|Could life survive on a Asteroid? On Earth there
are six characteristics of life. In the search
for alien life forms are the characteristics of
life the same?
|Question Date: 1999-04-30|
There is no intrinsic reason why life could not
survive on an asteroid. One theory for the origin
of life on earth posits that life originated in
microscopic water-filled pores in rocks buried
within the earth's crust. Here the environmental
conditions would have been stable, protected from
the ravaging effects of meteorite impact and
deadly UV radiation amongst other hazards extant
on the primitive earth some 4 billion years ago.
Because temperature and pressure go up as one
moves inside of an asteroid (or planet),
conditions compatible for the existence of
liquid water go up. In almost all theories, water
is the necessary medium for life's
As far as the search for
life, we can only hypothesize from our limited
experiences here on Earth. Very probably we are
underestimating the potential forms life could
These are very interesting
questions and astrobiology is the field of inquiry
that is most relevant to these questions. Some of
us at UCSB are actively involved in this research:
the origin of life and understanding the physical
conditions on earth 4 and 1/2 billion years ago.
This is a very fun job!!!!
I think it is theoretically possible that life
could exist on an asteroid, but the chances of
this happening would probably be small.On the
other hand, one theory on how life got started on
Earth is that the chemical building blocks of life
came to Earth by way of meteorites, which could
have been asteroids before they crashed to
I am curious as to what the six
characteristics of life are that you refer to.
Could you e-mail me back and tell me? Some recent
advances by mathematicians, biologists, and
philosophers this century has come up with a
definition of life that has three
characteristics: living things are self-bounded
(they have physical limits to their bodies); they
are self-generating (they can spring from nothing
or a seed or a single cell); and they are
self-perpetuating (they keep themselves going by
their own devices, mostly by regulating the flow
of energy). I got these from a book called The
Web of Life, by Fritjov Capra.
response to your question here are our six
characteristics of life:
> -Responds to
> -Growth and Development
> -Made of Cells
Thanks for sending me the
definition of life you use. This is not an easy
topic, and philosophers and biologists and
computer scientists all have something to say
I have a couple of puzzles, then, to
tickle your brains. Is a mule alive? (It cannot
reproduce.) What about a virus? Do plants eat?
Have fun thinking about these!
Scientists certainly think so. On earth, there
are places that you would think that nothing could
survive but it does. Typically this life occurs
as bacteria or some other microscopic life form.
This kind of life has been found in thermal vents
on the ocean floor where the water temperature
approaches boiling and there is so much sulfur and
toxic gases that most life forms would die. There
is no reason to think that life
survive other extreme environments.
>On Earth there are six characteristics of life.
In the search for alien life forms are the
characteristics of life the same?
question! Hard to answer. Suppose you are on
NASA's astrobiology team and your job is to design
probes that search for extraterrestrial life. You
have to first define life before you can design a
probe to search for it.
So, in these searches,
probes generally are designed to search for what
we define as the characteristics of "Earth" life
but scientists also try to expand the
possibilities as well. For example, it is not
necessarily true that all life in the universe be
primarily carbon-based (like it is on earth), so
how would you design a probe that was not
carbon-specific? It's very difficult to know what
to look for, and requires lots of
Also, many scientists now look at
Earth's own "extreme" environments (such as deep
ocean vents and Antarctica ice) and the organisms
that live there to modify the "characteristics of
life" that might be used as probe parameters. Some
people think that it might be more efficient to
search for living "planets" rather than individual
life on various planets or other bodies. Do you
have ideas about what kind of probe you would
build to search for that?
It is hard to imagine that earth-type life could
survive on an asteroid. It just doesn't seem like
the resources necessary to support life would be
available. On the other hand, life has been found
on earth in some places with very harsh
The scientific definition of
life is supposed to be very general and should
apply to all forms of life. There is always the
possibility of making a discovery that would
change how we look at life.
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