Imagine a 100,000 ton hunk of space rock, a meteorite weighing almost as much as two
Titanics, slamming into our planet. Imagine it is only 98 feet in diameter,
the length of a blue whale. Now imagine it hits the surface of our planet travelling at 28,600
miles per hour. The impact it would leave behind would look exactly like this.
But this is nothing compared
to what came before...or what could still be coming...this is Extreme Science.
The meteorite that impacted where we are now did so 50,000 years ago with the force of
2.5 million tons of TNT - making a crater that is a quarter of a mile wide and 560ft deep.
Millions of tons of Earth were ejected outwards, most melted by the heat of the impact. But that
wasn’t all the damage, oh no not at all. Let’s go to right before the meteorite hit.
There were grassy hills, forests.
Humans had yet to cross the Bering Strait. Ah, so peaceful. And then all of the sudden
BOOM everything in the immediate vicinity is vaporized. Winds exceeding 880 feet per
second blow across a 3 mile area. And
all vegetation in a 483mi2 area is destroyed.
All in all, the destruction would be enough to wipe out New York City but the crazy thing
is is that this meteorite wasn’t even that big. The Chicxulub Impactor is thought to
be at least 6 miles in diameter and the crater it made could fit 117 of the Arizona craters
in it. The Chicxulub Asteroid was responsible for causing the chain
of events that lead to the complete extinction of 3 quarters of all plants and animals on
earth 66 million years ago.
Asteroids are terrifyingly powerful but are also incredibly interesting and slightly misunderstood.
A lot of times we tend to use the term meteors comets, and asteroids interchangeably but they
are different even though they tend to come from the same place.
An asteroid is a relatively small rocky body that orbits the sun. A comet is a relatively
small object whose ice can vaporize from the heat of the sun forming what we sometimes
see as that trail of dust and gas behind it. A meteoroid is a small piece of comet or asteroid.
A meteor is the light phenomena from when a meteoroid enters our atmosphere and vaporizes,
commonly known as a shooting star. And a meteorite is what survives coming through our atmosphere
and subsequently crashes into Earth’s surface.
Scientists estimate the kind of meteorite that struck here in Arizona happens every
300 years. However, asteroids hitting our atmosphere are pretty common. About every
other week asteroids 3 feet in diameter come towards Earth, encounter our atmosphere and
burn up. Car sized ones hit about once a year and break apart to cause bolides, the technical
term for fireball. Really anything smaller than 82 feet wouldn’t make it to our surface.
Sometimes they come close though like in February 2013 near Chelyabinsk, Russia. The giant fireball
or “superbolide” was estimated to be 59 feet wide and 11,000 tonnes. Luckily it broke
apart before hitting our surface but it still was able to blow out windows, shake buildings
and injure over 1,000 people.
Now when I said an asteroid is relatively small, they can range in size from the 98.5
feet Arizona one to Ceres...a 600 mile in diameter asteroid that when it was first discovered
in 1801 was considered a planet. It is now referred to as
both a dwarf planet and an asteroid and as far as we know, it is the largest asteroid
in our solar system, and we only got our first good look of it fairly recently.
NASA says that an asteroid larger than 1.5 miles would cause catastrophic damage on a
global level. Think dinosaur level of extinction. In fact, you are more likely to die from an
asteroid impact than you are from a shark attack. So how could we stop that from happening?
Blowing it up like they do in movies is exactly what you don’t do. It would only create
meteoroids and we’d have no way of judging if all the fragments would be small enough
to burn up in our atmosphere. The European Space Agency and NASA are both testing ways
of changing an asteroid's course. Kinetic Impact would alter the trajectory of an asteroid
headed towards Earth by smashing something like a spacecraft into it - hopefully moving
the asteroid out of our way. Or there is ARM, the asteroid redirect mission, which would
slowly move the asteroid using a spacecraft’s gravitational pull and put it into lunar orbit.
It would also allow us to study and potentially mine it.
These programs and missions are still in early stages because we have yet to have any giant
asteroids come close enough to our planet to warrant their use. There is another interesting
theory when it comes to asteroids and that is that they are kind of like giant, rocky
seeds. It is called panspermia and it is the idea that maybe life, on some microscopic
level, travelled on board an asteroid and then was spread into a new home once it’s
means of transport crashed into the planet. So maybe,
just maybe, a meteorite may leave more of an impact on our landscape than a crater.
It might just change what life comes out of it. I’m Jake and I’ll see you next time
on Extreme Science.