Level 6
How Aliens Might Live With No Sun
Deep Water “Puka”
Up until about 30 years ago, people
thought that all the life on Earth needed
energy from the sun. Scientists thought that
you could not find life where it was really
hot, like in hot springs or geysers, or really
cold, like at the South Pole.
These ideas changed when people
who study the ocean explored the bottom of
the ocean. These scientists are called
Photo courtesy NOAA/U.S. Dept. of
Commerce
A “Black Smoker” is a hole at
the bottom of the ocean.
oceanographers. They found holes, which
they called vents, on the ocean floor where
very hot water comes out. They call these holes hydrothermal vents
because hydro means water, and thermal means heat.
Hydrothermal vents are many miles below the surface. Some
vents are called Black Smokers. Down this deep most of the water is
freezing and it is totally dark. Around these vents scientists found
clams, crabs, and giant tubeworms that are 6 feet (2 meters) long.
How can these animals survive so far from the sunlight, where
the water is either freezing or boiling? The tubeworms get energy
from the water from tiny bacteria in their “skin”. The clams feed on the
bacteria, and the crabs feed on the tubeworms.
Science in Hawai‘i: Nā Hana Ma Ka Ahupua‘a – A Culturally Responsive Curriculum Project
Retrieved & adapted from http://www.howstuffworks.com/alien-physiology2.htm
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Level 6
Finding these creatures at the bottom of the ocean showed that
it is possible for life to evolve in places without light from the sun, and
on other planets where there is no star near enough to make light
shine.
For example, maybe life exists on Europa, an icy moon of
Jupiter, which scientists believe has a water ocean beneath its icy
crust. Life has been found in other extreme environments as well.
Scientists found tiny plant-like organisms called lichens on
rocks in the Antarctic where temperatures often drop to 100 degrees
below zero and there is no liquid water. Also, heat-loving bacteria
have been found in hot springs where temperatures are higher than
the boiling point of water.
If life can evolve in extreme cold, heat and darkness on Earth, it
seems possible that life may exist in the extreme places of other
planets such as Mars.
ALIENS ON EARTH!
Photos courtesy NASA
Photo courtesy NOAA/U.S. Dept. of Commerce
Tubeworms around a hydrothermal vent
Lichen above (green, black, green-blue lines) on a rock from
the South Pole (left picture). Tiny bacteria from a hot spring in
Yellowstone National Park (right picture.)
Science in Hawai‘i: Nā Hana Ma Ka Ahupua‘a – A Culturally Responsive Curriculum Project
Retrieved & adapted from http://www.howstuffworks.com/alien-physiology2.htm
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Level 6
Rare Earth Hypothesis
Frank Drake and Carl Sagan think there are many planets with
intelligent life in the universe like Earth. Other scientists like Peter
Ward and Donald Brownlee guess they are wrong. They call their
guess the Rare Earth Hypothesis – and they think that life like on
Earth is one of a kind.
They say many chance events make Earth a unique place. It is by
chance Earth is the right distance from the sun, that Jupiter is nearby
to clear away comets, and that Earth doesn’t often have disasters that
kill every living thing. These scientists say it isn’t unlikely this could
happen elsewhere.
Science in Hawai‘i: Nā Hana Ma Ka Ahupua‘a – A Culturally Responsive Curriculum Project
Retrieved & adapted from http://www.howstuffworks.com/alien-physiology2.htm
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Level 6
Science in Hawai‘i: Nā Hana Ma Ka Ahupua‘a – A Culturally Responsive Curriculum Project
Retrieved & adapted from http://www.howstuffworks.com/alien-physiology2.htm
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