Do We Really Need the Moon?

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There are many moons in the solar system, but none like ours.

It exerts an extraordinary influence on Planet Earth,

keeping our world in balance.

But why is it so powerful?

I want to explore the relationship we have with our closest neighbour,

to see how the Moon has sculpted our planet and shaped our evolution.

Without the Moon, would we even be here?

'I'm Maggie Aderin-Pocock.

'I'm a space scientist and a lunar fanatic.

'I've always been mad about the Moon,

'convinced it plays a huge role in our lives.'

But I've always taken for granted that it is where it is

in the night sky, a quarter of a million miles away.

In this film I'm taking nothing for granted.

I'm going to find out what would happen if the Moon wasn't where it is now.

What if the Moon was in a different position,

closer or further away?

How different would our world be?

The Moon is a ball of rock out in space,

but it has the power to create great tides here on Earth.

This is Loch Etive on the west coast of Scotland.

Twice a day, the Moon drags 66 million tonnes of sea water through this loch.

The result, white water rapids.

The head of the loch is like a bottleneck.

Water is funnelled through a very narrow channel.

And for an hour or two, this becomes one of the wildest, wettest rides in the world.

These are the Falls of Lora.

That's what the locals call them.

In Gaelic, "Lora" means "noisy"

because as the tidal waters rush out of the loch, it gets very, very loud!

Kayakers come from all across the world to take the challenge of these waters.

But they have to paddle like mad just to keep up.

Even our outboard engine is struggling with the flow.

This is what the power of the Moon looks like up close.

My love affair with the Moon began as a child.

# I wish I was a spaceman

# The fastest guy alive... #

I was born in 1968, in the age of Apollo.

I took my first steps as Neil Armstrong took his giant leap.

Of course I was too young to know what was going on.

But the images became seared in my mind.

From an early age, I wanted to go to the Moon.

At school I struggled because I'm dyslexic.

But then I discovered science, and something clicked.

I wanted to become a scientist.

And sure enough, today I build satellites.

It's a mix of engineering and physics and I love it.

But now that I'm a space scientist, hardly anyone is talking about the Moon any more.

It used to be the new frontier,

our future.

Now it's seen as quaint, old-fashioned, irrelevant.

I think that's wrong,

completely wrong.

I'm still mad about the Moon,

not just because I want to be an astronaut and go there one day.

No.

I'm mad about the Moon because the more I find out about it,

the more extraordinary it seems.

The way its presence can conjure up this torrent of water,

and these waves.

And how does it do this?

With the help of gravity.

Gravity is a great universal force of attraction.

It keeps us firmly in our place on Earth

and keeps the Moon in orbit around us.

But while the Earth is attracting the Moon,

the Moon is also attracting the Earth,

pulling at our oceans.

So I have a set of scales, a metal block and a powerful little magnet.

You see, the force of gravity is very similar to magnetism.

They're both forces of attraction.

If I put the metal block on the scales,

you can see it weighs 1.3 kg.

When I put the magnet in and nudge it closer,

the block appears to weigh less.

You can see the needle moving.

That's because the magnet is attracting the metal towards it,

pulling it upwards, off the scales.

And that's what the Moon's doing.

It's pulling on the oceans, moving them upwards, away from the surface of the Earth.

The gravitational force of the Moon causes the oceans to bulge slightly.

And as the Earth spins,

this bulging produces high and low tides.

The size of the tides

depends on the distance between the Earth and the Moon.

The laws of physics are very clear about this.

The closer two things are, the more they attract each other,

the greater the gravitational force.

So we get the tides we do because the Moon is where it is, nearly a quarter of a million miles away.

But what if the Moon were closer?

If the Moon were a just a little closer than it is today

the tidal bulge would grow.

Low tides would be lower,

high tides would be higher.

And any low-lying coastline would be flooded.

But what if the Moon were much closer?

Five times, 10 times, 20 times closer than it is today.

How would that affect the tides and life here on Earth?

Another rush hour in London.

But this evening, as the sun sets,

a huge Moon rises,...

..20 times closer than normal.

This super-sized Moon exerts a super-sized gravitational force,...

..400 times stronger than we're used to.

And it creates a mighty tidal bulge.

Sea water pours across the British Isles,

London is flooded.

Hours later, the same tidal bulge hits the east coast of America.

And the story is the same.

It's New York's turn to disappear underwater.

A city submerged,...

..and all the work of the Moon.

Eventually, of course, the tide subsides.

And the waters retreat.

This scenario may seem rather far-fetched, like the plot of some disaster movie.

But something similar has happened.

Once upon a time, when the Moon was newly formed,

it really was so close, and it really was so powerful.

Let me take you back to the earliest days of our planet,

At this time, the Earth had no Moon,

it was orbiting the Sun alone

and it was being assaulted by rocks and comets.

Today, there are no scars left from this cosmic pinball.

But to get a sense of the damage that was done,

I've come to the Arizona Desert,...

..to a great hole in the ground.

This is a beautiful crater,

a near perfect circle a mile in diameter.

It was formed when a meteorite crashed into the Earth a mere 50,000 years ago.

That's nothing on the timescale we're talking about,

but it's amazing how much damage that one passing rock can cause.

The early Earth was bombarded with rocks. It must have been mayhem.

And then along came something much, much bigger.

Another planet the size of Mars, drifted into the path of Earth.

It was on a collision course.

It hit the young Earth with a glancing blow.

Imagine the power released by such a collision.

The impact sent a mass of liquid rock into orbit.

This debris coalesced into a ball.

And the Moon was formed,

just 14,000 miles away from the early Earth.

This was the closest point it could have been.

Any closer, and gravity would have pulled the debris crashing back to Earth,

and our moon wouldn't exist.

Today the Moon is just a rock reflecting the sun's light,

but back then it was a molten sphere, burning brightly.

It must have looked amazing, an enormous orange disc in the sky.

Imagine the scene.

The first moonrise over the early Earth.

Our world was no longer alone.

It had a huge, powerful neighbour.

And ever since, this has been a very different type of planet.

The collision that created the Moon reset the basic chemistry of Earth.

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