New Theory Explains Presence of Seeds of Life in Asteroids

By taking a new look at the early solar system, researchers have developed a theory outlining how biomolecules, considered the building blocks of life, were once able to form inside asteroids.

The theory takes into account a more accurate image of magnetic fields and solar winds that existed during the solar system's early years, the researchers from the Rensselaer Polytechnic Institute (RPI) explain.

One of the problems facing current theories is the fact that biomolecules require a wet, warm environment. The asteroid belt between Mars and Jupiter, however, is both cold and dry, and would have been more so back then when the Sun was dimmer than it is today.

"And yet we know that some asteroids were heated to the temperature of liquid water, the 'goldilocks zone,' which enabled some of these interesting biomolecules to form," co-author Wayne Roberge, a professor of physics within the School of Science at Rensselaer, and member of the New York Center for Astrobiology, said in a statement. "Here's the question: How could that have happened? How could that environment have existed inside an asteroid?"

Published in The Astrophysical Journal, the study reexamines a prevailing theory, which involves the interaction of plasma and a magnetic field. According to this theory, as asteroids move through the solar system's magnetic field, it experiences an electric field that pushes electrical currents through the asteroid, causing it to heat up.

"It's a very clever idea, and the mechanism is viable, but the problem is that they made a subtle error in how it should be applied, and that's what we correct in this paper," Roberge said. "In our work, we correct the physics, and also apply it to a more modern understanding of the young solar system."

In order for the theory to work, for example, the young Sun would have had to produce solar winds powerful enough to blow past the asteroids, "and that's just no longer believed to be true," co-author Ray Menzel explained.

The researchers also fixed what they say was an inaccurate calculation regarding the position of the electric field the asteroids would have experienced.

"We've calculated the electric field everywhere, including the interior of the asteroid," Roberge said.

The corrections bring to light a new possibility that, Menzel and Roberge say, is based in a correct assessment of the electrical fields, the solar wind and plasma conditions, and a mechanism called multi-fluid magneto-hydrodynamics.

Magneto-hydrodynamics is the study of the interaction between charged fluids and magnetic fields. Multi-fluid magneto-hydrodynamics, meanwhile, are a subset that applies to conditions in which the plasma is is very weakly ionized and neutral particles behave differently from their charged counterparts.

"The neutral particles interact with the charged particles by friction," Menzel said. "So this creates a complex problem of treating the dynamics of the neutral gas and allowing for the presence of the small number of charged particles interacting with the magnetic field."

The new theory, though promising, requires further exploration.

"We're just at the beginning of this. It would be wrong to assert that we've solved this problem," Roberge said. "What we've done is to introduce a new idea. But through observations and theoretical work, we know have a pretty good paradigm."