For what I could gather so far, it is legitimate the way that Steady State was legitimate a few decades ago: sure, it could be that way, but there is very strong evidence for Dark Matter and not much to seriously dent it so far.
Itâs not a paper disputing the existence of dark matter but a paper trying to explain what causes the effects of dark matter. So far WIMPs arenât looking too promising because we havenât detected any.
No. itâs a paper trying to explain what causes the observations, without the need of dark matter, assuming that some of the most elegant but forcibly admitted current known laws of physics could be âincompleteâ, not to say wrong.
On page 42
Again, dark matters looks like an artifice to me, and Iâm glad some scientists try to find a more elegant way to describe our universe. I violently caricature, but currently itâs like âlook at my theory : it explains 99,9999% of the observations we make, and it predicts a lot of phenomena never observed yet (but that will be observed later), if I multiply this parameter by 6âŚâ
Einstein was the most incredible and unreachable mind of humanity and his theory is incredibly elegant, and his understanding of the universe is largely too far for me. But he didnât find the theory of Everything. His theory is incomplete, in the same way as quantum mechanics is according to his own words.
That opens a wonderful door for the future of science, to think that weâre not able to explain every phenomena with our current theories, even if that doesnât prove weâre right or wrong about dark matterâŚ
I made science speculation for this here. For things not proven or at least not popularly accepted.
And on a side note: just assume everything about nature âweâ believe in is wrong. We shouldnât let our beliefs become fossils. âweâ have been murderously wrong before.
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We are saying the same thing. Dark matter is just the name we give to the causes of the effects seen. Why are you disagreeing ?
We never stopped trying to figure out what causes the effects of anomalous gravitation pull and this is another theory that will be tested. Most things you hear in popular science are just analogies to explain the concepts. Call it whatever you want the effect is still there.
Dark matter is just what we call that thing that causes the anomalous gravity that we see the effects of. The effects surely exist despite whatever name you want to call it. The investigation has been happening for decades and will continue for decades because there will always be somewhere deeper to ask questions.
You shouldnât prop people, science, or anything on a pedestal. Moderation is the key to success. Science is a very useful investigation tool and there are notable people whoâve used it with great results, but romantasizing it takes away from what actually happens: creating a theory, making claims, and trying to break those theories.
Thereâs nothing wrong with fudge factors. If I multiple by the wrong answer by some factor and it gives me the right answer every time and in every instance, whatâs the issue? For example, if I multiply the diameter of a circle and a fudge factor I get the circumference of the circle every time. That will never be wrong, so whatâs wrong with it? Iâm merely playing devilâs advocate, but whatâs wrong with big G? Maybe itâs just another of natureâs constants. For reference big G is is the gravitational constant and little g is usually 9.81 m/s^2.
Not everything we know is wrong. There are certain aspects of physics that we know for a fact. We have derived E&M itâs a done deal. Maxwell put it together in the late 19th century and is described very elegantly by 4 equations. Relativity was hidden inside Maxwellâs equations and led Einstein to realize that there is a speed limit on the universe and time is what has to give. Feynman reconciled it with QM in the 50s. Nothing will ever move faster than C through space-time. Iâm being as specific as possible so that doesnât include the process of wormholes or warpdrives that are loopholes around moving through space-time.
I didnât say that.
Just assume it is wrong. It makes correcting things easier.
Study State Universe. There is no life on other planets. There is the Milky Way and a few quasars and that is all the universe.
Science doesnât make laws any more as they keep being overturned. The oldest law is from Plato, it states : Anything that is extended is made up of smaller things. If String Theory is adopted it will end Platoâs law 
As far as we know with our current understanding.
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You take all of it too literally. Back in the day thatâs just what you called it because it was custom. Obviously, what we know and our customs have changed today. It makes no difference to call it a law or theory other than the semantics people will argue.
Newtonâs law works because here on Earth they work with a small degree of error in practical cases. Relativity is the next step, and like Newtonâs laws, it works with an even smaller degree of error in most cases.
Then you either misunderstand what Iâm saying or do not understand relativity. If you study relativity one of the axioms is that the maximum speed of moving through a medium is the speed of light. There have been a lot of experiments testing relativity and relativityâs predictions have been correctly observed. I specified that c is the maximum speed for moving through space-time you wonât get faster than that while moving through a medium.
Thatâs why I mentioned something like wormholes or warp, because thatâs the only way you can create a loophole to get to point A to B faster than light because youâre not actual moving through space-time, just taking a shorter path outside of spacetime. Since speed is distance/time changing the distance will change your speed. For example, in space-time the distance traveled might be 5 light years and you do it in 1 year thatâs faster than light, but taking a wormhole route might only be half a light year, so you actually never moved faster than light along your path. Thatâs the only way you could âmoveâ faster than light, but youâre not actually moving through space-time faster than c. I hope this makes sense.
âŚLight traveling through a vacuum and some more things and also things that travel faster than light canât deliver information. Einstein never said said nothing can travel faster then light. How long before Einstein is treated like Newton?
Donât be arrogant with what humans know. There is so much more to know and so much we have wrong.
Getting treated like Newton isnât all badâŚ
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Iâm really not sure what youâre trying to say.
