Water - origin of water on earth

Question 1

What is crucial for the existence of life on Earth?

Answer 1

Water

Water is essential for all known forms of life.

Question 2

What did conditions on Earth prevent when it formed around 4.5 billion years ago?

Answer 2

Condensation of water vapour into liquid water

The early Earth was too hot for water vapour to condense.

Question 3

What hypothesis suggests the origin of Earth’s water?

Answer 3

Water originated from asteroids and meteorites

Many asteroids contain ice and organic materials.

Question 4

What are carbonaceous chondrites?

Answer 4

One of the oldest groups of meteorites in the solar system

They contain hydrogen isotopes similar to those in seawater.

Question 5

What do eucrite achondrites contain that supports the hypothesis of water origin?

Answer 5

Ratios of hydrogen isotopes similar to those found on Earth

This adds credibility to the idea that meteorites contributed to Earth’s water.

Question 6

How might meteorites have contributed to the presence of water on Earth?

Answer 6

Released water vapour during an impact

This vapour could condense into liquid water due to Earth’s gravity.

Question 7

What is essential for living organisms?

Answer 7

Water

Without water, life as we know it cannot exist.

Question 8

What is the Goldilocks zone?

Answer 8

The area around a star where temperatures are favourable for water to exist in liquid form

Named after the story of Goldilocks and the three bears.

Question 9

What is the significance of exoplanets in the search for extraterrestrial life?

Answer 9

They may be located in the Goldilocks zone of other solar systems

Exoplanets are crucial in identifying potentially habitable environments.

Question 10

What technique do scientists use to analyze exoplanet atmospheres?

Answer 10

Transit spectroscopy

This technique analyzes light passing through a planet’s atmosphere.

Question 11

What indicates that a planet may have water?

Answer 11

A water signature

This is determined through the analysis of absorbed or deflected wavelengths of light.

Question 12

For an exoplanet to support life, it must have which characteristics? (List 3)

Answer 12

• A water signature
• Located in the Goldilocks zone
• Be large enough to support an atmosphere

These criteria help in assessing the habitability of exoplanets.