Identifying habitable worlds

Discovering planets with similar atmospheres to Earth

Locating planets with abundant water

Finding planets with the same size as Earth

It is the only form that can exist without an atmosphere

It is easier to find than ice or vapor

It allows for stable chemical reactions necessary for life

It is the most common form of water in the universe

It is too close to the sun

It has a very thin atmosphere

It is too large

It has too much gravity

A region with the most stars

A zone where planets are the same size as Earth

A belt where water can remain liquid

A region where planets have atmospheres

It lacks an atmosphere

It is too far from the sun

Its atmosphere is too thick with carbon dioxide

It has no water

Stars that emit extreme radiation

Planets with extreme weather conditions

Microbes that live in extreme environments

Planets that are extremely far from their stars

In the geysers erupting into space

In the liquid water ocean beneath its icy crust

In its atmosphere

On its surface

Its thick atmosphere

Its proximity to the sun

Its volcanic activity

The ocean beneath its surface

Life is rare in the universe

Life requires sunlight and oceans

Life can only exist on Earth-like planets

Life might exist in a variety of extreme environments

By finding planets with similar gravity to Earth

By studying Earth's atmosphere

By exploring and observing other planets

By analyzing the sun's habitable zone