a valid alternative to dark matter/energy theory?

Like I said. A dirty hack.

I've long been intrigued by the idea that dark matter might be the gravitational influence of matter in parallel universes.

Originally posted by @soothfast
I've long been intrigued by the idea that dark matter might be the gravitational influence of matter in parallel universes.

How can we have parallel universes if they each, in turn influence each other?

Originally posted by @christopher-albon
How can we have parallel universes if they each, in turn influence each other?

I have once heard of a cosmological theory that says gravitational effects can 'leak' from one universe to another (I presume through some kind of 'higher' dimension? ) even though each still has its own separate spacetime. But I have absolutely no idea what's the scientific credibility of that.

Originally posted by @humy
I have once heard of a cosmological theory that says gravitational effects can 'leak' from one universe to another (I presume through some kind of 'higher' dimension? ) even though each still has its own separate spacetime. But I have absolutely no idea what's the scientific credibility of that.

None, whatsoever. What if vampires suck the blood from fairies?

Originally posted by @humy
I have once heard of a cosmological theory that says gravitational effects can 'leak' from one universe to another (I presume through some kind of 'higher' dimension? ) even though each still has its own separate spacetime. But I have absolutely no idea what's the scientific credibility of that.

That particular theory was proposed to explain why gravity is a much weaker force than other forces, the idea being that most of the gravitational force is leaking into one or more parallel universe(s).

But any theory proposed as a quick fix or patch is (imo) suspect and should be taken with a grain of salt. My own particular quick fix would be to define gravity as an effect rather than a force... this idea isn't likely to catch on, but it does have the benefit of not relying on other (theoretical) dimensions or universes.

Originally posted by @christopher-albon
How can we have parallel universes if they each, in turn influence each other?

You can only have a physical theory of parallel universes if they influence each other, otherwise it's metaphysics.

Originally posted by @kazetnagorra
You can only have a physical theory of parallel universes if they influence each other, otherwise it's metaphysics.

Then point out that there is no such physical theory.

Like I have said many times, black holes are the dark matter!

http://www.pbs.org/wgbh/nova/space/black-hole-apocalypse.html

Originally posted by @metal-brain
Like I have said many times, black holes are the dark matter!

http://www.pbs.org/wgbh/nova/space/black-hole-apocalypse.html

nonsense; back holes cannot possibly explain the the rotation curve of galaxies because there isn't nearly enough black holes around to account for that gravitational effect and the rotation curve of galaxies is why most cosmologists (correctly or incorrectly but perfectly reasonably either way) think dark matter (probably) exists. We can estimate the number of black holes and their average mass from the ones we have so far detected and if there were that many black holes to explain the rotation curve of galaxies then we should have detected far more black holes than we actually have done. That is how cosmologists know for sure that black holes cannot explain that gravitational effect.

Originally posted by @humy
nonsense; back holes cannot possibly explain the the rotation curve of galaxies because there isn't nearly enough black holes around to account for that gravitational effect and the rotation curve of galaxies is why most cosmologists (correctly or incorrectly but perfectly reasonably either way) think dark matter (probably) exists. We can estimate the n ...[text shortened]... hat is how cosmologists know for sure that black holes cannot explain that gravitational effect.

Wrong.
Incorrectly but still reasonable????? Huff some more paint or whatever you are doing.

Watch the Nova program from the link I posted. Until you do that you are wasting my time.

Originally posted by @metal-brain
Wrong.
Incorrectly but still reasonable????? Huff some more paint or whatever you are doing.

Watch the Nova program from the link I posted. Until you do that you are wasting my time.

Incorrectly but still reasonable?????

I didn't say the theory was incorrect. It can be unknown to us whether a given theory is correct or incorrect and still be reasonable as in rational to assume probable on the limited current information available regardless of whether it is actually correct. Dark matter theory arguably currently goes into that category.

Watch the Nova program from the link I posted.

