# Clever Math Puts a Firm Number on the Amount of Dark Matter in Existence

Counting up the missing mass

Dark Matter Down The Drain Felipe Esquivel Reed, via Science

Dark matter, the material that makes up the majority of the matter in the universe, remains so mysterious that scientists don't even know how much of it there is, let alone how it behaves. However, using new calculations about the interaction between black holes and dark matter, scientists have deduced an upper limit on the amount of dark matter in the Milky Way.

The researchers calculate that the maximum dark matter density comes in with around seven times the mass of the sun dispersed through a cubic-light year of space. If a section of dark matter that dense filled the space of our solar system, it would weigh about 14,000 times more than the mass of the eight planets, the asteroids, and the Sun combined.

By maintaining a relatively high mass, our galaxy's dark matter generates enough gravity to hold the stars and nebulae together. Without that mass, everything in the galaxy would spin off into the void. However, if the dark matter within a particular cubic-light-year-sized volume of space reaches a density higher than 7 times the mass of the Sun, it would feed the super-massive black hole at the center of the galaxy so quickly that the black hole would grow out of control and devour the entire galaxy.

Interestingly, these findings also imply that the density of dark matter must remain relatively constant to prevent either of those outcomes. That means either dark matter isn't getting sucked into the black hole, or replacement dark matter is replacing whatever does fall into the black hole. Since nothing science has ever observed can resist the pull of a black hole, and since we also don't know where dark matter comes from in the first place, it looks like these new calculations might have raised as many questions as they answered.

[Science]

What if the dark matter is in fact black holes and the mass that we "know" are in fact grossly incorrect?

i don't see how this proves anything or answers any questions as the author states. if the density of dark matter is truly as high as the calculations state, then something should have been detected by now. dark matter research has been going on for many years and...zip. plenty of work but no results. granted there is mass that has yet to be "seen" and should be (mathematically) accounted for, but nothing near the scale that dark matter seems to suggest.

if anything this should help support MOND theory.

We have been plotting the movements of everything we can see, and it would be centered around something like that. The gravitational feild would make a huge effect on us, so why wouldnt we have seen it sooner? NO CHANCE OF IT AT ALL, it can Not exist.

the only reason we are getting mysterious gravitational pulls is because people keep deleting things from the archive memory....stupid dooku

@hamstrahammer - "Go to the center of the gravity's pull, and find your planet you will."-Yoda

It may sound silly but i find some analogy between mind and dark energy.Mind also can't be detected by physical mean as dark energy. Theoritically it exist but can't detect like mind-it exist but can't detect. All materail world float on black matter and all universe float on our mind.

@ Ananta

Ummmm... What?! I didn't understand a single sentence of that dribble.

If dark matter has gravity, I wonder if there can be a "dark matter black hole" (let's not consider a black hole that is a mix of normal matter and dark matter for the moment)? Would there be any way to tell the difference between normal and dark matter black holes? Dark matter has not been observed to interact with electromagnetism; even so, how would dark matter spiraling into a[ny] black hole behave? If there's no detectable result, where does the energy from mass falling down a gravity well go?

locutus, this answers precisely the sorts of questions that astro-physics asks. How much dark matter could there be or how dense can it be? the article gives you one sort of answer. So it leads to more questions. Since when is this not par for the course of science? And so what if this highlights the tentative nature of the claim of dark matter. tentative claims are also par for the course.

The claim that if there was so much then we should have detected it pretty much ignores that the nature of the dark matter currently is that the only way we can detect it is by the movements of the astrophysical bodies that we can detect in more conventional ways. It's by the movement of other physical masses that we have a loose detection of it. To insist that we should detect it in other ways is an a priori unsupported assertion that is forign to the empirical nature of science.

As for MOND, as a layman I can't judge that an alteration in our understanding of a force is preferable to an alteration in our understanding of the nature and quantity of objects that that force acts upon instead.

Granted, such strange possible implications pointed to in the conclusion of this article may indeed lead astro-physicists to reconsider dark matter, but I will wait to see what the experts do with this knowledge.

So many bright minds....
Yet we still have dark matter and dark energy.

The concepts of dark matter and dark energy - two things that we infer to exist, but have no direct proof - could just as easily be interpreted to demonstrate that we don't actually know the real laws of physics.

From another viewpoint, here is science positing the existence of something that cannot be seen, felt, detected or proven in any way. Yet scientists insist that it must exist. Sounds a lot like God.

I love facts they are always so accurate until proven wrong.

Kevin Wilson,
Where astrophysics anomalies are accumulating
faster than they are being resolved, is a sure sign of flawed models. On that basis, there is not even a workable Solar model. Snapping back magnetic fields...???? dont make me laugh.
You will not crack the stars /stellar mechanisms if you have not cracked the Sun. Workable, may be considered to be a model capable of forming the basis of a mathematical model. If we havn't a Solar model, we cannot possibly have Stellar or Galactic Core models. So we are unlikely to resolve exotic theories for dark matter and dark energy. Eating sarnis and drinking cokes for lunch down a however deep mine will not crack the problem, and heres a new twist.
Einsteins Law of equivilence precludes the resolution of dark energy, as the Universe could be in freefall, or simply a massive object could be in flyby. Take the day off...So whats going on. Hows this...All White and Blue Stars and Galactic Cores are Jetting Black Toroidal Objects.
These objects formed as a result of Tripple Triangular Collisions of Black Holes. These Pawnbroker configured collisions precipitated the creation of "Internal Event Horizons" and formed an object with an " Internal External Event Horizon Continuum " enabling core collapse and twin
jet initiation. Jetting and angular momentum completes the process... KW (CFSS) Take Bets....

Arrgh! These badly-written Pop-Sci articles are annoying!

Our solar system does not occupy anywhere near a cubic light year. The Oort cloud is only 40-80 light weeks out. So how does the writer figure that something 7X Sol's mass spread through a cubic light year can equal 14,000X Sol's mass in a much smaller volume?

It's almost like the science writers here are even more ignorant of science than most of the posters. That's sad.

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