Solar system simulation reveals planetary mystery

A snapshot of weather patterns around Mars, including blue-white ice clouds that are visible above the Red Planet’s Tharsis volcanoes. 

Credit: NASA/JPL-Caltech/MSSS

When we look at the Solar System, what clues show us how it formed?

We can see pieces of its formation in asteroids, comets and other small bodies that cluster on the fringes of our neighbourhood (and sometimes, fly closer to Earth.)

Are the orbits and sizes of the planets a natural byproduct of the formation, or are there features that happened because of rare events?

Scientists are focused on answering these questions to better understand how the Earth formed, and what this means for Earth-like planets around other stars.

For example, a new set of simulations showed that Mars is a rare planet. It can happen, but only in certain situations, at least, if the parameters of the simulations are correct.

Are these assumptions correct, or do other initial conditions need to be explored?

Finding the answers to these questions not only helps us understand where Mars comes from, but also our own planet.

This is interesting to astrobiologists because the Red Planet has extensive evidence of past water.

Results from the Opportunity, Spirit and Curiosity rovers on the Martian surface came across features that form in the presence of water, such as mineralised iron oxide known as hematite, or"blueberries," because of its shape.

"The formation of Mars is a long-standing problem. Most previous studies like this have not been able to reproduce an object with Mars' mass," said Rebecca Fischer, a doctoral candidate in geophysical sciences at the University of Chicago, who led the research.

"It is possible to reproduce Mars, but it only happens 5 percent of the time. If you only ran four simulations, you wouldn't see it happen," she says.

Fischer's work, called "Dynamics of the terrestrial planets from a large number of N-body simulations," appeared in the journal Earth and Planetary Science Letters in April.

More information: Rebecca A. Fischer, Fred J. Ciesla, "Dynamics of the terrestrial planets from a large number of N-body simulations," Earth and Planetary Science Letters, Volume 392, 15 April 2014, Pages 28-38, ISSN 0012-821X, dx.doi.org/10.1016/j.epsl.2014.02.011.

"Building the Terrestrial Planets: Constrained Accretion in the Inner Solar System." Sean N. Raymond, David P. O'Brien, Alessandro Morbidelli, Nathan A. Kaib arXiv:0905.3750 [astro-ph.EP] arxiv.org/abs/0905.3750