If you’ve ever wondered about dark matter, or been asked puzzled questions about it by your friends, now you have something to point to: this charming video by 11-year-old Lucas Belz-Koeling. (Hat tip Sir Harry Kroto.)
Dark matter draw my life style
The title references “Draw My Life style,” which is (the internet informs me) a label given to this kind of fast-motion photography of someone drawing on a white board.
You go, Lucas. I doubt I would have been doing anything quite this good at that age.
All points noted Gary. As for exaggeration, I’ve felt the wrath of the WIMP guys. And as for experiment, I’m not proposing one, nor am I advocating MOND. I just want people to pay attention to general relativity instead of forever banging the drum about dark-matter particles, as if relativity never happened. Yes, something “noninteracting and dark” is there: inhomogeneous spatial energy, which has a mass-equivalence and gravitational effect. Sadly ΛCDM employs the FLRW metric which “starts with the assumption of homogeneity and isotropy of space”. That’s a totally wrong assumption. Space has not been expanding uniformly. It can’t be homogeneous.
I read the comment written by Sparsh Joshi, it made me feel spechless. Did he know me, and imitated me and made fun of it? Jesus
John D:
depends on what you mean by particle – is it restricted to bosons and fermions
or is it anything with a complex phase that is more or less in the ballpark of fermions – if it is a bundle of energy then one can call it a particle, no matter how weird it is. It is logically possible to consider things that look like quarks but have no color, or have color but not ordinary spin – and are very different from leptons. It seems unreasonable to expect a Z to decay into pairs of these weird things.
Joel: the important criterion is stability. The only stable particles we know are photons along with neutrinos, electrons, protons, and their antiparticles. The Z-boson decays in 10^-25 seconds, it hardly exists. We’ve never seen a free quark, or any of the exotica proposed by SUSY. But we’ve known for a hundred years that “the energy of the gravitational field shall act gravitatively in the same way as any other kind of energy”. And that a gravitational field isn’t made of particles. But inhomogeneous spatial energy never seems to feature in any “dark matter explained” articles. Talking of which, I wrote one here when I was blogging last year. I should try to write up this sort of stuff as a paper I suppose, maybe with a co-author with some credentials to ride shotgun.
You got a point there Joel. In a way, saying dark matter is particular in nature is really just saying that it is something that is quantifiable. I think it is no surprise really that a lot of physicist have jumped on the dark matter particle band wagon. What are the other options really? Are we supposed to have them all advertising that General Relativity is just wrong and the greatest scientist of our time was in error with little support or evidence? They would be lucky to keep their jobs or even get hired in the first place. I don’t know anybody that would hire a physicist that would say that physics is wrong and one of the greatest physicist of all time was in error…
Strange, I had a dream last night that I was doing barrel rolls in a jet. I noticed that as the jet turned it distorted the image of the inside of the cockpit. Then it occurred to me that it wasn’t supposed to be able to do that. Then according to Einstein light curves in an elevator. I never seen things become distorted from riding one of those either…
John and John.: might have 4 generations of ‘dark oscillators’ – analogs of fermions and bosons, but different. I have no idea of whether one generation is stable and the others not. I thought of a cool 3d octonionic cubic/tetrahedral lattice approach but am just beginning to think about the simple stuff and reading t’Hooft and Creutz, and am more inclined to look at why muons are unstable than to worry about dark matter right now. Muons are weird enough ! I.I. Rabi said so. One has to be very careful about assumptions.
“What about baryonic dark matter?”
Not possible due to BBN constraints. Don’t understand? Look it up. These days it is easy.
“How did scientists falsify a repulsive electromagnetic force and deduce that a new force, dark energy, is pushing matter in the universe apart?”
Are you claiming that things in the universe are moving apart due to electromagnetic repulsion? It doesn’t fit the data. By the way, dark energy (as Sean has pointed out, a bad name; if you don’t want to call it the cosmological constant, call it smooth tension) doesn’t push things apart. We have known that the universe is expanding before we knew it was accelerating, but not because it is being pushed apart; it’s due to the initial conditions.
“That’s a totally wrong assumption. Space has not been expanding uniformly. It can’t be homogeneous.”
Where is your evidence?
Here. Look into gravitationally bound galaxies. In the raisin-cake analogy, the cake expands but the raisins don’t. Ergo space expands between the galaxies but not within.
John D, it makes me think that dark energy can be counter acted by gravitational forces, and they are somehow related. That would imply maybe it is a new theory of gravity we are looking for to explain dark energy.
If you looked at relativity in a way where time dilation didn’t really have much to do with the frequency of the clock in the light clock example (it had more to do with the measurements of the sides themselves), then spacetime dilation would be an actual consequence on measuring rods and rulers. If we thought of it that way, then length contraction would be an actual consequence on reality or spacetime itself.
If the universe was made only of energy close to the moment of the big bang, then the appearance of mass would make length contraction act in reverse. Material in the universe would slow down, so length’s would become larger moving much more slower than the speed of light than it was traveling at before.
Looking at it that way, all it would take to create the big bang would be a conversion from energy to mass somewhere in the universe. Then dark energy could cause expansion faster than light, because there is no speed limit to how quickly space can expand or contract so that two observers will always measure the same speed of light. In other words, there is no limit to the rate of change of length and time dilation in relativity that would be caused by a drastic change in velocity.
The universe itself may be zero in size from the frame of reference of light, and it never existed. It would just be the frame of reference of “mass” and “matter” that would make the universe appear to be larger in size.
John D, John Barrett, and then, also Phillip/Sean/every one:
Is that right? Do the raisins really don’t expand even as the cake does? Is this an experimentally observed fact? (Or at least, is it a fact that the raisins expand at some +ve rate that is much, much less than that of the cake, even if not zero?)
… I mean, I have no background in this area at all, and so, just wanted to have this assumption confirmed by those who know about these things. … If true, then, from what(ever) I gather, it should open a door to much simplification.
Best,
–Ajit
[E&OE]
It is true that the galaxy or any individual galaxy is not expanding with the expansion of the universe (that dark energy is held responsible for). Although, the expansion of the universe is seen as galaxies moving away from each other. Dark matter is held responsible for galaxies having stars in their orbits as tightly as they are seen to do, and dark energy doesn’t affect the inside of galaxies for some unknown reason. General relativity is unable to explain the gravitational forces of a single galaxy alone. That would make the theory only to be completely accurate on the scale of our solar system, because they galaxy would be the next scale up from that. Then dark matter can affect clusters of galaxies. I hope that helps, but it seems like it makes everything a lot more complicated.
P.S. Before the modern age and light pollution, the Milky Way galaxy could be seen with the naked eye, and it remains static in size.
Dear John (Barrett),
Thanks for your informative reply. Looks like what I gathered is way too little.
Re. your PS: I actually have very vivid memories from my early childhood (around 2nd and 3rd standard) when we would live in a jungle area (in Maharashtra, India), where there was no electricity, and of course no dust/smoke pollution, and so, the milky way could be very easily seen as a distinct patch majestically spread all over the night sky. I also remember how its shape would be different on the early winter mornings and then on the night of the same day. … And the stars would actually sparkle as if they were bright crystals… Got my introduction to constellations back then, starting with, as it usually happens in India, the “saptarshi” (Ursa Major)… You use it to locate the “dhruv taaraa” (North Star). … And, I also distinctly remember how, back then, I could easily see with the naked eye even the “arundhati” star (Alcor). … Impossible now. [sigh.]
… Anyway, thanks, again.
Best,
–Ajit
[E&OE]