Leaderboard

Just to clarify. The matter dominated era comes later; the first era was radiation dominated. What later became matter, with mass, was originally all massless radiation ( possessing the property of energy ), because the Electroweak force had not decoupled yet for the Higgs mechanism to give mass to Fermions, This would have been when the observable universe was in causal contact ( light/information has time to traverse it ) in order to establish an equilibrium that ensures isotropy and homogeneity, prior to a vacuum energy driven inflationary period that expanded that observable universe many many orders of magnitude. See Alan Guth, Electroweak symmetry break, and Inflationary Theory.

No matter was not "in the form of energy". That is the same confusion as before. There would have been radiation and fields (radiation is a form of oscillating field) that possessed energy. The entity is the radiation, or the field. Energy is one of its properties, along with other properties like direction, phase, frequency, amplitude and so forth. But my very limited understanding of this (I'm not even a physicist) is that when you try to extrapolate back you reach a limit at which our current theories of matter, radiation and fields etc break down. So we can't "see" any further back, even theoretically. Strictly, the big bang theory starts from the limit of credible extrapolation. All the stuff about singularities etc only has the status of conjecture, so far as I know.

To show off to the world what the US could do? Japan was already beaten. We also found out that the Nazis never developed anything close to an A bomb. Japan was already totally cut off from the world by US submarines and air force. No more imports so they were on the verge of starving. They were also having their cities systematically destroyed by huge B29 incendiary strikes, like the one that killed 100,000 people in Tokyo IN A DAY. All that happened by using the A bomb on Hiroshima and Nagasaki was to REVEAL to the world that such a weapon EXISTS. What they should have done, IMHO, is realize that nobody needs to know about IT, and that IT should be covered up so nobody else can create an A bomb. There should have been a HUGE, Manhattan-Project-sized, intelligence operation to do everything we can to make sure that no country can create such a bomb, except for the US. The US would TRY keep the A bomb a secret as long as possible. That would have saved so much money. Of course you can't keep something like that a secret forever, but at least stall it as long as possible. Or is this a naive proposal?

Analogy doesn't help much with this. It confuses things further. Very simply, so simply that it can't possibly be held to any degree of accuracy: the universe was extremely small, the matter in it was extremely dense and therefore extremely hot, and then the universe (which is everything there is) expanded rapidly (and the last point, working backwards, at which we can accurately measure it is what we call The Big Bang). At some point, the density of matter decreased enough to allow space between it to form, and the temperatures continued to fall. It could be that all that matter squeezed so small is similar to what happens in a black hole, but black holes happen inside the universe, and particles that fall inside are measured relative to the black hole, and no velocity can change that. When the whole universe is inflating itself so rapidly though, everything is different because everything is moving and expanding, everything in the universe is participating in the event. And I've probably made it worse.

Mining asteroids makes economic sense only if you leave the metals out there, for use in outer space endeavors. Imagine having tons of metal to work with that you didn't have to bring up from Earth's surface a few kilos at a time at hideous cost.

Yup, that’s a (quite common) misconception. We can only speculate about what might have been first, but what’s for sure it wasn’t just “energy” somehow existing on its own. That would be as silly as claiming that what came first was “momentum”, without saying the momentum of what. You can’t have a jug of energy any more than you can a jug of momentum, or velocity. All these are properties, not entities. Incidentally, “m” in Einstein’s equation does not stand for matter, it stands for mass, which, like energy, is a property of matter, not a free-standing entity. Another misconception is that the equation predicts “conversion” between energy and mass. What it actually says is that rest mass has energy. It’s not one or the other but both at once. The entities involved are radiation and matter. Energy and mass are properties. In the early stages of the big bang model, there is thought to have been radiation, and sub-nuclear particles, I think. It will have been these entities that possessed the energy.

Thanks for your explanation. But what if the "surface" or skin of the balloon, had a thickness of over 100 billion light years? Then the expansion would resemble what we can see, no voids would be seen, and we would not know the direction of the expansion. Are you suggesting that the big bang was not an expansion of energy? First there is energy. Much later, after it cools down, a huge amount of energy congeals into a small amount of matter, E = mc2, so E/c2 = m.

Well temperature is proportional to energy so in a way it is just a matter of choice of units whether one talks about temperature or energy in this context. To my way of thinking the distinction between the role of modes is not real, since all degrees of freedom that are excited (at NTP in gases vibrational modes generally aren't) contribute 1/2kT each to the overall energy - which means temperature, in effect. Yes, pressure is proportional to the temperature (or energy) in the translational modes, but it is also proportional to that in the non-translational modes too, as they are all equal. One test of the idea that the translational modes are special might be if one could make a case that the flow of heat is transmitted only through translational motion. I am sceptical, since the modes all exchange energy.

That's not a level of knowledge, that's an age range. We're a science DISCUSSION forum. We talk about science topics. Videos are difficult to discuss, and take a fixed amount of time to view. We prefer the written word, where we can assess a post very quickly for veracity and accuracy. We can talk about subjects for your channel, but we have no interest in helping you promote your channel, which is usually what people want when posting their own videos here. We would love to talk about Earth Science with you. Watching you talk about Earth Science? Not so much.

This would be contributions from distant sources, as opposed to local ones, as well as contributions from any non-zero cosmological constant. Basically anything that stops spacetime from being completely flat before you account for any local energy-momentum. I agree, in this type of scenario you have clear causation in an operational sense. However, I was really thinking more of an isolated system where all parts remain in free fall at all times. Energy-momentum is locally conserved (the divergence of the tensor vanishes) - but then so is curvature (Einstein tensor). You cannot locally create nor destroy Einstein curvature, any more than you can create or destroy energy-momentum. You can only shift these around, and have them change form - so which ‘causes’ which? Not directly, but it contains energy density.

If light is not of sufficient strength, the plants will stretch towards the source causing weaker stem growth and greater spacing between leaf nodes, and affect synthesis resulting in some blanching. I suspect but say can't say definitively that longer 'days' won't alter that. Stronger light generally results in shorter, more dense and vibrant growth.

There is a special happy feeling knowing one is not part of a garbage fire. Didn't walk from Springer Mtn to Mt Katahdin, but I walked some of it in Vermont and NH. It's all common sense stuff - pick your time (e.g. not winter in the north, not high summer in the South), bring a partner you don't mind having inspect you for tics, bring mosquito repellent, sturdy hiking boots, etc. Keep food in a bag and hang it from a high tree branch when you sleep, never in your tent. Take increasingly long walks before the trip, for several months, to build up muscles and spot any joint/tendon issues beforehand. Keep socks dry. Watch out for the protozoan fiend of Appalachia, Giardia lamblia. Do your homework on finding a high quality water filter that will strain out Giardia - pump filters are the best. Boiling water is a monumental PITA. Ditto cooking. Dried fruit, oat bars, pemmican, peanuts, trail mix, powdered milk or powdered non dairy drinks, are all handy sources that don't need fuel to prepare. Don't gather trail sources of food unless you know exactly what you're doing. Blackberries yes, mushrooms no. No sustained eye contact with bears. Etc.