A planet in our solar system could end all life on Earth

A terrestrial planet hovering between Mars and Jupiter could push Earth out of the solar system. (CREDIT: NASA/JPL/ASU)

According to a UC Riverside experiment, a terrestrial planet hovering between Mars and Jupiter could push the Earth out of the solar system and wipe out life on that planet.

UCR astrophysicist Stephen Cain explained that his experiment was intended to address two notable gaps in planetary science.

First, it is the gap in our solar system between the sizes of terrestrial and gas giant planets. The largest terrestrial planet is Earth, and the smallest gas giant is Neptune, which is four times wider and 17 times more massive than Earth. There is nothing between them.

“In other star systems, there are many planets with masses in that gap. We call them super-Earths,” Kane said.

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Another gap is located in relation to the Sun between Mars and Jupiter. “Planetary scientists often want something in between these two planets. It looks like wasted real estate,” he said.

These gaps can provide important clues about the architecture of our solar system and the evolution of the Earth. To fill them in, Kane ran dynamic computer simulations of a planet between Mars and Jupiter with various masses, and then observed the impact on the orbits of all the other planets.

The results, published in the Planetary Science Journal, were mostly disastrous for the solar system. “This fictional planet gives Jupiter a boost that is enough to destabilize everything else,” Kane said. “Even though many astronomers have dreamed of this extra planet, it’s a good thing we don’t have one.”

Comparison of planet sizes. (CREDIT: Alexaldo/iStock/Getty)

Jupiter is much larger than all the other planets combined; its mass is 318 times the mass of the Earth, so its gravitational influence is large. If a super-Earth in our solar system, a passing star, or any other celestial object were to disturb Jupiter even a little, all the other planets would be greatly affected.

Depending on the mass and exact location of the super-Earth, its presence could eventually eject Mercury and Venus, as well as the Earth, from the solar system. It can also destabilize the orbits of Uranus and Neptune by throwing them into outer space.

The super-Earth will change the shape of this Earth’s orbit, making it much less habitable than it is today, if not completely ending life.

If Kane reduces the mass of the planet and places it directly between Mars and Jupiter, he will see that the planet can remain stable for a long period of time. But small moves in any direction and “things go bad,” he said.

An artist’s representation of Kepler-62f, an Earth-sized planet orbiting a smaller and colder star than the Sun, about 1200 light-years from Earth. (CREDIT: NASA Ames/JPL-Caltech/Tim Pyle)

The study has implications for the ability of planets in other solar systems to host life. While Jupiter-like planets, gas giants far from their stars, are only found about 10% of the time, their presence could decide whether neighboring Earths or super-Earths have stable orbits.

These results restored Kane’s respect for the subtle order that holds the planets together around the Sun. “Our solar system is more finely tuned than I previously thought. Everything works like intricate clockwork. Add more gears to the mix and everything breaks down,” Kane said.

To learn more about scientific stories, check out our New Discoveries section at The bright side of the news.

Note: Materials provided by the University of California, Riverside. Content can be edited for style and length.

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