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CSI: Comet/Asteroid Scene Investigation

Don Yeomans, NEO Team Manager
What do we have here? Is that another PHA?

Paul Chodas, NEO Team Scientist
Take a look at the Palermo.

Don Yeomans:

Paul Chodas:
My guess is that this body is an Aten.

Don Yeomans:
Do we have a size?

Paul Chodas:
Got to be in the 300 meter range.

Don Yeomans:
Let's get on this.

You can think of the Near Earth Object program office as sort of a CSI unit. We discover these objects. We try and determine what they’re made of, where they’re going and just how dangerous they might be.

Paul Chodas:
In December of ’04, one of the new discoveries was an asteroid that later became known as Apophis.

Don Yeomans:
It’s an object about 270 meters long, that’s going to make an extremely close approach to the Earth on April 13th, Friday the 13th, 2029.

Paul Chodas:
This object isn’t a source for concern now, but back then, it had us worried.

So this is a representation of the Earth, and the orbit of the moon and the uncertainty region of Apophis.
All of the points on this line are possible locations for Apophis, and any one of these dots could be the actual asteroid.

Don Yeomans:
All of the numbers that we were seeing were well beyond what we had seen before, and the threat level, as a result, was elevated. 

The impact probability for a collision with the Earth in 2029 reached the three percent level; three chances out of 100 that it would hit.

Paul Chodas:
When we saw the impact probability rising, we put out calls for others to look on their, in their archives for images of this asteroid on previous dates.

Don Yeomans:
When we got additional observations from the optical telescopes and when we got additional radar data, the threat level went to zero in 2029 and only left a slight possibility of an impact in 2036.

Paul Chodas:
There is a possibility that after it goes by the Earth, it may pass through a small doorway, or keyhole, I call it, and be deflected by the Earth’s gravity into an orbit that would be about seven sixths of a year.

Don Yeomans:
The Earth would go around the sun seven times, the asteroid would go around the sun six times, and they would meet up at the same place, at the same time, April 13, 2036.

Paul Chodas:
It will be important to look at this asteroid in the year 2013. We hope to see it with radar, and then hopefully we will confirm that the asteroid will not pass through that keyhole. That should allow us enough time, if we unfortunately see that it is going to the keyhole, perhaps to mount some sort of mission to the asteroid to deflect it, and all we have to do then is deflect it away from that keyhole.

Don Yeomans:
We don’t let down our guard, not even for a day. It’s our job to monitor the inner-solar system and make sure that none of these objects are getting dangerously close to the Earth.

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