Several species of bacteria can survive in "hypergravity" environments more than 400,000 times Earth's gravity, Japanese researchers say.

Scientists at the Japan Agency of Marine-Earth Science say their findings suggest alien life could survive extreme conditions such as the high G-forces created during meteorite impacts and ejections, making the transfer of primitive life from meteors and comets to the early Earth a distinct possibility, SPACE.com reported Monday.

"The number and types of environments that we now think life can inhabit in the universe has expanded because of our study," lead author Shigeru Deguchi said.

Deguchi and his colleagues started out just wanting to measure the density of E. coli bacteria using a centrifuge.

But when they spun E. coli up to the equivalent of 7,500 G's, they found that the microbe was unaffected, reproducing and growing without problems.

"The finding was a total surprise to us, and stimulated our curiosity very much," Deguchi told SPACE.com."So we repeated [the] same experiments at higher G, and eventually found that E. coli proliferates even at 400,000 G, which was the highest gravity we could achieve by our instrument."

The results suggest transfer of lifeforms between worlds is a real possibility, researchers said, noting that Earth has been impacted by millions of tons of Mars rocks, which exploded off the Red Planet during meteorite strikes.

Meteorite-caused rock ejections can generate up to 300,000 G's, researchers said, and the new study indicates microbial life could survive such extreme events and continue to reproduce.