An asteroid about half the size of a football field will pass so near Earth during Friday's lunch hour that it will be closer than many communication and television satellites.
The hunk of rock that is about 150 feet in diameter with a mass of about 140,000 tons has no chance of hitting the planet, but it's the closest object of its size to pass by Earth that researchers knew of in advance since they began scanning the skies in the early 1990s. The asteroid, whose name of 2012 DA14 doesn't quite capture the excitement surrounding it, will be 17,200 miles from the Earth at 12:45 p.m. MST. Communication satellites orbit at about 22,000 miles out, and GPS satellites are about 11,000 miles out.
Seth Jarvis, director of the Clark Planetarium and a NASA Solar System Ambassador to Earth, said he hopes people will look at this asteroid's flyby as a "teachable moment" to understand the potential danger near-Earth objects pose.
"This asteroid is one of about 1,400 potentially hazardous asteroids being tracked by NASA, and none are at the moment any kind of imminent threat to the Earth, but it's a matter of when, not if," he said. "Eventually, we have to ask ourselves, if this asteroid is some distance from us, it becomes possible to do something about it. That's unusual because this would be the first time we would have the choice not to participate in a major natural disaster."
Scientists around the globe will be studying the asteroid to determine its shape and, more importantly, its trajectory as it will come close to Earth again in 2020. The probability of it hitting the planet then is again remote.
However, Jarvis wants people to think about what an acceptable risk is for an asteroid hitting the Earth. If NASA were to announce that a mile-wide asteroid had a 1 in 300 chance of hitting Earth in 30 years, would people be willing to cooperate internationally for 20 years and spend a collective trillion dollars to make that chance 1 in 300,000?
"You would never put your family on a plane if the chance was 1 in 300 that it ends in a fiery crash. That likelihood is more like 1 in 100,000, and that would ruin a couple hundred people's lives," he said. "Why would you ever risk the entire human race with those odds?"
There are several measures that could be taken, and none of them involve sending Bruce Willis or anyone else into space to detonate an atomic bomb on an asteroid hurtling toward Earth.
With 30 years of warning, international space agencies could take various approaches: they could paint the asteroid white to change its reflectivity and allow the pressure of the sun's rays to change its trajectory, they could use high-powered lasers to nudge it or orbit a heavy spacecraft around it to move it off its course.
But it's all about doing that early on, according to Edward Beshore of the University of Arizona, Tucson, deputy principal investigator for NASA's OSIRIS-REx asteroid sample return mission.
"If you're trying to deflect an arrow, you wouldn't need to apply much force to the arrow to make it widely miss the target if you could deflect it as it left the bow," Beshore said in a NASA statement. "On the other hand, if you had to deflect it right before it hit the target, you'd need to push on it a whole lot more to get it out of the way."
Amateur astronomers in Utah likely won't get to see the asteroid Friday night because by the time Utah is facing it, the asteroid will be more than 70,000 miles away and won't appear to be moving much.
Click here for more information, including graphics and animations showing the flyby of 2012 DA14.
NASA will broadcast a half-hour commentary about the asteroid's approach at noon. The commentary will be available via NASA TV and streamed live online. Click here to watch.
Astronomers in Europe and Australia also will provide NASA near real-time imagery of the asteroid, weather permitting, and it will be streamed here beginning at 10 a.m.
For three hours, beginning at 10 a.m., a Ustream feed of the flyby from a telescope at NASA's Marshall Space Flight Center in Huntsville, Ala., will be available. Click here to view the feed and ask researchers questions about the flyby via Twitter.
How to watch the flyby
O NASA will broadcast a half-hour commentary about the asteroid's approach at noon Friday. The commentary will be available via NASA TV and streamed live online at nasa.gov/ntv.
Astronomers in Europe and Australia also will provide NASA near real-time imagery of the asteroid, weather permitting, and it will be streamed at ustream.tv/nasajpl2 beginning at 10 a.m.
For three hours, beginning at 10 a.m., a Ustream feed of the flyby from a telescope at NASA's Marshall Space Flight Center in Huntsville, Ala., will be available at ustream.tv/channel/nasa-msfc. Source: Jet Propulsion Laboratory, NASA/AP