Re: Physicists discover that the structure of a brain cell is the same as the entire universe….

It is implied that it is composite.
Dark Matter would not be seen on it for,……

While the original article left me dubious on its validity and scientific value, your replies and those of others above really got me thinking… and left me lost in their wake.

As a casual observer of the cosmological and astrophysical scene, as well as an avid reader of Universe Today, all this left me more confused than ever. And even more skeptical about the scientific interest of the articles presented herein. I'm not too sure anymore of what credibility I should attribute to UT !

Thanks (sort of, lol)

About the non-testable predictions of String Theory: Let's wait a year or so.. The Large Hadron Collider at CERN is only about to begin operation.. There might be some interesting new observations at the energy levels it will reach. Maybe there won't be any surprises at all, but I definitely doubt that

the universe is keeping its mysteries for now.

it would be very interesting to me if we eventually discovered that the speed of life and force of gravity were in fact not uniform throughout the universe.

how strange and intriguing this all is to ponder. sometimes i look at the sun and can't believe it ever even formed.

What was taken as a shorthand to describe effects that couldn't be readily explained has taken a life of it's own beyond the original meaning, especially in a sound-bite culture

I don't think you know what you're talking about here. Dark matter is merely matter that does not emit any form of electromagnetic radiation. Because the matter in black holes does not emit light, you can say it is in fact dark matter.

I submit that quantum entanglement and quantum tunnelling are evidence supporting multiple dimensions.

Spontaneous quantum eruptions of paired particles in empty space is supporting evidence of multiple dimensions.

String Theory's consistent Quantum Theory of Gravity works where the standard model never has. Supersymmetry eliminates Quantum Theory's open-door-policy on spectacularly absurd particles like Tachyons.

A multidimensional universe, like dark matter, is still one hypothesis, unproven, but also like dark matter, has a statistically non-random positive distribution of supporting evidence, and an absence of directly conflicting evidence. Just because one scientist uses a telescope, and another uses mathematics doesn't mean either has the superior approach to the truth."

You miss the point. There is no observational evidence to support more than 3 space and 1 time dimension. It is a great disappointment; we casually bandy about the idea of multiple dimensions all the time, and it becomes part of our way of thinking. But the best research finds no physical evidence of multiple dimensions. Believe me, I was shocked to find this out. The real universe cold, cruel, and simple. One, two, three, and it only moves in one direction in the fourth.

The quantum phenomena are not evidence of multiple dimensions, they are predicted as events with a non-zero probablity. The string theories, as we all know, have not yet made any testable predictions. SR and GR make and have made many, many testable predictions, using 4-space, and have passed them all with flying colors.

Your postings are most informative and well considered. "We need to keep open minds, and explore ALL the possibilities" is so relevent in matters of cosmology. That said, I would like to acknowledge Jovica Aleksik's reference to "Dark Matter, Dark Energy" DVD course from The Teaching Company. Yes – a bit pricey (you can get the package during one of their frequent sales) but I could not stop watching the entire course, almost at one sitting! Sean Carroll from Cal Tech did the presentation. I can not do the material justice here (or anywhere else for that matter) but the thread that I got from Dr. Carroll's class was his openess to "ALL the possibilities" – including M-theory, string theory, and branes etc.

My copy of "DM, DE" is on loan to a friend now. I wish the public library would have a copy available for those so interested. Until then, good mentors like youself and others will continue to presnt us with "ALL possiblities."

Dark Matter and Dark Energy are mainly used as general and catch-all terms in astronomy. They are used to describe, in the broadest possible terms, something that exists that causes a corresponding effect.

Dark matter is the term that refers, in the broadest possible terms, to the implied cause of an observed effect. Namely, the effect that the magnitude of the gravitational force in most parts of the Universe appears to be greater than what we can account for by adding up the contributions from all of the observable matter that we know about.

Likewise, in a Universe whose expansion is apparently accelerating, our current understanding of gravity demands that there be a cause of this acceleration. The cause is termed 'dark energy', because it needs a name and nobody knows for sure what it might be.

Many scientists have proposed specific phenomena as being the answer to DM and DE – the theories are out there, and now we await the observations that will either cut them down or lend them credibility. But lets just remember that, in broad terms, the terms DM and DE are really just names for gaps in our current understanding… In this respect, there is nothing really wrong at all with the original article.

I'm too old and too broke to buy a series of discs that would cost more than auditing the best class in the field at Syracuse University.

But if you have studied the subject, do please give us an elegant and precise comparison of the implications of M-Theory and the problem of Dark matter. Oh Please!

I'd do it, but I once dropped-out of a calculus class, and my future as a cosmologist has gone downhill ever since.

