Sunday 29 March 2015

Gravitational Lensing, Quantum Foam and Back on my Old Stompin' Ground



‘I've been bitten, Lord, I've been stung. Well I was cornered, and I was almost hung. Well, I sure made a getaway and I'm almost back on my stompin' ground. Well, it's been written, many, many times it's been sung. It's well learned by the old folks, and unheeded by the young. Well, the grass may be greener but, me, I just want my old stompin' ground.’ With my grateful thanks to the late, great (awesome really) Rory Gallagher and Tony Palmer’s marvellous movie about RG’s 1974 Irish Tour for the lyric.

Yes, the Penguin is back; older but none the wiser. In the absence of an MG post for more than a year, I have decided that I must take up my pen again, or at least bang the bill against a few keys, and so try to make up for not only my enforced absence from mangling the English language but also to make some kind of redress over my e-pal’s betrayal of promises to make up for my lack.

I only returned the day before yesterday and what do I find in my email in-box? Further confirmation of Einstein’s theory of relativity! It seems, as predicted, that ‘gravitational lensing’ around massive objects like a galaxy (presumably with its attendant ginormous black hole at its heart) is the only answer to four separate images of the same, distant object; just like this.



And yet. . .

Amongst a year’s worth of SPAM in that same in-box, I also found evidence which seems on the surface to call into question general relativity’s ‘claim’ to be the final answer. It appears, in some cases, that gamma rays, highly energetic photons, arriving from a distant supernova or ‘black hole burst’* arrive at different times according to their energy levels; the lower energy levels reaching some seconds or even minutes after the more energetic photons. Why should this be? According to General Relativity, photons, light, should travel at the same maximum speed whatever their energy levels and only the medium in which they travel affect their velocity. This is why you get the bizarre diffraction when looking at an object half immersed in water; light travels more slowly through the denser medium. So what is causing the delay, although the evidence for this is highly controversial and subject to much heated debate amongst physicists about the veracity of the data gathered; ie does the time lag really exist?

If the data should prove accurate, the string theorists would no doubt point to the extra, folded-up dimensions (six or seven, depending on your fancy) which the lower energy photons must pass through more slowly; the cosmologists would point to dark matter, whatever that may be, as the cause; the quantum physicists, quantum foam, the countless particles that are forever winking in and out of existence on the borrowed energy of the universe and which might have a effect of the absolute velocity of the massless photons. Whatever the truth of the findings, one thing is clear. Humanity is no nearer to reconciling the classical theory of relativity and the quite bizarre and mind-numbing theory of quantum mechanics than it has ever been. How can the theories of the smallest and the largest, both accurate to five or six or seven or more decimal places be at such odds with each other?

Me, I am just a lowly, mentally challenged penguin and ill-equipped to cope with pondering the issues of the whichness of the why and the whyness of the how and I always amaze myself as to why such ideas should so captivate? Perhaps it is because I will never understand. It was all so much easier in humankind’s past; before Newton and the age of enlightenment; before Maxwell and Planck; before Heisenberg and Feynman; before Hubble and his damned telescope. In the past, all anyone had to do was possess a blind faith in the unknowable and a sure knowledge of a life everlasting.

I sometimes wonder whether you would not be happier if you had preserved a measure of that blissful ignorance and quenched the flames of your insatiable curiosity but the cat is now well and truly out of the bag and you can do no more than spend vast sums of money, time and intellectual expertise on such questions until you finally find a satisfactory answer; which in my estimation will be when Hell freezes over!

Talking of which, a student was once asked to write an essay on whether Hell was hot or cold. He gave the problem a considerable amount of thought and much consideration to the three laws of thermodynamics before settling on the notion that Hell was indeed hot or at least very warm. When asked, in a seminar, to explain his reasoning by his Professor, he replied: ‘Well, Mary Carpenter said during my first year at university that it would be a cold day in Hell before she ever slept with me. Since this implies that Hell is not already cold and Mary Carpenter has, after three years, yet to go to bed with me, I must conclude that Hell is currently hot.’

Oh, I had a small redesign and changed the picture to the right. MG has been very remiss in not providing a new one so I nicked one from the Daily Squee. Perhaps this will goad him into producing something original to grace my blog, although he says that his ability to draw and paint have been affected by the events of recent years. Your guess is as good as mine!

* Black hole bursts are detectable flashes of x-rays or other radiation when objects spiral into a black hole and get subsumed. If you don’t know what a black hole is (and it’s not a district of Kolkata) then look it up!

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