Astronomer David Nesvorny from the Southwest Research Institute in Texas believes that the solar system might have once contained a fifth gigantic planet, which was ejected deep into the galaxy in a moment of cosmic turmoil.
By looking at the population of the Kuiper belt — the icy-cold ring of asteroids beyond Neptune — and by studying the historical fingerprints left on the craters of the Moon, Nesvorny was able to piece together clues about our solar system’s adolescence.
He found that a dynamic instability, which occurred about 600 million years into the solar system’s life, greatly affected the orbit of our giant planets and scattered smaller bodies. Some moved into the Kuiper belt and others traveled inwards, marking their course as impacts on the Moon and planets.
But that scenario has a flaw. Slow changes in Jupiter’s orbit would have had a large effect on the orbits of the terrestrial planets. All hell would have broken lose, and the Earth could have collided with Mars or Venus. Something had to change.
“Colleagues suggested a clever way around this problem,†says Nesvorny in a press release. Instead of a slow movement, Jupiter’s orbit could have quickly changed, which would have altered the outer solar system but...
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