BLANDCorporatio wrote:Yes, he does. No, this doesn't mean his shows aren't usually full of bollocks as a result of some ill-conceived notion of dumbing stuff down/putting a sensationalist/speculative spin on things.
"Gravity doesn't pull; space pushes": ok, what does this mean? I know (a part of) what he means, but I don't think it comes across at all, which is why I'm no fan of his (or any) popsci.
0beron wrote:First, I think you're taking what is actually an analogy to explain the effect mass has on the "fabric" of space around it, and interpreting it as law. Physicists often use (and in some cases NEED to use) analogies to describe phenomenon that are not strictly physical in nature. More-over, the topic he's discussing is the relationship between TIME and space, not space/gravity by themselves.
And finally, yes I referenced a wikipedia article because that's the most easily accessible format...but it is all written from long established knowledge of gravitation as established by scientists including Newton, Einstein, and accepted/proven by modern physicists. While individuals such as Dr. Kaku might have their own way of describing it, I don't think ANY of them will deny that gravitation is an attractive force between any 2 objects.
Sorry for slamming your whole post based on this, I did go back and re-read and you made other good plot-point I like. But on this small aspect, you're just wrong (or at best, we're both right and they're different ways of saying the same thing), sorry.
BLANDCorporatio wrote:Here's the rub- Newtonian gravity works well enough most of the time to model what we see irl as gravity, and also the interpretation I know of it that's more modern (after Einstein) is not that far a departure from the concept actually. So I get (and agree with) what you're saying, gravity behaves like an attractive force. Also, I get where the "space pushes" thing comes from.
What I don't get, and this may be due to a gap in my knowledge, is why Kaku is keen on distancing gravity from pulling forces. Why would it be wrong to think about it in those terms. Maybe it's something about force unification and the models thereof, and the way they usually handle forces, and how those ways need to change to fit gravity in. I honestly don't know.
And, btw, I'm not finding out from Kaku, and it wouldn't be a justification, in my mind, to bash others who regard gravity as a force.
barawn wrote:I am a physicist, and let me say pretty clearly - it is a very bad idea to elevate popular science physicists, like Michio Kaku, Stephen Hawking, or Niel deGrasse Tyson to "these guys are authorities and every weird analogy they give must be right."
Pop sci physicists are typically theorists (if they're active physicists) or just trying to drum up interest in physics, which means they focus on "weird" stuff, like the crazier theoretical physics (like string theory, etc.). You have to understand, there is very little actual data backing up the crazy stuff these guys say. In some cases there's no data. They're just trying to make the little data they have look pretty in a way that they like. Or just putting out some crazy idea they've got. Roger Penrose was famous for having really nutty ideas that he made popular with absolutely no evidence.
Every few years or so, an actual result comes out from experimentalists that basically throws half of the wacky theories down the drain. Then you never hear about them again. So, really, don't give too much credit to what the theorists say. In a nutshell, we don't know how the hell gravity works. Only that it does. Anyone who says they do is fooling themselves.
I considered doing this as a PM, since it's off topic, but I'm trying to get input from 3 of you, so I thought that would be impractical. I know my posts get annoyingly long, so I will attempt to be concise, although such attempts often lead to the post above. So, I seem to have committed a logical fallacy, perhaps one of you can point out where I went wrong.
The scientific method is based on inductive reasoning. By it's very nature, it can only disprove things. It can never prove anything, because that would require disproving every other possibility, which is impractical if not impossible. So, scientists create theories and models to explain observable occurances. They create experiments to test them. If the experiments support the theory, it is still a theory, but it has support. If results contradict the theory, the theory is scrapped or revised. Here is an example. It was believed neutrinos have no mass, so they travel at the speed of light. Since they travel at the speed of light, time does not exist for them, and they never change. There are three types of neutrinos. The sun generates N electron neutrinos in a given span of time, and it only generates electron neutrinos. When scientists attempted to detect them, they were only detecting N/3 electron neutrinos from the sun. For a long time, scientist thought there was an error with the experiment. When they tested for muon and tau neutrinos as well, they found N/3 of them coming from the sun as well. So, the theory was revised so that neutrinos do have some mass, so time does exist for them, so the electon neutrinos coming from the sun can become the other types while traveling to the Earth. Also, neutrinos have been observed travelling faster than light, which, if it is supported, will mean the theory of relativity may need to be refined. Even a widely accepted theory, such as evolution through natural selection, is still a theory and can never be proven. Still, we all believe something. Every thought is my head is parroted from elsewhere, even if I can't remember from where. I adopt and accept the theories and beliefs that make sense to me and are explained/argued well to me. The alternative is to believe that we can't know anything and we can't prove anything which it seems to me would render any discussion moot.
