Hey, look, it's my alma mater. Back in the news for wonky gravity physics research. Gotta love it. https://huntsvillebusinessjournal.com/news/2023/07/30/solvin...
Ha, mine too! 2014
Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
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Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#12If there is distinct "negative mass" out there, does that mean that we can built FTL devices after all? Or do we also need negative energy?
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#13> The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers—which is all one could measure, mass-wise—is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell
Is "negative mass" a real thing in Physics or just some wild theory?
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#14Im not a physicist. But it doesn't sound that convincing to replace dark matter due to lack of direct evidence, with something even more exotic which also has no direct evidence
When space expands it produces gravity? Like a groaning ship ripped apart, something snaps, when nothing is produced and becomes a place, producing a small background ripple. Concentric from the big bang outwards, like growth rings, dragging apart lights and things. Its not a valid concept, but its a new idea, something to test, anything is better, then collecting data and watching the model drift away every day like…
It's like an LLM ate a whole bag of 2:1 gummies.
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#15Here's something I've wondered. If the universe is made up of 85% dark matter, does that mean we can assume black holes are also made up of the same ratio of dark matter to regular matter (or at least when it went into the black hole)?
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#16I wonder what Sabine Hossenfelder’s opinion on this would be .
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#17I wonder what Sabine Hossenfelder’s opinion on this would be .
I wonder what David Blair, Kip Thorne, Jerome Gauntlett, and a host of others might think.
There's a suprisingly large number of people in theoretical physics dabbling about with gravity, quantuum gravity, dark matter, et al.
Not all of them have a uTube channel.
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#18Nit: the title in the article is kinda wrong; Dark Matter is a set of observations for which we do not have a proper theory that explains it. It's not an "answer" or a "solution". We say it's "matter" because it interacts gravitationally.
So, I'm confused by why we say it's matter when mass and energy are equivalent.
Why have we concluded that it is matter and not dark energy.
Let's momentarily ignore the fact that the name dark energy was already taken for the force causing the universe to expand.
But can't both be attractive force and expansionary energy be different types of dark energy?
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#19Nit: the title in the article is kinda wrong; Dark Matter is a set of observations for which we do not have a proper theory that explains it. It's not an "answer" or a "solution". We say it's "matter" because it interacts gravitationally.
So, I'm confused by why we say it's matter when mass and energy are equivalent. Why have we concluded that it is matter and not dark energy. Let's momentarily ignore the fact that the name dark energy was already taken for the force causing the universe to expand. But can't both be attractive force and expansionary energy be different types of dark energy?
We consider it matter because of the scaling of its energy density. If say the universe expands by a factor, the energy density of matter ρ is ρ ∝ 1/a^3, for radiation it is ρ ∝ 1/a^4. The cosmological constant is actually a constant.
Radiation redshifts as the universe expands, but "matter" "just" "spreads".
Re: Gravity Without Mass: UAH Study Proposes Alternative to Dark Matter
#20Nit: the title in the article is kinda wrong; Dark Matter is a set of observations for which we do not have a proper theory that explains it. It's not an "answer" or a "solution". We say it's "matter" because it interacts gravitationally.
> because it interacts gravitationally.
... and behaves like matter