This is wrong. That is a basic axiom you have to accept to get anywhere in relativity. The finite value of c and its consequences have been challenged and observed by humanity for over a century at this point. Iâm not being arrogant or saying that we know everything, Iâm just stating what we have observed and that weâve never measured anything traveling faster than c in our universe in over 13.8 billion years. Iâm personally not holding my breath.
Itâs difficult to talk about it without talking about it with math. If youâre really interested in trying to figure out what more we could be wrong about I encourage you to research more about relativity so that you understand it better. In fact, the basic geometric derivation(using trains or cars and a light clock) of the lorentz transform can really help the fundamental understanding as well and I would start there.
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disclaimer: I am not an expert, I am not a physicist, I am not an astronomer. I have no idea what I am doing.
From discussions Iâve read about this paper, Iâve been led to understand that it states specifics of three major problems/âdark spotsâ in gravitation:
- Gravity on quantum scales
- Accelerated expansion of the universe / dark energy
- Extra gravity in places where we donât see matter, e.g. in the rotational speed of galaxies / dark matter.
Doesnât dark matter present a much larger problem than just rotation curves? Wasnât dark matter conceptualized not because of rotation curves but to explain how the large scale structure of the universe formed?
By my understanding, he solves these 3 issues of gravity by giving the theory that when matter is created some of the information associated with space gets localized into matter. This in turns a cluster of informationless space around the matter. In his model the comparison of information associated with matter, we can calculate how big the area of space is that matches the amount of information in matter, so we can calculate how big the area of informationless space around matter is, i.e. roughly how far away from the matter you have to go until the space is again filled with information. It turns out that this distance matches experimental observations of dark matter in galaxies. His theory seems only to portray dark matter as a force due to the creation of matter, but his theory predicts the relative amount of effective dark matter to normal matter.
The limitations of his theory do come to a halting stop when you think about something like the Bullet Cluster, and if this was really hitting on the nail, it would shed some light on it.
To supplement the Einstein discussion: there is nothing in the theories of relativity that explicitly negates the potential theory of faster than light travel. It is conclusive that accelerating past c is âforbiddenâ, as speed ends up asymptotically approaching it as you keep accelerating.
However, things are more complicated than saying âwell, stuff could go faster than lightâ. An example would be putting a speed greater than c into the equations gives results such as an imaginary (in the mathematical sense) mass for the particle. We have really no idea what that would physically mean, imaginary numbers never intrude into reality anywhere else. These kinds of thing, along with the lack of any experimental evidence for any kind of greater than c effect, are a strong suggestion that faster than light travel is not really possible.
That said, these problems do not constitute a proof. Also, even if faster than light stuff doesnât happen, itâs interesting to look at what our theories predict if it did.
Faster-than-light
https://en.wikipedia.org/wiki/Faster-than-light
FTL travel of non-information[edit]
In the context of this article, FTL is the transmission of information or matter faster than c, a constant equal to the speed of light in a vacuum, which is 299,792,458 m/s (by definition of the metre) or about 186,282.397 miles per second. This is not quite the same as traveling faster than light, since:
Some processes propagate faster than c, =====>>but cannot carry information <<=====(see examples in the sections immediately following).
Light travels at speed c/n when not in a vacuum but travelling through a medium with refractive index = n (causing refraction), and in some materials other particles can travel faster than c/n (but still slower than c), leading to Cherenkov radiation (see phase velocity below).
Neither of these phenomena violates special relativity or creates problems with causality, and thus neither qualifies as FTL as described here.
In the following examples, certain influences may appear to travel faster than light, but they do not convey energy or information faster than light, so they do not violate special relativity.
And more on a simple hunt! https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=things%20that%20travel%20faster%20than%20light
I had a boring childhood and watched way too much PBS.
Great! I see weâve arrived at the same conclusion then.
Case closed.
I had a boring adulthood and studied this.
oh shi-
And ten more
I just read an interesting idea that would explain the universe expansion, without the need of an accelerating expansion , and so without the need of dark energy. the article is in french and consist on an explanation of this idea by David Elbaz (astrophysicist)
I just found this in english
Oh my God this is amazing.
âAnd if you convert it back to molecular hydrogen, all that energy is released, so it would make it the most powerful rocket propellant known to man, and could revolutionize rocketry.â
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Unfortunately that also means itâll revolutionize weaponry.
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In the paragraph after that quote the author notes that the specific impulse would be around 1700 seconds. I have no idea how they came up with it but it would be useful provided it has good thrust, could be stored, and ignited on command. However, thatâs definitely not the most efficient fuels we have. Already, we can ionize xenon and boron at get them up to 2000-4000 seconds in electric engines but with far less thrust.
I think it may be an antimatter like novelty for awhile unless it is much much easier to generate and storeâŚI only skimmed but I didnât see an amount generated but did see that it required a ton of energy and pressure(~480 GPa) and diamond anvils. That canât be cheap.
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The difference is that MH would also give high thrust (without the N-word inconvenient of Orion). That said, at 6000 K, MH has such a high working temperature that no chamber can hold it, so actual ISP would be lower.
Note that this article is click bait. We were already pretty (though not quite) sure about the existence of MH, so this isnât a revolution. On the other hand, the big uncertainty of whether it is metastable doesnât seem to have been answered.
And If metastable MH can be made, the question will be whether it can be safely stored. No one wants to store 100MJ of power in a battery or an entire rocket tank of something that may spontaneously revert into 6000 K hot, detonating hydrogen if a stray cosmic ray hits it