Asteroid to pass Earth on Christmas Eve

Asteroid 2003 SD220 will pass safely, at more than 28 times the moon’s distance. Will it cause earthquakes? Gosh, no.


Image via Arecibo Observatory/NASA/NSF

A large asteroid is approaching the Earth-moon system and will provide a good opportunity for radar observations in the days ahead. Asteroid 163899 – also known as 2003 SD220 – will come closest to Earth on Christmas Eve (December 24, 2015). It’ll pass at a safe distance, and there’s no need to worry about reports claiming it will skim the Earth, or cause earthquakes. At its closest, asteroid 2003 SD220 will be some 6,787,600 miles (11 million km) from our planet’s surface. That’s more than 28 times the Earth-moon distance! It’s so far away that only professional and advanced amateur astronomers are likely to capture optical images of this space rock.

Don’t believe any media suggesting that this space rock may cause earthquakes. Those assertions are misleading and incorrect. Even if 2003 SD220 were passing closer, it’s doubtful earthquakes would result. In fact, there’s no scientific evidence that an asteroid’s flyby can cause any seismic activity, unless it collides with Earth, but – in this case – that clearly will not be the case.

This asteroid isn’t a newly discovered object. Its name – 2003 SD220 – indicates its discovery year. The Lowell Observatory Near-Earth Object Search (LONEOS) program in Flagstaff, Arizona discovered the asteroid on September 29, 2003.

One notable feature of this asteroid is its large size. Preliminary estimates suggested a size of 0.7 miles to 1.5 miles (1.1 km to 2.5 km). Now the size estimate has been bumped up, after recent radar observations from the Arecibo telescope in Puerto Rico. The new observations suggest the asteroid is about 1.25 miles (2 km) long.

The asteroid is thought to have a very slow rotation of about one week.

Although some other asteroids such as 2015 TB145 (the Halloween asteroid) and 2004 BL86 (January, 2015) were visible using 8″ telescopes, the Christmas asteroid will be much more difficult to see because of its distance.

However, using radio telescopes, astronomers are already observing this asteroid by bouncing radio signals from the space rock’s surface. The Arecibo Observatory in Puerto Rico is studying asteroid 2003 SD220 from December 3 to 17, while the Goldstone Antenna in California is analyzing the space rock from December 5 to 20.

Image credit: Arecibo Observatory/NASA/NSF

Image via Arecibo Observatory/NASA/NSF

This space rock – whose shape can be compared to a chicken tender – will make its approach to Earth on December 24, 2015 but will return again in 2018. NASA astronomer and asteroid expert Lance Benner said in a Goldstone radar observations planning document:

2003 SD220 is on NASA’s NHATS list of potential human-accessible targets, so observations of this object are particularly important.

The 2015 apparition is the first of five encounters by this object in the next 12 years when it will be close enough for a radar detection.

The Near-Earth Object Human Space Flight Accessible Targets Study (NHATS) is a program developed to identify those near-Earth objects that may be well-suited for future human-space-flight rendezvous missions.

Although this is a huge asteroid, there is no danger of a future collision. The orbit of asteroid 2003 SD220 is well known and NASA has verified that the space rock will not pass at any dangerous distance during the next two centuries.

Image via NASA

The path of asteroid 2003 SD220 through our solar system. Image via NASA

Bottom line: Asteroid 163899 – aka 2003 SD220 – will pass safely, at more than 28 times the Earth-moon distance, on December 24, 2015. Astronomers at Arecibo in Puerto Rico and Goldstone in California are taking this opportunity to study it with radar as it approaches. It’ll pass too far away to be visible in small amateur telescopes. Media reports suggesting that this space rock may cause earthquakes are misleading and incorrect.