Supermoons aren’t that special – but the Moon absolutely is

Dear The Internet,

Want to know a secret about supermoons? They’re not that rare, not that special, and not obviously different to normal moons unless you’re really familiar with what they look like normally.

But here’s a secret about the Moon: it’s FREAKIN’ AWESOME and any excuse to make people go outside and look at it is a good one.

"There's a moon in the sky / It's called the Moon". You nailed it, B-52s.

“There’s a moon in the sky / It’s called the Moon”. You nailed it, the B-52s.

The Moon is unique because it’s made out of a bit of Earth that was blasted off and congealed in orbit. No other moon in our solar system appears to have been created that way.

Generally moons are made of bits of detritus from the formation of the solar system that clumped into vaguely spherical bodies around bigger planets (which is how most of them were probably formed), or captured asteroids (Mars’ tiny moons Phobos and Deimos, which will eventually crash to the surface) or cometary bodies that got trapped by gravity (everything orbiting around Pluto, and Neptune’s moon Triton orbits in the opposite direction to  the planet’s many other moons because it was an interloper that passed too close, which is incredibly weird and great).

Our Moon was created in a catastrophic collision between the newly-formed Earth and (we now think) a small protoplanet that was moving very, very fast about four and half billion years ago while the solar system was still forming.

What’s even more awesome is that it’s basically the reason you exist.

Earth has nice predictable seasons because the Moon’s gravity stops Earth wobbling wildly on its axis the way that, say, Mars does, meaning that life had a chance to get going without the entire place becoming encased in ice as a hemisphere turned away from the sun or burned to a crisp from millennia of direct sunlight.

That might be the reason there doesn’t seem to be life teeming all over the universe: maybe those first replicating chemical processes develop easily enough, but most planets don’t have stable temperatures that would let complex molecules develop long enough to establish that early foothold for life. After all, life started on Earth about 3.8 billion years ago but didn’t get more complex than bacteria for around three billion years. So life would appear to have needed things to be stable for a good long while in order to get its act together down here. And the Moon provided that.

Also, those dark bits that make it look like a face: that’s ancient lava flow. The Moon used to be geologically active. That’s goddamn amazing.

Oh, and by pure coincidence you’re fortunate enough to live in the only period in history where the Sun and the Moon are the same size as seen from Earth: the Moon used to be much closer and is slowly moving away from us (an echo of that collision that created it), but right now it’s the perfect size to completely block out the Sun during a solar eclipse. Seeing a total solar eclipse might be one of the rarest experiences in the universe, and Earth gets to do it every year or so.

The Moon: it’s incredibly fascinating and crucial to the existence of every species, including us. Our ancient civilisations weren’t crazy to worship it.

So it’s definitely worth a glance now and again.

Yours ever,

APS

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Stephen Hawking vs the Space Aliens, or “Cosmologists Say The Darndest Things!”

Written 5 July 2010

Stephen Hawking is, let’s be clear, a smart fellow.

In fact, “smart” doesn’t really appear to do him justice as a description: he’s a freakin’ genius. And if there’s one thing that he’s a big ol’ geniusin’-freak-genius about, it’s the cosmos. He knows his cosmos like the back of the hand with which he moves his chair. If there’s a person more au fait with the secrets of the universe, it’s hard to imagine who’d they’d be.

Stephen Hawking, welcoming our new insect overlords (not shown)

Stephen Hawking, welcoming our new insect overlords (not shown)

Gamma ray bursts? He’s totally down with them. Expansion of the visible universe? Got that nailed. Mathematical models explaining how black holes will eventually evaporate due to the fleeting appearance of particles that bubble up in the quantum foam of space-time? This dude quite literally wrote the book on it. The man is a seriously bright sort of a person.

So: why does he occasionally say such silly, silly things?

You see, here in Australia, the Discovery Channel is about to screen the fist episode of Into The Universe with Stephen Hawking, a show about the cosmos (good) which is zippy and informative (good) and this episode should pique people’s interest on the biggest subject of all: the origins of life (also good).

Where things get the tinsiest bit not-good is just after he says some very reasonable things about how the universe appears to be made up of pretty much the same stuff all over – there don’t appear to be completely different elements to the west of the Universe, the same laws of physics appear to apply everywhere we look and so on – and that it’s therefore reasonable to assume that life has probably turned up elsewhere. That’s all fine (if speculative, at least until we find some evidence that there’s life anywhere else – currently, it’s Earth: 1, Entire Rest Of Universe: 0).

Then again, the notoriously liberal media are aware that space aliens have a right-wing agenda. Maybe Hawking is on to something…

So far, so uncontroversial.

Then he gets into a bit of fun, if somewhat pointless, speculation about what life might look like on other planets (spoiler alert: big ol’ suction-snouts), which pads out the running time a bit and gives the animators some showreel footage for any future job interviews at LucasArts, and then raises the question “how might we try to communicate with other interstellar civilisations?” before concluding “we shouldn’t, since it might make them come and steal our resources.”

