Jaime Rudas's latest activity

As a curious fact, it seems that Hubble never actually called it that. The earliest appearances of the term 'Hubble constant' that I...

Yes, the Hubble constant ##H_0## is constant in space, not in time.

Actually, that constant wasn't just 'invented' 100 years ago; it's a direct consequence of applying general relativity to a homogeneous...

Yes, when we talk about cosmological distances, we generally refer to space-like separations between comoving objects.

Another way to visualize what 70 km/s/Mpc is equivalent to is to show that something expanding at that rate will double its size in...

Yes, but to measure the Hubble constant, you need to know the distances.

Redshift tells you the distance only if you already know the rate at which the universe is expanding.

The linear expansion rate corresponds to around 7.1⋅10-11 1/year so you can get the "equivalent speed = distance/year" if you multiply...

If the Earth were expanding at the same rate as the current expansion of the universe, then two cities 1000 kilometers apart (Paris and...

I believe that for a model of reality to be predictive, its fundamental principles must correspond to reality and its mathematical...

Such is Mathematics.

I think, at rock bottom, math is motivated by an abstraction of physical reality. Why that abstraction was chosen, and even why to...

I would say (imo) no. But, geometry is definitely an approximation or idealization of what we see in nature. Developing the logical...

Frenkel says (4:32): "Mathematics does not come to us from physical reality." Is there really anything that could not come from...

Plasma explosions would be fine for a fictional projectile weapon - just don't say how they would work. It is fiction - there isn't any...