Clearly a title designed to grab viewers. I confess a dislike to this kind of wording because it implies that we might all be wasting our time, and that we’ll one day have to throw away all our textbooks. The homeopaths out there say “ha!” and start prescribing leeches again. But this is a mistake. When Einstein corrected Newton on gravity, it did not overturn 300 years of teaching. If our model of the universe, known as the Standard Model, can be improved by a newer model, all physicists would welcome it. And since we know the Standard Model doesn’t cover everything, we hope this will happen. The program showed scientists discussing “unwelcome” wrinkles in new evidence, which doesn’t fit the model. These are never “unwelcome” – scientists love to see well-derived new evidence, because it invariably leads us to new models and new ideas. A well-known physicist once told me over a beer that the most boring thing that could come out of the LHC is the Higgs Boson. What they really want, is a whole new world of unexplained phenomena.

My main gripe with the show, but really with the presentation of cosmology in general, is in the repeated assertion and explanation of the Big Bang as an explosion. The BBC used two common effects repeatedly. The fireball explosion (82 times) and the inflating balloon (86 times).

Let me state this clearly. The Big Bang was not an explosion, or at least, not as we see one: from a single point, expanding spherically outwards into empty space. This model is both inaccurate and misleading. We know that this is not true due to measurements of cosmic drift, the Hubble Effect. Everything is moving away from everything else. This is explained in my textbook with a balloon! The idea is that points drawn on the surface of a balloon get further from each other as the balloon expands. I contend that this is a misleading explanation because your average student will not be able to get his mind away from the fact that this is a balloon, inflated from a central point – and will therefore miss any explanation of the surface detail.

My preferred explanation of cosmic expansion is to use the grid of shifting measurement detailed in a previous musing. I shall expound further on this notion here, and describe how I imagine the expansion of the universe, in my mind. If you haven’t read that post before, please do so, to clarify any doubts you may have of an infinite universe that is able to expand without a central point.

I shall start in the present. At the current time, the Universe contains an even distribution of galaxies, which can be broadly seen to be without start nor end nor centre.

Some time ago, we believe matter in the universe to have been closer together. In your mind, for this mental experiment, I would like you to imagine that instead of matter being closer together, I would like you to imagine that matter was larger. For the sake of argument, twice as large. And I mean, on every level, from the computer your read this on, down to the atomic level and below.

Between that time and now, let’s say matter has simply collapsed together, become more compact, with more space around it. There is no need for a driving “dark energy” to inhabit the darkest regions between the galaxies; it is the galaxies themselves that draw together. This effect is greatly outweighed by gravity, so the stars and galaxies we see can still stay together.

I’d like you to imagine back further, to the time immediately after the Big Bang. Picture for me the Universe to the scale we see it today, but that protons and neutrons are enormous – the size of planets. Electrons are like footballs bouncing around the gaps. And there are loads of them – no vast gaps of space that we see between planets. There is the same number of atoms in the universe then and now. So everything is so close together, what with being so large, that collisions are commonplace, and that everything gets very hot.

Again, fast-forward to today. Everything has shrunk together, remaining attached by the forces we’re familiar with, the electromagnetic holding atoms together and gravitational holding gas clouds together. As spaces grew between particles, the particles were pulled one way or another, clumping to form stars, planets, galaxies, black holes.

How would we see this today? As a gradual separation of galaxies, the Hubble Effect, which might appear to accelerate slightly, as the groups of matter become more dense. We’d see strange effects near the edges of galaxies, where the collapse at the core was filtering out to the edges. You might see flat rotation curves.

And how could we back up a concept of collapse rather than expansion? What could explain this? I’d like to turn to every cosmologist’s adversary, quantum theory. With the scales of particles so large in the early universe, it’s easy to see that the probability waves of quantum theory could play a major role. Even today, we don’t know at what scale the quantum systems break down. We’re as close to knowing whether Schrödinger’s cat could be a real quantum system as when it was first proposed. Perhaps systems could be larger in the early universe. Perhaps it is not that the particles were larger, but that their wave function was larger.

Mass can be considered a concentrated point of energy. The conversion of tiny quantities of mass into energy is what fuels nuclear reactors and atomic bombs. And we know mass distorts spacetime, an effect we see as gravity. Could this distortion be fuelling cosmic collapse?

But regardless of any scientific justification, I find the mental model of matter collapse far more appealing than cosmic expansion. There are no balloons or explosions (regrets to the BBC effects/repeats dept), with their implicit ideas of central expansion, so it’s a lot easier to understand.

Does it make sense to you too?

