The really annoying thing about time travel stories

I’ve always wanted to invent a time machine so I could whip back in time to stop Hitler before he did anything evil. Of course there are a couple of problems. First is I’d be joining the back of a LOOONG queue. The other is that our friend Albert Einstein tells us it’s impossible.

But even if a time machine could be built, nobody’s really figured out what it entails. Here’s the deal.

The Horsehead nebula, Barnard 33, as seen by Hubble. Wonderful, wonderful imagery.

The Horsehead nebula, Barnard 33, as seen by Hubble. Wonderful, wonderful imagery.

Science fiction is rife with stories about time travel, variously either as social commentary, H. G. Wells style, or as cautionary tales – witness Ray Bradbury’s wonderful A Sound of Thunder. Invent a time machine, go back in time and change the past – and you’d better watch out.

Of course, if things change so you don’t exist, then you can’t have invented the time machine. Which means you didn’t go back in time. Therefore you do exist, so you did invent the time machine and… Yah.

Or there’s Harry Harrison’s hilarious Technicolour Time Machine, about a movie maker who uses a time machine to cut production costs on his period drama by going back to the actual period. What I’m getting at is that there’s a gaping great hole in all of this. And it’s an obvious one.

Suppose you COULD time travel. Suppose you’d built a machine to do it. You decide to whip back twelve hours. And promptly choke to death in the vacuum of deep space.

Nikolai Tesla with some of his gear in action. Public domain, from http://www.sciencebuzz.org/ blog/monument-nearly-forgotten-genius-sought

OK, so it’s not a time machine, but this is what one SHOULD look like. Nikolai Tesla, being spectacular with AC electricity (he’s reading a book, centre left). Public domain, from http://www.sciencebuzz.org/ blog/monument-nearly-forgotten-genius-sought

What gives? The problem is that everything in space is moving. Earth is rotating. Earth also moves around the Sun, which itself is orbiting the galaxy, which itself is moving as part of the Local Group, and so forth. We don’t notice or even think about it because we’re moving with the Earth. If we take Earth as our reference point, it’s fixed relative to us. And that leads us to imagine that  time machines are NOT moving through space – Wells, in particular, was quite explicit that his time machine was fixed and time moved around it.

But actually, a time machine that did this – that stayed ‘still’ relative to Earth would have to move through space, because Earth is moving.

Let’s reverse that for a moment. What say your time machine doesn’t move in space at all. You move back and forth through time, but your absolute spatial position is fixed. Not relative to Earth, but relative to the universe.

You leave your lab and leap back 12 hours. Earth won’t be there – it won’t have arrived. Leap forward 12 hours – same thing, only Earth’s moved away. If you’ve only moved a few seconds, you might find yourself plunging from a great height (aaaargh!). Or buried deep in the Earth (choke).

So for a compelling time-machine story you need to have a machine that not only travels anywhere in time, but also anywhere in space. And, of course, any relative dimensions associated with both. That’s right. A machine that travels anywhere through time and relative dimensions in space.

Heeeeeey, wait a minute

Copyright © Matthew Wright 2014

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Why this week’s comet landing is way better than celebrity butt-fests

This week’s landing on Comet 67P/Churyumov-Gerasimenko was a landmark in space history – not because the comet apparently bore a passing resemblance to the Kardashian backside that was competing for place in the news, but because surface gravity on 67P is about one millionth Earth’s. You don’t land so much as drift in and try like hell to stay there.

Potential landing sites on the double-lobed Comet 67P/Churyumov-Gerasimenko. Copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Potential landing sites on the double-lobed Comet 67P/Churyumov-Gerasimenko. Copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Add to that the fact that the cometary surface is like a rugged boulder-field and you have a recipe for Ultimate Challenge. That’s what made the landing so risky – and why ESA’s Philae lander was equipped with harpoons, ice-screws, and a down-firing thruster. When they failed, Philae landed on the comet, then bounced a kilometre back into space before the comet’s lazy gravity pulled it back. It was also a funny sort of bounce because the comet isn’t a sphere – it’s more like a dumb-bell. When Philae came down a second time, it bounced again before eventually settling.

