Super-Earth unlikely able to transfer life to other planets

March 20, 2012 by Brian Peloza

While scientists believe conditions suitable for life might exist on the so-called "super-Earth" in the Gliese 581 system, it's unlikely to be transferred to other planets within that solar system.

"One of the big scientific questions is how did life get started and how did it spread through the universe," said Jay Melosh, distinguished professor of earth and atmospheric sciences. "That question used to be limited to just the Earth, but we now know in our there is a lot of exchange that takes place, and it's quite possible life started on Mars and came to Earth. There's also been a great deal of discussion about the possible spread of life in the universe from star to star."

and Mars meteorites have been found on Earth, which led Melosh to previously suggest living microbes could be exchanged among planets in a similar manner.

A Purdue research team has found that, in contrast to our own solar system, the exchange of living microbes between "super-Earth" and planets in that solar system is not likely to occur.

Laci Brock, a student studying interdisciplinary physics and planetary science, and Melosh will present those findings Tuesday (March 20) at the 43rd Lunar and Planetary Science Conference in The Woodlands, Texas.

Brock examined the because Planet d, known as super-Earth, falls in a "" where could possibly exist.

"Laci has found the somewhat surprising result that it is very difficult for materials to spread throughout that system in the same way it could take place in our solar system," Melosh said.

All four planets found in Gliese 581 are within close proximity to their central star, which results in large orbital velocities, Brock said. However, the initial velocity of material leaving Planet d is not enough to allow exchanges among planets.

"Planet d would have a very small chance of transferring material to the other planets in the Gliese system and, thus, is far more isolated, biologically, than the inner planets of our own solar system," Brock said. "It really shows us how unique our solar system is."

Melosh said a more extended solar system would be needed for exchange of materials among planets.

"None of the solar systems that have been found so far would have opportunities for exchange of life among the different planets like what our own solar system offers," he said.

The Opik-Arnold method was used to simulate 10,000 particles being ejected from Planet e and super-Earth. The velocity ranges of the particles were scaled from each of the planet's orbital velocities, which is very high by solar system standards due to the close proximity to their .

"Ejections from Planet d have a low probability of impact on any other planet than itself, and most ejected particles would enter an initial hyperbolic orbit and be ejected from the planetary system," Brock said.

Several members of Purdue's planetary sciences department are attending the 43rd Lunar and Conference, presenting research on possible biologic contamination of Mars' moon Phobos by from the surface of Mars; the formation of jets on comets; and gravity anomalies around large lunar craters.

"Purdue has quite a showing of different people at this conference to showcase their work," Melosh said.

Explore further: Hunting for transits of Super-Earth GJ 581e

More information: 43rd Lunar and Planetary Science Conference:

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4.4 / 5 (7) Mar 20, 2012
So... they only simulated 10,000 particles? You could get more than 10,000 particles of planetary debris from one asteroid hit. What's the time frame that these particles were allowed to fly around space in the simulation?

From this article, the study seems a little under-done. A "low probability" becomes an almost certainty when the planet is hit more than 10 times and the debris is allowed to float around for billions of years. Are they considering the possibility of once existent planets being thrown out of said solar system?

Another note, why must a solar system depend on it's own celestial objects to transfer life from one place to the next when they can have invaders thrown from other nearby solar systems?

5 / 5 (1) Mar 20, 2012
"and most ejected particles would enter an initial hyperbolic orbit and be ejected from the planetary system," Brock said."

However, it only takes one successful landing for a transfer to occur.
not rated yet Mar 20, 2012
All of this is of course contingent on a living organism surviving an interplanetary journey lasting likely thousands or millions of years. So far there is no evidence this is possible. Hopefully it is.
3.5 / 5 (2) Mar 20, 2012
"and most ejected particles would enter an initial hyperbolic orbit and be ejected from the planetary system," Brock said."

However, it only takes one successful landing for a transfer to occur.

Notice he said 'most' and low probability, which is not saying totally impossible. It is just that his simulation didn't show much in the way of interplanetary interaction in that way. It was only a simulation and of course not as detailed as the real thing, so there is still a chance life forms could have crossed over. It would have to be to a planet that was also in or near the goldilocks zone for any known kind of life form to thrive on the new planet. If for instance, mars rocks with live or dormant bacteria were to hit venus, it doesn't take a rocket scientist to see that bacteria would not have the chance of a snowball in hell, what with a 1000 degree atmosphere 1000 pounds per square inch and full of sulfuric acid.
3.7 / 5 (6) Mar 20, 2012
Life itself is improbable yet here we are. This is a senseless exercise but entertaining. Face it. Computers can only be as smart as the programmers. Life is not about probability it is about possibility.
5 / 5 (1) Mar 20, 2012
I know Melosh was highly motivated to find something interesting out of a negative result, but a Rare Earth claim isn't it. The system found to date are heavily weighted with observational bias (towards superEarths, say) and if there is one thing what jumps out of them is that they are all individuals. We should expect many systems to be like ours in regards possibilities for transpermia.

Which isn't a very interesting process for astrobiology in any case, since the speed with which life arose here shows it is an easy process.

@ OdinsAcolyte:

"Life itself is improbable yet here we are."

A very open ended description.

- If you mean individual life, it is contingent hence improbable to repeat.

- If you mean life of the biosphere, the long lived biosphere shows populations have high probability to populate it.

- And if you mean the transition from chemical to biological evolution, the speed with which it happened here shows it is probable indeed given a habitable planet.
not rated yet Mar 20, 2012
There would be some small probability that the earth may be hit by ejecta from there if the material leaves the stellar system. But even less chance that anything live would survive an interstellar trip. Though for most of an interstellar journey it would be extremely cold and frozen. Since life forms would be destroyed by intrinsic radioactive elements in the ejecta, planets with surface rocks low in potassium, uranium and thorium would have a bigger chance of seeding life through the universe.

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