Close Encounters of the Worst Kind

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Credit: Near-Earth Object Program
(JPL/NASA)

Sometimes I have trouble sleeping, thinking about what might happen tomorrow. Recently, astronomers identified another of those potential close encounters of an asteroid with Earth. But I am not losing sleep over this one.

An asteroid named 1950 DA was first discovered by the Lick Observatory in 1950. It's a rock about a kilometre wide which faded from view for five decades. But currently, it's a greater hazard than any other known asteroid. It will, they claim, have a close encounter with Earth on March 16th 2880. Given the thirty generations between now and when it might hit us, I’m pretty relaxed about this one!

The orbit of the 1950 DA has been mapped using precise radar data and a 51 year span of optical data. How close an asteroid like this will actually approach the Earth depends on a number of properties we can’t yet know for sure. It’s shape, how it spins, how it reflects light and heat into space, all these subtly alter its course over centuries. For example, the process of radiating solar heat in one direction, will slightly nudge the asteroid in the opposite direction. Although the effect is very small, multiplied over centuries, it could make the difference between a hit and a miss.

So next time you can’t sleep at night, think of something more pressing than potential trouble from 1950 DA, almost nine centuries from now.