Obviously my title is tounge-in-cheek. Many people have to work hard to turn theories into truths. However, here are some things that get talked about a lot as fact, but really are just good theories. When verified by direct observation, most of these will be considered a nobel-prize winning, ground-breaking new frontier in physics. Until then, they are just good ideas, waiting to be verified.
Dark Matter & Dark Energy - [Read More about Dark Matter and Dark Energy]
Dark matter is hypothetical matter that feels no effect from electromagnetism, so we cannot see it. Its presence can only be inferred by the gravitational influence it exerts. Galaxies do not rotate as expected by Newtonian dynamics. The Coma cluster of galaxies also has properties that gravity cannot explain.
Dark energy is similarly mysterious, but even less easy to understand. It is a kind of energy that permeates the whole universe, driving it apart and causing it to expand. These two things together purportedly make up 96% of the content of the Universe.
Physical cosmologists study dark matter and dark energy with great interest. Change their names to ‘gravity not doing it what it should’ and things can look slightly different. A branch of physics labelled MOND (MOdified Newtonian Dynamics) tries to explain the observational evidence without adding in unknown forms of matter and energy. There are also many scientists who feel that ‘dark energy’ gives the wrong impression and that this stuff might be normal matter that we simply don’t see for some reason.
So either gravity is wrong or matter is. That is quite a dilemma for astrophysicists to resolve.
Gravitational Waves - [Read More about Gravitational Waves]
Now, I’ve gotten in trouble before for having a beef with gravitational waves, so I’ll try to be kinder here. Gravitational waves are fluctuations in the curvature of spacetime which transmit the energy of gravity and propagate its effects through the universe. Light’s energy is transmitted to us by fluctuations in the electromagnetic field, this would be an alternative spectrum of waves, detectable by completely different means.
The study of gravitational waves has received a nobel prize (1993, I think?) when they were indirectly detected in a binary system containing a pulsar. The orbital energy in the binary system was seen to decay in exact accordance with the theories of gravitational wave physics.
Einstein’s general relativity explains gravitational waves very well - in fact if gravitational waves don’t exist there is a big problem. The problem comes along when you find out that no one has ever detected a gravitational wave. People have been trying for quite some time.
I often see graphs which explain this lack of detection. Basically gravity waves may just be too subtle to be detected by current methods. The answer is to build larger, more complicated observatories (in space preferably). The plans are already made. If they don’t find them then, either a new idea gets floated, or a new graph gets drawn and an even bigger detector is created.
I hope they find them before too much money gets spent!
The Higgs Boson - [Read More about the Higgs Boson]
The Large Hadron Collider (LHC) had to be shut down for a little while and so its main target: the Higgs Boson remains an unknown and unverifiable character.
Imagine you had a really nice cake. You studied this cake for a long time and you managed to figure out exactly how it was made. You could tell me the proportions and nature of the original ingredients, the length of time for which it was baked even the exact colourings used in the icing. What you don’t know though, is the type of spoon that the cook used. Without knowing this you will never truly have understood how the cake was made – and you will never managed to recreate it. If it turns out that there was no spoon then your whole theory falls apart!
The Higgs Boson is that spoon.
Without the Higgs Boson the whole framework of our understanding of particle physics is incomplete. The LHC should be able to detect it. If it can’t, then there may be a problem and the standard model of patricles will need to be reconsidered. If it is found, then we would have a complete understanding of the particles that make up the Universe. That would be profound and powerful. We may find out one way or the other in 2009.
Panspermia - [Read More about Panspermia]
How did life on Earth begin? Well one idea is that it came to our little rock from space. This notion is called Panspermia and it is actually as old as modern science. Early musings on evolution in the 18th Century considered that the original germs came from space.
Fred Hoyle (who died in 2001) and Chandra Wickramasinghe (who is now based in Cardiff’s astrobiology centre) were early proponents of Panspermia in its modern form. They also suggested that lifeforms continue to enter the Earth’s atmosphere, and that they might still cause epidemics and provide new genetic material for the planet.
The problem with Panspermia is that it solves a complicated problem (how did life spontaneously begin on Earth) with an even more complicated solutiom (how did life spontaneously begin elsewhere and then travel across billions of miles of interstellar space). For this reason, many need a lot of convincing about the idea.
String Theory - [Read More about String Theory]
String Theory is the name given to a branch of physics and maths that aims to describe the Universe in terms of multi-dimensional vibrating strings. No this isn’t Pratchett. It would be a way to combine the as-yet irreconcilable theories of quantum mechanics and general relativity – this is something of a holy grail in modern physics.
