Scientists have a working theory on how life may have come to Earth via an asteroid. But how did life get onto an asteroid in the first place? Several theories exist, but they're all a little bit different. Scientists at Rensselaer Polytechnic Institute, however, have come up with a new theory that could properly explain how organic material forms on an asteroid.
The theories most often taught in astrobiology revolve around the idea that the asteroids were once warm enough that they could sustain liquid water, which is necessary for organic molecules to form. The space where they originated in is cold, so how did they get heated up to the right temperature? One theory states that the asteroids were heated radioactively, similar to Earth’s interior. The other popular theory involves how plasma interacts with a magnetic field. However, both of these theories are based on the assumption that the asteroid belt between Jupiter and Mars was once warm enough to do do this. Unfortunately, these theories don’t work because the sun was much dimmer back then than originally thought, meaning that the area was even colder than it is now.
The Rensselaer scientists started by looking at the theory involving magnetic fields. That theory states that an asteroid creates an electric field when it moves through a magnetic field. This heats up the asteroid. This theory makes the assumption that a strong solar wind was present, but that has been disproved.
However, starting with this theory gave them something to work with. They used a new understanding of how the process works, and re-calculated the electric field. With that, they determined that something called multi-fluid magneto-hydrodynamics was also at work on the asteroids. This regards how plasma interacts when introduced to a magnetic field. Generally speaking, the plasma’s neutral particles rub up against other particles and create friction. This friction creates heat. This heat creates the correct temperature for organic molecules to form.
Although the scientists feel that this theory is a good one, they still believe there are more questions to be asked and answered regarding the origin of life on asteroids.