### Physics

Scientific American recently published an article by Max Tegmark, which provides calculations for a particular kind of infinite universe.
http://space.mit.edu/home/tegmark/PDF/multiverse_sciam.pdf

Although I think his use of the word “infinite” is a bit loose, he is careful to define exactly what he means, and his logic is scientifically valid. His argument is as follows:
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No, it’s not Coriolis forces or gyroscopic stability. It’s all down to the front wheel geometry. A ridable bicycle will have the front wheel contact point a short distance behind the point where the straight-line projection of the steering pivot meets the ground.

Such a bike can be pushed by hand, held only by the saddle. As the bike leans, the front wheel steers into the lean providing a stabilising torque.

Here are two good articles. The first is a classic, widely quoted.

http://www.dclxvi.org/chunk/tech/trail/

Just in case you thought you knew what QM was about, it’s really about negative probabilities and how they vector sum. It says so right here.

No-one can or ever will observe an event horizon. It's a theoretical mathematical construct with no physical reality. It's also in a region permanently hidden by view. It's also (in my submission m'lord) not formed yet.What we see is the radiation emitted by matter that has come under the influence of a gravitational field so strong and so localised that we believe it could not be explained by anything other than a BH.It's a proof by exclusion ie not a proof by construction. Mathematicians love those, but in the real world there's always another possibility.

Assume you have a collapsing star of around 10 solar masses. It cannot form a neutron star (too big) so it collapses down to thousands, then hundreds, then tens of Km in diameter. The Schwarzschild radius is maybe 50 Km. [I don't have an exact figure, but the formula is r=2*G*m/c^2. ]As matter is rushing inward towards this 50 Km target, time as viewed from a nearby inertial frame of reference slows right down. As an observer we see the light from the matter shifted to deeper and deeper red. Although we won't see it, right at the event horizon the light would be shifted to zero wavelength, zero intensity and the matter would be stationary. This corresponds to time standing still in our frame of reference. We know that time continues to pass in the frame of reference of the matter itself, but that isn't the point. For us, no matter can cross the event horizon within any finite period of time eg the life of the universe.Another way to look at it: just before a 50 Km event horizon exists there was a 49 Km event horizon, with lots of the mass still outside and unable to reach the event horizon within the life of the Universe. Before that it was 48 Km, and 47 Km, and so on. There is no way for the event horizon to get started.

My guess is that most of what we know of as candidate black holes are actually "candidate black holes in the process of formation". Maybe in the time available they have spawned an actual microscopic black hole with lots of mass just outside the event horizon; maybe they don't even get that far.

I can't find any detail commentary on this. Everyone acknowledges the time dilation, but they fail to comment on its implication related to the life of the Universe.