How Mars could affect life on Earth
Although it might seem like a beautiful, distant object up there in the night sky, according to a new study, Mars may be having a dramatic effect on the sea here on Earth.
The recent research builds on scientists’ knowledge of the Milankovitch Cycles, which are wobbles in the Earth’s orbit around the Sun. These wobbles, which occur in repeated patterns (or cycles) over many thousands of years, move Earth closer or further away from the Sun, changing the amount of energy our planet receives and affecting its climate. Energy from the Sun also affects ocean currents (movements). This is because the oceans absorb the Sun’s energy and store it as heat, and water moves in different ways as it warms. That’s why the Milankovitch Cycles end up affecting ocean currents.
In the new study, researchers say they have found a new, separate cycle that affects Earth’s movement over a much longer period – 2.4 million years. This “grand cycle” is caused by the gravity (a force that pulls objects together) that Mars applies to Earth.
The researchers looked at nearly 300 deep-sea drill cores (tubes of material that are taken from the sea bed when drills dig down). These cores reveal how material in the ocean settles on the sea bed.
This material, called “sediment”, is moved around by currents, so by studying it researchers can work out how the sea’s currents have changed over time.
The researchers compared the layers of sediment in the drill cores with the movement of the planet Mars over a long period of time. They discovered that at times when Mars was closest to Earth – so the effect of its gravity was strongest – there were changes in the layers of sediment. This suggests that Earth’s currents were moving in different ways. The researchers concluded that the pull of Mars’s gravity does have a slight effect on the route the Earth takes around the Sun. This would affect how much energy the Earth receives from the Sun, so it could lead to bigger changes in ocean currents over time. These currents carry heat around the world and affect our climate and all living things.
Not all scientists are convinced by the importance of Mars. Some say that human-influenced climate change is having a far bigger impact on our oceans.