You mean the one that says "We're sorry, but this video is not available in your region due to right restrictions."? That is the only one I see in your link.
It cannot be watched from my computer.
And it has irrelevance to your claim even if I was allowed to watch it because novas have little (if anything) to do with dark matter. If you deny this, I challenge you to explain to us what novas have got to do with back holes being (according to you) dark matter.

Until you do that you are wasting my time.

How is failing to waste my time watching something irrelevant wasting your time? You make no sense.

I have already corrected you; astronomers/cosmologists know from their observations that dark matter cannot possibly all consist or even merely mainly consist of black holes. There simply isn't nearly enough of them for that.

Originally posted by @humy

Incorrectly but still reasonable?????

I didn't say the theory was incorrect. It can be unknown to us whether a given theory is correct or incorrect and still be reasonable as in rational to assume probable on the limited current information available regardless of whether it is actually correct. Dark matter theory arguably currently goes ...[text shortened]... tions that dark matter cannot possibly all consist or even merely mainly consist of black holes.

I already saw the program on TV and it has information that you need to know before making the claims you are making. Look for it on youtube or another link. I'm sure you can find one that works for you.
We may find out soon who is right.

http://earthsky.org/space/1st-direct-black-hole-2018-image-event-horizon-telescope

To be clear I have never said ALL dark matter consists of black holes, just that most of it is in the form of black holes. I have made that statement before on this forum if you recall. Remember that space rock in the shape of a cigar that is said to have come from another solar system? Before it entered our solar system it could not be seen, so technically it used to be dark matter.

When you watch it you will learn a lot from it. You will learn about super massive black holes and how black holes in the center of galaxies have been under-estimated in size. You will learn how computer models are estimating the size of black holes to match those inconsistencies that you mentioned.

Take some very good advice. Watch the program before I embarrass you once more. You are jumping the gun again. It is a 2 hour program but well worth the time.

Originally posted by @kazetnagorra
You can only have a physical theory of parallel universes if they influence each other, otherwise it's metaphysics.

There is SOME evidence of parallel universes in the CBR record, some anamolies explained by possible outside universe 'banging' into ours:

https://news.nationalgeographic.com/news/2010/12/101227-universes-circles-cosmic-background-radiation-big-bang-science-space/

Originally posted by @metal-brain
I already saw the program on TV and it has information that you need to know before making the claims you are making. Look for it on youtube or another link. I'm sure you can find one that works for you.
We may find out soon who is right.

http://earthsky.org/space/1st-direct-black-hole-2018-image-event-horizon-telescope

To be clear I have never s ...[text shortened]... ss you once more. You are jumping the gun again. It is a 2 hour program but well worth the time.

To be clear I have never said ALL dark matter consists of black holes, just that most of it is in the form of black holes.

Then you are still clearly wrong and your link is irrelevant as it clearly isn't evidence of most dark matter being black holes.

black holes in the center of galaxies have been under-estimated in size.

Totally Irrelevant; black holes in the center of galaxies, no matter how large, cannot explain the gravitational effect observed that is explained by dark matter.
Why not just learn for once real science instead of your load of ignorant delusional made-up crap? Here is were you should start;

https://en.wikipedia.org/wiki/Dark_matter

Can you show a single science link that shows how dark matter is mainly black holes?
ALL the evidence for that is against it.
For example;

https://briankoberlein.com/2017/04/01/black-holes-dark-matter/
"...
Dark matter comprises the majority of mass within galaxies, so if it was comprised of small black holes, there would have to be a lot of them. If these black holes were fairly large (say, on the order of a solar mass or more) then we should observe them distort starlight that they pass in front of though an effect known as gravitational microlensing. We’ve watched a lot of stars over time, and there has been no microlensing. If they were small black holes (about the mass of a moon) then there would be so many of them that they would distort the light from gamma ray bursts, and again we haven’t seen any evidence of that. If the black holes were really tiny, then Hawking radiation would have caused them to evaporate away long before now.
..."

and if you for once just bother to search and read the relevant science links, you will find they ALL confirm that same thing above and NONE contradict it.

I believe the evidence of what the science says over your ignorant word any day.
That evidence clearly shows dark matter, assuming it exists, is NOT mainly black holes.