This Asteroid Could’ve Caused an Apocalypse—Now It’s Barely Missing Earth

Asteroid Apophis is something

that is going to come really close to earth.

On April 13, 2029,

Apophis will pass at a distance of 4.9 earth radii,

which is about 1/10th of the earth-moon distance.

At the time when Apophis was discovered in 2004,

it had this chance of impact of 4%.

That is the highest probability that we ever knew

for any other asteroid.

A kilometer-sized object,

which is really global devastation,

something that size, coming this close,

yeah, this one is the closest that we know of.

First thing you do is like,

okay, who can get more measurements?

Then you pool all the resources,

see all the telescopes,

see if you can get a good radar,

because the odds are, with more measurements,

the chances of impact is going to disappear.

Last time we observed it in January 2013,

we got some really, really precise measurements

of its position

resulting in a very precise orbit determination.

They have completely eliminated any chance of impact.

So the statistics for earth impacts

is something that is small.

That happens probably once every several centuries.

Something that is larger,

something that we should really worry about,

those are on the orders of like,

500,000 years to a million.

We're looking at some very rare events,

and I think it's important to note

that we have discovered more than 95%

of the objects that are a kilometer in size or larger.

So, if there were any big asteroids

near the earth population,

we would have found them by now.