For me the three-bounce landing (at 15:34, 17:25 and 17:32 GMT on 12 November) has a wow factor well beyond landing on a comet for the first time e-v-a-h. It’s also about gravity – and that means it’s about Einstein, one of my favourite physicists. Let me explain. Gravity doesn’t just cause celebrity butt-sag, after a while. It’s also why the comet’s where it is today. Fact is that 67P/Churyumov-Gerasimenko experienced a gravitationally-driven orbit change in 1959, when an encounter with Jupiter dropped its perehelion (closest approach to the Sun) from 2.7 to 1.3 astronomical units, giving the comet its current 6.45 year period. That’s why it’s where it is now.

Gravity is also how ESA got the probe to the comet. It was boosted, during a decade-long journey, by gravity assist manoeuvres, swing-bys of Earth and Mars that exploited space-time curvatures around the planets to accelerate the probe (three times) and decelerate it (once), without burning a single gram of fuel.

Ain’t physics neat. So just what is gravity? This looks like a stupid question. Actually, it isn’t.

Rosetta's long odyssey to the comet - with slingshot gravity boosts from Earth and a de-boost from Mars. NASA, public domain.

Rosetta’s long odyssey to the comet – with slingshot gravity boosts from Earth and a de-boost from Mars. NASA, public domain.

The thing is, we think of gravity as a ‘force’. But actually, according to Einstein, it isn’t. We just perceive it as such. Here’s why. Science started looking at gravity in earnest when all-round super-geek Sir Isaac Newton worked out the math for the way gravity presented in everyday terms, which he published as part of his Philosophiæ Naturalis Principia Mathematica in 1687. His gravitational theory worked (and still works) well at everyday level – you could calculate how apples might fall, figure out planetary movements and so on (the key equation is    F = G \frac{m_1 m_2}{r^2}\ , which defines the force between two point-sources of defined mass.) Newton’s triumph came in 1838 when astronomers realised that Uranus wasn’t quite where it should have been, based on the tugs of the known planets. French mathematician Urbain Leverrier and British mathematician John Couch Adams, independently, reverse-engineered the data to pinpoint where an unknown planet should be – and sure enough, there it was. Neptune.

Albert Einstein lecturing in 1921 - after he'd published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

Albert Einstein lecturing in 1921 – after he’d published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

But as science began fielding more data, it became evident that Newton’s equations didn’t account for everything – which is where Albert Einstein comes in. His General Theory of Relativity, published in 1917, is actually a theory of gravity. General Relativity supersedes Newton’s theory and portrays gravity by a totally different paradigm. To Newton, gravity was a force associated with mass. To Einstein, gravity was not a force directly innate to mass, but a product of the distortion of space-time caused by mass/energy, which bent the otherwise straight paths of particles (‘wavicles’), including light.

The proof came in May 1919 when British astronomer Sir Arthur Eddington measured the position of Mercury during a solar eclipse. Mercury’s perehelion – the closest point to the Sun – precessed (moved) in ways Newton couldn’t account for. Einstein could – and the planet turned up at precisely the place general relativity predicted. Voila – general relativity empirically proven for the first time. I don’t expect that Einstein leaped around going ‘woohoo’, but I probably would have. And general relativity has been proven many, many times since, in many different ways – not least through the GPS system, which has to account for it in order to work, because space-time distortion also causes time dilation. (If you want to live longer, relative to people at sea level, live atop a mountain).

Einstein’s key field equation, as it eventually evolved, is G_{\mu\nu}\equiv R_{\mu\nu} - {\textstyle 1 \over 2}R\,g_{\mu\nu} = {8 \pi G \over c^4} T_{\mu\nu}\, – which I am not going to explain other than to point out that it could be used to calculate the space-time distortion caused by the mass of, say, a Kardashian butt. This would be a hideous waste of brain-power, but at least means I’ve managed to put both Einstein’s field equation and a reference to society’s shallow obsession de jour in the same sentence. As an aside, I also think Einstein got things right in more ways than we know. I don’t say this idly.

