Extraterrestrial Life in the Solar System

Extraterrestrial Life in the Solar System

(extra) - terrestrial

(outside of or beyond) - having to do with the Earth

Multiple Choice

Which place would we NEVER discover native extraterrestrial life?

• Trappist-e

• Mars

• Earth

• Venus

Conditions for Life

• Liquid Water

• Chemical Elements

• Energy (Heat)

Multiple Choice

All life-forms on Earth require nourishment, liquid water, and ________ to survive.

• energy

• shelter

• plants

• ice

Multiple Choice

Which factor influences the temperature of a planet?

• mass of the planet

• density of the planet

• radius of the planet

• distance from the star to the planet

Story Time!

Once upon a time there was a little girl who broke into a house in the woods . . . She tasted the big bowl of porridge but it was too hot! She tasted the medium size bowl of porridge but it was too cold! She tasted the little bowl of porridge and it was just right, so she ate it all up!

The Goldilocks Zone

For each star, there is a distance to the star where planets would be too close to support life and a distance where they would be too far away to support life. In between is the "Goldilocks Zone" where the distance is "just right." This is also known as the habitable zone.

Multiple Choice

What is the “Goldilocks” zone?

• A zone on the Earth where most people want to live.

• A zone where planets get the right amount of heat and light for liquid water to exist

• A zone in our Solar System where aliens live.

• A zone in our Solar System where aliens live.

In this system the planet is just barely in the habitable zone.

In this system, there are 4 planets too close to the star and 1 planet too far away!

Multiple Choice

Which planet would be the most likely place to observe for life?

• A

• B

• C

• D

Multiple Choice

In our solar system, the "goldilocks zone" includes the orbits of Venus, Earth, and Mars. Why would scientists consider Mercury unable to have life?

• Mercury is too small

• Mercury is too close to the Sun.

• Mercury doesn't have a moon.

• Mercury spins too slowly on its axis.

Venus

• Until recently, scientists thought it was too hot on Venus for life to exist.

• Lately, scientists have suggested that life could exist in the upper layers of the Venusian atmosphere, where it is not quite so hot.

• In September (2019) a compound called phosphine was discovered in Venus' atmosphere which suggests there could be life.

Why is life possible on Earth?

• We are in the habitable zone for our Sun.

• The magnetic field of the Earth protects us (and our atmosphere) from the Solar Wind.

• Liquid water and organic compounds are abundant on the surface.

Multiple Choice

The magnetic field of Earth protects life against -

• falling meteors from outer space.

• high energy particles from the Sun.

• ultraviolet radiation from the stars.

• debris ejected from the Moon.

Multiple Choice

Earth’s atmosphere contains water vapor and carbon dioxide. These greenhouse gases are important because they -

• are substances animals need to breathe.

• trap thermal energy in the atmosphere.

• protect against magnetic particles.

• create Earth’s gravitational field.

Multiple Choice

Even though the moon is in the habitable zone, why is there no life there?

• no atmosphere

• No water

• Exposed to solar radiation

• All of these are correct

Mars

• Scientists think that a long time ago Mars' atmosphere was thicker and there was liquid water on the surface.

• Mars rovers have found both water and organic compounds - the chemical "building blocks" of life in Martian soil.

Multiple Choice

Which of the following discoveries about Mars suggests conditions that may have once supported life? Mars has –

• small amounts of water in the soil.

• the tallest mountain in the solar system.

• two moons orbiting the planet.

• only a small amount of atmosphere.

Life Outside the Habitable Zone

Moons with Oceans

Europa

• Under a crust of ice, there is evidence that Europa has a deep liquid water ocean.

• Tidal forces from Jupiter stretch Europa, probably causing the cracks on its surface, and possibly causing geothermal activity under the ocean.

• Europa has a magnetic field - which is further evidence of some moving liquid under the surface.

Enceladus

• Like Europa, Enceladus has an ocean under a crust of ice.

• The Cassini spacecraft imaged jets of water coming out of Enceladus.

• Some areas of Enceladus are free of craters, which means the ice is being renewed.

Titan

• Only world outside of the Earth that has lakes and rivers on the surface.

• The lakes are made of liquid methane - not water.

• Has an atmosphere and many organic compounds have been detected.

Multiple Choice

The energy for possible life in the ocean of Enceladus or Europa would probably come from

• the Sun

• light reflecting off the planet

• heat from below the ocean caused by tidal forces

• nuclear fusion in the core of the moon

Multiple Choice

What do we learn from studying the atmospheres of exoplanets?

• If there are chemicals in them associated with life.

• If the planet is in the habitable zone.

• If aliens are trying to communicate with us.

Poll

Your final assignment for this unit will be to design an alien species that could live somewhere in the Solar System. Which place do you think you might have your alien live?

• Venus

• Mars

• Europa

• Enceladus

• Titan