SoylentNews is people
SoylentNews
Bizarre 'dark fluid' with negative mass could dominate the universe – what my research suggests
It's embarrassing, but astrophysicists are the first to admit it. Our best theoretical model can only explain 5% of the universe. The remaining 95% is famously made up almost entirely of invisible, unknown material dubbed dark energy and dark matter. So even though there are a billion trillion stars in the observable universe, they are actually extremely rare.
The two mysterious dark substances can only be inferred from gravitational effects. Dark matter may be an invisible material, but it exerts a gravitational force on surrounding matter that we can measure. Dark energy is a repulsive force that makes the universe expand at an accelerating rate. The two have always been treated as separate phenomena. But my new study, published in Astronomy and Astrophysics, suggests they may both be part of the same strange concept – a single, unified "dark fluid" of negative masses.
Negative masses are a hypothetical form of matter that would have a type of negative gravity – repelling all other material around them. Unlike familiar positive mass matter, if a negative mass was pushed, it would accelerate towards you rather than away from you.
[...] My model shows that the surrounding repulsive force from dark fluid can also hold a galaxy together. The gravity from the positive mass galaxy attracts negative masses from all directions, and as the negative mass fluid comes nearer to the galaxy it in turn exerts a stronger repulsive force onto the galaxy that allows it to spin at higher speeds without flying apart. It therefore appears that a simple minus sign may solve one of the longest standing problems in physics.
(Score: 1, Interesting) by Anonymous Coward on Thursday December 06 2018, @10:15PM (5 children)
You are missing nothing. Look into MOND, they predict all sorts of stuff exactly with no free parameters (although there is some freedom due to uncertain data-dependent ones): https://tritonstation.wordpress.com/ [wordpress.com]
Now, MOND is more of an empirical relationship that remains to be explained than a theory per se. However, any theory is going to have to explain MOND and it simply seems impossible that dark matter could do this.
(Score: 1, Interesting) by Anonymous Coward on Thursday December 06 2018, @10:24PM (4 children)
This article is especially good: https://tritonstation.wordpress.com/2018/07/26/a-brief-history-of-the-acceleration-discrepancy/ [wordpress.com]
As the data gets cleaner, it fits the predictions of MOND better and better. Amazing.
(Score: 2) by Immerman on Thursday December 06 2018, @11:52PM (3 children)
To be clear, MOND offers no predictions or explanations - it's just a description of the observed galactic rotation curves, not an attempt to explain them. The only "predictive" quality it has is that newly measured galaxies will have the same observed rotation curve as previously measured ones. And it's plagued by that one big unknown "falloff function" that makes the whole thing rather squishy. I don't recall even seeing any rough estimates for it, without which MOND can describe pretty much any rotation curve observed, making it valueless.
There are various MOND-based theories that interpret the description in various ways - is it the attractive force of gravity that goes non-inverse-square at low accelerations? Or the relationship between force and acceleration? Or something else entirely? They all start at the simple descriptive formula supplied by MOND, and then go off in various different directions from there.
(Score: 0) by Anonymous Coward on Friday December 07 2018, @12:18AM (2 children)
Sorry, but you basically have no knowledge of MOND,
Here is a prediction (not post-diction) using MOND for the CMB spectrum. It got the second peak exactly with no free parameters: https://core.ac.uk/download/pdf/25263787.pdf [core.ac.uk]
I don't even want to bother explaining further to someone harboring so much misinformation.
(Score: 2) by Immerman on Friday December 07 2018, @01:09AM (1 child)
So, do they finally have an estimate for the critical acceleration and falloff function? Last time I checked they had neither - without which you could describe literally *any* galactic rotation curve.
(Score: 0) by Anonymous Coward on Friday December 07 2018, @01:46AM
I have no idea what you are trying to refer to.
It has always been that MOND becomes apparent at around a0 = 10^-10 m/s^2 (https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics). And yes, MOND has been used to fit every galatic rotation curve based on the amount of light emitted with no free parameters. It does not fit non-existent galaxies though.