Origin of oceans and waterworlds Boris Pestoni, Vytenis Šumskas University of Zürich AST 202 The Universe: Contents, Origin, Evolution and Future March 22, 2016

S 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

Until now we have found water in the following objects / regions: Out of Proto_ Rings the planetary disk Asteroid Comets of Mars Moon Earth Milky of the Milky belt Saturn Way Way

Water of ✓ ✓ ✓ ✓ crystallization Water ice ✓ ✓ ✓ ✓ ✓ ✓ ✓ Liquid water ✓ ✓ ✓ ✓ Steam ✓ ✓ ✓ ✓ ✓ ✓

Supercritical ✓ water 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 Ocean planets

S Hypotetical exoplanet with an icy S Icy planets can move to orbits where their surface of volatiles such as water, ice melts into liquid form, turning them ammonia, and methane; into ocean planets;

S Although we know many icy S Hypothetical exoplanet with the surface objects there are no known ice completely covered with water; planets; S Until now the most likely ocean planet is S Best candidate: MOA-2007- BLG-192 Lb. Gliese 1214 b (GJ 1214 b).

Thanks for your attention.

Questions?