65 million years ago a comet screamed in from space and caused an extinction level event. Slamming into the planet at 44,000 mph, the 10 mile long flying mountain of rock and ice created an explosion billions of time bigger than an atomic bomb. The sky went dark from debris blown into the atmosphere along with the ensuing fires. The planet dropped into climate change on an apocalyptic scale and 90 percent of all species were wiped out. The age of dinosaurs came to an abrupt and catastrophic end.

If only they knew what we know.

For the last few decades astronomers have been practicing a new art called “Planetary Protection”. The goal of this long term project has been to ensure that humanity never gets caught with its collective pants down a’la asteroid/comet impacts. A few weeks ago the true fruits of that effort were revealed and it gives real hope that - if we can work out all the other challenges we face - then we might get a shot at becoming a truly long-term civilization. Sure, climate change, nuclear war and killer AI might still get us but maybe, just maybe, killer rocks from space will not.

The first phase of planetary protection was finding all the killer space rocks out there. That job is not finished yet but astronomers have done a great job cataloging all the extinction level beasts. Now that we know where they are, we can turn to the really hard problem: what do you do if one is heading straight for us.

If you’ve seen movies like Armageddon or Deep Impact, you know one strategy is to get out there and blow the whole thing to smithereens with nukes. That’s actually not a great idea. Some of those smithereens might not be so smithereen-y. The debris can still be big enough to rain down hell on your planet.

A better idea is to get to the asteroid when it’s far away and nudge it enough to change its course.

Back in 2022 NASA pulled off an audacious experiment called DART were they played with exactly this idea. The space agency drove a spacecraft head first into one member of a “binary asteroid” pair called Didymos and Dimorphos (it was Dimorphos they wacked). NASA chose the binary because their orbits around each other served as a kind of precise clock. Any changes from the collision between DART and Dimorphos could be precisely monitored. The collision produced some amazing images and it quickly became clear that the idea had worked. The orbital period of the pair (i.e. how long it takes to complete one rotation) had been altered by 33 minutes.

Just last week, however, scientists published a new, longer term study that followed not just the asteroids motion relative to each other, but how they moved - together - around the Sun. That research showed that the speed of the pair through space had shifted by 42 millimeters per hour. That change may be small but its consequences are huge. Space is really big. If you can get to potential killer asteroid soon enough even a small nudge will change a devastating direct hit into harmless fly-by.

Think about what this means for a minute. If the dinosaurs had the kind of space technology we are now developing, they would still be here. They could have saved themselves. Maybe they would have had another 100 million years of fun and frolic.

Come to think of it, we can all be thankful they didn’t have this science. They only reason you and I are here is becuase the asteroid which took out the dinosaurs gave our rat-like mammal ancestors the chance to claim the empty earth. When the age of dinosaurs ended, the age of mammals began.

Now, we have a path to avoid the dismal Dino-fate. This is the power and the promise of becoming a true space-faring race.

— Adam Frank 🚀