Image courtesy of NASA/JPL-Caltech.
Joel Kontinen
Billions of years ago Mars hosted lakes, streams and perhaps
even a huge ocean according to evolution believing scientists.
A remarkably hardy bacterium can survive pressures similar
to those generated when asteroid impacts blast debris off Mars, a new evolutionary
study has found.
The findings, published earlier this week in the journal PNAS Nexus, may prompt scientists to reconsider
where life could exist across the solar system and
could lead to a reassessment of "planetary
protection" rules designed to prevent contamination between worlds.
"Life might actually survive being ejected from one
planet and moving to another," study co-author Kaliat Ramesh, a mechanical
engineer at Johns Hopkins University in Maryland, said. "This is a really
big deal that changes the way you think about the question of how life begins
and how
life began on Earth."
Researchers recently exposed the bacterium Deinococcus
radiodurans to the pressures experienced during an asteroid strike. The microbe
survived, suggesting that impacts could spread life from planet to
planet.
The new findings lend support to a long-debated theory known
as lithopanspermia,
which proposes that life
can spread between planets by hitching a ride on
fragments of rock blasted into space by massive impacts. The idea
remains unproven.
For the study, Ramesh and his colleagues tested the
endurance of Deinococcus radiodurans, an exceptionally resilient
bacterium found, among other places, in Chile's high-altitude deserts. With a
thick outer shell and a remarkable ability to repair its own DNA, D.
radiodurans is famously tolerant of intense radiation, freezing
temperatures, extreme dryness and other harsh conditions similar to those found
in space. It has been nicknamed "Conan the bacterium," after all.
To simulate the forces involved in an asteroid impact,
the researchers sandwiched samples of D. radiodurans between two
steel plates. Using a gas-powered gun, they fired a projectile at roughly 300
mph (480 kph), subjecting the microbes to pressures between 1 and 3
gigapascals.
Nearly all of the microbes survived impacts generating 1.4
gigapascals of pressure, while about 60% remained alive at 2.4 gigapascals. At
lower pressures, the cells showed no signs of damage, though researchers
observed ruptured membranes and some internal cellular damage at higher
pressures, the study reports.
"We continuously redefine the limits of life,"
Madhan Tirumalai, a microbiologist at the University of Houston who was not
involved with the new study, told The New York Times.
As the pressure increased, the researchers also detected
heightened activity in genes responsible for repairing DNA and maintaining cell
membranes.
"We expected it to be dead at that first
pressure," Lily Zhao, a mechanical engineer at JHU who led the experiment,
said in the statement. "We started shooting it faster and faster. We kept
trying to kill it, but it was really hard to kill."
The experiment eventually ended, the statement read, because
the steel structure holding the plates "fell apart before the bacteria
did."
This study
does not take the existence of a Creator as established. Only God can give life to planets such as Earth.
Source:
Sharmila Kuthunur 2026
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