Life existed long before Earth came into being, and may have originated outside our solar system, scientists claim.
Researchers say life first appeared about 10 billion years ago -
long before Earth, which is believed to be 4.5 billion years old.
Geneticists have applied Moore's Law - observation that
computers increase exponentially in complexity, at a rate of about
double the transistors per integrated circuit every two years - to the
rate at which life on Earth grows in complexity.
Alexei Sharov of the National Institute on Ageing in Baltimore,
and Richard Gordon of the Gulf Specimen Marine Laboratory in Florida,
replaced the transistors with nucleotides - the building blocks of DNA
and RNA - and the circuits with genetic material.
Their findings suggest life first appeared about 10 billion
years ago, far older than the Earth's projected age of 4.5 billion
years, 'TechNewsDaily' reported.
Like in the 2012 sci-fi movie Prometheus, as our solar system
was forming, pre-existing bacteria-like organisms, or even simple
nucleotides from an older part of the galaxy, could have reached Earth
by hitching an interstellar ride on comets, asteroids or other inorganic
space debris.
However, the calculations are not a scientific proof that life
predates Earth - there's no way of knowing for sure that organic
complexity increased at a steady rate at any point in the universe's
history.
"There are lots of hypothetical elements to (our argument) ...
But to make a wider view, you need some hypothetical elements," Sharov
said.
Sharov said that if he had to bet on it, he'd say "it's 99 per
cent true that life started before Earth - but we should leave one per
cent for some wild chance that we haven't accounted for."
The theory of "life before Earth," if found true, debunks the
long-held science-fiction trope of the scientifically advanced alien
species.
Moreover, if genetic complexity progresses at a steady rate,
then the social and scientific development of any other alien life form
in the Milky Way galaxy would be roughly equivalent to those of humans,
the report said.
"Contamination with bacterial spores from space appears the
most plausible hypothesis that explains the early appearance of life on
Earth," researchers said.
