Mars Causes Ice Ages

So is it possible Mars, so small and so far away, actually affects our weather?

Permeating space are fields. A term introduced by Michael Faraday half way through the 1800s to explain what he imagined was around a magnet to allow it to do its “magneticism,” then formally defined by James Clerk Maxwell. Faraday could see the effect on a magnet and wondered how it happened. The notion of fields, and their closely aligned forces, are still abstractly difficult to conceptualise. “Field” seems an unusual technical word to choose, but at the time science was struggling to understand interactions without contact and what energy was, so the term gave the region of space an independent reality.

Imagine a wind blowing constantly across an ocean. Think of this as a field. A situation, location, potential for doing something if the right thing is in the field. Now put a sailing ship in the midst of the “wind field: and it is affected, it is forced in some way. It’s position and speed and shape change, purely because of its interaction with the wind.

There are 4 known forces of nature, that’s probably all of them, but never say never. The strongest is the Strong Nuclear Force, holding atoms together so that they stay atoms, and which when unleashed creates super power(s). Get it? Then the Weak Nuclear Force. Not weak, it handles all chemical reactions which Nobel used to reward great physicists, showing just how powerful it really is. The one we are probably most familiar with nowadays is the Electromagnetic Force, once thought to be two different things, but good old Maxwell showed they are two sides of the same coin. It is strong enough when you think of it, driving electric motors and lightning. Shows how strong the forces inside and around the atom must be by comparison. Poor old gravity is the weak one. It is so weak that even with a mass the size of the earth, you can jump in the air and defeat it. At least for a second or two, then you need the energy of one of the other forces to stay up. Or grab a ladder.

There is a field for each force. Three of them use quantum particles: photons, gluons, bosons. Poor old gravity does not seem to have a particle associated with it, not stopping scientists from searching for a “graviton” so who knows? Never say never. Instead Einstein described the gravitational field as becoming warped if ever a mass is in it, so the mass then rolls around instead of being stationary. Two of them would roll towards each other. The demonstrations are like marbles rolling around in a dish.

But the interesting thing is, the really interesting thing is, that gravity has infinite range. Regardless of how far apart two masses are, or how small the mass, they are attracted to each other.  If there were just two atoms in a gigantic universe, and they were at opposite sides of that universe, over time they would come together. They probably hit with enough force to interfere with the electromagnetic field surrounding each of them and make a new molecule. Hitting with enough force and they may collide internally and make an entirely new atom and some debris. Actual image of two atoms below.

All of this goes under the banner of “Action at a distance”. Wikipedia explains “Action at a distance is the concept in physics that an object’s motion can be affected by another object without the two being in physical contact; that is, it is the concept of the non-local interaction of objects that are separated in space….  Newton’s law of universal gravitation is based on action at a distance. Historically, action at a distance was the earliest scientific model for gravity …” That was what perplexed Faraday.

So not two atoms but two massive bodies, the Earth and the Moon. And not infinite distance apart, but a quarter million miles away, which from a human perspective is pretty far. At the speed of rockets it takes up to a week travelling between them. We are all very aware these days that the tides are caused by the gravitational effects between them. That has a direct effect on our weather, since tides cause coastal anomalies, which can expose more of earth’s surface, which gets hotter, for instance.

Earth’s oceans are a fluid. I remember at school being surprised to learn that fluids in the physical sense, which are something that can flow, can also be solid or gaseous. Sand can act like a fluid for instance. So it is perhaps less well known that the gravitational effect between the Earth and the Moon creates “tides” in the atmosphere which can affect weather patterns subtly. By creating barometric pressure changes for instance, and subtleness is all it takes.

But what about two planets. Mars and Earth, this time up to as much as a quarter billion miles apart? Mars is half the size of Earth, with one-tenth of our planet’s mass, and even at the nearest point in its orbit is over 33 million miles away. Just visible in the sky. Just as the Moon’s gravity drives the oceans’ tides, Mars’s gravity is now understood to play a significant role in shaping longer-term climate patterns on Earth, including the conditions that trigger ice ages. The moon does not even do that. In fact the size and proximity of the moon  stabilises some aspects of our weather by locking in out tilt, which is what creates the seasons.

That is the crux of it actually: the tilt of our planet which affects how much solar energy we receive. Called Milankovitch cycles, these are long-term variations in Earth’s orbit and axial tilt that affect how much solar energy the planet receives, influencing climate changes over thousands of years. These cycles are responsible for the timing of ice ages and interglacial periods throughout Earth’s history. They are predictable events despite the complexity of the orbits of the two planets.

   

As reported by Jordan Strickler in ZME Science, ‘Stephen Kane, a professor of planetary astrophysics at the University of California, Riverside and study author, said he had his doubts to begin with. Recent studies have tied deep-ocean sediment layers to Mars-linked cycles, implying that the planet’s gravitational nudges show up in Earth’s geologic record.

He just didn’t expect the weight of the impact.

“I knew Mars had some effect on Earth, but I assumed it was tiny,” Kane said. “I’d thought its gravitational influence would be too small to easily observe within Earth’s geologic history. I kind of set out to check my own assumptions.”

Milankovitch cycles are long, predictable variations in Earth’s orbit and spin — changes in orbital shape (eccentricity), axial tilt (obliquity), and the wobble of Earth’s orientation (precession). Together, they alter how sunlight is distributed across seasons and latitudes, setting the tempo for glacial and interglacial periods.

An ice age is a long period during which the planet has permanent ice sheets at the poles. Earth has gone through at least five major ice ages over its 4.5-billion-year history. The most recent began around 2.6 million years ago and is still ongoing. 

One Milankovitch cycle is driven mainly by the gravitational pull of Venus and Jupiter and takes 430,000 years to complete. Over that time span, Earth’s path around the Sun gradually shifts from nearly circular to more elongated and then back again. This change in orbital shape affects how much solar energy reaches the planet and can influence the advance or retreat of ice sheets.

That 430,000-year cycle stayed intact in Kane’s simulations, regardless of whether Mars was present. But when Mars was taken out, two other major cycles, one that takes 100,000 years to complete, and another stretching 2.3 million years, disappeared entirely.

“When you remove Mars, those cycles vanish,” Kane said. “And if you increase the mass of Mars, they get shorter and shorter because Mars is having a bigger effect.”’

Kane graduated from Macquarie University with a Bachelors of Science in Physics in 1994. In 1995 Kane received First Class with Honors at the same institution for his work studying a galactic extended source, which he identified as a previously unknown supernova remnant. In 2000 Kane received his Ph.D. from the University of Tasmania with a thesis focusing on gravitational microlensing, the bending of space by gravity which has a variety of astrophysics applications, including the discovery of exoplanets.