Here’s the scenario as Hawking proposes it:

Highly advanced civilisation develops incredible technology. Said technology, which includes mighty spaceships, requires enormous energy demands. Civilisation depletes resources on home planet due to said energy demands. Civilisation leaves its ruined planet and becomes spacefaring, roaming the cosmos looking for new planets to plunder. Earth, being covered in awesome things like water and air and other nice stuff, is a tempting target – especially after we draw attention to ourselves by sending radio waves to the rest of the Universe. The spaceships lay waste to Earth, taking what they need before moving on. It’s not explicitly said, but I can only assume that the White House is the first target, followed by other photogenic landmarks around the world.

Now, I should make clear that I’m not and never have been Lucasian Professor of Mathematics at Cambridge University, but I’m prepared to proudly hold my BA (+ Philosophy hons) high and say this in response: bollocks, Professor Hawking.

And, if I may expand: bollocks bollocks bollocks and bollocks.

My testicle-heavy riposte isn’t simply in response to the implied notion that civilisations automatically become spacefaring when they get to a certain level of technology – although I am going to paddle in that metaphorical estuary for a moment since I think it’s a briny point worth making.

Obviously a civilisation can’t become spacefaring unless it reaches an enormously sophisticated level of technology but – as we’re learning here on Earth – creatures that have developed on a terrestrial planet are, by definition, not designed to live in space. Evolution, it turns out, is not speculative.

We marvellously adaptive and ingenious humans have scurried all over the planet’s surface but even we haven’t colonised the deep ocean trenches or inside volcanoes or up in the stratosphere, since we die under those pressures/temperatures/lack of breathable atmospheres.

Yet all those environments are much, much less alien to us than space: gravity is much the same, for example, and we’re still protected from cosmic rays and highly charged particles by the Earth’s magnetosphere. In space, human bodies are entirely inappropriate for the conditions.

Everything from the way our circulation works to the degree of radiation our cells can take before the DNA is damaged has evolved as per Earth-surface standards. Any species evolving on any other planet is going to develop to thrive under the conditions of that planet – the local gravity, the amount of energy it gets from its sun, the weight of its atmosphere and so on.

These are not simply curly technical problems likely to be solved via advanced spacecraft engineering. Any sophisticated technological species will have to be very highly evolved which means it’s going to be adapted to its specific environment – not the resource-poor vacuum of space.

It’s just possible that there are life forms of some sort floating in the thin gas between the stars, but they’re not going to be sophisticated enough have civilisations. Something as simple as a virus could possibly survive in deep space, but a virus can’t develop starship technology: they’d never find arc welders tiny enough, for one thing.

Develop enough to have complicated things like brains that can even conceive of space travel and, somewhat ironically, you’re going to be so well suited to your environment that you won’t be able to leave it. Genetic engineering might mitigate some of these problems, in the far off sci-fi future, but my deep love of Star Wars isn’t enough to shake my suspicion that there are exactly zero mighty starships currently ploughing the galaxy’s spacelanes.

But that’s a secondary issue. The main reason why I have a gonad-themed response to Hawking’s position is that a civilisation which is so energy starved that they’re forced to roam about the place plundering other planets will seek to use as little energy as they can in the process. It’s simple economics: there’s no point plundering a planet’s resources if you use up more energy in the act of plundering than you gather post-plunder.

This means that if there are viable plunderin’ alternatives a) said fleet of hypothetical starships are probably not going to explore the planets deep in a star’s gravity well, since they will be harder to survey and energy-expensive to leave, and b) they’re not going to waste energy dealing with a technologically-advanced indigenous society, even one whose powers are feeble in comparison, because dealing with any threat of combat, however small, is always going to use more energy than dealing with no threat at all.

Of course, as noted, that’s assuming that there are viable plunderin’ alternatives: but what if Earth is totally special?

We’re back at the thing Hawking was talking about before, how the Universe is made of much the same stuff and the laws of physics are universal. In other words, there’s nothing unique to Earth compared with the rest of the solar system (aside from life, or so it appears).

There’s plenty of water out there, especially in the Kuiper Belt and the Oort Cloud at the edge of the Solar System: a plundering civilisation could happily harvest comets out there without any interference. Carbon, hydrogen, oxygen, nitrogen, iron, hydrocarbons, methane – they’re all on other planets and moons, often in easier-to-get-at forms. Why bother even running an assessment to see whether these pesky humans pose any threat at all when you could save time and fuel merrily harvesting minerals off the moons of Neptune, say, with no living thing within billions of kilometres of you?

In any case, I find the idea of any civilisation traveling from star to star in search of anything whatsoever to be unlikely in the extreme, simply because of the staggering distances involved.

A civilisation facing ruin from resource depletion would surely be more likely to focus all of their efforts on drawing as much energy as possible from their sun, for example, than they would on pissing energy away building huge spaceships and hoping like hell they found something to burn out there in the cosmos. A theoretical interstellar civilisation might want to pop by our planet for many reasons, but I don’t think grabbing a metaphorical cup of sugar (or carbon) is likely to be one of them.

Or, to put it another way, bollocks.