All Life Needs Water. Why?

Could aliens drink something else?

Matt J Weber 🦢
7 min readNov 8, 2017


Nothing on our planet can survive without water. It covers 70% of the surface and about 60% of our body is composed of nothing but water.

Water is everywhere. It’s a good thing too. Because without it, life as we know it would not be possible.

But what is it about water that makes it so essential to living things?

There are organisms on Earth that do not need oxygen to live. They metabolize hydrogen or methane or a number of other compounds. Plants breathe CO2 and get much of their energy from the Sun through photosynthesis. There is life at the bottom of the oceans which have never seen the sun and get all of their energy from hydrothermal vents on the seafloor.

But all life on Earth shares one thing in common: we all need water to live. Without exception.

Good thing it’s so abundant.

Water is found everywhere on our planet.

It’s even been found on Mars. There’s probably a little bit on our Moon and Jupiter’s moon Europa is basically a big ball of frozen water.

And when we aim our spectroscopes out at the universe, water is one of the most common molecules we find.

That alone might be enough to explain why we depend on it so much. You certainly wouldn’t want to hinge the existence of life on a comparatively rare and scarce molecule.

But its abundance is only one reason why life depends on it so much.

Water has some pretty amazing properties that make it an ideal substrate for life.

For one, water is a liquid across a wide range of temperatures on Earth. A liquid is a much better transport medium for nutrients and other life-necessary compounds than a solid. It just happens that most of the water on Earth can exist in its liquid form.

Water is also a great solvent. It has been called the universal solvent because so many different kinds of substances can be dissolved in water. All life needs to take in substances to generate energy and flush out waste products and toxins. Because of water’s knack for dissolving…