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Origin of oceans and waterworlds

Boris Pestoni, Vytenis ŠumskasUniversity of Zürich

AST 202 The Universe: Contents, Origin, Evolution and FutureMarch 22, 2016

Contents

S Origin of water on Earth

S How did the oceans form?

S States of matter of water

S Is water a peculiarity of the Earth?

S Extreme worlds: ice planets and ocean planets

Water on Earth

S ~71% of the Earth’s surface is covered with water.

Water on Earth

S Only 0,02% - 0,06% of our planet’s total mass is water.

S Nonetheless, Earth is called “The blue planet”.

Oceans on Earth

S The age of Earth’s oceans is estimated to be nearly the same as the age of Earth: 4 - 4,4 billion years.

Oceans on Earth

S The planet cooled.

S It became covered in gas.

Oceans on Earth

S The longest rain in the history of Earth.

S Eventually water gathered in the deepest parts of surface.

Other sources of water

S ≥50% of Earth’s water came from outer space.

Water in asteroids

S How do we even know it?

States of matter of water

Water in the universe

Out of the

Milky Way

Proto_planetary disk of the Milky

Way

CometsRings

of Saturn

Asteroid belt Mars Moon Earth

Water of crystallization

✓ ✓ ✓ ✓

Water ice ✓ ✓ ✓ ✓ ✓ ✓ ✓

Liquid water ✓ ✓ ✓ ✓

Steam ✓ ✓ ✓ ✓ ✓ ✓

Supercritical water

✓

Until now we have found water in the following objects / regions:

Overview of the Solar System

Imbalance of water on planets

S The reason that there is clearly more liquid water on the Earth than on the other rocky planets of the Solar System is, until now, not completely understood.

Extreme worlds: ice planets and ocean planets

Ice planets

S Hypotetical exoplanet with an icy surface of volatiles such as water, ammonia, and methane;

S Although we know many icy objects there are no known ice planets;

S Best candidate: MOA-2007-BLG-192 Lb.

Ocean planets

S Icy planets can move to orbits where their ice melts into liquid form, turning them into ocean planets;

S Hypothetical exoplanet with the surface completely covered with water;

S Until now the most likely ocean planet is Gliese 1214 b (GJ 1214 b).

Thanks for your attention.

Questions?