UN to establish asteroid defence plan

Updated October 29, 2013 19:10:00

In February this year a meteor exploded above Russia injuring 1,000 people. No one knew it was coming. Now the United Nations has decided to establish an asteroid defence plan. How will it work and what will it do?

Source: PM | Duration: 4min 38sec

Topics: planets-and-asteroids, european-union, russian-federation


DAVID MARK: In February this year a meteor exploded above Russia injuring 1,000 people. No-one knew it was coming.

Normally when an asteroid is threatening Earth, the best course of action is to send Bruce Willis to deal with the problem. But now the United Nations has decided to take a more scientific approach. It's voted to establish an asteroid defence plan.

How will it work and what will it do?

Dr Alan Duffy is a post-doctoral research fellow from the Astronomy Department at the University of Melbourne.

Dr Duffy, we've been hearing about the threat of asteroids for more than a decade now. Is it just good luck that there has been no serious collision in recent years?

ALAN DUFFY: I think that's right. We're talking about chance here. What's the chance that we're going to get hit by a dangerous asteroid? Earlier this year, Russia lucked out. It did get hit by an asteroid. About a thousand or so people were injured. So this acted as a real wake-up call that it's not just chance. This is going to happen to us sooner or later.

DAVID MARK: So you say Russia lucked out, but injuries to a thousand people could be seen as bad luck, but you see that as a wake-up call?

ALAN DUFFY: I do. This object was about 17 metres across, which is hefty but by the scale of things, if it was 10 times larger, then you could have had an explosion about 1,000 times the size of the atomic blast that took out Hiroshima. So it was bad luck of course for Russia, but it could have been infinitely worse.

DAVID MARK: I understand that only a fraction of those sorts of objects have actually been discovered. What are the actual numbers? How much do we really know about the objects out there that could destroy a city?

ALAN DUFFY: Well our best guess is that we've found barely 1 per cent of all of these objects. That's a terrifying number, and that means that there are possibly a million or so of these killer asteroids out there and one of them does have our name on it. It's just simple probability.

DAVID MARK: Well the UN has acted. It's set up an asteroid defence plan. How exactly will it work? What will it do?

ALAN DUFFY: The first step in its plan is - well, it's actually set up, the International Asteroid Warning Group. So that's a body which will share information between all the member states. Once they find an asteroid, then they'll pass the problem on to the Committee on the Peaceful Uses of Outer Space. They'll actually try to coordinate a mission to deflect this asteroid.

DAVID MARK: So will a UN vote actually make any difference?

ALAN DUFFY: Anything that reduces the time it takes for humanity to deal with this asteroid is a fantastic thing. This is a real positive.

For example, if we see an asteroid coming and we have 10 years to figure out a response, then we can nudge it aside relatively easily. If we leave it, if we're mired in a quagmire of legal issues and who is supposed to deal with it and we leave it until one year, then we have almost no hope.

DAVID MARK: Because you mentioned earlier that if an object is discovered, then a committee would be set up. Now I don't know if committees are generally very good at deflecting asteroids. Normally, Bruce Willis does that sort of thing, but you argue that that will help the cause.

ALAN DUFFY: That's right. It's a committee and as you say, that's never going to strike fear into the hearts of these asteroids, but the committee is necessary. It has to be a global response because it has to be a global share of the blame if it goes wrong because right now if we have Armageddon, we have our Bruce Willis hero who goes up thanks to NASA and then explodes the asteroid and debris hits all over the Earth, well, who's responsible? Actually, in this case, probably NASA.

So this is not going to be undertaken by just any one country, nor should it be, so having a committee is the first and logical step.

DAVID MARK: Now you've mentioned options for what to do if an asteroid is discovered, and you've said that the best option would be deflection. How does that work?

ALAN DUFFY: So there are two ways to deflect an asteroid. The first is you take your spaceship and you fly just beside your asteroid and just gently start to judge it, literally just push into the asteroid, and we're talking an incredibly small amount of force needed, and over time, that builds up and the asteroid just sails by. So if you have 10 years' warning, you can do it very easily, but if you have only a year's warning, you have to nudge it a lot harder.

The second is my favourite, which is the gravity tractor, and as you fly up to the asteroid, it has a tiny bit of gravity and it will pull your spaceship. And your spaceship is a lot smaller and it will have gravity pulling back on the asteroid, and if you just slowly keep inching away from the asteroid, letting gravity do the work, you can actually pull this asteroid out of the path of the Earth.

So it's a very neat idea. It's not been tested, so we would want to try and demonstrate this works before doing it for real.

DAVID MARK: Dr Alan Duffy is an astrophysicist from the University of Melbourne.