Transcript What makes a world habitable

Bell Quiz
1. What is something on the test you
remembered after you left the test? An
answer you would have changed.
2. What do you like on tests more: M/C
Matching, short answer, T/F
3. List some things that you think make
earth a good place for living things
4. What places in the solar system contain
life?
5. Do you think it is possible that life exists
elsewhere in the universe? Yes or No
EPOD
APOD
What makes a world
habitable?
1. Temperature
• 15ºC to 115º C
• High temperatures cause DNA
to break down
• Low temperatures slow down
reactions
2. Water
• All living things
require water at
some point. It needs
to be warm enough
that it is not frozen
and cold enough
that it doesn’t
evaporate away.
3. Atmosphere
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Insulation
UV protection
Meteorite impacts
Biochemical source;
such as oxygen for
respiration
4. Energy
• Needed for life processes
• Light or chemical energy
5. Nutrients
• Constant supply
needed
• Processes that
provide nutrients,
like volcanoes, and
earthquakes are
needed
Earth
• 1. Enceladus
The sixth-largest moon of Saturn
has been called the most
promising bet for life thanks to its
welcoming temperature and the
likely presence of water and
simple organic molecules. The
surface of the icy moon is thought
to be about 99 percent water ice,
with a good chance of liquid
water beneath. Observations
from the Cassini probe’s 2005
flyby of Enceladus suggest the
presence of carbon, hydrogen,
nitrogen and oxygen — organic
molecules thought to be
necessary to develop life. And the
moon seems to have a boiling
core of molten rock that could
heat the world to the toasty
temperatures needed to give rise
to life.
• 2. Europa
Jupiter’s moon Europa also seems a possible
stomping ground for E.T. due to its potential
water and volcanic activity. Though the surface
seems to be frozen, many suspect that buried
underneath is an ocean of liquid water. Volcanic
activity on the moon could provide lifesupporting heat, as well as important chemicals
needed by living organisms. Microbial life could
potentially survive near hydrothermal vents on
Europa, as it does on Earth.
• 3. Mars
As far as planets go, by far the frontrunner for life is our next-door neighbor,
Mars. The red planet is the most Earthlike of solar system planets, with a
comparatively similar size and
temperature range as our own planet.
Large bodies of water ice lie on Mars’
poles, and there’s a reasonable chance
of liquid water beneath the surface. The
puny atmosphere on the planet is not
strong enough to shield the planet
against lethal solar radiation, though
microbes could potentially exist beneath
the surface. Evidence also suggests
that Mars may have been even more
habitable in the past. Geologic features
imply that liquid water once flowed
across the surface, and volcanic
activity, now dead, once flourished,
recycling chemicals and minerals
between the surface and the interior
• 4. Titan
Saturn’s largest moon
looks suspiciously like it
might have hosted life,
because its thick
atmosphere is rich in
compounds that often mark
the presence of living
organisms. For instance,
Titan’s air is filled with
methane, which is usually
destroyed by sunlight. On
Earth, life constantly
replenishes methane, so it
might similarly be
responsible for the
methane on Titan. Titan is
rather cold, however, and if
liquid water exists, it must
• 5. Io
Jupiter’s moon Io is one of
the few solar system moons
to support an atmosphere,
and it contains complex
chemicals promising for life.
Volcanism on the moon also
makes it warmer than many
others — another good sign.
Io is still a long shot, though,
because its location inside
Jupiter’s magnetic field
means it is constantly being
pelted with lethal radiation. Its
violent surface also seems
inhospitable, with
temperatures often too cold
to support life, as well as
molten hot spots that are
equally deadly.
Temperature °C
Mercury:
Venus:
Earth:
Mars:
Jupiter:
Saturn:
Uranus:
Neptune:
-137 to 425
462
-88 to 58
-143 to 17
438
407
-346
-347
Mars- Yes or No?
Bigfoot?
3 kinds of space colonization
• Free Space
• Lunar
• Planetary
Things needed to make
colonization possible
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Materials
Energy
Transportation
Communication
Life Support
Radiation Protection