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What If Mars Moved Closer To Earth? | Unveiled

VOICE OVER: Noah Baum WRITTEN BY: Caitlin Johnson
Humans have long been fascinated by Mars. We've sent probes, orbiters and rovers to the Red Planet, and hope to one day send astronauts to the Martian surface. But the solar system is a big place, and our planetary neighbour is around 50 million miles away! So, what would happen if Mars moved closer to Earth? In this video, Unveiled rewrites the rules of space to find out!
Transcript

What if Mars Moved Closer to Earth?


Outer space is so inconceivably huge that even the comparatively close planet, Mars, is millions of miles away and almost impossible to reach. Our dreams of interplanetary exploration start, and even sometimes end, with Mars. But what would happen if this journey was just a little but easier?

This is Unveiled, and today we’re answering the extraordinary question; what if Mars moved closer to Earth?

Mars actually moves closer and further away from Earth all the time, because the orbits of both planets are elliptical and not perfectly spherical. At its furthest, it’s an enormous 250 million miles from us; when we and the Red Planet are on opposite sides of the sun. But, in 2018, Mars moved the closest to us it had been for 15 years, when it was “only” 35.8 million miles away. This period of close orbit is called “opposition” and actually occurs roughly every 26 months - though, again because of our elliptical orbits, exactly how close Mars and Earth are from each other differs every time.

So, that’s how much Mars naturally moves toward and away from us; but could something happen to make it draw even closer to us than it already gets? Well, a big enough, prolonged impact from an exceptionally enormous cluster of asteroids could do the trick, sending Mars out of its orbit and, if the angles are right, straight towards us. But the chances of that happening are essentially zero. Meanwhile, there are some who suggest we could artificially move Mars, with rockets, by bombarding its far side and forcing it to shift… but, if we really did want to do that, the energy and technology required is still centuries out of our reach.

But wait, why is moving Mars even a thing that anyone would even consider? Reason number one is that there’s a hope that if Mars were to in some way budge Earthwards then it could move further into the solar system’s habitable zone and produce Earth-like conditions. But there’s already a problem here… because most scientists agree that Mars is actually already in the habitable zone - meaning its proximity to the sun isn’t the major reason why it currently doesn’t appear to sustain life. Sure, moving Mars further toward the sun (and therefore us) would serve to improve its prospects - particularly for potential visitors from Earth - but it wouldn’t fix everything.

The main reason Mars isn’t teeming with life right now is because it doesn’t have a magnetosphere – or, at least, what remains of its magnetosphere is so weak it’s redundant. Motion in the partially liquid core of the Earth is what produces our magnetosphere, which deflects most unwanted particles away from us. Mars’s core, at a point in the distant past, is thought to have turned solid, leaving the atmosphere to become extremely thin with nowhere near enough oxygen for life. Bringing Mars closer to the Earth (and the sun) wouldn’t fix this problem, and in fact, it might make things even worse. Earth’s robust atmosphere is what protects us from solar radiation, but Mars doesn’t have that kind of protection. Move it closer to us, then, and it would get bombarded with more and more radiation, unless something was done to shield it first. While theoretically, it is possible to reboot Mars’s magnetosphere if we were able to turn its core molten again, once more the technology to do so doesn’t exist…

NASA reportedly does have some ideas on how to create an artificial magnetic sphere for Mars, although theories on how to implement it are arguably even more farfetched than any previously mentioned plan to purposefully move the planet in the first place. Earth would essentially “launch” an enormous magnetic field to smother our neighbour with, deploying it all across the Red Planet before regularly “topping it up” in the same way. It’d be a round-the clock and incredibly expensive job, but were we ever to reach such a point then Mars could be liveable… and any successful attempt to move it closer to us would only improve the situation, providing a safer climate and a shorter commute. They’d be the first two steps in the grandest of grand terraforming schemes, and would ultimately enable the planet to begin terraforming itself under new conditions.

But what if we weren’t actively targeting and trying to move Mars, and it just shifted closer of its own accord? While, again, this wouldn’t restore its magnetosphere and magically make it habitable, it would have some benefits. It would reduce the distance of its orbit around the sun, for one thing, meaning that it stays much closer to us for much longer periods of time, making our own “Mars missions” a lot easier in every possible way. Journeys to the Red Planet would be much shorter, meaning that we could send humans more easily and more frequently. It would take a lot less fuel to get there; travelling astronauts would need less food and essentials; the spacecraft carrying them would therefore be lighter, meaning they could reach higher speeds. It would also be easier to bring anyone actually on Mars back in case of emergency, since they wouldn’t have to wait months on end for opposition to roll around.

It wouldn’t be all good news, though. The prospect of another planet moving towards our own - whether it’s inching quite slowly or picking up speed - could understandably create panic. Yes, we’d suddenly find our options increased in terms of terraforming and relocating to Mars, but we’d also be worrying over when (if ever) it’ll stop beelining this way. The worst-case scenario would be planet-on-planet impact. With Earth travelling through space at 67,000 miles per hour, and Mars at 53,000, a collision would destroy us both. While the remnants of the planets could someday reform into a new, possibly larger planet, perhaps also with the potential for life, such an event would definitely spell the end for humanity as we know it. Luckily, space is so vast that the chances of that actually happening are incredibly slim… What’s more likely is that a roaming Mars would fall out of the solar system completely or plummet into the sun. Fortunately, it would miss us; Unfortunately, all of those positives gained by Mars moving closer to Earth would’ve been lost, too.

That said, even if Mars were to move and then somehow stop at a closer but seemingly “safe” distance from Earth, we’d still face other major issues linked to orbital resonance - where Mars’ new position interferes with Earth’s own spot in the solar system. Right now, everything orbits the sun in a balance, and it’s an arrangement that suits us rather well, situated on a planet where life can prosper. But, if Mars gets too close for comfort, we could find ourselves edged out of the Goldilocks Zone. Failing that, we could become locked in a gravitational tug-of-war with Mars… It’s a war that we, as the larger object, would win, but it could see Mars brought into our own gravitational field, acting as though it’s a spectacularly large second moon. Under these extreme circumstances, we could expect mass flooding due to wildly out of control ocean tides; whole sections of the world map forced underwater; and even changes to how the seasons work. We could even see Mars and the regular moon smash into each other, littering us with debris!

All of that is, of course, incredibly unlikely even in the almost equally unlikely event that Mars would begin to head our way in the first place. But space has often proven to be a very unpredictable place, and it’s worth remembering that our own place within it has really come about thanks to the perfect alignment of a lot of celestial business. Were Mars to encroach further into the habitable zone around our sun, then perhaps we could even witness the emergence of organic life on its surface. Although the lack of a molten core and magnetosphere would still be massive stumbling blocks, were these to be somehow overcome then we’d have front-row seats to alien evolution…

But, best not get ahead of ourselves! The most probable outcome is that our standard missions to Mars would be made a lot easier; trips to Red Planet would be much shorter and more frequent; and permanent human settlements on the Martian landscape could crop up much sooner than even the most optimistic projections promise today. And that’s what would happen if Mars moved closer to Earth.
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