I've suggested (& published in 21 journal papers) a new theory called quantised inertia (or MiHsC) that assumes that inertia is caused by relativistic horizons damping quantum fields. It predicts galaxy rotation, cosmic acceleration & the emdrive without any dark stuff or adjustment. My Plymouth University webpage is here, I've written a book called Physics from the Edge and I'm on twitter as @memcculloch

## Monday, 12 August 2013

### Inertia fails at light speed?

Icarus Interstellar are organising a Starship Conference in Dallas this week (15-18th August) focusing on possible ways to travel to the stars and I wish them the best: one challenge to the status quo is more valuable to progress than a thousand confirmations. Since I can't be there (and I wish I could), I thought I would summarise what MiHsC has to say on the difficult subject of faster than light travel.

According to special relativity, as the velocity of an object approaches the speed of light its inertial mass approaches infinity and so you cannot put in enough energy to produce any acceleration: the object now has an infinite tendency to keep going at the same speed. If true, this means that c is a cosmic speed limit and, since even getting close to c would take huge amounts of energy, it would take decades to travel to the nearest habitable stars.

MiHsC, if experimentally confirmed, offers a new model of inertia and challenges this picture. If you imagine a spacecraft with a powerful enough engine that it can get close to the speed of light. Eventually, if only special relativity was true, it would maintain a constant speed somewhat less than c determined by the power of its engine. However, MiHsC does not allow objects to have constant speeds, because then the Unruh waves seen by the object would be greater than the Hubble scale (Theta) and unobservable in principle (using Ernest Mach’s suggestion that if things cannot be observed in principle, then they do not exist). Therefore MiHsC predicts there always has to be a minimum acceleration of 2c^2/Theta = 6.9x10^-10 m/s^2 in nature. So, even as relativity boosts the inertial mass towards infinity, the Unruh waves making up that inertia start to disappear. This predicted minimum acceleration agrees with the observed cosmic acceleration.

To be fair, this minimum acceleration is not particularly fast: it would cause an increase in speed from zero to 60 mph in 8500 years, or from zero to the speed of light in the lifetime of the universe (something that is intriguing in itself), but the interesting parameter is the Theta (the Hubble scale =2.7x10^26m) in the denominator of 2c^2/Theta. This is the huge number that makes the MiHsC acceleration so small. It represents the event horizon at the Hubble-scale. What if we could produce a local event horizon, reduce Theta, and boost this relativity-proof MiHsC acceleration..?