Transcript Inhabitable Zone Notes2015.ppt

Inhabitable Zone Notes
“Life in the Goldilocks Zone”
• Inhabitable Zone- area in outer space that
CAN support life
NOT
– Also known as the “Habitable Zone”
– Earth is the only planet in this zone thus
meaning the it’s the only planet where life exists.
• Uninhabitable Zone- anywhere in outer
space where life CANNOT exist.
Inhabitable Zone
Uninhabitable
Sun
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The inhabitable zone is the only spot in space where life can exist because it meets
all 4 necessary components for life which will be listed on the following slides.
Earth
The 3rd planet
from the sun
= Too hot
= Too cold
= Just right
In our solar system, the habitable zone extends from after Venus to just before
Mars, so Earth is the only planet within it.
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4 Necessary Components for Inhabitability:
(What is needed for life to exist)
1. Mass’ affect on Gravitational Pull

The sun having the largest mass of any
object in the solar system causes a
gravitational pull on all planets. Each
planet’s distance from the sun corresponds
to its mass.
Highlight this 1st component

The terrestrial, rocky planets are dense but less
massive. Earth has the highest mass of the
inner planets.

The gas giants have low density but have more
mass to counteract the force of the sun.
Earth’s mass enables it to be the perfect
distance from the sun making it the only
planet in the inhabitable zone.
1. Mass’ . . . continued

More mass= stronger pull of gravity

A planet much smaller than Earth struggles to hold on to it’s
atmosphere due to the lack of gravitational pull towards the planet;
over time the gases would diffuse into space.

A planet with a very large mass will hold onto any gases surrounding
it, and become densely clouded like the outer planets of our solar
system and are not suitable for life.
Highlight this 2nd component
2. Composition of the Atmosphere

Earth’s gravity is strong enough to retain
it’s atmosphere. Earth’s atmosphere has
changed over time.

Today, Earth’s atmosphere consists of


78% Nitrogen

21% Oxygen

1% Other (Argon, water vapor, etc)
Solar wind’s force blows away the
atmosphere of the planets closest to the
sun which makes them uninhabitable.
NASA article: Gravity’s effect on Atmospheric Composition
Highlight this 3rd component
3. Presence of Liquid water

Presence of liquid water is directly related to a planet’s
distance from the sun.


Too close to the sun results in 100% evaporation
Too far from the sun results permanent frozen water (ice) if water even
exists on the planet

Life cannot survive without water in its liquid form.

Liquid water exists on Earth due to the rotation of the planet
which regulates the amount of time the water is exposed to
the sun.
Highlight this 4th component
4. Temperature

A planet’s temperature is directly related to its distance from the sun.

Too close to the sun = too hot

Too far from the sun = too cold

Temperature in the inhabitable zone = just right

Other factors that contribute to Earth’s temperature:

Geothermal energy from convection currents from Earth’s Core

The Greenhouse Effect “aka global warming”
Assignment:
Summarize the information in these notes.
1.Start with the definition of Inhabitable Zone
2.Explain why this area is referred to as the “Goldilocks
Zone”
3.Discuss how Earth has ALL 4 necessary
components of inhabitability.