Strange

Yes, most of them are still active

I would say it is different because the brain constructs our concept of the present from inputs that come from a variety of sources that can differ by up to almost a second in the time they happened. Plus, it fills in any missing bits using memory and invention. And the concept of a continuous present (or even a continuous world around you) is also an invention of the brain. You get intermittent inputs; for example, the input from your eyes are ignored during saccades movement but you don't notice because the brain fills the gaps by back-filling with the signal you get after the movement stops. You get varying quality information; for example peripheral vision is fuzzy and monochrome and yet you see a detailed colourful world even out of the corner of your eye.

[And I have done it again, too! Sorry.]

No. It doesn't apply to all science and physics. It is not even the "common thing". There are very many things that we know with a great deal of certainty (that is nearly all of science and physics). There are some things which we are not completely sure about. And there are some things that we are really unsure about. The important point is to understand that in those cases, it is OK to say "we don't know". That is not the same as saying "everything is a guess".

Look, there is a big difference between data, based on actual measurements, and guesses. For example, we can measure the distance to the Moon, just as easily as you can measure the size of a piece of paper. Similarly, we can measure the brightness of Betelgeuse. Because we can measure it, and gather data, it is NOT a guess. A "guess" would be that the moon is the size of a penny and only about a metre away. A "guess" would be that Betelgeuse is as bright as the moon, or the sun or a candle. But science does not use guesses. Science uses data based on measurements. Why is that so hard to understand. There is a huge difference between "science uses data based on measurements" and "science is just a guess". Only someone who is deliberately trying to start an argument would say something like that. [Edit: cross-posted with swansont's comment about this being off topic]

Try a dictionary. I will report this for trolling and suggest the thread is closed.

The brightness of Betelgeuse is measured. Therefore not a guess. (Vacuum decay would be off topic so I am not going to discuss it other than to say the theory is based on measurements. Therefore not a guess.) No. I didn't say that.

For example, imagine you look at Anna on the other side of the room and you think she is about 1.60m tall. That is a guess. (Or, perhaps, an estimate based on the size of things around them. If I asked you how tall my cousin Bob was, then that would have to be a complete guess.) On the other hand, we could get several people to measure how tall Anna is. We might get numbers like 1.72m, 1.71m, 1.69m, 1.71m, etc. From this data (ie. actual measurements) we can can calculate not just her height, but also the errors or accuracy of the measurements.

That is a good summary of the methods being used and the results. I would caution that trying to predict future behaviour based (purely) on past behaviour is fraught with all sorts of risks. If we don't fully understand the mechanisms and causes, then it may not be much better than trying to predict the weather based on what it was like yesterday. No. There is a big difference between a guess and data (even if we know the data is not 100% accurate).

Or, to put it another way: we don't know. One of the most important (and hardest) lessons to learn in science is that "we don't know" is a valid answer. And often it is the only, or the best, answer we have. All other answers have a level of uncertainty associated with them, so we rarely (if ever) know things for sure.

Could you explain why you think a "a body of mass M" is not a "mass density distribution". And can you also explain why this is required. That would be much more helpful. Thank you.

Not sure it is what you are looking for, but this is a really good overview of what the equations of GR mean, and what the consequences are (in relatively simple mathematical and physical terms) for some special cases: http://math.ucr.edu/home/baez/einstein/

Oh, it's on the tip of my tongue ... what's the word for something that sounds profound but isn't ... Our brain wants us to think it is. But actually, it happened a while ago.

I would say it is an illusion. When we think we are perceiving the present, it is something that has been created by the brain from inputs spread over several hundred milliseconds. So, really, we are living in the past (or pasts) but are completely unaware of it. The only time we notice it is when we experience illusions like deja vu or chronostasis.

That is not a new theory. And not really a theory, just the meanderings of a philosopher. Also, you shouldn't link to such appalling examples of "journalism" (blogging). Note the complete lack of proper references, for example. And no mention of the fact that Dr.Skow made these statements when promoting a book he wrote.

It has always varied. Form what I can see in the graph, the variation has decreased as it has got dimmer. (But it might have stayed the same as a proportion. One would need the raw data to know that.)

It would be spectacular. And we would learn a huge amount about how stars work. That nothing interesting happens.

That is the best outcome. But it isn't likely to happen soon. I don't know how much the variation is due to measurement error (difficulty measuring the brightness, effects of the atmosphere, etc) and how much is due to the brightness varying a lot. I think one of the effects is convection in the outer layers of the star. This would be very variable.

As you can see from the graph the (measured) brightness varies quite a lot over the short term. That means it can be hard to be sure whether the dimming has stopped, is continuing or has reversed. Only time will tell. Anyway, the absolute worst that can happen is that it completely fades from view (but I'm not even sure if that is possible).

! Moderator Note As noted, you have had good answers. If you don't like them then you would need to produce evidence that shows them to be wrong, not just resort to insulting people. (And that goes for everybody.)

They don't learn it. That is what "instinctive" means. Although very few things are purely instinctive (in higher animals). If you wanted to build certain behaviours in to an AI (by suitable programming) I'm not sure why that would be "pseudoscience". I heard an expert in AI saying that we probably hadn't reached the level of a frog yet. Presumably it will have been given the goal of finding the most efficient mode of locomotion. Or perhaps of imitating human locomotion. Quite possibly. Genetic algorithms are commonly used to develop used to develop optimal engineering solutions. But we can also short-circuit the need for evolution by doing "intelligent design". Who says they need to be the same? Who says they need to be acquired? Baseless assertion. And who says that they need to, anyway?

! Moderator Note This is not Science News. It is not even science. Move to a more appropriate location.

Exactly. Did anyone say otherwise. CRTs work pretty well. And SLAC.

If the universe is finite, then it is curved such that if you went off in a straight line you would eventually end up back where you started. Like flying round the world; you eventually get back to the place you left. And the very large time is because the universe is very nearly flat. So if it is curved, it is like a very large sphere that looks nearly flat (a bit like the Earth when you look around you) so it would take a long time to go all the way round.

Eternal means existing for an infinite amount of time. Even if the universe had a beginning (we have no evidence of that) then it could still go on existing for an infinite time n the future. According to that law, whatever matter exists now must always exist so the universe must always exist and so it must be eternal. But ... it is actually a law of conservation of matter and energy (matter can be converted to energy and vice versa). The fact that matter cannot be created or destroyed does not mean that it is finite. If the amount of matter is currently finite, then it must always have been finite (ignoring some being converted to energy and back). If the amount of matter is currently infinite, then it must always have been infinite. Current theories say that the universe does not have a boundary. Either it is infinite or it is curved back on itself. No, we don't know that.