Physics: Is There A Fifth Force?

Physical forces rule our cosmos, and since we’re a part of the cosmos, they govern our existence as well. Even if we’ve never studied physics, we all know about gravity, and to a lesser extent, electromagnetism. We don’t tend to have any obvious day-to-day perception or connection with the two nuclear forces, but rest assured, if they didn’t exist, you wouldn’t either. Is that it, the sum total of all the forces that rule the Universe?  Perhaps there awaits the discovery of a fifth, or more forces - or perhaps not.

We know a great deal about the various forces that control our Universe – there’s gravity, electromagnetism, the strong nuclear force (which binds the atomic nucleus together) and the weak nuclear force (responsible for radioactivity). Are they collectively adequate to explain life, the Universe and everything – especially life?

Coming to terms with (for lack of a better phrase) a fifth force, call it a ‘life-force’, I would have to superficially agree that assuming the existing four forces (and their associated particles) aren’t sufficient to adequately explain life, evolution, the mind, memory, sleep and dreams, musical creativity (be it bird songs, whale songs, or human songs), a sense of self, intelligence/intellect, morality, emotions, curiosity, and all those other bits and pieces we associate with living things, then we may indeed have to postulate yet another force – a ‘life-force’.

In other words, is there a fifth force needed or required to bridge the gap between non-life and life? Finding another force in the Universe isn’t all that unprecedented – I mean we didn’t know about the nuclear forces until the (roughly) third decade of the last century, less than 100 years ago.

Many cultures have or currently think there is a ‘life-force’, some sort of mystical vitality force or unspecified bio-energy fields, that’s required to breathe life into otherwise inanimate objects, objects otherwise composed of the same sorts of chemicals that make up rocks and things. It tends to be a relatively New Age or Eastern (Asian) philosophy. However, believing in a fifth force, a ‘life-force’, and proving it are two entirely different things. Biologists, biochemists, etc. haven’t exactly rushed to update their textbooks with a chapter on a ‘life-force’ that underpins their field of study.

But if there is some sort of ‘life force’, then presumably it ultimately can be detected and measured. There would also have to be some sort of ‘life force’ particle – all the other universal forces have associated particles (electromagnetic forces have the photon particle; gravity has the theoretical graviton; the strong nuclear force has gluons). Of course, such a force particle may have properties that are beyond our technology to detect – so far anyway. By analogy, there are lots of massive particles theoretically postulated to exist by particle physicists. Those ultra-massive particles are theoretically predicted via the concept of super-symmetry (SUSY). But, even if SUSY is correct, our atom smashes or particle accelerators don’t yet have the required energies to produce them and thus verify the SUSY particle theory.

Unfortunately, I’ve yet to come across any scientist, say a physicist or a cosmologist that speculates on there being yet another unknown physical force in the universe (as opposed to a ‘life-force’, which of course would also have to be a physical force, a physical property of the Universe). Finding a Theory of Everything (TOE), the Holy Grail of physics that unites the existing forces as separate manifestations or phase transitions of one ultimate force, is proving hard enough with only four forces to deal with. A fifth force would surely put the cat among the pigeons! You’d need to ask yourself would this hypothetical fifth force operate over long distances (like gravity and electromagnetism), or tiny distances (like the two nuclear forces). What would be the properties of any associated particle(s)? My knowledge and abilities aren’t adequate to figure all that out, but perhaps there are those who might like to run with the idea.

Okay, an elusive and theoretical ‘life-force’ aside, following some speculation on the nature of ‘dark energy’, that force which is causing the expansion rate of the Universe to accelerate, I strongly suspect that ‘dark energy’ implies the existence of a fifth force in our Universe. Recall that the four known forces are 1) gravity; 2) electromagnetism; 3) the strong nuclear, and 4) the weak nuclear. The strong and weak nuclear forces operate on much too short a distance scale (atomic lengths) for either to account for ‘dark energy’. “Dark energy’ operates over large scale distances. ‘Dark energy’ is unlikely to be electromagnetic in nature – otherwise it wouldn’t be ‘dark’ (photons anyone?). ‘Dark energy’ could hardly be due to gravity (pull pressure) since ‘dark energy’ is antigravity (push pressure).  Now the theoretical particle that is assumed to convey the gravitational force is called a ‘graviton’. Perhaps there is such a thing as an anti-graviton particle, but then we haven’t even trapped a graviton yet – it’s still a beastie in the crypto-zoology realm of theoretical particle physics, so an anti-graviton is heaping speculation on another speculation. Anyway, if one assumes that none of the known forces adequately accounts for the nature of ‘dark energy’; then the unification of physics, the Holy Grail ‘Theory of Everything’ has gotten near infinitely more complicated!  All of this sounds like a good area for observational cosmologists and theoretical particle physicists to have a serious chinwag over several rounds of drinks to come to terms (if possible) with the elusive elements – extra types of forces and the associated matter related particles that convey those forces.