What If the Moon Was 2x Closer to Earth?

VOICE OVER: Noah Baum WRITTEN BY: Craig Butler
The moon is already the biggest and brightest thing in the night sky. But, what if it looked even bigger? What if the moon was twice as close to the Earth? Would our lives be radically different? Or would we just carry on as usual, only with more moon to look at once darkness falls...

What If the Moon Was 2x Closer to the Earth?

In modern pop culture, our Moon has been tunefully likened to a ‘pizza pie’, linked to various lycanthropic characters, and has served as a cinematic backdrop for many an iconic scene. For the most part, we'd seemingly be fine with a bigger one – if only for the aesthetics.

However, our perception of the size of the Moon depends on how close it is to the Earth. And, if we’d rather a larger lunar focal point for our summer night romances, the Moon would have to be much nearer. But, would there be repercussions? And would it all be worth it? What would happen if the Moon was two times closer to the Earth?

Barring some truly unusual event, it’s unlikely that the Moon will ever actually get any closer to our planet. In fact, it’s been moving farther away from us for millennia. Sure, it currently sits 380,000 kilometers away, and it only shifts about 3.8 cm (or an inch-and-a-half) every year, but the distance between us and it is still gradually increasing… Which doesn't bode well for a ‘large and in charge’ moon one day filling our nighttime skies.

But, of course, if it did edge closer, it’d be more than a matter of having something beautiful to look at. The Moon affects the Earth in different ways. Most obviously, it shapes its tides. But the effect isn’t necessarily linear; there are all sorts of variables that come into play. So, we can’t assume that moving the Moon twice as close would mean every effect would simply double. Still, it’s certain that whatever the exact degree, there would be some big changes.

Let’s start with the tides. The Moon’s gravitational pull on the Earth causes what’s called a tidal bulge, which is responsible for the high and low tides of the Earth’s waters. As a solar side note, the Sun also influences our tides… but not to the same extent. With the Moon twice as close, the high tides would be much, much higher and low tides much lower. Many current coastal areas would therefore get routinely flooded – which means the shift would reshape the world map.

These new extremes would, of course, result in changes to the areas affected by the tides, creating much larger intertidal zones – which would have an undoubted effect on the wildlife that lives or feeds in these areas. For example, wading birds might find their foraging environment changed. Sea turtles that lay eggs on land might need to travel further thanks to higher tides – which means that newborn turtles would also face a far lengthier journey after hatching to reach the sea.

On a larger scale, should the distance between us and the moon be halved, the effects would definitely fall at our door, too. The greater intertidal zone means that many docks and piers would have to be rebuilt and extended, so that ships were not grounded during low tide. Drainage systems would also need to be reconfigured to accommodate the greater influxes of water during the high tides. In general, we’d all have to relocate further inland, and to higher ground. That’s because there’d be a sharp increase in the size and number of tidal waves, which would be more bad news for people and animals living near coastlines.

The shifting moon would spell more than just these tidal changes, however. Earthquakes and volcanic reactions would also likely increase. As with the water, the Moon’s gravitational pull also has an impact on the Earth’s crust, and therefore on the temperature of the magma beneath it. A stronger gravitational pull caused by a closer proximity would shift tectonic plates more easily, triggering unprecedented eruptions and seismic activity.

Aside from the physical Armageddon that could (and likely would) be triggered, even our most fundamental experiences would alter, as the length of days and nights would change. Right now, with the Moon very slowly moving away from us, a day on Earth actually extends by 15 millionths of a second every year. But, if the Moon were suddenly twice as close, the new-found gravitational force would cause the Earth to spin faster. Analysts can’t conclusively predict exactly how much faster, but it would be enough to shorten the days significantly.

Indirectly, this would wreak havoc on our circadian rhythms, disrupting our sleep patterns and affecting our health. And though nights would be shorter, a bigger moon would be a brighter one – perhaps making it even more difficult to fall asleep (as if the knowledge of imminent tidal waves wasn’t enough to keep you awake already!). Shorter days would also mean less time for plants to receive the sunlight they need to thrive, as well as less time for the Earth’s atmosphere to warm up. Shorter nights would limit this effect, but the new patterns would almost definitely prove tricky for various species of plant life to adapt to. Animals would also find difficulties in adjusting, especially those who are nocturnal or diurnal by nature and would have shorter periods of time available to them for their activities.

The speed at which a planet spins also has a direct effect on the winds that are produced. This means that, were the Moon to move closer, our Early windspeeds would also increase – meaning storms and hurricanes would be even more deadly than they currently are. But even just a quickening of everyday winds would have an impact. Trees and plants that have shallow roots would be more likely to fall. Given that many of our most indispensable vegetables – including widely utilized produce like broccoli, kale, spinach, cabbage, onions, and corn – have shallow roots, our diets would almost definitely change. Meanwhile, maple, ash and many oaks trees also tend to have shallow roots, putting them at risk of being toppled by high winds – as well as creating another potential danger for anyone or thing still striving to survive. Throw in the probable increase in the frequency of mudslides, due to soil instability, and the overall picture is of an unforgiving and extremely challenging environment.

One final effect that the Moon has on the Earth is to help stabilize its axial tilt. Our closest satellite helps keep the so-called “wobble” of the tilt reduced so that, while there is some variation, it’s not huge. This effect would be more keenly felt if the Moon were closer, shortening the wobble further… The results of this are hard to predict, but it could bring about less variation among seasons, and possibly lessen the strength of the Earth’s magnetic field – which would render our planet and us much more vulnerable to harmful solar radiation. Over the long term, such a development could even drastically deplete our atmosphere – leaving Earth inhospitable.

One fleeting upshot of this thankfully hypothetical Moon shift is that it would take us less time to reach it, which could open the door to humans easily visiting in order to learn more about our nearest neighbor. But, it really is the slightest of silver linings – especially as, in all likelihood, no one would be alive to man the rockets for the journey. All in all, a lunar location change is the very last thing we’d need, want or be able to deal with. Yes, in theory it’d make for a stunning photo opportunity. But, in practice, it’d be all kinds of chaos.