Somewhat disconcerting news: When the radar at Arecibo Observatory in Puerto Rico spotted it, astronomers realized the space rock was larger than they had thought. Today’s estimate is about 0.8 miles wide.

AD

Let us, for a moment, consider a scenario in which a 0.8-mile-wide asteroid strikes Earth.

First, the magic number for total apocalypse is 60 miles. That’s how big an asteroid would need to be to wipe out human life.

AD

This asteroid is far from that number, but if it hits, let’s say, Washington, D.C., it’s large enough to destroy everything and everyone from New York City to Raleigh, N.C. (I apologize to the people of Raleigh for dragging you into Washington’s apocalypse.) The thermal radiation radius would be much larger.

At six miles wide, even the asteroid that led to dinosaur extinction was much smaller than the Earth-obliterating scenario. It leveled everything within a couple thousand miles and tossed giant debris into near-space, which then fell back into the atmosphere as giant fireballs.

AD

According to the Planetary Science Institute, there’s a hypothesis that the giant fireballs heated Earth’s surface to boiling temperatures, which killed everything that walked or crawled on land, but creatures that burrow in the ground would have been safer.

AD

“This may explain why mammals replaced giant reptiles after the impact,” the Institute writes. “Tiny primitive mammals may have emerged from their dens, to find that their giant reptile competitors were mostly gone.”

Neat!

Now, on to the big event: deep impact — which, it turns out, is going to look nothing like the movie and everything like your worst nightmare.

First, watch this video. I think it probably gives you a sense of what will go down. (You don’t need to have the volume up, but I highly recommend it — the Pink Floyd soundtrack is great, particularly the wild sing-screaming that times with the flaming debris raining down on Earth.)

Here’s the obvious disclaimer: We really have no idea what this doomsday scenario will look like. We’ve never experienced it before. But physics is a tried and true science that I tend to rely on, so when physics tells me an asteroid this large would release 1031 Joules of kinetic energy, I take note. That’s how much energy the sun releases in a day.

Think about that for a minute. But don’t dwell! Breathe easy.