swansont

If there’s no past, present or future, because they are human constructs, how is it that “relativity implies a block universe, which is to say that the future already exists”? If future is a human construct, not part of relativity. These statements are inconsistent.

Your scenario “If a time traveler went back in time and changed something, no matter his motivation, could we know?” requires that time travel be possible. They are based on what physics has to say. But there is no scientific basis for this, because it’s not based on science. You can propose whatever you want, but like most fiction, if you delve too deep Into detail you will find problems. How does a memory get erased? How do things broken in one timeline get repaired if they don’t get broken in the new one? But you can propose a different answer and have the same justification that that would be how it goes. An experiment, even a thought experiment, has to have a consistent outcome.

Time travel is theoretically possible under specific conditions, but the kind of arbitrary time travel you describe is not. Here’s a link from the other time travel thread describing what can and can’t happen with time travel https://www.preposterousuniverse.com/blog/2009/05/14/rules-for-time-travelers/ I don’t see where I ridiculed you or suggested that there was deception. I critiqued your conjecture, and you’ve been here long enough to know to expect that. Getting feedback should allow you to improve your question.

I don’t think this is a true statement. How does it imply a block universe, where “the future” already exists? What future? IIRC the possibility of time travel is limited, it’s not arbitrary. You can only go back to a time after you built a time travel device. edit: #8 https://www.preposterousuniverse.com/blog/2009/05/14/rules-for-time-travelers/

Also note that the Hawking radiation, strictly speaking, doesn't come from the BH itself. The effect is initiated at the surface or just outside the BH. So both statements can be true.

The thought experiment is underconstrained because it’s fictional. How can you be sure that people don’t turn bright plaid when they time travel? Because they chose that to be the story line. It’s fiction. How do you know the memory wouldn’t exist? Why does this have to be true? It’s just an assertion. There’s no science that backs this up. You could just as easily assert that we would know. We could get temporal headaches and crave chocolate milk.

I don’t think they know the actual truth, because they accept whatever fiction TFG, or FOX news, etc., peddles, as truth. I’m not sure what would happen if they stopped making stuff up, but why would they? Also not sure what this has to do with answering my question.

Here’s math that shows what the temperature needs to be for the universe to not be opaque; it’s around 3000 K https://thecuriousastronomer.wordpress.com/2016/06/13/the-temperature-of-the-universe-at-recombination-decoupling/ https://ned.ipac.caltech.edu/level5/Sept02/Kinney/Kinney3.html That happens at a redshift of around z = 1100

The CMB is not a remnant of the big bang itself, even though some descriptions say or suggest this. It's from the recombination, which happened about 380,000 years after the big bang, when the universe was cool enough to form atoms without them immediately ionizing again. That happened everywhere, so the radiation is from everywhere in the universe. The universe has expanded since then, and so the radiation has cooled https://www.cfa.harvard.edu/research/topic/cosmic-microwave-background#:~:text=Light from recombination was very,as the cosmic microwave background.

Right, but there is no semi-classical Bohr-like model to lean on here. By the time we knew that neutrons and protons were composite particles we knew about wave-like nature of the constituents, which means they take up space. At the time of the Bohr model they were considered hard spheres.

They can have a rough finish, but it's more that they have curved convex surfaces, so even with a glossy finish, the light diverges upon reflection.

As TheVat was hinting, the notion is derived from the Bohr atom picture of a small nucleus with some electrons in planetary orbits. Much like our solar system, if you only counted the sun and planets, most of the volume of a sphere defined by the outermost orbit is mostly empty. Virtually all of the mass and occupied volume is at the center. Fundamental particles, though, not composites. Neutrons and protons do have a size.

Once you’ve decided to violate physical law, lots of fictional scenarios become possible.

I asked “Are there any polls saying that this is a big issue with voters not already going to vote for TFG?” So items of interest to GOP voters doesn’t answer this question. Most/all of them are voting for TFG. They are not the ones who will be convinced by facts, anyway. They’re too far into the cult to be deprogrammed.

Light hitting at a large angle, as measured from normal (90 degrees). It just “grazes” the surface Reflection at 90 degrees (called normal incidence) reflects about 4%. As the angle increases it goes up for parallel polarization, and drops for the perpendicular polarization (it goes to zero a Brewster’s angle, where all light is transmitted) and then increases. Out at 70+ degrees reflection is quite strong, but it would be difficult for you to have sunlight reflected into your eyes at a large angle. I wish I had thought to mention that 😉

! Moderator Note I said we’re not going there

It’s a book. Which means it’s not peer-reviewed. And was written by a neuro-psychiatrist. Your own source says it’s not possible to say that there is cellular intelligence, so how do you come to that conclusion? Other of your sources say “It is argued here” and “if the results stand up” which indicates that these are not consensus views.

No, it’s a diffuse reflection, but since there’s a lot of area undergoing reflection and not much to absorb the light, it’s very bright. Glass transmits a lot of the light, and only reflects a lot at grazing incidence.

! Moderator Note This is just a re-post of previous material. No outstanding questions have been addressed, and there is still no mathematical framework. Don't bring it up again.

! Moderator Note We're not going there. This is off-topic and bad-faith framing of the discussion.

It's not a scientific hypothesis, and the evidence against biblical creation is legion. There are scientists who accept the existence of a deity, but for many it probably boils down to the words of Laplace, "I have no need of that hypothesis."

Diffuse reflected sunlight is not all reflected sunlight. Specifically, it excludes specular-reflected sunlight. Anything that acts like a mirror is undergoing specular reflection. A car has lots of convex curved surfaces, so it probably reflects less light into your eye - you wouldn't see the image of the whole sun, which likely mitigates the danger. Also, look up snow blindness. A situation where diffuse reflection can be a problem.

Homo sapiens has always walked upright; that behavior predates the species. Yes, humans and chimpanzees have a common ancestor. Which means that a chimp did not turn into a human, as you claimed.

If only one could use a search engine to find basic information like this https://en.m.wikipedia.org/wiki/Recent_human_evolution (bipedal locomotion started perhaps 6-7 mya, so this is actually a pretty tame threshold. A lot of variation in humans has occurred since then. Homo sapiens emerged a few hundred thousand years back, so there’s been speciation since then)

Are there any polls saying that this is a big issue with voters not already going to vote for TFG? “68% of Americans say immigration is good for the country today” 27% say it’s bad, but if they are already in TFG’s camp, it’s not going to sway the election. https://news.gallup.com/poll/508520/americans-value-immigration-concerns.aspx And, as Phi has suggested, the do-nothing GOP can be blamed for not passing legislation; the president can’t pass laws by himself. It might also be pointed out that this is a manufactured concern (surprise!) seeing as the number of immigrants in 2021 was about 1.5 million, lower than any pre-pandemic year this century. It was ~2.5 million a year under TFG, pre-pandemic https://usafacts.org/state-of-the-union/immigration/