Joel Kontinen
Many exoplanets are weird and have highly eccentric orbits. In contrast, our solar system seems to be very different.
A recent study conducted by Elke Pilat-Lohinger of the University of Vienna, Austria, points out the role of the Saturn and Jupiter in keeping Earth friendly to life.
Using computer models, Dr. Pilat-Lohinger examined how “changing the orbits of these two giant planets might affect the Earth.”
Reporting on the research, New Scientist writes:
“Earth's orbit is so nearly circular that its distance from the sun only varies between 147 and 152 million kilometres, or around 2 per cent about the average. Moving Saturn's orbit just 10 percent closer in would disrupt that by creating a resonance – essentially a periodic tug – that would stretch out the Earth's orbit by tens of millions of kilometres. That would result in the Earth spending part of each year outside the habitable zone, the ring around the sun where temperatures are right for liquid water.”
It seems that Saturn’s distance from Earth is not the only parameter that matters:
“Tilting Saturn's orbit would also stretch out Earth's orbit. According to a simple model that did not include other inner planets, the greater the tilt, the more the elongation increased. Adding Venus and Mars to the model stabilised the orbits of all three planets, but the elongation nonetheless rose as Saturn's orbit got more tilted. Pilat-Lohinger says a 20-degree tilt would bring the innermost part of Earth's orbit closer to the sun than Venus.”
The research was published in the International Journal of Astrobiology.
Some time ago, Geoffrey W. Marcy, professor of astronomy at the University of California at Berkeley, acknowledged that our solar system is a rarity.
Source:
Hecht, Jeff. 2014. Saturn's calming nature keeps Earth friendly to life. New Scientist (21 November).
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