Airbrush

Everything has a temperature. A hypothetical total void, that has no atoms at all, and is beyond the visual horizon of all matter, over 14 Billion LY from the nearest atom, so there are not even any stars seen, that void would be black and be absolute zero. It would also be without time because space-time cannot exist without matter. It would not be space-time, it would only be timeless space, until that region is impinged upon by a local big bang, then the clock starts again.

For the reasons above we would not see any blue shifted galaxies outside our local group. Blue shifts only occur within a galaxy cluster where galaxies are orbiting their combined center of mass, and only when such galaxies are coming together for a collision.

If there were no atoms in a region of space then I think that region of space would be absolute zero, unless there can be some heat from light radiation passing through the void. We just cannot see anywhere that there are NO ATOMS. Atoms are everywhere. Do we know the real density of space in the middle of a great voids? Beyond our visual horizon there may be totally empty regions of space where even regions as large as millions of light years across contain zero atoms. In those totally empty areas it should be absolute zero. Why not?

This place is amazing. Someone asks what I felt was a silly question, and knowledgeable people bend over backwards trying to help. Generous folks.

Pun intended. Anyhow the word degree does not distract from the concept of absolute zero. The temperature of cosmic microwave background radiation (CMBR) is about 2.7 Kelvin above absolute zero. Does that little bit of heat come from the free atoms scattered about in nearly empty space? Maybe absolute zero does exist, but only way, WAY out there in totally empty space, where there are not even any hydrogen atoms.

Our visible universe is not necessarily ALL space and time. There could be others very far away, or hidden in higher dimensions. Anywhere there is matter, then there is space-time. Even the great empty voids between superclusters have some atoms, about one hydrogen atom per cubic meter. Our universe (our space-time) may be only a local phenomena. There may be other space-time universes quadrillions of light years away. Where there is no matter there is only space, not space-time. Space-time requires matter. I just made this up, but it seems logical to me.

Thanks for the info NowThat and Martin. I should study the sticky material and some tutorials. Great stuff. Back later.

The opposite sides of our visible universe are already separating at greater than light speed. Also, if the furthest we can see in every direction is about 12 Billion light years, and the quasars that we see are actually about twice as far away (2 X 12 = 24 Billion LY) in both opposite directions, because they have been moving away from us at near light speed for over 12 Billion years, then we are already admitting that the outer edges of our visible universe had only a little over 13 Billion years to travel 24 Billion LY in opposite directions, for a combined separation speed of about 48 Billion LY in only a little over 13 Billion years, then the light speed limit is broken anyhow. How do you explain that?

I was in Costco reading from a book about the universe that the immense power coming from quasars may have something to do with matter and antimatter coming into contact, which was new to me.

I don't like the balloon analogy because it expects you to deny your own common sense that the universe is 3 dimensional. I prefer the supernova analogy for the universe. The universe is like a large-scale supernova and our entire visible universe is part of the expanding outer shell which surrounds an immense void, quadrillions of light years across, that may have a SUPER-supermassive black hole at the center of it all.

Hello NTWK. I heard the jets were caused by extremely high temperatures outside the event horizon, but wikipedia has a couple of other explanation of these extreme phenomena called "relativistic jets". "Because of the enormous amount of energy needed to launch a relativistic jet, some jets are thought to be powered by spinning black holes. There are two competing theories for how the energy is transferred from the black hole to the jet. "Blandford-Znajek process - This is the most commonly agreed theory for the extraction of energy from the central black hole. The magnetic fields around the accretion disk are dragged by the spin of the black hole. The relativistic material is possibly launched by the tightening of the field lines. Penrose mechanism - This extracts energy from a rotating black hole by frame dragging. This theory was later proven to be able to extract relativistic particle energy,[7] and subsequently shown to be a possible mechanism for the formation of jets."

This is very interesting. The most energetic things we know about (GRB, supernovas, quasars, bipolar jets, etc) involve black holes. This must mean that when gas, dust, and other matter gets compressed into a black hole, just before it enters it is crushed into such high temperatures that whatever is outside the event horizon is accelerated away at near light speed, making the hydrogen bomb look like a tiny spark. I don't know about matter and antimatter reacting. If there was any antimatter around it would have been annihilated immediately on contact with matter, before approach to the black hole. From Wikipedia: "Because of the enormous amount of energy needed to launch a relativistic jet, some jets are thought to be powered by spinning black holes. There are two competing theories for how the energy is transferred from the black hole to the jet. "Blandford-Znajek process - This is the most commonly agreed theory for the extraction of energy from the central black hole. The magnetic fields around the accretion disk are dragged by the spin of the black hole. The relativistic material is possibly launched by the tightening of the field lines. Penrose mechanism - This extracts energy from a rotating black hole by frame dragging. This theory was later proven to be able to extract relativistic particle energy,[7] and subsequently shown to be a possible mechanism for the formation of jets."