[jaf656s]

The reality is closer to:

We have a lot of observational evidence that the equations are very accurate.

But when we put all the mass we know about into the equations, the result of the equation doesn't match our observations.

Since we have a lot of evidence that the equations are very accurate, then it's more likely that there's more mass we haven't accounted for.

(at least for dark matter)

[ars]

That's dark matter, dark energy is something else entirely, with much flimsier data and evidence.

[jaf656s]

whoops, I thought they said dark energy/matter