1. Life forms should fill a niche in
a balanced ecosystem, based on a food chain of eating and being eaten.
2. Life forms should naturally
converge on the safest, most beneficial environments for them.
3. Having said that, any environment
that can support life, will eventually support life. Even a harsh environment,
like extremely hot and cold places on Earth, provide an advantage to life
forms, in that any lichens and microbes that can survive there are safe from
other predators that can't.
4. Life forms should naturally
optimise their biology to fit their environment. This means forming an optimal
size, speed, lifespan, an optimal number of offspring, an optimal daily food
intake, an optimal metabolism, and an optimal intellect. This is why so many
animals survive for millions of years without improving their intellect.
5. Life forms should mate in such a
way as to pair the strongest, healthiest couples to produce the strongest
offspring. Offspring should have mutations that over time will make their
species stronger and more resilient.
Scientists
also consider how an alien planet might differ from Earth, and how this would
affect wild life. They ask:
1. What kind of sun is there? How
strong is it? A planet is dependent on its sun for the energy required to power
life. So any planet would adapt to its sun. Red dwarf suns give off less heat
and light, so any plants growing on a planet might appear black, to absorb as
much energy as possible.
2. Is the planet in the "goldilocks"
distance from the sun? This means it's not too hot, not too cold, but just
right for liquid water, or at least liquid something.
3. Another option for a goldilocks
environment would be the moon of a very large planet, like Jupiter. Jupiter and
Saturn's moons are constantly stretched and squashed in their elliptical
orbits, causing a great deal of friction and heat. So, even though there's no
atmosphere, and it's quite far from the sun, it can still have warm zones, even
on surface. Jupiter's Io has warm spots around its many volcanoes.
4. Is the planet close enough to the
sun so that it's "tidally locked", meaning that one side always faces
the sun, while the other is always in darkness. Our moon is tidally locked to
Earth, which is why we always see the same face on it. This would create
fearsome winds on an alien planet.
5. Does the solar system have a
large planet like Jupiter to pull away all the asteroids and comets that would
otherwise bombard it, killing all life forms?
6. Are there large amounts of
carbon, hydrogen, oxygen, and nitrogen? Are they present in an atmosphere?
These are all required for life, as we know it.
7. Are there oceans of liquid at a
stable temperature (preferably water)? How deep are they? Is the entire planet
made of liquid? Scientists regard liquid as necessary, in order to mix various
elements in ways that create life - single celled organisms.
8. What's the gravity there? Lower
gravity can allow for larger creatures. Higher gravity may require animals with
many legs to move around.
9. What's the density of the
atmosphere? This determines the possibility of flight, and the size of wingspans
necessary for flight. The denser an atmosphere, the easier it is to fly and
float.
10. What's the oxygen level in the
atmosphere? More oxygen also allows for larger creatures. It also increases the
risk of fires.
Based on
these concepts, the aliens that scientists most expect to find will be:
1. Micro
organisms, Viruses, Bacteria: These are the most likely forms of life. On
Earth, they survive in dry deserts, lakes of arsenic, cave walls full of
sulphuric acid, and miles underground, some of whom don't even need oxygen to
live.
2. fungus
3. simple
plants and trees: On Earth, we separate plants and animals, but on alien
worlds, there might be life forms that combine aspects of both. On a water
world, these plants may have gaseous bladders to keep them buoyant, so they
don't sink to the bottom. On a world with a very thick atmosphere, these same
plants might use gaseous bladders to float in the air.
4. herbivores,
possibly grouping in herds
5. carnivores
that hunt them, possibly solitary, almost certainly more intelligent than its
prey. Some will hunt in packs in order to corner and ambush prey. Some may even
work as a hive.
6. flying
creatures similar to birds.
7. If there
are oceans of water, scientists expect fish-like creatures, as they are
the most efficient shape in water.
8. If a
planet commonly experiences high winds, there might be "land whales,"
an animal that filters micro-organisms from the air, in much the same way that
whales do in water. Combine this with a dense atmosphere, and you could have
"sky whales," swimming through the air much like how our
whales swim in water.
No comments:
Post a Comment