Turns out, if
conditions had been just a little different an eon ago, Venus, not Earth, would
have been our home.
The idea isn't so
far-fetched, according to a hypothesis by Rice University scientists and their
colleagues.
The researchers
maintain that minor evolutionary changes could have altered the fates of both
Earth and Venus in ways that scientists may soon be able to model through
observation of other solar systems, particularly ones in the process of
forming, according to scientist Adrian
Lenardic.
The paper, he said,
includes "a little bit about the philosophy of science as well as the
science itself, and about how we might search in the future. It's a bit of a
different spin because we haven't actually done the work, in terms of searching
for signs of life outside our solar system, yet. It's about how we go about
doing the work."
Lenardic and his
colleagues suggested that habitable planets may lie outside the
"Goldilocks zone" in extra-solar systems, and that planets farther
from or closer to their suns than Earth may harbor the conditions necessary for
life.
The Goldilocks zone
has long been defined as the band of space around a star that is not too warm,
not too cold, rocky and with the right conditions for maintaining surface water
and a breathable atmosphere. But that description, which to date scientists
have only been able to calibrate using observations from our own solar system, may
be too limiting, Lenardic said.
"For a long time
we've been living, effectively, in one experiment, our solar system," he
said, channeling his mentor, the late William Kaula, who is the father of space
geodetics, a system by which all the properties in a planetary system can be
quantified. "Although the paper is about planets, in one way it's about
old issues that scientists have: the balance between chance and necessity, laws
and contingencies, strict determinism and probability."
Lenardic noted,
"But in another way, it asks whether, if you could run the experiment
again, would it turn out like this solar system or not? For a long time, it was
a purely philosophical question. Now that we're observing solar systems and
other planets around other stars, we can ask that as a scientific
question."
"If we find a
planet (in another solar system) sitting where Venus is that actually has signs of life,
we'll know that what we see in our solar system is not universal," he
added.
The paper also
questions the idea that plate tectonics are a critical reason Earth harbors
life. "There's debate about this, but the Earth in its earliest lifetimes, let's say
2-3 billion years ago, would have looked for all intents and purposes like an
alien planet," Lenardic said. "We know the atmosphere was completely
different, with no oxygen. There's a debate that plate tectonics might not have
been operative."
The study appears in
journal Astrobiology.
Representative
Image
Source:
ANI
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