Philae lander departing the Rosetta probe for its historic rendezvous with the comet. Copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Philae departing the Rosetta probe for its historic rendezvous with the comet. Taken by the orbiter’s OSIRIS camera. Copyright ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

One of the key things about both Newton and Einstein is that their theories treated clumps of particles – a mass such as the Earth for instance – as if the gravity originated in a mathematical point at the centre of the mass, even though the gravity (‘space-time distortion’) is produced by every particle within that mass. And that works perfectly at distance. But in detail an uneven distribution of mass –  a mountain range, for instance, or even a celebrity butt – can introduce local pertubations. Small – but calculable. It’s because of ‘mass concentrations’ that satellites we put around the Moon eventually crash, for instance.

Which brings me back to the science adventure on 67P/Churyumov-Gerasimenko, 28 light-minutes away outside the orbit of Mars. With a long-axis diameter of around 5 km and a composition of loose rocks held together by ices, 67P/Churyumov-Gerasimenko doesn’t have enough mass to bend space-time much. It has, in short, almost no gravity. Orbiting it, as Rosetta has been doing since 6 August, is more like a lazy drift around it. To land is more akin to docking than anything else. There’s not a lot to hold Philae ‘down’, and it doesn’t take much to bounce off. To that we have to add the dumb-bell shape of the comet’s nucleus, which produces complex (if gentle) space-time curvatures, meaning a ‘bounce’ on the comet isn’t going to be a simple parabola like a ‘bounce’ on Earth.

All of which underscores the tremendous technical achievement of the landing – bounces and all. The final lesson? Don’t bother with celebrity butt. Einstein and comets are FAR more interesting.

Copyright © Matthew Wright 2014

Is Comet Siding Spring going to turn our Mars probes into shredded tinfoil?

Shiver in your shoes, Martians! This month – specifically, 19 October at 18:28 Zulu – Comet C/2013 A1 ‘Siding Spring’ makes its closest approach to Mars. The nucleus, a few kilometres in diameter, will come a smidgeon under 120,000km from the red planet.

Mars from the Siding Spring nucleus at closest approach - a picture I made with my trusty Celestia astronomy package.

Mars from the Siding Spring nucleus at closest approach – a picture I made with my trusty Celestia astronomy package.

That’s close. Though not as close as once feared. When the comet was first discovered by Robert H. McNaught in January 2013, using the 20-inch Upssala Schmit telescope at Siding Spring observatory in New South Wales, it was thought likely to hit Mars. It was only later, after multiple observations and cross-checks, that the orbit was refined.

Good news is that this is a tremendous opportunity – and there’s a fleet of orbiting satellites up there for the purpose.  Two, the US MAVEN and India’s Mars Orbit Mission (MOM) – arrived just last week. That puts a lot of instruments in close proximity, and the Indians have plans to use MOM to check for methane on the comet as it brushes past. The Mars Reconnaissance Orbiter will use its HIRISE camera to look at the comet nucleus and activity. Mars Odyssey will check out the coma. MAVEN will make a range of observations with eight different instruments. Even the rovers on the ground, Curiosity and Opportunity, will point their cameras at the sky – Curiosity’s ChemCam, which can pick up the composition; and Opportunity’s PanCam, which will give us a visual from the surface of Mars.

More shenanigans from my Celestia software. This is a view looking from inside the coma towards Mars and the Sun at closest approach.

More shenanigans from my Celestia software. This is a view looking from inside the coma towards Mars and the Sun at closest approach.

