Transcript Habitable Zone Notes.ppt

Habitable Zone Notes
“Life in the Goldilocks Zone”
Necessary Components for Life:
1. Gravity

The sun’s large mass causes a gravitational pull on all planets. The
smaller the mass of the planet, the stronger the gravitational pull
and thus the closer the planet is to the sun.

Earth’s mass enables it to be the perfect distance from the sun.
Earth is the only planet in the habitable zone: area the space that
has ideal conditions to enable life to exist.

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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The habitable zone is the only spot in space where life can exist
because it meets all 8 necessary components for life.
Earth
The 3rd planet
from the sun
= Too hot
= Too cold
= Just right
Necessary Components for Life:
2. Energy Source: The Sun

The sun is the vital energy source for life on our planet. Producers
get their energy from the sun through photosynthesis, fueling the
food web on Earth.
Producers are the start of the food web
Necessary Components for Life:
3. Temperature

The sun radiates thermal energy that is absorbed by Earth.

Other factors that increase the heat of Earth to a temperature that can
sustain life include:

Geothermal Energy from Earth’s Molten Iron Core

The Greenhouse Effect

Plate Tectonics: Divergent, Convergent, and Transform plate boundaries
Convection Currents provide geothermal energy
Necessary Components for Life:
4. Green House Heating

Large amounts of green house gases, such as Carbon Dioxide, reflect
that heat back to the surface of a planet and warm it.

The ability of a planet to retain it’s gases, depends on the
composition of the atmosphere and the strength of the planet’s
gravity.
READ ONLY: Greenhouse gases are a positive until we over-increase the amount of them. Burning
fossil fuels release pollutants into the air and increases the amount of carbon dioxide. The more
carbon dioxide in the air, the warmer the planet will get. Since plants convert CO2 into O2 through
photosynthesis, removing plant life will also increase the amount of CO2 in the atmosphere.
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Greenhouse Effect aka Global Warming
The greenhouse effect is a process by which thermal radiation from the sun is absorbed by
atmospheric greenhouse gases (Carbon Dioxide, Water Vapor, and Methane), and is re-radiated in all
directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results
in an elevation of the average surface temperature above what it would be in the absence of the gases
The primary source of Greenhouse gases are from the burning of fossil fuels (coal, oil, and natural gas).
Volcanic eruptions and decomposition in landfills also increase greenhouse gases.
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Advantages of Greenhouse Gases
1.
The gases slow down the rate that heat leaves the Earth
System
2.
Without greenhouse gases, the Earth would have
freezing temperatures
Disadvantages of Greenhouse Gases
1.
Global warming
2.
Melting of Polar Ice Caps
3.
Rising Sea Levels
4.
Flooding of Costal Areas
5.
Increase of storms and
hurricanes
6.
Increase in tropical
diseases (malaria)
Necessary Components for Life:
5. Plate Tectonics

Plate Tectonics create volcanoes release the greenhouse gas, Carbon
dioxide, into the air which causes a planet’s temperature to rise.


Early Earth had many Volcanoes, putting large amounts of Carbon
dioxide into the atmosphere.
Plate tectonics
 regulate the surface temperature of the planet
 create a magnetic field -- Van Allen Radiation Shield-- to block the planet from
the deadly solar winds
 create dry land on a water-covered world
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Earth’s magnetic field
Van Allen
Radiation
Shield
Necessary Components for Life:
6. 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


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78% Nitrogen
21% Oxygen
0-.4% Water Vapor
.93% Argon
.03% Carbon dioxide
Trace amounts of Neon, Helium,
Methane, and Hydrogen
Necessary Components for Life:
7. Mass

Planets must have the ideal mass to promote the existence of life.

More mass= stronger pull of gravity

A planet smaller than Mars could not hold on to it’s atmosphere, over
time the gases would diffuse into space.

A planet with a very large mass will hold onto any gases surrounding
it, and become a densely clouded like the outer planets of our solar
system and are not suitable for life.
Necessary Components for Life:
8. Presence of Water

Liquid water is directly linked to the existence of life.

In order for LIQUID water to exist, warm temperatures are
essential.

Temperatures needed for water to be a liquid:

32-212⁰F or 0-100⁰C
To make each of the 8 necessary components stand out
in your notes, pick one of the following:
HIGHLIGHT
BOLD
BOX IN
Habitable Zone Notes
Necessary Components for Life:
1. Gravity
EXAMPLE
•
•
The sun’s large mass causes a gravitational pull on all planets. The
smaller the mass of the planet, the stronger the gravitational pull and
thus the closer the planet is to the sun.
Earth’s mass enables it to be the perfect distance from the sun. Earth
is the only planet in the habitable zone: area the space that has ideal
conditions to enable life to exist.
– In our solar system, the habitable zone extends from after Venus
to just before Mars, so Earth is the only planet within it.
2. Energy Source: The Sun
The sun is the vital energy source for life on our planet. Producers get
their energy from the sun through photosynthesis, fueling the food web
on Earth.
Assignment:
Sketch the picture of the Habitable Zone shown below.
Explain what this term means (in your own words) and why
this is also referred to as the “Goldilocks Zone”
USE the 8 Necessary Components for Life to support your answer.