Friday 26 July 2013

Going for broke



How are your finances doing? Great? OK, then you need not read any further. Unless you happen to be worried about the future...
Do you have problems balancing the books? Failing investments? Can’t figure out how to pay for that sofa/midlife crisis sportscar/house or how to support yourself in your old age? You may as well stop reading as well, because there won’t be any solutions offered here.  Unless you think that someone else doing badly will make you feel better…
The news this week provided a reminder that things don’t always work out as you might wish.  Optimism can turn into despair surprisingly quickly.
Go back to the 1950s - a time of excitement about the future (and perhaps just a little bit of worry that the world might come to a rapid end in a nuclear apocalypse, but let’s forget about that for now). This was an era of blossoming industry and the growth of the middle class as a force in society. A time of optimism.
In Detroit – the Motor City – cars were made to represent to spirit of the time. Fabulous cars! Exciting cars! Production lines churned out cars to provide the wheels for a nation.
Move into the 1960s. The birth of pop music and a relaxed way of life. The future was looking great. Fabulous science fiction was written, telling us how glorious everything would soon be. We would have robot helpers. Man would colonize the Galaxy. Towards the end of the decade Neil Armstrong took his famous small step. Man had landed on the moon and would never look back.
In Detroit, cars were made. Big cars. Cool cars.
Skip forwards a couple of decades.
Detroit is a derelict city. Just declared bankrupt. The mere idea seemed ridiculous not long ago, but apparently it can happen. The city of the future turned into the first real post-apocalyptic landscape in just a couple of decades. Factories are left derelict. Houses are left standing just as families left them, with cutlery in the drawers and books still on the shelves. An entire city walked out and didn’t come back.
Cars are made elsewhere…
We have not been back to the moon for many decades. The other planets seem incredibly distant, and let’s not think about the Galaxy. Science fiction has become much darker (please don’t mention vampires!). The vision of the future seems much less optimistic.
What happens next?
Will Detroit rise like a phoenix from the ashes?
That would be nice, but… the ghost towns left from the gold rush suggest it may not work out that way.
Who knows what will happen? If we allow greed to remain the main driver of society (let’s just look at how the banks are behaving, shall we?) then there does not seem to be much hope. 
We need to inject a bit of sanity in society, a bit of restraint.
We need to allow ourselves to dream the dreams of the future from the past (get it?).
I for one really want my robot helper, and I want it soon.



Tuesday 16 July 2013

Nothing stays the same


Travelling back from Poland this last weekend, I was given time to think. Quite a lot of time, in fact. The plane was cancelled so I had to stand in line – most patiently, with no food and/or drink – for around 6 hours while the airline staff tried to figure out the options. I managed to get home in the end, which I guess represents some level of success. I also learned that you can make a transfer through Vienna airport in less than 30 minutes, even without a boarding card. Well impressed with that! Might have been a new world record.
Anyway.
After a couple of hours of standing in line, I started experiencing the effects of gravity. At first my feet felt a bit sore. A bit later the calf muscles were aching. Later still, I was acutely aware that I had feet… and that they did not agree with the shoes anymore.
The experience made me think of a talk I went to a couple of years ago on the topic of the constants of nature.  These would be things like the speed of light, the gravitational constant, the charge of the electron and so on. They pop up all over physics and relate to how strong various effects are. Now, the question is; what if these aren’t actually constant at all, but change as the Universe evolves? Who says that the speed of light has remained the same since the Big Bang? Why could the strength of gravity not vary as time passes?
Uh?
Actually, my experience in that airport would be fully consistent with gravity getting stronger the longer you stand in a queue.
But maybe this would be expecting things to change a bit fast…
I’m also not thinking about the fact that walking up stairs gets harder as you get older. That’s not a change in gravity, just the perception of it.
I am thinking about a gradual shift and how this would affect the world around us.
If the constants of nature change, then the Universe could end up rather different provided you wait long enough. This is fun to think about. For example, change the relation between the gravitational constant and the speed of light and you can suddenly make smaller or larger black holes with a given weight. Fiddle with Boltzmann’s constant (which enters in thermodynamics) and you can adjust how hot the black hole is, as well. Finally, jiggle Planck’s constant and you can make quantum physics relevant at a completely different scale. 
You can come up with the weirdest things this way.
And thinking about it may keep you entertained.
Which is a good thing.
Especially if you have to stand around waiting for 6 hours…

Saturday 6 July 2013

Equally true today?