The Canadian researchers looked at images of an apparently empty patch of sky as stars and galaxies passed behind it. They observed consistent lensing (by comparing the stars and galaxies to where they SHOULD be seen at any given time, or observing dual-images of the observed objects) caused, presumably, by gravitation that had no observable source. And that's the crux of the issue.

Dark Matter cannot be a cloud in space. It allows light to pass through, and does not obstruct the passage of light in and of itself. A better name for it would be "invisible mass," but the acronym "IM" was already taken. However, the idea is that this "exotic" mass is massive enough that it's gravity can bend light. Now, this is admittedly profound, almost reminiscent of Copernicus's crystal spheres upon which the stars of the firmament were suspended. And there is an enormous amount of science behind this. and the amount of the universe, in theory, occupied by this dark matter and equally enigmatic dark energy, is more than half the universe. If you think of it as black dust, it would obscure the vast majority of the visible object in the night's sky.

But when we call it "Dark Matter," we are making some shortcut presumptions which are not literally true. If it is a substance, which we have not established, then it directly violates the strict definition of matter. It is made up of nothing like any of the elements in the periodic table, even the mostly imaginary ones.

I am more than satisfied that we are observing something important, and that it's effects are lensing artifacts and a relationship with matter and spacetime… but we don't know enough to understand whether there is some invisible non-stuff squeezing everyting, or if the observations point toward another nuanced error in Newton's equations. Newtonian physics works pretty well, but we know, from a few moonshots, that Newton's equations are ever so slightly off.

But you see, they shouldn't be. Their iron-clad assumptions are woven libreally through Einstein's explanations, and Albert's devotion to Newton made it impossible for him to grasp the Quantum Mechanics universe of Neils Bohr. Nothing in the standard model of three spatial dimensions plus one time dimension, combined with the observed evidence, is sufficient to establish dark matter as a reality, but also fails to explain what we see in telescopes.

The best answer now is, we don't know what's happening yet. We need to keep open minds, and explore ALL the possibilities.

So we should build a huge radio telescope array on Mars, and financially subsidize every mathematician/physicist on the planet.

Or we could live in the dark for another hundred years, for that matter.

And while I'm here… Kip Thorne for President.

I submit that quantum entanglement and quantum tunnelling are evidence supporting multiple dimensions.

Spontaneous quantum eruptions of paired particles in empty space is supporting evidence of multiple dimensions.

String Theory's consistent Quantum Theory of Gravity works where the standard model never has. Supersymmetry eliminates Quantum Theory's open-door-policy on spectacularly absurd particles like Tachyons.

A multidimensional universe, like dark matter, is still one hypothesis, unproven, but also like dark matter, has a statistically non-random positive distribution of supporting evidence, and an absence of directly conflicting evidence. Just because one scientist uses a telescope, and another uses mathematics doesn't mean either has the superior approach to the truth.

Mathematically, cosmological theories including multiple dimensions are not simply wonderful fun, they are at the forefront of scientific understanding. Throughout history, theorhetical physicists have used mathematics to point the way, and the experimentation was years catching-up.

Newton, Einstein, Hawking, many many more, discovered in mathematical analyses things that it took researchers decades to establish with experimental observations.

But to my mind, Dark Matter is not an elegant theory, it's a first shot in the dark at explaining something we should not be seeing by saying that something is there which can't be seen. Something which is neither positive nor negative, and not zero. We've even had to invent whole new particles to try and explain it away. Never mind that none of these particles have ever been observed in any of the tens of thousands of particle interaction experiments we've ever conducted. So we need to add yet another hypothesis to explain why we've never detected anything like Dark Matter itself.

And I'm saying that if you run the observations through M-Theory's supersymmetry, you get explanations rather than more anomalies, and we don't have to come up with names for any new particles.

The rule in science is, keep it as long as it's useful. The standard model is useful for many things, but we keep seeing the seams where our wrapping paper just doesn't fit so neatly around the box. That doesn't mean we have to throw it out, but it also doesn't mean that we must limit science to only wht we can test right now. Mathematics opens doors to things we might be able to test a hundred years from now. And the sooner we start understanding what the possibilities are, and what they aren't, the better we'll know what we need to test, and how useful it will be.

Is the cloud moving in such a way that we can see it pass in front of a section of space that had earlier observed? If not what are the changes we are observing in the light from objects beyond the dark matter? I am confused….

But that doesn't stop me from enjoying all the science fiction that uses multiple dimensions, including this article.

I also firmly believe that the answers lie in understanding higher dimensions and how they interact in the observable 3d world we live in. M-Theory seems to be leading the way.