A new planet
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Mar 29, 2014
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#4
Perhaps RPaulB is confused. Any political jokery aside, I have to take the peer-reviewed scientists' word that this is a planet, which is the interesting thing.
Yep.
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I alway heard that gravity travels at C.
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Mar 30, 2014
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#10
Slight problem.
We have plenty of photons from supernovae, from gamma frequencies to infra-red ones, that have in some cases travelled billions of light years. What these photons say is that you don't know what you're talking about.
Mar 30, 2014
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#11
Conflagration_Planet wrote:
I alway heard that gravity travels at C.
This is indeed a consequence of the Einstein field equations, and is consistent with all of the evidence. The evidence also shows that RPaulB's claim of gravity increasing for slow objects is nonsense.
If RPaulB could reproduce the prediction of the magnitude of the precession of the orbit of Mercury while rejecting general relativity, he would gain some credibility. With all due respect to him, I would bet at very short odds that this day will never come.
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Mar 31, 2014
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#13
Don't you know that general relativity does not distinguish between any type of energy? All that matters is the energy-momentum 4-vector at each point in space time. Dark matter is simply a sort of substance we have detected through its gravitational effects that is not yet detectible in any other way.
It's just no good saying (for example) "the precession of mercury is due to magic pixies moving stones between the objects and this is why light bends too". You have to make a quantitative calculation of the effect that magic pixies with certain properties (for example gravitons that "carry mass") would have , and then apply it to examples.
By the way, gravitons don't carry mass any more than light carries protons. So good luck with that.
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Mar 31, 2014
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#15
There is no detectible difference between GR and Newtonian gravity for a planet at that distance. Your claim the planet "does not fit with GR" is a complete figment of your imagination. This is not the behaviour of a scientist.
There is no conflict between any accepted scientific observation and GR. The observations do require the existence both of dark energy (entirely modelled in the cosmological constant) and dark matter (simply to explain inferred mass that is not known forms of matter). These facts do not compromise the accuracy of GR at all (it has allowed for dark energy since its first conception, and which makes no distinction between types of matter, so works the same with dark matter as with ordinary matter).
Elroch wrote:
Conflagration_Planet wrote:
I alway heard that gravity travels at C.
This is indeed a consequence of the Einstein field equations, and is consistent with all of the evidence. The evidence also shows that RPaulB's claim of gravity increasing for slow objects is nonsense.
If RPaulB could reproduce the prediction of the magnitude of the precession of the orbit of Mercury while rejecting general relativity, he would gain some credibility. With all due respect to him, I would bet at very short odds that this day will never come.
I agree.
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You say you are wrong ? Are you sure you are wrong ? No one in this forum is ever wrong. Ask them. I would like to know a little more about dark matter too.
Apr 5, 2014
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#19
Dwarf planets are a subclass of the class of planets, like gas giant planets are.
Apr 5, 2014
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#20
RPaulB wrote:
Instead of me proving GR is wrong with mercury
which you can't do. Indeed Mercury constrains accurate theories to a small class that makes similar predictions to GR.
why don't you prove GR is RIGHT by working out what Dark Matter is ?
That you ask this question indicates a very unscientific attitude. It doesn't matter to GR what dark matter is: GR does not distinguish between different types of energy at all (all that matters is the distribution of the energy-momentum 4-vector field). Indeed dark matter could be absolutely indetectible in any way except through gravity without compromising GR at all. At present, we don't know that this is not the case.
We already have limited information about the distribution of dark matter in our galaxy. https://en.wikipedia.org/wiki/Dark_matter_halo#Milky_Way_dark_matter_halo Such information will get more and more precise over time. GR could only be proven false if the gravitational field was shown to be inconsistent with being the result of a distribution of mass (strictly speaking, with the distribution of energy-momentum, but most of the energy has low gamma). I predict that as time goes by, theories that explain gravitational fields by other mechanisms will have more and more problems with the data (as they already have serious problems with some observations).
For an interesting example of a possible dark matter phenomenon, see http://www.sciencedaily.com/releases/2006/07/060703163148.htm
http://www.washingtonpost.com/blogs/the-fix/wp/2014/03/26/scientists-maybe-found-a-new-planet-in-our-solar-system-its-called-biden/