-
Posts
25528 -
Joined
-
Last visited
-
Days Won
133
Content Type
Profiles
Forums
Events
Everything posted by Strange
-
There are far more options than that. Many of which have been tried. As more and more evidence is gathered the idea of dark matter as some form of matter (rather than a modification to the laws of gravity, for example) is overwhelming. I don't think he is been hammered violently. He is been treated far more gently than many engineering project reviews I have been in. However, his proposal has a number of rather fundamental flaws. He is, naturally, being asked to address those. p.s. you might want to ask the mods to move your hijack to a separate thread... Kepler's law is simply irrelevant to galaxies and galaxy clusters. That is one of the many problems with this proposal. I suppose I could come up with yet another variation on the modified gravity theories that have been tried. The thing is, none of them fit the facts. And they use a whole set of ad-hoc assumptions.
-
Just using Newton's law of gravity is enough to show the problem. As this is an N-body problem, I guess that the expected behaviour can only be found by simulation (but I don't really know). Kepler's law is not applicable here for the same reason it is not relevant to galactic rotations. The Wikipedia page points out that there are three independent ways of calculating the mass of a galaxy cluster, and they are all in agreement that there must be much more matter than is visible. http://en.wikipedia.org/wiki/Dark_matter#Galaxy_clusters_and_gravitational_lensing (The same page also shows that I was wrong about Zwicky's observations of galaxy clusters being the first evidence that dark matter was required; apparently, there were earlier observations from the Milky Way.)
-
But if it were the energy stored by space, then dark matter wouldn't be mainly associated with matter (but sometimes clearly separated from it). I'm glad you said that. Actually, the initial requirement was to explain the motion within galaxy clusters (another piece of inconvenient evidence that you are ignoring). It was only later that it was realised that dark matter also solved the galaxy rotation curve problem (and several others).
-
Not surprising as Kepler's law is not applicable - for rather obvious reasons (that you refuse to address). You think they should just ignore the evidence and not attempt to explain it? By the way, how does your theory explain the gravitation lensing caused by dark matter? Even when separated from a galaxy...
-
Say your plate consists of 100 protons. (Disregarding the fact this impossible and therefore the entire argument is meaningless). Now add another one: there are now 101. Repeat. 102 protons. Repeat ... However many protons you add, it will be 100% protons. (And nonexistent.)
-
In a way, it a more complex version of a pendulum: the force of gravity tries to bring the object (disk, plate, pendulum bob) to a minimum energy state, but inertia makes the object it overshoot and so gravity then pulls it back the other way. Without friction or other energy losses you would have a perpetual cycle of restoring force -- overshoot -- restoring force -- overshoot ...
-
It is not clear what this questions means. (It is also not clear how it is related to the rest of the thread.) Is it simply: "Given the current state of the world, can one predict the future state?" This has been discussed in several threads recently. The answer is "yes, within limits". There are random process (at the quantum level) and chaotic processes which both make accurate, long-term predictions difficult or impossible. But actually, it looks like you are saying less than that. Are you just saying: "Is the world deterministic?" (any given current state, it will be changed by laws which operate on it). If so, again, the answer is yes. But some of those laws are probabilistic rather than purely deterministic (in other words, the laws define a range of possible outcomes).
-
When two planets collide what is their terminal velocity?
Strange replied to Robittybob1's topic in Classical Physics
You can confirm this with an online calculator: http://hyperphysics.phy-astr.gsu.edu/hbase/vesc.html Put in 1 for the mass (number of Earth masses) and 23500 for distance (the number of Earth radii) and you get a result of 73 m/s. -
When two planets collide what is their terminal velocity?
Strange replied to Robittybob1's topic in Classical Physics
See post 96 -
"Shall" sounds pretty dated to me, as well. I don't think the word is part of my idiolect.
-
There is a constant force there due to the presence of the entire mass of the Earth underneath. This force can be treated as if it comes from a point about 6,000km away. There will also be a contribution from the stone worktop, Moon, the Sun, Jupiter, Betelgeuse, the Andromeda galaxy and the rest of the universe. These all become increasingly insignificant (which is good, because they are all changing constantly). If you wanted to use maths, you could work out exactly how insignificant each one is. As it is, you seem to be saying that, locally, you can treat gravity as a constant force, even though its source may be a long way away. That is often true. But not always: consider tides, for example.
-
Citing a crank as a source doesn't really help your case.
-
Why? Googling for emissivity of lava brings up results with values between 0.83 and 0.9. Why would a molten not be similar to that?
-
Actually, I think it is more common as a suggestion/exhortion: Let's go!
-
How did you come up with this value? Are there any materials which have emissivity this low? Some materials which resemble parts of the Earth's surface: Asphalt: 0.88 Concrete: 0.91 Ice: 0.97 Snow: 0.8 to 0.9 Water: 0.96 http://en.wikipedia.org/wiki/Emissivity#Emissivities_of_common_surfaces The lowest value there is polished silver (0.02). So you are saying that the Earth's average emissivity is 10 times less than that. Sounds implausble.
-
I don't think so. But it sounds a little unnatural to me. And perhaps more of a demand, with an implied "or else" at the end!
-
Good point.
-
That was my understanding too (which would make Silber5's claims about LET untrue). But I am not that familiar with it, either.
-
Yes. The first is abnormally formal; I can't imagine anyone saying it in modern English. Actually, on second thoughts, the first could be interpreted as requesting permission: "Mom, [will you] let us ride on the train." (The second form can't be used that way.) Note that the comma is essential. "Mom let us ride on the train" has a completely different meaning. This is the comma of direct address, aka the Donner Party comma (*); it makes the difference between "Let's eat, Grandma" and "Let's eat Grandma". (*) What? Too soon?
-
Which researchers? Which group? What research?
-
When two planets collide what is their terminal velocity?
Strange replied to Robittybob1's topic in Classical Physics
That is the funniest thing I have heard for a long time. "88% of spreadsheets have errors" http://www.marketwatch.com/story/88-of-spreadsheets-have-errors-2013-04-17 -
Simply repeating the same argument doesn't really help. Especially when the universe contradicts you. You need to show that absolute simultaneity is consistent with the speed of light being the same for all inertial frames of reference. Or you need to show what is wrong with Maxwell's equations.