String theory is a broad name for a collection of theories – some of which disagree with each other – but all of which boil down to the principle described above. The trick is, you cannot disprove string theory. You would need an experiment so large and powerful that it would require orders of scale larger than our Solar System. We are a very, very long way from achieving this.
The strings themselves would be so fantastically small as to be possibly prohibited from measurement by nature itself. Lengths and timescales so minute that we could never measure them.
One hope for string theory is that we may see evidence of hidden dimensions when the LHC begins operations. However this could also be evidence of other things, and not necessarily a win for string theory.
For these reasons, many consider string theory not to be science, but rather mathematics. One day in the distant future we build the right apparatus and experimentally test this outlandishly cool idea. It may be right – or it may just be a mathematically self-consistent way to explain particle physics and gravity.
Summary
Popular ideas are not always good ones, nor are they necessarily bad. The work being done to advanced science in the five areas above is extremely important. However so is the work being done to provide alternative ideas and theories. Nothing in science is proven until it is proven.
great article man. It’s nice to see someone question String Theory, too many people are too in love with it.
Rob — excellent post! I’ll try to add to your list with my own entry and send a link when it goes up (this weekend?)
One of the common arguments against evolution is, “it’s just a theory.” Somehow we need to disabuse people of that use of the word ‘theory’. But how are we to do that when it’s called ‘String Theory’, which by any other name still smells, um, not like a rose.
Awesome post Rob! You’ve said some things here that many were thinking (but don’t want to say in case they lose their funding!). Your take on gravitational waves is excellent. I recently wrote about LIGO and thought “wow, this is a lot of money being spent on something that doesn’t work. What a load of tosh.” I also read a paper saying that we need a gravitational wave detector with a baseline from here to the Moon to stand any chance of detecting a ripple.
And the best research done to date with LIGO was a publication that “proved” a local pulsar was being driven by a smooth (i.e. no lumps) spinning neutron star. They know it is smooth because LIGO didn’t detect any gravitational waves from the thing… but LIGO has never detected any frickin’ gravitational waves! I realise it’s got something to do with characterizing the pattern of waves generated, but please. I think there are a lot of frustrated LIGO physicists out there.
But don’t touch my Higgsy. He’s out there, I can feel it.
Dark Energy Identified:
Based on laboratory simulation, I believe dark energy is actually the energy contained in traveling shock waves. See ISBN 978-1-4343-0661-6 (sc)
String Theory is obsolete with M theory.
that and evolution
Could someone please tell me why evolution is not on this list? It has just about the same level of probability as panspermia. The amount of crap that is getting serious funding out there is just amazing.
@Michiu – String theory, as a term, can be used alongside M-theory. They can be considered different aspects of a similar problem. String ‘theory’ in this article could really be string ‘theories’, since there are quite a few of them.
@rhorow and @diehardevolutionist – I think you have missed my point. Evolution is not on the list exactly because it is not like Panspermia. Evolution is a theory with mountains of evidence behind it. The large-scale idea of evolution – as the natural selection of entities by gradual (and sometimes random) improvement – is solid and an excellent description of what we see in the world.
The more interesting and precise ways in which the same concept can be applied to other smaller or unrelated systems is more interesting and possibly more fringe. Can software evolve if we allow it to copy itself, for example? Do traffic systems evolve, or even the Earth as a giant organism (like Gaia theory).
These are smaller studies but they could be on this list. Evolution, like the Big Bang, is a theory with an awful lot of real life evidence behind it. for that reason it does not sit in the same category as panspermia or string theory.
Money for gravitational wave detectors would increase if and when a detection is made, as further funding/detections would allow astrophysics and cosmology to be done. I’m assuming you would be less concerned about the money set aside for gravitational wave research in that case, the same is surely true for funding bodies.
Honestly, if Advanced LIGO, which is already fully funded by the NSF, does not see anything then that could be the end of projects like LISA & EGO and future funding for interferometer detectors.
All IMHO…
In my opinion, the Big Bang is the most questionable, right next to dark matter. The fact that the basic idea in astronomy is that the universe is limited is almost crazy, yet both of these theories support that belief.
Saying that the big bang happened is saying there was an explosion of space. But as we all know, you can’t get something from nothing…so something would of had to exist before this explosion of space, and if that was the case, something would of had to exist OUTSIDE of that. So to say that the big bang started all of this is inaccurate, and will forever be unprovable.
As far as dark matter goes, it also follows the belief that the universe is limited, and that 96% of it is made up a material that we have never had any hands on in studying, or even had supporting proof for the claims of its volume, or if it even works as we believe it does.
Aside from those two, I would have to say Einstein’s theory of relativity… just because the mechanics from which the theory is based on, have never been observed by humans and currently can not be physically or theoretically proven.