Newtonian physics, according to my understanding, holds that space is empty. It is simply a place for matter to do its thing. Gravity propagates instantaneously. There is no attempt to explain how
it does it. It is the scientific equivalent of "a wizard did it." It works very well, but there are discrepancies, the classic one being the perihelion precession of Mercury. General Relativity, with the concept of curved space-time, seems to me to be the most widely accepted and supported theory that attempts to explain the how
of gravity. The basis is that space is not empty. Space is its own stuff with its own properties. Gravity propagates at the speed of light. What we observe as acceleration due to gravity is a relativistic effect caused by the observation of the inertial movement in a straight line of an object by a non-inertial observer. It is caused by space itself due to the distortions of space caused by mass. While there are discripancies in General Relativity as well, there is also a great deal of support, including the perihelion precession of Mercury, the apparent movement of stars during a solar eclipse and the frame-dragging effect observed by Francis Everitt's satellite.
Newtonian Gravity is very intuitive. I fit our perceptions. The very phrase "gravitational pull" has become idiomatic in English. I prefer the model that attempts to answer the questions Newton didn't answer, how and why. General Relativity is the most acceptable model to me that answers those questions. The difference between someone's perceptions and the best explaination of which I'm aware for the actual cause was the point I was trying to make. In a predetermined world, a family may be hiking. There is a landslide that kills all but one of them. The survivor blames a cruel god or fate. That is perception. In reality, the family was hiking at that moment because of foregone, predictable chemical reactions in their brains. The landslide happened at that moment due to soil composition, water saturation, the presence or absence of roots and other geological processes. While the survivor perceives fate as a malicious entity, fate is actually the solution of a complex equation. I wasn't trying to attack the assertion that gravity pulls, though. At the time, I just thought it was a clever opening to my response.
Dr. Michio Kaku is the co-founder of string field theory. Of course he has an agenda. He wants to get his theory to have as wide an acceptance as possible. He enjoys being a talking held. Television shows enjoy him being a talking head. After the earthquake in Japan, he did a circuit of the news shows describing what a nuclear meltdown was. Still, I wasn't using him as a source for his own theories. I was using his explaination of Eistein's, which, I'll admit, I made the assumption he had a good grasp on. I like his explaination, even if he is giving it his own spin. The fact that space-time is its own thing was a hard one for me to originally to wrap my head around, and I suspect it is a problem for others. Space has its own observable properties, such as dark energy, which barawn
mentioned. While one can discuss geodesics, gravitomagnetism or the observed acceleration in universal expansion, it is hard to understand without accepting that space-time is its own stuff, or at least it was for me. When I parrot Kaku by saying space pushes you down, it is a dumbed-down explanation, but I like because it clearly demonstrates that space-time is something that has its own properties and exerts an observable force, even if it is a relative force. Once I was able to understand space-time as a thing, I was able to understand things such as gravitational lensing and dark energy's role in universal expansion. While I may not buy everything the pop sci guys are selling, such as string field theory or quantum gravity, I think they do have value as a gateway to more basic concepts such as General Relativity.
I don't claim to be an expert on anything. I would describe myself, intellectually, as a jack-of-all-trades but master of none. I find almost everything fascinating. I read articles on physics, which leads to articles on astrophysics, which lead to articles on astronomy, which leads to articles on space exploration, which leads to articles on space suit construction, which leads to articles on textiles, which leads to articles on fashion. New things constantly catch my interest, so I move on to a new topic before mastering the old, only to eventually return at a later date. I know a show on PBS is not a peer-reviewed journal. The first thing I thought of was to find a clip on YouTube, but I found the transcript instead. It was just the first citation that popped into my head. Still, I can accept anyone's views. I may find them unlikely or prefer a different model, but I can accept the possibility they are right. A non-existence of evidence is not evidence of non-existence. Also, perceptions skews observations. I find it plausible that aliens have visited Earth. I find it equally plausible that space is too vast and no species has ever advanced enough to visit here. As I said in the beginning, we can never prove anything. So, I apologize that it appeared I was attacking those that support Gravitational Attraction. I apologize for bashing the Wikipedia article without reading it (although, in my defense, I've witnessed far too many people citing articles there as evidence that were just wrong. Although, that was much more a problem ten years ago than today.) Finally, I apologize to 0beron
. I perceived your response as dismissive and rude, so I responded in kind. It was both uncalled for and broke the One Rule. So, I am sorry.
Still, I can't understand when my brain melted. It all seemed so clear in my head, but I obviously messed up somewhere since something got lost in the translation. I'm not even sure if that makes sense.
As for the characters as PCs in a video game analogy, there are video games where the PC can't die. If they normally would die, they just get scars or lose money. There are also games where there is an inescapable event where the PC dies no matter what. That would remove the need to have a save function. Wanda could be a PC in a game the developers designed so the PC can't die until they decided he will die. Still, the analog to a quest NPC that has immunity until a scripted event is equally as valid.