Mars’s gravity shapes ice ages on Earth, new research finds
Mars is half the size of Earth, one-tenth the mass of our planet, and the closest point in its orbit is more than 33 million miles away. But new research highlights the red planet’s extraordinary impact on our world.
Just as the Moon’s gravity drives tides in the oceans, it is now understood that Mars’ gravity plays an important role in shaping long-term climate patterns on Earth, including the conditions that trigger ice ages.
Stephen Kane, a professor of planetary astrophysics at the University of California, Berkeley, launched a research project after reviewing recent studies linking changes in Earth’s climate to slight gravitational tug-of-war from Mars.
“I knew Mars had an impact on Earth, but I assumed it was very small,” Professor Kane said. “I thought the gravitational effect would be too small to be easily observed in Earth’s geological history. I set out to check my own assumptions.”
Previous studies have shown that patterns preserved in deep-sea sediment layers reflect long-term climate cycles hypothesized to be influenced by Mars, despite its small mass and great distance from Earth.
But Professor Kane took a very different approach and ran large computer simulations of the behavior of the solar system and the long-term changes in Earth’s orbit and tilt that determine how sunlight reaches our planet’s surface over tens of thousands to millions of years.
These orbital and displacement cycles, called Milankovitch cycles, are central to understanding how and when ice ages begin and end.
An ice age is a long period of permanent ice sheets at the planet’s poles. The Earth has experienced five, perhaps six, major ice ages in its 4.5 billion year history. We are currently experiencing the Quaternary Ice Age, which began 2.6 million years ago and reached its peak, or glacial maximum, during the Anglian phase, when the ice sheet extended south to the Isles of Scilly off Cornwall and now as far as North London.
Among the five or six major ice ages that ravaged our planet, lasting millions of years, there were also smaller cycles in which ice levels fluctuated.
The research team found that computer models predict that Mars has a certain influence on these shorter cycles – one lasting about 100,000 years and the other lasting about 2.3 million years.