Just over half a century ago a gravity meeting was held in Warsaw. The leaders of the field gathered to discuss the key issues of the area. Among the experts was Richard Feynman, the maverick genius that fathered a fair part of modern physics. He was not at all impressed by the meeting. As he described his impressions in an often quoted letter to his wife (taken from the entertaining autobiography Surely you are joking Mr Feynman?);

I am not getting anything out of the meeting. I am learning nothing. Because there are no experiments this field is not an active one, so few of the best men are doing work in it. The result is that there are hosts of dopes here and it is not good for my blood pressure: such inane things are said and seriously discussed that I get into arguments outside the formal sessions (say, at lunch) whenever anyone asks me a question or starts to tell me about his “work.” The “work” is always: (1) completely un-understandable, (2) vague and indefinite, (3) something correct that is obvious and self-evident, but worked out by a long and difficult analysis, and presented as an important discovery, or (4) a claim based on the stupidity of the author that some obvious and correct fact, accepted and checked for years, is, in fact, false (these are the worst: no argument will convince the idiot), (5) an attempt to do something probably impossible, but certainly of no utility, which, it is finally revealed at the end, fails, or (6) just plain wrong. There is a great deal of “activity in the field” these days, but this “activity” is mainly in showing that the previous “activity” of somebody else resulted in an error or in nothing useful or in something promising. It is like a lot of worms trying to get out of a bottle by crawling all over each other. It is not that the subject is hard; it is that the good men are occupied elsewhere. Remind me not to come to any more gravity conferences!

It just happens that another gravity meeting is being held in Warsaw next week, and I am going... Just before travelling, it is interesting to reflect on how the area has changed in the last decades. On the one hand, things have changed enormously. On the other hand, you can argue that many of Feynman’s comments are equally valid today.

Let me explain.

Feynman wrote his letter at a time when Einstein’s General Relativity (that describes gravity) was pursued mainly by theorists and mathematicians. The theory had been tested, but as Feynman points out, there were no current experiments. And physics tends to progress by theory and experiment going hand in hand.  However, astronomy observations were about to undergo a revolution. Radio and X-ray observations were just around the corner and they were destined to change our view of the Universe completely. Through these new windows it became apparent that we live in a violent Universe where stars end their lives in massive explosions, there are systems that flare and exhibit enormously powerful outflows and perhaps most astonishingly… black holes are plentiful. Einstein’s theory has been central to our current understanding of these amazing phenomena.

There was, of course, no way that Feynman could have seen this coming.

Following this revolution, General Relativity must be a vibrant research area, right?

Maybe not quite…

The reason is that many of the exciting ideas, like black holes, that originated from Einstein’s gravity have now become part of mainstream astronomy. The change has come about in such an astonishing way that gravity theorists have been left behind. Astronomers often don’t see the need for the intricate mathematics required to actually understand the theory. They seem quite happy with a more handwaving discussion of the phenomena…

This – pretty much as in Feynman’s day – leaves General Relativity as a comparatively small area with stalwart groups and individuals pushing on even though the main focus is elsewhere (high energy physics and colliders, cold atom gases, metamaterials, nanotechnology,…) And just as half a decade ago we don’t have experiments. Actually, we do, but we are still waiting for them to provide the goods. The difference is that this time we expect great things to come, so there is an undercurrent of excitement.

Having looked at the programme for next week’s meeting I think I will be able to find presentations that cover the numbered list in Feynman’s letter. No problem. This is obviously not great. However, regardless what happens next week I am unlikely to compose my own Feynman-esque letter to my suffering wife.

Why not?

First of all, the first direct detection of gravitational waves – as elusive as they have proved to be – should only be a couple of years away. When the current LIGO detector upgrade is complete and data is taken, they should see something. If they don’t then much of what we believe is true about the Universe is wrong (which would be interesting in itself!). Secondly, electromagnetic observations of neutron stars and black holes are becoming increasingly precise. We are not far from the point where astronomers will have to know Einstein’s theory if the want to understand their data. Won't that be fun?