Bad news is that this fleet of satellites took years to get up there, cost billions of dollars – and are basically irreplaceable. The nucleus won’t get near Mars. But the coma of dust and debris surrounding it will. Estimates are that during the several hours it takes Mars to pass through the comet’s coma, the planet will be peppered with about five years’ worth of normal meteor activity. It’s all small stuff – nothing more than 1cm diameter, most of them only fractions of a millimetre. But the relative speed is 56 km/sec (200,000 km/h). That’s – uh – impressive. At that speed a 1 gram mass has a kinetic energy of 15,680,000 joules, or 4.35 kwH. In human terms? Enough to run a domestic fan heater on high for a couple of hours. Woah! And that’s just one particle. There are going to be a LOT of particles skidding past Mars.

More Celestia fun; a picture I made of planetary orbits at the moment of Siding Spring's Mars encounter.

More Celestia fun; a picture I made of planetary orbits at the moment of Siding Spring’s Mars encounter.

Precautions have included adjusting orbits so the probes will be on the opposite side of the planet from the comet 100 minutes after closest encounter, when the dust is estimated to reach its highest density. The MRO shifted its orbital parameters to that end on 2 July, while Odyssey did so on 5 August and MAVEN on 9 October. Still, that’s not a complete fix – they’ll travel back around into the danger zone soon enough. Other precautions include pointing the spacecraft so more delicate components are shielded by less crucial elements. And MAVEN will be put into a partial shut-down mode. Once the danger’s past, they’ll restart the science.

By 22 October, according to mission timelines, it’ll all be over. And, if the cometary debris hasn’t shredded them into tinfoil, they’ll be back to their normal work exploring the red planet.

Is Earth in any danger? None whatsoever. Even if we were at closest approach to Mars, the comet wouldn’t affect us – but as it happens, we’re nearly a quarter-turn away from Mars in any case, just at the moment. That’s not the issue – the issue is the several billion dollars worth of science equipment we’ve got around Mars at the moment, its survival – and the science we’ll get from them during this once-in-a-lifetime opportunity.

Copyright © Matthew Wright 2014

Apocalypse now: why we must fear a Carrington storm

On 28 August 1859, British astronomer Richard Carrington noticed something unusual on the Sun. A flare, larger than anything he’d seen before.

Solar flare of 16 April 2012, captured by NASA's Solar Dynamics Observatory. Image is red because it wa captured at 304 Angstroms. (NASA/SDO, public domain).

Solar flare of 16 April 2012, captured by NASA’s Solar Dynamics Observatory. Image is red because it was captured at 304 angstroms. (NASA/SDO, public domain).

Three days later, Earth lit up. Aurorae erupted as far south as the Carribean. All hell broke loose in telegraph systems across the world. Lines began spraying sparks. Operators were electrocuted. Other telegraphs worked without being switched on.

Later, we figured it out. The sun ordinarily blasts Earth with a barrage of fast-moving protons and electrons; the solar wind. Most is deflected by the Earth’s magnetic field – particles are trapped by the field, forming the Van Allen radiation belts.

Flares add to this in two ways. The first is through intense electromagnetic radiation – a mix of X-ray frequencies produced by Bremmstrahlung, coupled with enhanced broad-spectrum radiation as a result of synchotron effects – both of them slightly abstruse results of relativistic physics. This strikes Earth, on average, 499 seconds after a major flare erupts in our direction. We’re safe on the surface from the effects; the Earth’s magnetic field and atmosphere stops even radiation on a Carrington scale. In 1859, nobody noticed. But today, astronauts on the ISS wouldn’t be safe. Nor would our satellites.  So aside from the human tragedy unfolding in orbit, we’d lose everything associated with satellites – GPS to transaction systems to weather to Google Earth updates and everything else. Gone.

Buzz Aldrin on the Moon in July 1969 with the Solar Wind Experiment - a device to measure the wind from the sun. Public domain, NASA.

Buzz Aldrin on the Moon in July 1969 with the Solar Wind Experiment. (NASA/public domain).

It gets worse. Some flares also emit a mass of charged particles, known as a CME (Coronal Mass Ejection). Seen from the Sun, Earth is a tiny target in the sky. But sometimes we are in the way, as in 1859. The problem is that a CME  hitting Earth’s magnetic field compresses it. Then the CME passes, whereupon the Earth’s magnetic field bounces back.