One day, his watch breaks and starts running fast. It takes twice as long, according to the watch. Completing the same distance took twenty minutes. He buys a new watch.

The following week, some wanker at the council moves his tube station 400 yards further away. According to his new watch, the journey again takes twice as long as usual: twenty minutes. The man blames cheap foreign imports, and buys a new watch.

I have a grid in three dimensions. It’s held together with wires, will balls at the joints. Each wire is 10cm long.

The next day, I measure my grid with a ruler. Each wire is now 20cms long. But none of the balls look any further apart. I buy a new ruler.

I throw away my grid and buy a new one. It’s bigger.

A lot bigger.

My grid has balls one light-year apart. Each ball is held in a rigid cubic system as before. My grid extends to infinity in all six directions: up, down, to the left, to the right, in front, and behind. Infinitely.

I know what you’re thinking: “You must have huge balls”. But I don’t like to brag.

I measure the distance along the wires between the balls, not with a ruler, but with light and a stopwatch. A ball sends out light, and I time exactly one year before the light reaches the next ball. That’s one light-year.

All over the grid, it always takes one year for light to reach the next ball.

The next day, a fine summer’s day in 1665, Newton invents gravity. This does not go unnoticed.

Each one of my balls has a large mass, and so a strong gravitational pull. Each ball attracts every other ball around it, not just the nearest, but all of them. It’s quite a shock to my grid, but my grid still hangs together. I rush out and measure my wires again. To my relief, each wire, measured by pulses of light, is exactly one light-year long.

All is well and good, and my grid holds steady. Of course, it does not collapse in on itself, because it extends infinitely in every direction. As each ball pulls those around it, they are equally pulled away by those more distant. Each ball has an equal pull on its left and its right.

For 250-odd years, my grid hangs together, perfectly happily. Occasionally I step outside to admire my balls (steady), by the light of the moon.

In 1915, some bloke called Einstein completes his General Theory of Relativity. In it, he invents several fundamental principles. Mass-energy equivalence, for example, as shown by the famous equation e=mc^2. Woo.
Something else he does is change gravitational theory. Newton is now proved wrong, for gravity is not a force, it is a distortion of space and time caused by masses.

I have to admit, this funny-looking bloke has me scared. I rush out to check on my beautiful, infinite, gleaming grid and see whether it has been affected. And I find some disturbing results.

Near each of my massive balls (by which I mean, my balls with mass), there are some weird effects happening. Close to the surface of each mass, I find that time is running more slowly.

I dig out my trusty stopwatch and wait for the light. A ball emits light, and the light travels more slowly than usual near the ball. Further from the ball it picks up speed as it moves along the wire away from the ball, but then slows again as it gets near the other ball. In total, my stopwatch shows that two years have passed.

Shit. The bastard’s only gone and ruined my grid. I go back inside to sit down and have a calming cup of tea.

Edwin Hubble catches my attention in 1929. He’s spent ten years looking closely at my grid, and he’s found something more peculiar still. He watches as many balls as he can, from the one ball he’s sat on. He’s been looking at the light beams all over my grid and he’s worked out that my grid is expanding.

I’m incredulous. “Where would it expand to?” I ask, “It’s infinite, FFS.” But the arrogant fool is insistent. Look at the evidence, he says.

The distances, as measured by light, between each ball, are getting further apart. Ipso facto, the grid is getting bigger. I have a quick check, and he’s right. A beam of light now takes 3 years to get from one ball to another.

But if I’m honest, those balls look a bit smaller. They’ve taken some of the mass that was hanging between the balls, and they’ve pulled it in. They’ve squeezed themslves together. Effectively, they’ve become bigger and denser masses, I wasn’t expecting that. With tighter, more compact masses, the light travel time is more affected by the gravity, and so it takes longer to get between the balls.

But my grid is still the same size. Or is it?

Did my watch break, or did someone move the tube station?

Odd, eh?

Reason being, Einstein’s Equivalence Principle – which forms part of his General Theory of Relativity.  This states that an accelerating frame of reference is indistinguishable from a frame under the influence of gravity.

What does that mean?  It means that the force holding you in your seat right now would feel exactly the same as you’d feel if you were sitting in a rocket in space, but accelerating at 1g.

Pretty obvious, pretty boring so far.  However, we also know that Moving Clocks Run Slowly.  If you’re moving through space, you move through less time than someone outside of your frame of reference.

And that gets interesting.  One of the consequences is that a photon (a “ray” of light) does not pass through time at all.  It moves so fast that it never ages.

If you wave your arm, then your hand is fractionally younger than your elbow.  And yet they’re still attached.

