“Spooky” Asteroid to Pass Near Earth on Halloween

Scientists are predicting that the largest asteroid to approach Earth will fly by on Halloween night.

It’s been nicknamed the “Great Pumpkin” and the “Spooky” Asteroid, but in reality, scientists have a good handle on 2015 TB145, the asteroid scheduled to approach Earth on Saturday night.

2015 TB145 is approximately 400 m (1,300 feet) in diameter and will pass by the Earth just beyond the moon’s orbit.

"The trajectory of 2015 TB145 is well understood," said Paul Chodas, manager of the Center for Near Earth Object Studies at NASA's Jet Propulsion Laboratory, Pasadena, California. "At the point of closest approach, it will be no closer than about 300,000 miles -- 480,000 kilometers or 1.3 lunar distances. Even though that is relatively close by celestial standards, it is expected to be fairly faint, so night-sky Earth observers would need at least a small telescope to view it."

Approximate times for the flyby in EDT. If you want to observe the asteroid, you’ll need a small telescope. Photo credit: NASA/JPL-Caltech

If you do angle your lens to the sky this week, you’ll be joining hoards of astrophysicists all eager to take advantage of this opportunity. Except that they’ll be tracking the flyby on Halloween with the 34-meter (110-foot) DSS 13 antenna at Goldstone. Radio waves emitted by the antenna will bounce off the asteroid and be collected by the National Radio Astronomy Observatory’s Green Bank Telescope in Green Bank, West Virginia and the National Astronomy and Ionosphere Center’s Arecibo Observatory, Puerto Rico.

Some scientists are particularly interest in the asteroid because of certain peculiar characteristics: it’s oblong orbit is steering it below the plane of our flat solar system and it’s been clocked at 35 kilometers (22 miles) per second — unusually fast for an asteroid. These are both qualities more commonly seen in comets.

Unlike asteroids, a comet is chemically active. As its orbit approaches the sun, a comet may start to vaporize, emitting a tail of dust and gases. Asteroids, on the other hand, are inert (inactive) bodies of rock.

If 2015 TB145 is a comet, Lance Benner of NASA’s Jet Propulsion Laboratory says “this would be the first time that the Goldstone radar has imaged a comet from such a close distance."

Comets are believed by some to have brought the first organic molecules to Earth, kickstarting life as we know it. Like asteroids, however, they also present a very real danger to life on Earth.

2015 TB145 was discovered on October 10, 2015 by the NASA-funded Near-Earth Object Observation (NEOO) Program, sometimes called the “Spaceguard.”

The NEOO Program tracks all asteroids and comets destined to pass within 30 million miles of Earth. Based on ground- and space-based telescopes, NEOO scientists map the predicted paths of these objects and determine whether they threaten the planet. So far, none have.

But what will we do when NEOO finds an asteroid that spells doom for humanity? According to Neil deGrasse Tyson in a recent episode of StarTalk, two popular strategies have been proposed. The first and simplest strategy is to blow it up. This low-tech solution may be cost-effective, but the debris from the explosion could be just as damaging as the asteroid itself.

The better strategy, Tyson argues, is to deflect the asteroid ever so slightly. This method would use technology called a Gravitational Tractor Beam that hasn’t yet been developed. Watch Tyson’s explanation of the technology in this video:

Based on materials provided by NASA.