Q+A: Can NASA Really Predict — and Divert — Harmful Asteroids?

AsteroidThe name “Planetary Defense Coordination Office” evokes such sci-fi motifs as laser canons pointed skyward and angry, space ship-riding aliens.

In actuality, the Planetary Defense Coordination Office (PDCO) that NASA announced earlier this month deals with things that could pose a much more real threat to Earth: asteroids.

NASA was charged by Congress with seeking out and tracking near-earth objects — asteroids and comets “entering Earth’s neighborhood.” The office will also take the lead role in dealing with any potential risks to the planet.

More than 13,500 near-Earth objects have been discovered to date. They range in size from simply a meter or two all the way up to kilometers. And roughly 1,500 more are being discovered each year.

Now, with Congress earmarking $50 million to fund an office dedicated to these objects, are they really all that threatening? And is there actually the potential to stop one targeting Earth?

Drexel’s Gordon Richards, PhD, professor in the College of Arts and Sciences, has already worked on a project dedicated to mapping the night sky and is signed on for another expansive project. He weighs in on what the new office could contribute to the scientific community and Earth as a whole.

Is the Planetary Defense Coordination Office a formalization of work that NASA was already doing?

It does appear that NASA is trying to tie together work that is already being done. There are at least a dozen (independent) telescope facilities that regularly discover asteroids — and not just the near-Earth ones.

Some of these telescope facilities are parts of other projects, but a number of them are specifically designed for the task. So it makes sense to think about the problem under one coordinating umbrella.

How accurately can these objects be tracked and can we really determine if one is on a collision course?

As you can imagine, the answer is that “it depends.”

An example might be the best way to answer.

The asteroid “Apophis” caused a bit of a stir back in 2004 when it was determined that it had a small chance of hitting Earth in 2029. Before it was determined that it wouldn’t, the uncertainty in the path was about two Earth diameters.

Is it realistic to think that these objects can be diverted or prevented from a strike with Earth?

The idea of a “gravity tractor” is a very real possibility if there is enough advanced notice. We only have to alter the orbit a little bit to avoid a collision that is a long time away.

However, we don’t know about every possible impacter. The event in Chelyabinsk in 2013 was a stark reminder of that. That object had an estimated size of only 20 meters compared to the ones larger than 140 meters that NASA is charged by Congress to find.

How worried should we be about near-Earth objects?

It is worth noting that, while near-Earth asteroids are certainly a real threat that we shouldn’t ignore, I would argue that it is more of a long-term problem. Probably even longer-term than climate change and certainly longer-term than the need to cure cancer.

The current list of objects considered risks — none of them considered significant at the moment — can be found here.

Media interested in talking with Richards should contact Frank Otto at 215.571.4244 or fmo26@drexel.edu.

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