Equally astonishing is that a clock on a high tower will run faster than a clock at the bottom of a tower.  I would have thought this is because it is simply moving faster (since it’s on a further radius from the earth).  But actually, it’s because the bottom of the clock is under the influence of gravity, and due to the Equivalence Principle, that clock is accelerating.

Ok, so this is exciting.  Because that means us earth-dwellers are moving through time faster than those in space. (Spacemen actually age less quickly, but this is because they orbit at 17,000mph). (If our clocks are running slowly, then we’re passing through time faster – think about it over a beer).

So if gravity is cumulative enough to hold the galaxy together, then what on earth is the time curve like for the disc?  The galaxy must spin in a very funny way, if the centre of the galaxy is passing through time at a faster rate than the outside.  Actually, galactic discs really do have very odd spin ratios, attributed to dark matter.  How fast is time passing out in Extra-Galactic Space?  Does it pass at all?

Or, let’s face it, at the time of the Big Bang?  Everything was much closer together back then, gravity must’ve been a massive force, and though other short-range forces would dominate, they wouldn’t have gravity’s influence over time.  Perhaps that question isn’t relevant, because everything was uniformly dense.  But you can imagine this might drive “inflation”, where the early universe did some things in strange amounts of time.

Now, back to the Black Holes.

A Black Hole is sufficiently dense that nothing (except imaginary particles like gravitons) can escape.  Not even light.  Something that dense does really weird things to time.

According to my physics books here, if you fell into a black hole, you wouldn’t notice anything particular peculiar.  Except for the whole crushing-to-death thing.

To me watching, it would take an infinite amount of time for you to fall in.

So actually, you would watch the Universe end around you, probably in a very Douglas Adams style.

Now that’s a funny concept.

And here’s the question:  assuming this is so, how did Black Holes ever grow?  Presumably all the holes we can see are primordial, because it would have taken longer than our mere 13.7 billion years to see anything fall in?

Physics: gotta love it.

Yet this only works with the data from Gravitational Lensing if we model the mass of the galaxy in line with the observed light of the galaxy. This sounds ok, but is in direct conflict with dark matter theories – where we believe 90% of a galaxy’s mass must lie outside the visible disc, in a large near-spherical halo. If they take dark matter into account, the GL figures are all ~10% too low – and there’s too much agreement between other methods (WMAP, Chandra, HST Key Project) to allow that.

So really, GL is offering information on dark matter rather than on the Hubble Constant, which is quite a surprise. Hopefully the report has made that clear.

I’ve had a week off work to finish up, and it’s been a long time since I’ve been able to work on the project, so it’s been a busy week! I’ve had to catch up on stuff I already knew, and I know the report isn’t as polished as I would have liked. But it should hit all the targets.

Review of feedback from TMA03:

Abstract – good, but I need to explain more to non-astronomy people.  This should be fine, but of course it’s hard to do that when all you’re reading is hardcore science papers

Contents – good.

Introduction – good, but omitted discussion of the objectives of the paper.

Literature review – good.  “In the final ECA report be sure to keep the ‘critical’ aspects of your analysis (‘critical’ in the sense of comparing/contrasting different results and theories, discussing any contested ideas or controversial issues, evaluating different perspectives/proposals etc.) to the fore.”

All in all, a good result from TMA03.  I need to do more research to find more contentious issues, so I can focus the review section a bit more.  That should be easy to do – previously I was ignoring these to try to get a better picture of the established consensus.

Obviously, I’m focused on the gravitational lensing aspects of this, so this is where more research comes in.

I did a big reorganisation of the report this morning, and I’m much happier that it matches what’s required.  The previous feedback has really only focussed on RTQ comments, and that’s been useful this time.

I’ve put a lot more work in than last year, and that shows  

I have 800 words done there.  1200 (ish) more to do.  I can fill this up with info on non-param mass models, no problem.  Mr Saha has reams on the stuff.  And Mr Kochanek disagrees with him.  Awesome

So far, so good.  Just wish I had another month, and more sunshine…

Hours today: 12

Just confirming with the tutor about the review – I think this is the full report, I guess excluding the Intro.

Hours: 5

So, I can do a ‘trial’ abstract, I can draw together enough for an introduction, and I’ve got a content plan sketched out for the contents list.  I’m ready to write.  Two thousand words is a lot to get done in a short time, and I may not meet that much by the deadline, but I should be most of the way there.

Busy week, it will be, to get it done by then

This weekend, I need to review the papers, information and ideas I’ve collected, and put together at least 80% of TMA03. Last year, this wasn’t as bad as it first looked:  once I had the structure sorted and material together, everything just flowed from there.

Hours so far: 2 (and it’s only noon )