Colliding Galaxies Reveal Colossal Black Holes

Matt_dk writes "New observations made with the Submillimeter Array of telescopes in Hawaii suggest that black holes — thought to exist in many, if not all, galaxies — were common even in the early Universe, when galaxies were just beginning to form. Astronomers have found two very different galaxies in the distant Universe, both with colossal black holes at their hearts, involved in a spectacular collision."

Comments

It doesn't seem that surprising.

[IndustrialComplex]

I don't think that discovering early black holes is all that surprising given that concentrations of matter were much greater early on.

What I want to know, is how did the universe expand beyond its own swartzchild radius?

Re:It doesn't seem that surprising.

[JustinOpinion]

What I want to know, is how did the universe expand beyond its own swartzchild radius?

It didn't.

To compute the Schwarzschild radius of the universe, we need to know its mass. Recent measurements suggest that the universe is flat, and so may have infinite mass. However at a minimum we can count up the mass within the observable universe. The observable stars in the universe have a mass of ~2*10^52, but they are overwhelmed by dark matter, which brings the total mass within our observation volume to ~4*10^53 kg. So the Schwarzschild radius for the universe is:

r = (2*G*m)/(c^2) = 2*(6.7E-11 m^3kg^-1s^-2)*(4E53 kg)/(3E8 m/s)^2 = 6E26 m = 60 billion light-years.

Since the observable universe is ~46 billion light-years in radius, this means that the Schwarzschild radius of the universe is bigger than what we consider to be "the universe." In other words, we are well within the Schwarzschild radius, leading some people to describe the universe itself as a massive black hole that we are actually inside of.

The universe probably has a mass larger than what we can observe, making the radius even larger than the above estimate. If the universe truly has infinite mass, then the radius is infinite. In other words, the universe may not have a Schwarzschild radius at all.

This is also a decent description.

Re:It doesn't seem that surprising.

[gnick]

Schwarzschild radius:

The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is a characteristic radius associated with every mass. It is the radius for a given mass where, if that mass could be compressed to fit within that radius, no known force or degeneracy pressure could stop it from continuing to collapse into a gravitational singularity.

Thanks a lot... Before I was peacefully ignorant, but now you've tossed out a perfectly good question and revealed to me yet another topic for my List of Things I Know That I Don't Know...