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TL;DR: The relative abundance of the four states of matter shows us that many of the things that we’re used to on Earth, like seeing a river of running water, are some of the rarest sites in the universe.

Solids, liquids, and gases are the three states of matter in traditional physics and chemistry, but more recently a fourth has been added. Plasma.

Plasma is made when a gas has been heated or electrified such that its atoms turn into ions.

It also looks really cool.

Plasma sounds pretty rare and exotic, but this is actually a bias that comes from where we live.

Most of the universe is nothing but empty space. Every now and then there is a bunch of something, usually in the form of a star – and they are almost entirely made of plasma.

In total, 99% of theย matter (or more accurately, the ordinary matter) in the universe isย plasma.

It’s not rare or exotic at all. It’s just rare on Earth.

Down here we see it in very hot fires and for a brief moment in lightening strikes. We’ve artificially created it in devices like plasma globes, plasma TVs, Teslaย coils, and in neon lights.

I think it’s pretty cool that our TVs now contain the fourth state of matter.

A unique perspective

The funny thing is that what we’re used to on the Earth is really what is rare and exotic. It’s here that we see a mix of the other three states (gasses, liquids, and solids) all in one place.

One of these in particular is relatively rare in the universe. Liquids.

Most of the universe is cold outer space, far from the warmth of stars. Out here, nebulaeย form giant gas clouds and everything else is frozen solid.

It’s only within cosmic specks of dust called planets and moons where geologic activity is strong enough to melt their insides into liquid.

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Even more rare is liquid on the surface of these planets and moons. This happens to a tiny subset who are near stars but not too far away, in a zone between extreme heat and extreme cold.

A state of transition

The chart below visualises this zone by showing the state of each element as it moves between extremes of temperatures. The green liquid state only exists for a short period until it gets too hot and it boils into a gas.

The state of each element at different temperatures.

The difference between states

But why does matter change at all?

To a physicist, the difference between the traditional three states of solids, liquids, and gasses is the closeness of their atoms. Atoms in a gas are far apart, and in a solid they are closely compacted together. In liquids they are somewhere between.

Heat forces their atoms apart. Heat is another word for the vibration of atoms and the higher the temperature, the more the atoms will push each other away.

Heat doesn’t affect all atoms equally, because some of them have a strong attraction for each other.

Metals, like gold and uranium, tend to still be solid at high temperatures because their atoms are strongly bonded, and it takes a large amount of heat to force their atoms apart – that is, to melt them.

Likewise at room temperature water is a liquid but oxygen is a gas. They’re at the same temperature and so are vibrating at the same rate, but water molecules have a moderate attraction to each other, but oxygen molecules do not.

Working under pressure

The last major influence on state comes from pressure. The higher pressure atoms are under, the more they are forced together.

The Earth’s atmosphere exerts pressure on everything below it. If it suddenly disappeared, everything on the surface would be exposed to the vacuum pressure of space. Our oceans would evaporate into gas, along with all the water in our bodies, and many other dire consequences.

This is one of the reasons why astronauts need space suits.

During a test at a NASA facility in 1965, a leaky spacesuit exposed an astronaut to a vacuum. He quickly passed out but when he was revived, he said that the last thing he remembered was feeling the saliva on his tongue boiling away.

A narrow road between extremes

So liquids can only exist in a narrow band between extremes of temperature and pressure, which is what makes them so rare in the universe.

As liquids are the precursor to life, finding the places within this strict balance is crucial in discovering whether or not we are alone in the universe.

Originally posted 2018-07-19 21:20:48. Republished by Blog Post Promoter

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