The bad juju is the oscillation, which causes inductiion on a huge scale. Induction is a principle of electromagnetics, discovered by Michael Faraday in September 1845 when he moved a conductor through a magnetic field, generating electricity down the conductor as long as it moved. It also works vice-versa – a moving magnetic field induces electricity in a stationary conductor. And electricity can be used to create magnetism. We’ve been able to exploit the effect in all sorts of ways. It’s how electric motors and loudspeakers work, for instance. Also radio, TV, bluetooth, ‘wireless’ internet broadband. Actually, pretty much everything. When inducing an electric current with magnetism, the strength of current is a function of (a) the size of the conductor, and (b) the flux of the magnetic field. Maxwell’s equations apply. The longer the cable, the more current generated in it. That’s how aerials work – like the one in your cellphone, ‘wireless’ router, laptop – and so the list goes on.

Now scale it up. Earth’s magnetic field moves, generating electrical current in all conductive material. Zzzzzzt! That’s why so much current was generated down telegraph lines back in 1859 – they were immense aerials.

Geothermal steam from the Taupo system is used to generate power - up to 13 percent of the North Island's needs, in fact. The techniques were developed right here in New Zealand.

Geothermal power station at Wairakei, New Zealand. This generates up to 13 percent of the North Island’s needs. Note the power lines – vulnerable to induced voltage in a Carrington event.

Fast forward to today. Heavy duty devices like a toaster or kettle don’t contain enough conductive material to induce voltage that will fry them during a CME event, and that’s true of most appliances – though your phone or computer might be damaged, because microprocessor chips and hard drives are vulnerable to very small fluctuations. Personally, if I knew a Carrington storm was coming, I’d unplug my computer at the CPU (the power cable acts as an aerial). But none of it will work afterwards anyway. Why? No mains power. That’s the problem – the power grid. Those 220,000 volt lines. They’re plenty big enough to suffer colossal induced voltages, as are the cable windings inside the transformers that handle them. Power grids around the world go boom.

Yes, we can rebuild the system. Eventually. Estimates suggest a minimum of five months in the UK, for instance, to get enough transformers back on line. Always assuming they were available, which they might not be if every other country in the world also wanted whatever was in stock. In any case, the crisis starts within hours. Modern cities rely on electrically pumped water. Feeling thirsty? Maybe you’re lucky enough to live near a river. You struggle through crowds dipping water. Struggle home with a pan of muddy liquid. No power – how do you boil it? You have a barbecue. What happens when the gas runs out?

Now think about everything that relies on electrically pumped water. Nuclear power stations.  Their diesel generators are not designed to run for weeks or months. Think Fukushima. Over and over. I am SO GLAD I live in nuclear-free New Zealand.

This isn’t speculation. A CME-driven grid burn-out already happened to Quebec in 1989. Luckily the solar storm wasn’t colossal. Studies suggest that 1859 storms occur every 500 years or so, but we’re learning about the Sun all the time, and that may change. We had near-misses from dangerous CME’s in 2012 and earlier this year. We’re vulnerable.

A CME might not take down the whole planet. All depends on its size. But it could still do colossal damage. A study in 2013 put the potential cost of another Carrington storm at $US2,600,000,000,000. If you stacked 2.6 trillion US $1 notes, one on top of another, the pile would be 291,200 km tall, which is a shade over 75 percent the average distance of the Moon. That’s without considering the human cost. But there are ways to ameliorate the issue. Including shutting down the grid and disconnecting things if we get warning. If. The take home lesson? Remember the Carrington storm. Fear it.

If you want to read about how we might cope after a big CME, check out the novels by New Zealand author Bev Robitai. Sunstrike and Sunstrike: The Journey Home.

 

Copyright © Matthew Wright 2014

 

Finding another Earth isn’t easy. Unfortunately.

