Mark your calendar for April 13, 2029. An asteroid more than a thousand feet across will swing so close to Earth that it will be visible even without binoculars.

Jess Cox
Graphic by Lindsay Unger

This once-in-a millennia event will give University scientists a chance to answer long-standing questions about these solar system wanderers.

Named Apophis, after the Egyptian spirit of evil and destruction, the asteroid was discovered in December of 2004 by astronomers at the University of Arizona.

At first, it was feared that Apophis would hit Earth in 2029. The asteroid weighs almost 55 million tons with a length of about 1,350 feet and would certainly live up to its name if it struck Earth.

However, a flurry of observations by astronomers around the world has eliminated the possibility of impact.

Even if the asteroid were to hit the planet, scientists believe the damage would not, cause any lasting global effects due to the asteroids relatively small size. To put that into perspective, the asteroid that may have killed off the dinosaurs was probably six miles in length.

The 2029 approach of Apophis will still be the closest of any near-Earth asteroid on record. At a distance of just 22,300 miles, it will be as close to the Earth as communications satellites and much closer than the moon.

This extremely close pass gives scientists who study asteroids an unprecedented opportunity. A team of researchers led by Daniel Scheeres, a University associate professor of aerospace engineering, has suggested a mission to place instruments on Apophis. They hope to determine whether the asteroid is a monolithic rock or a “rubble pile” held together only by gravity.

“By properly placing instruments on the asteroid Apophis during its flyby of the Earth in 2029, we should be able to measure and determine these and many other properties of that asteroid,” Scheeres said.

“The gravity field of the Earth will cause the spin rate of the asteroid to change and should cause surface and sub-surface failures across the asteroid,” Scheeres added.

These effects are measurable and will tell scientists a great deal about the structure of Apophis.

Astronomers stress that it is important to learn as much as possible about asteroids. They are remnants of early planet formation and carry within them clues about the history and evolution of the solar system and our own origins.

But more importantly, Apophis is one of many thousand asteroids whose orbits bring them close to the earth. Although it will not hit earth, we will not always be so lucky, and data gathered on a mission to Apophis may be vital in dealing with more dangerous asteroids. It may end up that the Egyptian spirit of destruction will provide the information that will save us in the future.

 

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