Friday the 13th, 2029 ~ very close call...

On April 13, 2029, asteroid 2004 MN4 will fly past Earth only 18,600 miles (30,000 km) above the ground. For comparison, geosynchronous satellites orbit at 22,300 miles (36,000 km). "At closest approach, the asteroid will shine like a 3rd magnitude star, visible to the unaided eye from Africa, Europe and Asia--even through city lights," says Jon Giorgini of JPL. This is rare. "Close approaches by objects as large as 2004 MN4 are currently thought to occur at 1000-year intervals, on average.

No one in recorded history has ever seen an asteroid in space so bright.



Friday the 13th, 2029

Asteroid 2004 MN4 will come scarily close to Earth on April 13, 2029, but it will not hit.

Friday the 13th is supposed to be an unlucky day, the sort of day you trip on your shoe laces or lose your wallet or get bad news.

But maybe it's not so bad. Consider this: On April 13th--Friday the 13th--2029, millions of people are going to go outside, look up and marvel at their good luck. A point of light will be gliding across the sky, faster than many satellites, brighter than most stars.

What's so lucky about that? It's asteroid 2004 MN4 ... not hitting Earth.

For a while astronomers thought it might. On Christmas Eve 2004, Paul Chodas, Steve Chesley and Don Yeomans at NASA's Near Earth Object Program office calculated a 1-in-60 chance that 2004 MN4 would collide with Earth. Impact date: April 13, 2029.

The asteroid is about 320 meters wide. "That's big enough to punch through Earth's atmosphere," devastating a region the size of, say, Texas, if it hit land, or causing widespread tsunamis if it hit ocean, says Chodas. So much for holiday cheer.

Asteroid 2004 MN4 had been discovered in June 2004, lost, then discovered again six months later. With such sparse tracking data it was difficult to say, precisely, where the asteroid would go. A collision with Earth was theoretically possible. "We weren't too worried," Chodas says, "but the odds were disturbing."
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Instead, what we're going to have is an eye-popping close encounter:

On April 13, 2029, asteroid 2004 MN4 will fly past Earth only 18,600 miles (30,000 km) above the ground. For comparison, geosynchronous satellites orbit at 22,300 miles (36,000 km). "At closest approach, the asteroid will shine like a 3rd magnitude star, visible to the unaided eye from Africa, Europe and Asia--even through city lights," says Jon Giorgini of JPL. This is rare. "Close approaches by objects as large as 2004 MN4 are currently thought to occur at 1000-year intervals, on average."

The asteroid's trajectory will bend approximately 28 degrees during the encounter, "a result of Earth's gravitational pull," explains Giorgini. What happens next is uncertain. Some newspapers have stated that the asteroid might swing around and hit Earth after all in 2035 or so, but Giorgini discounts that: "Our ability to 'see' where 2004 MN4 will go (by extrapolating its orbit) is so blurred out by the 2029 Earth encounter, it can't even be said for certain what side of the sun 2004 MN4 will be on in 2035. Talk of Earth encounters in 2035 is premature."

In January 2004, a team of astronomers led by Lance Benner of JPL pinged 2004 MN4 using the giant Arecibo radar in Puerto Rico. (Coincidentally, the Arecibo dish is about the same size as the asteroid.) Echoes revealed the asteroid's precise distance and velocity, "allowing us to calculate the details of the 2029 flyby," says Giorgini, who was a member of the team along with Benner, Mike Nolan (NAIC) and Steve Ostro (JPL).

More data are needed to forecast 2004 MN4's motion beyond 2029. "The next good opportunities are in 2013 and 2021," Giorgini says. The asteroid will be about 9 million miles (14 million km) from Earth, invisible to the naked eye, but close enough for radar studies. "If we get radar ranging in 2013, we should be able to predict the location of 2004 MN4 out to at least 2070."

The closest encounter of all, Friday the 13th, 2029, will be a spectacular opportunity to explore this asteroid via radar. During this encounter, says Giorgini, "radar could detect the distortion of 2004 MN4's shape and spin as it passes through Earth's gravity field. How the asteroid changes (or not) would provide information about its internal structure and material composition." Beautifully-detailed surface maps are possible, too.

The view through an optical telescope won't be so impressive. The asteroid's maximum angular diameter is only 2 to 4 arcseconds, which means it will be a starlike point of light in all but the very largest telescopes.

But to the naked eye--wow! No one in recorded history has ever seen an asteroid in space so bright.

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"...is there a cool program that would show where Jupiter's position is on this date?
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Just do a google search there are several programs.

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In all seriousness -- what would we do if this thing was going to impact?

 

Hopefully some more members jump on this bandwagon...
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Congressman Backs Asteroid Agency

A plan to assign a government agency the task of protecting the Earth from a catastrophic asteroid strike is being endorsed by a senior member of the U.S. House Science Committee.1

But a related space mission to track an asteroid that may hit Earth in 2036 can't seem to get off the ground.

The appointed agency would have the authority to deflect or destroy a threatening asteroid, most likely with the help of NASA and the Defense Department. It would also mobilize emergency-response teams if an asteroid impact could not be avoided.

Support for Schweickart's other proposal has not been so positive. Schweickart has called on Congress to authorize a $300 million mission to place a transponder on a 1,050-foot-wide asteroid known as 2004 MN4.