Are you looking for a second Earth? We need to – humanity is on the fast track to ruining our one.

Simulated Exo-Earth. A picture I made. Apart from the fractal artefacts, does anybody notice what's wrong with it?

Simulated Exo-Earth. A picture I made. Apart from the fractal artefacts, does anybody notice the science issue that I didn’t correct?

Of course it’s not an easy task. A planet discovered the other week with the help of Kiwi astronomers underlines the problems. Four astronomers here in New Zealand contributed data to the OGLE microlensing follow-up network program in 2012. The results were published recently – and the good news is, OGLE found a planet.

OGLE, incidentally, stands for ‘Optical Gravitational Lensing Experiment’. An apt acronym. It works by exploiting a quirk of Einstein’s theory of relativity – that mass distorts space-time. Massive stars bend light around themselves, acting as ‘lenses’ and enabling us to point a telescope at the massive star, and so detect faint objects passing directly between us and them, that we wouldn’t otherwise be able to observe. The gravity lens around the distant star is known as an ‘Einstein Ring’, and the method is usually used to pick up planets orbiting in the ‘halo’ of a star – the debris orbiting it, like our Oort Cloud. These are known as Massive Compact Halo Objects (MACHOS). Cool or what?

Anyhow, back to the news. The planet is called OGLE-2013-BLG-0341LBb, and it’s about 3000 light years away in the constellation Cassiopeia.

The good news?

- It orbits its sun at 0.8 AU – nearly the distance of Earth (yay!)

- It’s about Earth sized – mass is thought to be only twice ours (yay!)

- That doesn’t imply twice our surface gravity (yay!) [I can’t calculate it unless I know the radius and density of the planet, which I don’t, but if density is the same as Earth, average 5.5 g cm <exp>3, then the surface gravity won’t be double because surface gravity is also proportional to the radius. Just saying.]

- It’s orbiting just one star in a binary pair (Tattooine, sort of – yay!)

Let me illustrate mass vs surface gravity. Although it has a mass 14.5 times that of Earth, 'surface gravity' on Uranus is just  89 percent that of Earth. That's because the radius is about 4 times Earth's. I made this picture with Celestia.

Let me use Uranus to illustrate mass vs surface gravity. Although it has a mass 14.5 times that of Earth, ‘surface gravity’ on Uranus is just 89 percent that of Earth. That’s because the radius is about 4 times Earth’s. I made this picture with Celestia.

So is this Earth 2? Well, if I were you I’d take warm clothes. The bad news is that the star is a red dwarf, 400 times less energetic than the Sun, so the planet has a surface temperature of 60 degrees Kelvin – in centigrade, a chilly -210 degrees. (Booooo!)

The search for Earth-like planets has got exciting lately as we’ve developed the tech to discover them. Problem is, the gear is not good enough to image them directly. We can’t learn much other than the size and orbital distance – from which we can derive its year, mass and temperature. If we’re lucky, we might also get a handle on its atmospheric makeup, via spectrography as it transits its sun.

For these reasons, usually when we detect a planet that’s otherwise in the ‘goldilocks’ zone, we don’t know whether it’s actually like Earth. It might be like Venus – runaway greenhouse with sulphuric acid, crushing atmosphere and oven-like temperatures. We don’t know. Don’t forget, if astronomers 3000 light years away were using the same techniques to analyse our solar system, they might conclude there were two Earths here from the planetary mass and orbital data.

The way things are going, of course, we’re likely to end up with two Venuses. Venuses? Venii? You know what I mean.

And it’s a worry.

Copyright © Matthew Wright 2014

Flying saucers and other aerial crockery

A UFO was caught over the South Island the other week by an Australian film crew. By “UFO” I mean “unidentified object” which was “flying”. We don’t know what it was – and the objects could have been an artefact of the video.

Jupiter rising over Io - a picture I made with my Celestia installation

Jupiter rising over Io – a picture I made with my Celestia installation

Needless to say, I am certain they weren’t alien spacecraft, any more than any other UFO is.

