I can’t believe I have only just now stumbled upon this – evidence for an alternative to the mysterious dark matter and dark energy. They might not be needed to solve anything!

Long story short, there are voids in space where time goes faster, because time is connected to matter and gravity.

The problem is that this model uses a simplified equation that assumes the whole Universe is smooth, and expands at the same speed everywhere. But it’s far from smooth out there: we see a colossal cosmic web, criss-crossed by filaments of galaxies separated by vast voids emptier than we can comprehend.

Timescape cosmology takes that ‘lumpiness’ into account. More matter means stronger gravity, which means slower time – in fact, an atomic clock located in a galaxy could tick up to a third slower than the same clock in the middle of a void.

When you stretch that over the huge lifespan of the Universe, billions more years may have passed in the voids than in the matter-dense areas. A mind-boggling implication of that is that it no longer makes sense to say that the Universe has a single unified age of 13.8 billion years. Instead, different regions would have different ages.

And since so much more time has passed in the voids, more cosmological expansion has taken place there. Therefore, if you look at an object on the far side of a void, it would appear to be moving away from you much faster than something on this side of the void. Over time, these voids take up a larger proportion of the Universe, creating the illusion of an accelerating expansion, without needing to conjure up any dark energy.