This solar system montage of the nine planets and four large moons of Jupiter in our solar system is set against a false color image of the Rosette Nebula. The light emitted from the Rosette Nebula is due to the presence of hydrogen (red), oxygen (green) and sulfur (blue). Most of the planet images in this montage were obtained by NASA’s planetary missions, which have dramatically changed our understanding of the solar system in the past 30 years. Credit: NASA/JPL/ASU
Experiment shows the fragility of our solar system.
A terrestrial planet hovers between Mars and Jupiter would be able to push Earth out of the solar system and wipe out life on this planet, according to an experiment from the University of California, Riverside (UCR).
UCR astrophysicist Stephen Kane explained that his experiment was intended to address two notable gaps in planetary science.
The first is the gap in our solar system between the size 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 in between.
This illustration shows the approximate sizes of the planets in our solar system relative to each other. Outward from the Sun are the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune, followed by the dwarf planet Pluto. The diameter of Jupiter is about 11 times that of Earth and the diameter of the Sun is about 10 times that of Jupiter. Pluto’s diameter is slightly less than one-fifth that of Earth. The planets are not shown at the appropriate distance from the Sun. Credit: NASA/Lunar and Planetary Institute
“In other star systems, there are many planets with masses in that space. We call them super-Earths,” Kane said.
The second gap is in position, relative to the Sun, between Mars and Jupiter. “Planetary scientists often wish there was something between the two planets. It seems like wasted real estate,” he said.
These holes could provide important insights into the architecture of our solar system and into the evolution of Earth. To fill them in, Kane ran dynamic computer simulations of a planet between Mars and Jupiter with a variety of masses, then observed the effects on the orbits of all other planets.
The results, published in Planetary Science Journal, were mostly catastrophic for the solar system. “This fictitious planet gives Jupiter a push that’s just enough to destabilize everything else,” Kane said. “Despite the fact that many astronomers have wanted this extra planet, it’s a good thing we don’t have it.”
Artist’s concept of Kepler-62f, a super-Earth-sized planet orbiting a star smaller and cooler than the Sun, about 1,200 light-years from Earth. Credit: NASA Ames/JPL-Caltech/Tim Pyle
Jupiter is much larger than all the other planets combined; its mass is 318 times that of Earth, so its gravitational influence is profound. If a super-Earth in our solar system, a passing star, or any other celestial object perturbed Jupiter even slightly, all other planets would be profoundly affected.
Depending on the mass and exact location of a super-Earth, its presence could eventually eject Mercury and Venus as well as Earth from the solar system. It can also destabilize the tracks Uranus and Neptune and threw them into outer space as well.
The super-Earth would change the shape of this Earth’s orbit, making it far less habitable than it is today, if not ending life altogether.
If Kane reduced the planet’s mass and placed it directly between Mars and Jupiter, he saw that it was possible for the planet to remain stable for a long period of time. But small moves in any direction and “things would go bad,” he said.
The study has implications for the ability of planets in other solar systems to host life. Although Jupiter-like planets, gas giants far from their stars, exist only about 10% of the time, their presence can determine whether the neighboring Earth or super-Earth has stable orbits.
These findings gave Kane a renewed respect for the delicate order that holds the planets together around the sun. “Our solar system is more finely tuned than I appreciated before. It all works like intricate clockwork gears. Throw more gears into the mix and it all breaks,” Kane said.
Reference: “The Dynamical Consequences of a Super-Earth in the Solar System” by Stephen R. Kane, 28 Feb 2023, Planetary Science Journal.
DOI: 10.3847/PSJ/acbb6b