Ice and the origins of life on Earth ⏲️ 6 Minute English

Hello. This is 6 Minute English from BBC

Learning English. I’m Sam.

And I’m Neil.

Have you ever made a snowman or enjoyed

a cold drink on a hot summer’s day?

Slippery in winter and cooling in summer,

ice is made when water gets so cold

it freezes. But there’s much more to

ice than skiing holidays and cold drinks.

Yes, in an exciting discovery, the

James Webb Space Telescope recently

detected the coldest ices ever in outer space,

something Nasa scientists think could

explain the origins of life on Earth.

For years scientists have debated how

life started on our planet. Billions of years

ago, long before the dinosaurs, animals

or even plants existed, the Earth had a

watery environment of oxygen-free gases

and chemicals known as the primordial soup.

It had the potential for life to develop,

but something was missing.

So how did we jump from the primordial soup

to the first living plants,  animals, and eventually

humans? And how does ice fit into the story?

That’s what we’ll be finding out in this

programme, and as usual, we’ll be learning

some useful new vocabulary as well.

But first I have a question for you, Neil.

We know ice is frozen water, but do you

know the chemical symbol for water?

Is it: a) H2O, b) HO2 or c) H2O2?

Well, I really hope I get this right.

I think the answer is H2O.

OK, we’ll find out or check if you’re right

later in the programme. Astronomer,

Professor Melissa McClure, worked with the

Nasa scientists who found ice on Europa,

one of Jupiter’s moons. Here she explains to

BBC World Service programme, Science in

Action, one theory linking ice to

the beginnings of life on Earth.

There's sort of these two alternatives for how

you could have had life arise on Earth, and one

is that the very basic building blocks, like

water, and methane, and CO2 – like, those

molecules were definitely brought to Earth

by ices in comets, and maybe once they

were on Earth, then they reacted with

either geothermal heat or some kind of lightning

strike to form more complex molecules.

Earth’s primordial soup lacked the building

blocks of life – a phrase describing the

most basic biological and chemical units

needed to support living things,

elements like oxygen and carbon.

Professor McClure thinks these missing

elements were brought to Earth in comets - large

bright balls of dirt and ice which travel around

the Sun in outer space.

It’s possible that when comets hit Earth

billions of years ago, elements in the ice were

scattered and struck by lightning – a bright

flash of light produced by electricity moving

in the atmosphere. This resulted in the

complex molecules needed for life on Earth.

Exactly how this happened is not known,

but it involves biomolecules, molecules like

DNA which are found in living things. Ice is

not a biomolecule, but when it mixes with

carbon, the atoms in ice molecules

change to produce complex molecules – and

that’s when interesting things start to happen.

Here’s Professor McClure again, explaining

more to BBC World Service’s, Science in Action.

If they have a carbon atom in them then

they’re complex organic molecules, so

things like very simple alcohols like methanol

or ethanol, like what you would drink, are

complex organic molecules. And these

molecules could react and start a sort of a

reaction chain that would eventually lead

to something like a biomolecule.

Ice can react with other elements to create

organic molecules, for example the alcohol,

methanol. Here, the adjective organic means

related to living plants and animals. That’s

different from how we use the word to talk

about ‘organic food’, meaning food that

hasn’t been grown using artificial chemicals.

When these organic molecules met the

primordial soup - so the theory goes - it

produced a chain reaction – a series of

chemical reactions in which one change causes

another. It was this chain reaction which

created the first living cells and eventually,

humans. Quite impressive for a

little piece of frozen water!

Speaking of water, Sam, what was the answer

to your question about the chemical

symbol for water. I said it was H2O.

Which was the right answer, Neil! Each

molecule of water, and ice, contains

two atoms of H, that’s hydrogen, joined to

one atom of oxygen. OK, let’s recap the

vocabulary we’ve learned from the programme,

starting with primordial soup – the

environment on Earth before there were

any plants or animals, which

created the conditions for life.

The phrase the building blocks of life refers

to the most basic biological and chemical

units needed to support

living plants and animals.

A comet is a large object travelling in space

which orbits the sun and

has a bright, burning tail.

Lightning is a flash of bright light produced

by electricity moving in the atmosphere.

The adjective organic means relating to

living plants and animals. And ‘organic food’

means food which has been

grown without using chemicals.

And finally, a chain reaction  is a series of chemical

reactions in which one change causes another

which in turn causes another.

Once again, our six minutes are up. Goodbye!

Bye bye!