I can hear the howling. ‘But the universe is big, surely other planets must have life?’

Sure. Space is enormous.  No doubt life’s emerged elsewhere. But – again – it doesn’t follow that the aliens have developed civilisation, jumped into spacecraft, and flown here. It particularly doesn’t follow that they’ve done so merely to lurk mysteriously on the edge of our vision, violating cows, revealing themselves to lone witnesses on dark country roads, and so on. Or that they’d be big-headed, big-eyed, child-bodied versions of us with an ethical view that fixes the faults of western society.

The fact that lay-people presented with partial evidence can’t explain an observed phenomenon doesn’t prove it’s an alien spaceship. The fact that science can’t explain it from partial data doesn’t, either. That’s false-premise logic.

I’ve seen plenty of weird aerial stuff myself. The best was over Wellington in April 1986, when I spotted a slow-moving fireball parallel to the southern horizon, shedding sparks. I knew what it was. The thing was moving in the direction I’d expect from the usual orbital paths, the only ‘unidentified’ part was whether it was US or Soviet.

Spacewalk to assemble the ISS, 12 December 2006. New Zealand is below - North Island to the right, South to the left. My house is directly under the aerial centre-frame. Photo: NASA, public domain, via Wikipedia.

Spacewalk to assemble the ISS, 12 December 2006. NASA, public domain, via Wikipedia.

To me the phenomenon of ‘space aliens’ is a product of the way western culture is conditioned to think. The trigger was the mid-twentieth century assumption that Earth was archetypal and that every world capable of supporting life would bear one intelligent species, probably a bipedal hominid. In due course, this would become civilised, space-faring and visit other worlds. Just like Europe’s explorers during the age of exploration.

It is no coincidence that we decided aliens were visiting just as we began to take spaceflight credibly. The idea emerged in June 1947 when US pilot Kenneth Arnold reported nine boomerang-shaped objects paralleling his aircraft near Mount Rainier. A journalist misquoted that as ‘saucers’, which promptly became the shape of the interlopers thereafter. The origin of that shape as a journalists’ misquote was rather lost amid the flood of blurred photographs of aerial lampshades that fringe enthusiasts were subsequently able to provide as proof of their own encounters.

Blue sunset on Mars - for the same reason skies are blue on Earth. An approximately true colour image by the Spirit rover at Gusev Crater, 2005. Photo: NASA/JPL, public domain.

Blue sunset on Mars – for the same reason skies are blue on Earth. NASA/JPL, public domain.

These 1950s-era aliens came from Mars or Venus and looked like us, only with handy super-powers such as telepathy. Alas, the Mariner and Venera probes of the 1960s revealed Venus was a runaway greenhouse oven – and Mars was a cold, cratered world without breathable air. Luckily it turned out, after that discovery, that the aliens really came from well-known stars on the school science curriculum, like Aldebaran. Then in 1978 Stephen Spielberg’s Close Encounters of the Third Kind hit the cinema, and the current alien trope followed.

You get the picture.

My take? We have had civilisation for an eye-blink against the age of the Earth. It may only last another eye-blink, by that scale. Who says aliens have the same capability at the same time? They might have flourished and gone a billion years ago. Or their time might be a billion years in the future.

Space is also immense. Who says they’d find us anyway? Or that we could be important? To give that a sense of proportion, our sun’s invisible, without telescopes, from just under 60 light years.* I’ve heard it argued that ‘they’ could hear our transmissions – TV, radio, radar and so on. Actually, we’re just as invisible that way too. In theory I Love Lucy – which began transmission in 1951 – has just reached the planet we photographed, orbiting Beta Pictoris, 63 light years away. Actually our broadcasts, even high-frequency radars, don’t get that far because of the inverse square law, coupled with natural background radio noise. Our stuff’s lost in the static. Yet our galaxy is 100,000 light years across. Feel small? You should. And if aliens did arrive, would we recognise them as life? Or be able to communicate? They’re alien, remember. Maybe they’d be too busy talking to their own kind – you know, other algae.