The George E. Brown Jr. Near-Earth Object Survey Act would require NASA to expand its catalog of near-Earth objects to include objects down to 100 meters in diameter. The agency currently catalogs objects down to 1 kilometer in diameter.

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Update...

NASA researchers have begun considering whether the US needs to tag the asteroid, known as 99942 Apophis, with a radio beacon before 2013.

Timing is everything, astronomers say. If officials attempt to divert the asteroid before 2029, they need to nudge the space rock's position by roughly half a mile - something well within the range of existing technology. After 2029, they would need to shove the asteroid by a distance as least as large as Earth's diameter. That feat would tax humanity's current capabilities.
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An asteroid, headed our way

Humans live in a vast solar system where 2,000 feet seems a razor-thin distance.

Yet it's just wide enough to trigger concerns that an asteroid due to buzz Earth on April 13, 2029 may shift its orbit enough to return and strike the planet seven years later.

The concern: Within the object's range of possible fly-by distances lie a handful of gravitational "sweet spots," areas some 2,000 feet across that are also known as keyholes.

The physics may sound complex, but the potential ramifications are plain enough. If the asteroid passes through the most probable keyhole, its new orbit would send it slamming into Earth in 2036. It's unclear to some experts whether ground-based observatories alone will be able to provide enough accurate information in time to mount a mission to divert the asteroid, if that becomes necessary.

So NASA researchers have begun considering whether the US needs to tag the asteroid, known as 99942 Apophis, with a radio beacon before 2013.

Timing is everything, astronomers say. If officials attempt to divert the asteroid before 2029, they need to nudge the space rock's position by roughly half a mile - something well within the range of existing technology. After 2029, they would need to shove the asteroid by a distance as least as large as Earth's diameter. That feat would tax humanity's current capabilities.

NASA's review of the issue was triggered by a letter from the B612 Foundation. The foundation's handful of specialists hope to demonstrate controlled asteroid-diversion techniques by 2015.

Last Wednesday, representatives from the foundation met with colleagues at NASA's Jet Propulsion Laboratory (JPL) to review the issue. The foundation's letter marks the first time specialists in the asteroid-hazard field have called for a scouting mission to assess such a threat.

"We understand the risk from this object, and while it's small, it's not zero," says David Morrison, the senior scientist at NASA's Astrobiology Institute at the Ames Research Center at Moffett Field, Calif.

The call for a reconnaissance mission also illustrates how far the field of asteroid-hazard assessment has come.

"Ten years ago, we would have been blissfully ignorant," says Donald Yeomans, who heads NASA's near-Earth object project at JPL. Today, at least five programs worldwide are hunting down near-Earth objects. NASA is well on its way toward achieving its goal of cataloging 90 percent of the near-Earth objects larger than 0.6 miles across by 2008. And it is devising ways to ensure that information about potential hazards reaches top decisionmakers throughout the government.

Based on available data, astronomers give Apophis - a 1,000-foot wide chunk of space debris - a 1-in-15,000 chance of a 2036 strike. Yet if the asteroid hits, they add, damage to infrastructure alone could exceed $400 billion. When the possibility of the asteroid passing through two other keyholes is taken into account, the combined chance of the asteroid hitting the planet shifts to 1 in 10,000, notes Clark Chapman, a senior scientist with the Southwest Research Institute in Boulder, Colo.

"A frequent flier probably would not want to board an airliner if there's a 1-in-10,000 chance it's going to crash," he says.

The asteroid in question was discovered last June. Initially, it looked as though it might strike Earth in 2029. But additional observations eliminated that possibility. Instead the asteroid will come within 22,600 miles of Earth - just inside the altitude where major communications satellites orbit. The asteroid will be visible to the naked eye in the night skies over Europe and western Africa, where it will appear a bit dimmer than the North Star.

But this estimated distance carries an uncertainty that spans several thousand miles either side of its expected path - a region of space that includes three gravitational keyholes.

JPL's analysis will look at several factors. One involves estimating whether additional ground observations will be sufficient to resolve the question of whether the asteroid will pass through one of the keyholes. The asteroid belongs to a class known as Atens, which orbit the sun in less than a year and pass through Earth's orbit. Because Atens spend so much of their time in the direction of the Sun, observations from Earth are difficult. After next year, the next opportunity to gather data on the asteroid from the ground will come in 2012-2013.

In addition, questions remain over how long a tagging mission - and if necessary a deflection mission - would take to plan and execute. If missions can be mounted in six years or less, NASA could postpone a decision to tag the asteroid until 2014. This would give astronomers time to incorporate their latest observations as they refine calculations of Apophis's orbit. But if a tagging mission took seven to eight years and a diversion mission took another 12 years, the case grows for launching the tagging mission sooner rather than later.

Dr. Yeomans, the head of the near-Earth-object program at JPL, says the next step is to examine whether additional ground-based observations are likely to solve the collision riddle in a timely fashion.

"I can't stress this enough: The overwhelming most-likely scenario is that radar and optical data this year and next or in 2012 and 2013 will completely remove the impact probabilities," he says.

"If this is the case, why are we worried now? If it's a 1-in-15,000 shot and we come up a loser," there's still time to mount a tagging and a deflection mission, he says.

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