Asteroids, meteors and meteorites: Everything you need to know

Source: 1News

Asteroids. Rocks that have been floating in space for millions, probably billions of years, travelling for light-years.

If you're lucky you might even see one coming to Earth, like Wellington did a few weeks ago. If you're even luckier, you might find one. But do you get to keep it? And what's with all the different names?

Let's start at the beginning.

The basics

What name we use depends on where the rock is and what it is doing.

At the beginning of its journey, we refer to it as an asteroid - a rock in space.

Once that asteroid enters Earth's atmosphere it's referred to as a meteor.

"We also call it a shooting star," says space commentator Matthew Pavletich.

It's at this point most meteors' journeys end, burning up and never making it to the ground.

If it does, it's referred to as a meteorite.

"If you see it streaking across the sky to land near you, on Earth, then it is referred to as a fall," says Pavletich.

"Then, if you stumble across it, it is a find."

But the chances of that are slim.

The Eta Aquariids meteors captured by an amateur photographer.

Location

About 100 tonnes of space rocks fall to Earth every day. Most tend to fall into water or uninhabited places, which cover most of Earth.

Antarctica is a hotspot for meteorites because of its size and temperatures that cool the rocks down quickly as they enter the atmosphere, reducing the chance they'll explode due to the heat.

Topographic World Map on Kavraisky VII Projection.

Ownership

If a meteor was to fall onto private property - becoming a meteorite - it belongs to whoever owns the land.

"The accepted wisdom is that if it lands on your land, it's yours," says Pavletich.

If it falls onto public property, the rule of thumb is first in, first served.

Finders can choose to keep, donate or sell meteorites.

In New Zealand there are regulations around verifying and selling. The 1975 Protected Objects Act restricts export without permission from the Ministry for Culture and Heritage.

There's been only nine confirmed meteorites in New Zealand, and only two have ever been seen to 'fall'. Most were donated for further scientific research.

LIBYA APRIL 2016 (SOUTH AFRICA OUT): The Oasis meteorite crater in Libya on April 17, 2016.

Verification

So how do you know a meteorite isn't just a rock?

Astronomy educator and astrophotographer Josh Aoraki says there are three checks you can do before getting it officially tested by a museum or geology department.

The first sign is the rock is in a random place where a rock shouldn't be. Second, it has the appearance of a teardrop - most do because of the way they fall to Earth. And finally, the rock is magnetic - asteroids are ionised in space.