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I really don’t know.
Change is afoot (and not before time, we old folk might say). Much of the cosmologists’ current edifice may
yet come tumbling down.
Thinkers down the ages have all claimed to understand
the cosmos. They’ve never been right
yet, and I see no reason why they should suddenly be right now.
We old folk have an advantage here because we’ve seen
it all before. The story has changed
beyond recognition in our lifetime, so we are already conditioned to imagine
that it is likely to go on developing just as fast.
The cosmologists may be getting closer to the truth of
the matter, but I don’t believe that they will ever get to the bottom of
it. That cosmologist who, many years ago
now, said something like “the most un-understandable thing about the Universe
is that we understand it” was being both arrogant and stupid. (I have to admit though to having been just
as arrogant and stupid in my time – though fortunately not in public.)
When I was a kid, the textbooks were still telling us
that the Universe was eternal and unchanging – mainly the eminent astronomer
Sir James Jeans if I remember rightly.
Nobody seemed to worry about the huge amounts of energy were being used
up, just keeping the stars going. And
that’s only the first of the impossibilities of it.
The Universe was believed to follow
Then along came Einstein, and others equally
remarkable though less famous. Together
they blew this simple story out of the water.
The Universe was far more complicated than astronomers had ever dreamed
of. Oh, and Einstein’s theory of
Relativity also explained the Mercury problem.
Then there was the ‘debate’ between Big Bang and Fred
Hoyle’s Steady-State theory. Indeed, it
was Hoyle who originally invented the name ‘Hot Big Bang’ as a term of
abuse.
The history of Science is full of episodes like
this. Before
At the end of the 19th century, physicists
thought that they understood their world too.
Young bloods were actually advised not to take up physics, because there
was nothing more to learn. But Einstein
and others transformed Physics as much as they transformed astronomy.
The recent crop of cosmologists have made a number of
assumptions which they often didn’t realise they were making, but which could
easily be wrong. This isn’t me talking
here. Cosmologists themselves remind
each other of it from time to time – in top journals.
For a start they took the Laws of Physics – as derived
in one miniscule patch of the Universe and over an infinitesimal period – and
assumed that they would apply perfectly throughout the whole of space and
time. In a sense, they could do no
other. If that’s all the information you
have, then you must do your best with it.
The problem came when they started to believe it. I’m an engineer, and we are trained never to
believe anything that hasn’t been thoroughly checked out – over its entire
envelope of interest.
But the cosmologists did the opposite. Instead of treating Big Bang and their new
cosmology with caution, they raised it to the level of dogma. You wouldn’t think that scientists would do such
a thing but they do. ‘Behavioural’
scientists also took it as an article of faith that animals were no more than
machines (more). The behavioural folk are only now extricating
themselves from the mess that this left them in.
An article in Science
(3 August 07) suggests that astronomers are now beginning to catch up with us
engineers. It contains the comment that
“… this inference requires that
I’ve not read that Big Bang itself is currently under
threat, though please don’t waste too much brainpower on the details! Astronomers can now actually see what was
happening only 400 thousand years after it.
This is the mysterious background radiation that we hear about from time
to time. The radiation is in fact a wall
of hot fog, and it represents the instant that the young Universe became
transparent. The Universe has expanded a
thousand fold since then. The radiation
that this wall of fog emitted has been stretched out until it’s no more than a
faint microwave hiss. Everything that
the astronomers observe from then on seems to fit the cosmologists’ theories. They fit within limits anyway. Unfortunately the devil is always in the
detail, which is why we have to reserve judgement.
Until recently, astronomers and cosmologists were
arguing fiercely over how long ago the Big Bang was. It’s difficult to understand why. The difference between the two camps was
never more than about ‘a factor of two’, which you’d think was pretty good
going under the circumstances; especially considering that both camps had to
rely on these notorious assumptions. Now
however the different groups seem to have homed in pretty well on a single date
– 13.7 thousand million years ago I think – though as soon as you think you’ve
nailed it, they change it again!
We used to be expected to believe that there was
nothing before Big Bang, and that time started at that moment. This was always
a pretty implausible tale to many of us.
And fortunately the cosmologists are beginning to question it too. They are even looking at the background
radiation for clues on what might have been happening in the run-up to it. The evidence might lie in the tiny variations
shown in this NASA map. The Internet
provides conflicting numbers on just how small these fluctuations are. So all I can say at the moment is that
they’re tiny.
We also used to be told that the Universe would
eventually start contracting again, and would end in a Big Crunch – possibly to
be followed by another big bang. But
this would mean that the expansion ought to be slowing down, or at least
staying the same. And a few years ago,
the astronomers observed that the expansion actually seemed to be
accelerating. However I’ve recently
read that this acceleration could be an artefact, resulting from assumptions
that … You can fill in the rest.
For a number of years now, the cosmology that follows
Big Bang has been in trouble. Indeed the
Science article that we mentioned
above goes on to describe the situation as “preposterous”. There are too many things that don’t quite
fit (where have we heard this before?).
A number of add-ons have been affixed.
Off the cuff, I can remember string theory, multiple dimensions, dark
matter and dark energy. But still things
don’t quite work.
One fairly basic problem is that there’s not enough
‘observable’ matter in a galaxy to stop it flying apart. I’ve never understood why this is a
problem. I’d have thought that you could
posit enough dead stars to provide all the extra mass the cosmologists
need. But apparently not. This is why they had to invent a mysterious
new form of matter, this dark matter, to get them off the hook. The experimentalists are now busy looking
for dark matter. At the time of writing
they’ve not found it yet, but they are still looking.
But others are contemplating more drastic measures,
like questioning the basic laws of physics.
Not before time, you might think.
One new theory is ‘Modified Newtonian Dynamics’, or MOND. MOND points out that ‘
MOND seems to be gaining ground fast. The Science
article describes all the mysteries that MOND explains, plus a few that it
doesn’t. I don’t think we should worry
too much about the latter. It’s only a
first stab after all.
And once the
scientists have started questioning their articles of faith, who knows where
they will end up!
© C B Pease, February 08