Put another way – sure, we see stuff in the sky we can’t explain. But that doesn’t mean it isn’t explicable. Or that ‘aliens’ are among us.

Thoughts?

Copyright © Matthew Wright 2014

 

* Geek time. Muahahahaha. Stellar brightness is measured by magnitude, an inverse scale in which lower is brighter. The true magnitude of a star is its absolute magnitude. But this fades with distance (inverse square law), so its visual magnitude, the brightness we see from a distance, is less. This is known as the apparent magnitude. Any star of apparent magnitude greater than about 6 is invisible to the average naked eye. The distance where the apparent magnitude (m) fades to invisibility can be calculated from the absolute magnitude (M) using the distance modulus equation r = 10<exp>((m-M)/5+1) where r is the distance in parsecs. If you apply that to the Sun, absolute magnitude 4.83, you discover it fades to apparent magnitude 6 at about 57 light years, which is about 0.057 percent the diameter of the galaxy.

 

 

My hypothesis that English is a loose language

I’ve always thought English is a loose language. Take the words ‘theory’ and ‘hypothesis’, for instance. Even dictionary definitions sometimes mix their meanings up.

Albert Einstein lecturing in 1921 - after he'd published both the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

Albert Einstein lecturing in 1921 – after he’d published the Special and General Theories of Relativity. Public domain, via Wikimedia Commons.

Scientifically, the word ‘theory’ means a ‘hypothesis’ that has been established to be true by empirical data. Take Einstein’s two theories of relativity, Special (1906) and General (1917). We call them ‘theories’, by name, but everybody with a GPS-equipped cellphone or GPS system encounters proof that Einstein was right, every time they use it.

This is because GPS satellite clocks have a correction built into them to cope with Special Relativity time dilation that occurs because they’re moving at a different velocity than the surface of the Earth. It’s miniscule –  6 millionths of a second loss every 24 hours. There’s also the need to cope with General Relativity time acceleration relative to the surface of the earth, because they’re in orbit, putting them further away from the mathematical centre of Earth’s mass than we are on the surface of the planet. That totals 45 millionths of a second gain every 24 hours.

If all this sounds supremely geeky and too tiny to worry about, millionths of a second count,  because its on differences at that order of magnitude that GPS calculates positions. If the net relativity error of 39 millionths of a second every 24 hours wasn’t corrected, GPS would kick up positional errors of up to 12 km on the ground. Einstein, in short, was totally right and if we didn’t use Einstein’s equations to correct GPS, we’d be lost. Literally. Yet we still call his discovery a ‘theory’.

Hypothesis,on the other hand, is the idea someone comes up with to explain something. Then they run tests to figure out the rules. Take gravity. Everybody knew it existed. However, Newton figured he could come up with rules – his hypothesis. Once Newton had a hypothesis, he was able to run experiments and sort out actually how it worked – creating his theory of gravity.

Neptune. A picture I made with my trusty Celestia installation (cool, free science software).

Neptune. Discovered by mathematics, thanks to Newton’s theories. A picture I made with Celestia (cool, free science software).

One of the reasons why these explanations are called ‘theory’ is because science sometimes finds refinements. Einstein’s theory of General Relativity is also a theory of gravity, integrating the extremes of time and space Einstein described in his Special theory. It replaced Newton’s theory. But that didn’t mean Newton was wrong in the terms he observed and described. On the contrary, his equations still work perfectly for the things around which he developed the theory.

So in the strictest sense, ‘hypothesis’ means ‘how we think things work’, while ‘theory’ means ‘how we’ve shown things to work’. Science sometimes creates supersets of theories, like onion skins, that explain things differently – but usually don’t invalidate the core of the earlier theory.

And my hypothesis, which I think should be elevated to theory status on this evidence, is that English is a pretty loose language. Thoughts?

Copyright © Matthew Wright 2014

 

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