA said further refinement of its orbit is expected to be made as more observational data is obtained, adding the possibility of comet 2013 A1 impacting the surface of Mars cannot be excluded.
"However, since the impact probability is currently less than one in 600, future observations are expected to provide data that will completely rule out a Mars impact," NASA said.
The comet has been on a million-year journey to finally arrive to the inner workings of our solar system. 2013 A1, or Siding Spring, could feature volatile gases that short period comets often lack due to their frequent returns to the sun's neighborhood.
If comet Siding Spring actually impacted Mars next year, scientists believe it could equal about 20 billion kilotons of TNT, or about 1,600,000 atomic bombs. The comet is predicted to be roughly between 12.5 to 25 miles in diameter.
Robert McNaught discovered the comet back in January at the Siding Spring Observatory in Australia. He has discovered 74 comets and 467 asteroids.
Although an impact is unlikely to occur on Mars next year, the astronomical event could still offer up some great opportunities for observations. The tail of the comet can spread across an area of hundreds of thousands of miles, so when a planet the size of Mars passes through the coma, it could provide outstanding eye candy in the sky. An atom in the coma colliding with an atom on Mars' atmosphere would be heated to the temperature of the Sun's corona, producing bright aurora-like lights.
Mars isn't the only planet being treated to a spectacular view of a comet in the coming months, and days. Comet STARRS C/2011 L4 is making its way towards Earth and will be offering backyard astronomers a naked-eye view in the next week. Then, later this year, comet ISON will be potentially creating a once-in-a-lifetime sky show.
Comet ISON will be lighting up the sky as it approaches in November, potentially even becoming as bright as the moon in our sky. This comet will be traveling through the sun's atmosphere on November 28 of this year, and it could be so bright it is visible during the day for a short amount of time. However, due to the unpredictability comets have to offer, all of these expectations could be more fluff than fact.
“I´m old enough to remember the last ℠Comet of the Century´. It fizzled. Comets are notoriously unpredictable,” said Don Yeomans of NASA´s Near-Earth Object Program.
“Whatever happens, northern sky watchers will get a good view,” NASA officials said. “For months after it swings by the sun, Comet ISON will be well placed for observers in the northern hemisphere. It will pass almost directly over the North Pole, making it a circumpolar object visible all night long.”