Transcript Our Habitable Earth

Our Habitable Earth:
What conditions allow Earth to support and maintain life?
List the basic requirements
for human survival:

What conditions allow Earth to support and
maintain life?
 Proximity to the sun
 Atmosphere
 Gravity
 Magnetic Field
 Liquid Water
Proximity to the Sun
How does proximity to the Sun contribute
to a planet’s temperature and ability to
support life?
Proximity to the Sun
 The Earth resides in the Habitable Zone of our nearest star…the
sun!
 The Habitable Zone is the region around a star where it is
possible for a planet with the correct atmospheric pressure to
maintain liquid water on its surface
 Too far and the planet would be too cold for liquid water; too
close and the planet would be too hot for liquid water
The Sun
 The sun provides the radiant energy to provide all producers
(autotrophs) the ability to create their own food through
photosynthesis.
 The earth is tilted at an angle, as it revolves around the sun
the earth is tilted towards or away from the direct rays of the
sun- this is what gives us seasons.
 Temperate weather on Earth allows for life.
The Sun
Atmosphere
How does the
presence and
composition of an
atmosphere help
to determine a
planet’s surface
temperature?
Atmosphere
 The atmosphere is like a blanket
around the Earth -- and is made up of
78% nitrogen, 21% oxygen, 0.9%
argon, 0.04% carbon dioxide and
trace amounts of other gasses.
 The atmosphere does two main
things –
 It absorbs energy from the Sun
(traps heat).
 Recycles water and other
chemicals (water cycle).
Layers of the atmosphere
Martian (Mars) Atmosphere
Gravity
 The Atmosphere is held in place
due to gravity.
 The gravitational pull of an
object is due to the mass of the
object.
 Too little mass and you would
not have much of an atmosphere
(like the Moon or Mars)
 Too much mass and the air
pressure would squash a human
flat (like Jupiter or Saturn)
Magnetosphere
 A complex, invisible region that surrounds Earth.
 The magnetosphere protects us from Solar Winds and Storms,
which occur when highly energized particles are ejected from
the sun.
 The magnetosphere is formed by the motion of the molten iron
in the core of the Earth.
 The magnetosphere is responsible for the magnetic field that
allows us to use compasses and forms the magnetic North and
South Poles.
 http://www.youtube.com/watch?feature=player_embedded&v
=ujBi9Ba8hqs#! -- First 2 minutes
Magnetosphere
Water
Water is necessary for life as we know it. What evidence
is there that water may exist now or may have existed at
one time on other celestial bodies?
 All of the water on or near the earth is called the
hydrosphere.
 This includes the oceans, rivers, lakes, and even the
moisture in the air.
 97 % of the earth's water is in the oceans.
 The remaining 3 % is fresh water; ¾ of the fresh
water is solid and exists in ice sheets/glaciers.
Water
Water on other Worlds
 Evidence for water on Mars:
 Mars has defined polar regions that contain water ice
 Mars rover Curiosity has identified a streambed
Water on other Worlds
 Evidence for water on Europa
(Jupiter’s 6th moon):
 Galileo Spacecraft inferred
through observation the
presence of a global salt water
ocean containing more water
than is present on Earth covered
in a thick, ice shell
 Tidal forces on Europa (gravity
interaction between Jupiter,
Europa and the other moons)
would be enough to keep the
interior of Europa liquid
HOLD ON!
 Gliese 581g?
 Astronomers have spotted a planet beyond our own solar
system in what is sometimes called the Goldilocks zone for life:
Not too hot, not too cold. Juuuust right.
 Not too far from its star, not too close. So it could contain liquid
water. The planet itself is neither too big nor too small for the
proper surface, gravity and atmosphere. It's just right. Just like
Earth?
 We’ll see what future study of this finding brings us…
Exo-Planets
May 10th, 2016 – NASA announced from data obtained through the Kepler Telescope,
the discovery of 1,237 new exoplanets, 550 are thought to be rocky, 9 of the rocky
planets are in the habitable zone. We now know 21 total exoplanets that are rocky and
in the habitable zone.