Impact Planet Earth: Talk The Talk

However, if the topic should come up in conversation during more relaxed moments, you might find yourself grasping for a more descriptive or informative comment or two...

Luckily, there’s no shortage of astronomical and historical jargon to dip into.

IS IT A BIRD, IS IT A PLANE ...?
Good point, what’s a good word for all those rocky objects that might come at us from space? For simplicity you need a word that encompasses comets, meteorites and asteroids... and this word is: bolide. As in "bolide impact".

But even within the meteor family, you need to know your way-out-there objects from your hey-look-what-I-just-found objects...

Strictly speaking, a "meteoroid" is a rocky body which is minding its own business, outside the Earth’s atmosphere.... A "meteor" is the name for the same object once it has entered the Earth’s atmosphere.... And a meteorite is a meteor which has made it to the Earth’s surface.

HOW FAST?
Well, they don’t hang about these incoming asteroids...

You’ve heard of UFOs ... but NEOs could be the next popular craze for cosmic worriers. NEO stands for Near Earth Objects. Which possibly weren’t the previous time we looked. Gulp.

HEARD THE ONE ABOUT THE ASTEROID AND THE DINOSAURS?
The theory that the dinosaurs were killed as the result of a massive asteroid is known as the "Impact Extinction Hypothesis" and it was proposed by Louis and Walter Alvarez in 1980. The idea is: if a large enough asteroid hits the earth, the amount of rock and other debris thrown up into the atmosphere could block out the sunlight for long enough to wreck the planet’s ecosystem.

The Chicxilub crater in Mexico is known to be the site of this impact. Chicxilub is pronounced CHICKSIE-LUB ... and the impact happened 65 million years ago.

Scientists often talk about "events around the K-T boundary" ... what are they going on about? Is it rude??

Basically there are various time periods in the Earth’s history - of which the Jurassic era is probably the most famous, due to Steven Spielberg. The phase between the Cretaceous period and the Tertiary period covers the mass extinction which includes the dinosaurs dying out. Hence K-T. So why’s it not called the C-T boundary? Because ’C’ is already used for the Carboniferous period, which was the time when the world’s major coal deposits were laid down.

There are few theories in science as sexy as the idea that a giant asteroid put paid to all those giant dinosaurs. Even Hollywood couldn’t have done better. No wonder it’s an idea which the media and many have taken to their hearts. But it is NOT an established fact. Scientists are still arguing fiercely over it.

If you want to play devil’s advocate with a passionate impact-extinction believer, say:

1. The dinosaurs were dying out already before the impact.

2. There was a great deal of volcanic activity going on at the time, that would have stressed the animal population whatever else happened.

But whatever else did happen, 70% of species were wiped out. And the species which then went on to prosper were not necessarily the ones that were in a position of dominance beforehand.

CONVERSATION CLINCHER
Whether or not the asteroid exterminated the entire dinosaur population, one thing is true. Those that were around at the time would have had only 5-6 seconds warning that something weird was happening with the sky...

And that’s what we’d have too if we didn’t spot an approaching danger before it entered our atmosphere.