I was reading this Phys.org article about an alternative to Dark Matter which links to this page about Massive Gravity which loses me pretty much immediately.
Okay, I get that the central idea is that there is a force-transfer particle called a graviton which is not massless and therefore does not travel at the speed of light and that the LIGO experiments give some bounds, but after that I’m lost. I mean, if this is the case, how are we not able to test this from Earth? The article mentions that the Sun’s bubble is 50,000 AU so we’re inside it, but should we not be able to test the effects with loosely coupled star pairs, like Alpha, Beta, and Proxima Centauri where the partners are outside each others’ bubbles? Or simply passing stars? Similarly, shouldn’t the effect change with distance? Just as the problem with Mercury helped Einstein, can it not help us here? Anyway, I’m lost, so can someone enlighten me in simple terms?
It’s too bad that the use of “massive” here means “has mass” rather than “large”.
The Wikipedia article says the upper bound on the mass of a graviton is 7.7×10[sup]−23[/sup] eV/c[sup]2[/sup]. Multiply that by 1.782662×10[sup]−36[/sup] to get kg.
That’s just a wee bit on the tiny mass part of the scale.
(The problem with “nearly” lightspeed dark matter particles is that they will disperse rather quickly out of galaxies so their effects on galactic rotation won’t have lasted the last 14 billion years. Which is no doubt why the OP is not thinking about this in terms of dark matter.)
