The smoky remnants of the 2008 TC3 impact of 2008 TC3 over Sudanese skies (NASA)
This was a very impressive achievement for asteroid hunters; detecting a small meteoroid and predicting its location of impact was a world first, a testament to the astronomers working on asteroid surveys all over the world.
What if 2011 MD Did Hit Us?
Last Wednesday, the 5-20 meter-wide 2011 MD was spotted, but this time with over five days notice - once again, a fantastic achievement considering the asteroid's size There seems to be much relief that 2011 MD missed us, but truth be told, this asteroid would have hit the atmosphere and exploded much like 2008 TC3 did. Although the air burst would have likely been more energetic (as it was larger than 2008 TC3), 2011 MD certainly wouldn't have caused any major damage to the ground, least of all to populated areas.
Depending on its composition, 2011 MD would have disintegrated, with the potential for small meteorite debris to scatter across the South Atlantic Ocean.
If 2011 MD was on a collision course, I have little doubt that a warning would have been issued for air and sea traffic, with the potential for redirected or delayed flights in the South America/South Atlantic region, depending on the predicted location of atmospheric entry.
Undoubtedly there would be mild panic - what if astronomers underestimated it's size?! - and a huge amount of media coverage.
With a few days of notice, scientists would be jetting down to the southernmost tip of the Americas in the hope of observing this historic impact. Although spotting the impact during the day would be a difficult task, depending on atmospheric conditions, a "boom" might be heard and infrasound arrays would measure the energy of the impact on the atmosphere.
Apart from the obvious scientific advantages of observing a meteoroid slam into the Earth's atmosphere, 2011 MD would have acted as a warning shot; a planetary flesh-wound of sorts. We live in a cosmic shooting gallery, it's only a matter of time before something bigger has us in its cross hairs.
Of course, this is all conjecture. 2011 MD flew past, probably to never be seen again. It missed Earth. But for the future of asteroid detection, I think that's a shame.
A Matter of Time
The problem with mankind is that we procrastinate.
The reason why we invest very little money in near-Earth object surveys is that the risk perception is very low. After all, how many asteroids have really caused problems in recent years?
There was that nasty dino-killing space rock, 65 million years ago. Oh yes, and that Tunguska thing in 1908. Something obviously hit Arizona 50,000 years ago, too.
But why worry? All these cosmic collisions happened in the distant past, we don't need to be worried now, do we?
The inner solar system may seem nice and peaceful, but much larger space rocks than 2011 MD are floating around and many are extinction-level events.
Fortunately, astronomers are confident that they've spotted most of the large, kilometer-wide "potentially hazardous asteroids," but a lot more work needs to be done to survey the skies for the smaller rocks that may not wipe out a civilization, say, but could cause upset for a densely populated city. It's only a matter of time before our planet gets hit.
What's more, if we had more telescopes looking for asteroids of all shapes and sizes, we might be able to spot the ones heading for us well ahead of time for us to do something about them. But to deflect (or nuke) an asteroid we'll need an in-space infrastructure. All this takes money, and unfortunately, money is what we're lacking.
As Phil Plait put so succinctly in the Discovery Channel's "Bad Universe":
"Every few hundred years, we're hit by something really large, like, football field-sized; definitely big enough to take out a city. But the ones that give me nightmares, the ones that truly scare me, are the asteroids that can cause what scientists call ‘extinction-level events.'"
Perhaps getting hit by a small asteroid - like the fairly harmless 2011 MD - would have shocked the world enough to ask the question: What are we doing about the threat of getting hit by something bigger? Could it have provided political pressure to direct more funds into near-Earth object search programs?
Alas, 2011 MD lives to fight another day, asteroid detection remains underfunded and asteroid deflection remains a distant hope.
Image credit (top): Corbis (edit by Ian O'Neill)