I seriously doubt the idea that space is expanding and I'll tell you why. I've lived in this house for a long time and the space in the pantry closet, clothes-closets, linen-closet, storage cabinets, medicine chests and even the rooms themselves hasn't increased an iota. Worse than that, the space has definitely decreased. My garden shed is a good example. Over the course of time I have had to build two extensions to it in order to counteract the so obvious contraction of space to which we are all subject. It's now triple its original size and almost out of space again!
Now I'm not asking any of you to risk your Ph.D. thesis on my idea of the contraction of space. I hope you will believe me when I say that my attachment to the contracting space idea has not biased me against the expanding space idea. However, I must confess that I do have problems accepting the expansion of space idea. It seems to raise many more questions than it answers.
Long ago I learned that the red shift of light from galaxies was a Doppler effect caused by the galaxies moving away from each other. Now everyone says, "No, the red shift of light from galaxies is caused by the expansion of space." Does that mean that the galaxies are not moving away from each other after all? Or does it mean that the galaxies are moving away from each other without causing a Doppler effect for their light? If the galaxies are not receding from each other, what does that say about the evidence for Hubble's law that the recession velocity of a galaxy is proportional to its distance from us? Is Hubble's law a meaningless coincidence? Doesn't the idea that expanding space stretches wavelengths make the expanding space theory smell a little like the abandoned ether theory?
It's all so puzzling. Why should the wavelength of light be the only thing affected by the expansion of space? Beats me. If the expansion of space causes light to lose energy, where does that energy go or what is it changed into as it is being lost? Is light exempted from the conservation laws so that it can just pass out of existence?
Does the expansion of space idea imply that light continually loses energy as it travels through space? If light energy is created as quanta, shouldn't it lose energy as quanta? Does one quantum of light magically (and not continually) split off a femto-quantum from time to time as it travels through expanding space? How would a quantum of light know when to do a femto-shift? Do those femto-quanta somehow get together to recombine so we can detect them? Or do you think we should chuck quantum theory?
Doesn't the equivalence of energy and mass mean that if the expansion of space causes light to lose energy, it should cause material objects to lose mass? Isn't it true that what's sauce for the goose is sauce for the gander? Who would deny E equals m c squared? If light travelling 99 percent of 15 billion years has lost say 90 percent of its energy, wouldn't the expansion of space have caused the galaxy that emitted that light to have lost say 90 percent of its mass? And where would all that mass have gone? (Now that' s what I would call a real weight loss program!) Would you propose a reverse of the old Bondi/ Gold hypothesis, where, instead, one hydrogen atom would pop out of existence every so often in order to accommodate the expansion of space?
Don't counter that light loses energy because it moves through space but galaxies don't. Are you crazy enough to think that there is any mass object that doesn't move through space? Wouldn't just one thing that doesn't move take us straight back to absolute motion? Do you want to waste the last hundred odd years since the Michelson-Morley experiment and subsequent developments of SR and GR?
If the height of a hill increases as you climb it, you may be dreaming or in an imaginary world. Something like that doesn't happen in the real world. Can't you see that two attempts to explain the red shift raise so many new things to explain that both the previous explanations are probably unrealistic?