Strange

How is that relevant? We do know that the universe has always been completely and homogeneously full of matter and energy. And that it was small enough for it to be in thermal equilibrium; therefore it was also small enough for the gravitational effect of the matter to spread through the entire universe. Again, you are adding nothing new.

That would be true if mass could appear from nowhere. Then its gravitational field would spread out with c and beyond that there would be no gravity. However, mass cannot appear from nowhere so the gravitational field extends throughout the whole universe (which could be to infinity). This is all described by GR. You have added nothing new (except inventing the idea that mass can appear from nowhere, which is nonsense).

Any Hawking radiation emitted by black holes would be too little to be detected. Only really tiny black holes would emit detectable amounts of radiation. So, no, there is no evidence that black holes emit radiation.

That would be general relativity, the Einstein Field Equations: http://math.ucr.edu/home/baez/einstein/ These describe how spacetime curves and how that curvature spreads out at the speed of light. You are not "adding" anything.

As you are having trouble understanding Einstein's description why not find a modern text on the subject, maybe even one in your own language. I find Einstein's writing to be quite hard to follow, in part because the style of writing 100 years ago was just more wordy and formal than modern English. (The only reason I have tried to read it is because various crackpots insist on using it as their source even though they find it confusing.) There are quite a few videos that explain these things with all sorts of animations to explain the concepts. It can't be. It follows mathematically from the invariant speed of light.

Here is the source for the info on these impurities in polypropylene. It comes from some work at University of Alberta 10 years ago. Couldn’t find any updates on it. https://www.sciencedaily.com/releases/2008/11/081119173218.htm

I don't know where you get that idea from. It is wrong. Exactly.

The mass of the black hole is a tiny fraction of the mass of the galaxy so it will only have a significant effect on the stars very close it to. It has no effect on the orbit of the Sun around the galaxy for example. I don't see how the orbiting objects would reduce the mass of the black hole. The Moon doesn't reduce the mass of the Earth.

I make it about twice as far as the Kuiper belt. This might be useful for comparison purposes: https://en.wikipedia.org/wiki/Orders_of_magnitude_(length)#Astronomical_scale

You don't like durian!?

The radius of the event horizon is about 2x1013 metres. That is about the same as the distance from the Sun to Voyager 1 (which is just outside the Solar System). The black area in the image is the "shadow" of the black hole (created by gravitational lensing of the photon sphere) and is 2.6 times the size of the event horizon (see the video poster earlier for a good explanation of that). Edit: so looking at that diagram again, it would appear that Randall has got the comparison wrong. Which I am rather surprised about.

I don't know what an "Evol" is. Presumably some sort of stupid religious insult. The time it took for humans to develop agriculture is irrelevant to the evolution of modern humans. But note that agriculture depends on the domestication of plants. This is only possible because evolution happens. Again, do you have any evidence for these claims? Please provide evidence that Noah arrived in spaceship from another planet. I have not heard this before, so I assume you have some very compelling evidence. So was Noah from Mars? Or from another Star system completely? Is he related to Xenu, the alien that Scientologists worship?

That is a good point. I did intend to say in my previous reply that "density" is a pretty meaningless concept for a black hole. However, we know the mass and the volume (although that isn't really well defined) so we can calculate an average density, even if it doesn't mean much. The infinities come from a naive application of GR, which we are pretty certain does not apply any more at that point. But you seem to be confusing density and mass. The density can (in principle) be infinite with a finite mass, and it is the mass that makes one black hole larger than another. (But yes, one infinity can be larger than another. But that is a separate discussion!) I wasn't talking about the inside of the black hole, but the black hole overall. (There is another thread where I have made exactly the same point: we know nothing about what happens inside a black hole.) It is the mass that stops light escaping, not density. The (probably non-existent) singularity has infinite density. The average density of the black hole (assuming a sphere of the same radius, with that mass) is relatively low.

This is a science forum, not a Sunday school, so: do you have any evidence that evolution is false? If not, we can ignore your claims.

The corollary of that is that the tidal forces near the event horizon are much smaller for a large black hole than a small one. So, popular science articles always seem to say that you would be torn apart as you fell into a black hole. But in the case of a supermassive black hole you wouldn't notice anything at all as you fell through the event horizon. (Other than a slight sense of regret, maybe.)

As time dilation only depends on speed, not acceleration then (if you ignore gravity) you can just take the orbital speed and use special relativity. Wikipedia has a neat graph showing the relative contributions of gravity and orbital speed for different altitudes: So at low altitudes, the effect of relative speed dominates (clocks on ISS run slower than those on Earth) while at higher altitudes, gravitational effects dominate and so clocks run faster than on Earth. https://en.wikipedia.org/wiki/Time_dilation#Combined_effect_of_velocity_and_gravitational_time_dilation You cannot orbit the Earth at "near light speed" (it is greater than escape velocity). So you would need rockets continuously pushing you towards the Earth.

For a satellite orbiting the Earth, there is an effect due to their velocity and also an effect due to the difference in gravity between the Earth and the height of the orbit. For example, GPS satellites travel at about 14,000 k/h. This means their clocks run slower by about 7 microseconds per day. However, because the satellite is on average about 19,000 km above the Earth, their clocks run faster by about 46 microseconds per day. So, overall the clocks run faster by about 39 microseconds per day.

Perhaps you need to ask a more specific question. Your initial questions were very general and so the answers, necessarily, are very general as well.

! Moderator Note You need to provide some context for the discussion. Please read the rules of the forum. Rule 2.7 "members should be able to participate in the discussion without clicking any links or watching any videos. Videos and pictures should be accompanied by enough text to set the tone for the discussion, and should not be posted alone".

You would also need to consider the Doppler effect which would increase the frequency of signals when they are approaching you and reduce them when travelling away.

There are various lines of evidence for the existence of black holes. Some of these are things like X-ray sources that correspond to what is predicted for accretion disks around black holes. That is quite indirect and requires a good understanding of the relevant physics. A much more obvious example is the orbits of the stars around Sagitarius A*. These are orbiting an object that is very massive (determined by their orbits) and very small. Something that small and that massive could only be a black hole. And, of course, we know have direct observation of the event horizon (or, more accurately, the "shadow" of the event horizon - not really shadow at all!) The density decreases with the size of the black hole. This is because the mass is proportional to the radius, but the volume is proportional to the cube of the radius. Large black holes can have a density less than that of water. This all comes from general relativity.

Good question (I did wonder about that myself). I don't think so. For example, say two objects that were orbiting one another were to fall into a black hole (large enough that tidal forces did not disrupt them much). Before they fall in, they would be generating gravitational waves. Inside the event horizon, the curvature of space-time is such that the only direction for the gravitational waves to travel is towards the singularity. The could not reach the event horizon and certainly not outside it.

! Moderator Note If you want to ask questions about standard physics like this, please start a new thread.

Even in a neutron star atoms and nuclei no longer exist. The particles are compressed to a much denser and more complex state. We don’t know what happens in a black hole. According to GR everything is crushed to a point but is probably not realistic.

What is "it"? What is new?