14 Feb 08
Is it real or is MOND a better explanation of the strange behaviour of galaxies? Are physicists just making it up as they go along or is there some truth in this dark matter malarkey?
I have to declare an interest here, I am currently researching how stars move in galaxies and what might be causing them to move too fast. The favoured explanation is dark matter but there is currently no real evidence for the existence of dark matter.
14 Feb 08
Originally posted by KeplerTake it to the science forum --->
Is it real or is MOND a better explanation of the strange behaviour of galaxies? Are physicists just making it up as they go along or is there some truth in this dark matter malarkey?
I have to declare an interest here, I am currently researching how stars move in galaxies and what might be causing them to move too fast. The favoured explanation is dark matter but there is currently no real evidence for the existence of dark matter.
14 Feb 08
1 edit
Originally posted by KeplerWell, I think that all this dark matter stuff is currently the best explanation for the affect on galaxies' movement scientists have found this far. However, my statement is very general. Astronomy isn't my favourite science, I don't know much about it. Nevertheless, it's still quite interesting to read about astronomy, so I'm looking forward to read some wiser answers.
Is it real or is MOND a better explanation of the strange behaviour of galaxies? Are physicists just making it up as they go along or is there some truth in this dark matter malarkey?
I have to declare an interest here, I am currently researching how stars move in galaxies and what might be causing them to move too fast. The favoured explanation is dark matter but there is currently no real evidence for the existence of dark matter.
Btw, what is MOND?
14 Feb 08
Originally posted by KeplerI refuse to respond to this obvious attempt to encourage a new science forum.
Is it real or is MOND a better explanation of the strange behaviour of galaxies? Are physicists just making it up as they go along or is there some truth in this dark matter malarkey?
I have to declare an interest here, I am currently researching how stars move in galaxies and what might be causing them to move too fast. The favoured explanation is dark matter but there is currently no real evidence for the existence of dark matter.
14 Feb 08
1 edit
Originally posted by KeplerThe only real existence of dark matter is the fact that galaxies are moving too fast. Other than that we have nothing.
Is it real or is MOND a better explanation of the strange behaviour of galaxies? Are physicists just making it up as they go along or is there some truth in this dark matter malarkey?
I have to declare an interest here, I am currently researching how stars move in galaxies and what might be causing them to move too fast. The favoured explanation is dark matter but there is currently no real evidence for the existence of dark matter.
Astrophysicist map out the galaxies and throurgh estimatives of what they saw they can give an aproximate number of stars on a given region. Taking into acount the average mass of each star the mass of the aglomerate can be estimated. Then it's just using Newton's thirld law and calculate the accelarations. Now the accelaration is always bigger than the one calculated. Not just a little bigger but a lit bigger. And so either we have really lousy telescopes and we are missing out on the real universe and only watching tiny bits or there is this big mass that doesn't react in any other way other that gravitationally. Pretty bold assumption but seemingly necessary.
But then a few guys came along and said: "What if F=ma isn't a universal law but it's only valid at our vicinity?" A pretty reasonable question since everything that we found out untill now in the newtonian realm was approximate. SO this is how MOND came about. But the main problem with MOND is that they don't say what is in fact the real formula to which F=ma is an aproximation. And I guess this why people haven't used MOND much this days. But on archiv there are some articles on it if you want to take a closer look.
14 Feb 08
Originally posted by KeplerThanks. The only thing that's written there is that it attempts to explain galactic rotational curves without invoking dark matter and in some cases it reduces to MOND. There is no description on how the theory attempts to explain it. However, it seems to me that one must know a lot of math to understand TeVes (Tensors is what I'm mostly afraid of) and I'm just going to start calculus after about a year. I just started trigonometry. (11th grade)
Have a look at TeVeS while you are there.
14 Feb 08
Originally posted by adam warlockFrom what I can see there is as much evidence for one theory as there is for the other. The people who favour MOND don't explicitly say how gravity works at low accelerations and those that favour dark matter haven't a clue what it is. I currently favour MOND (TeVeS actually) because it is simpler than dark matter (Occam's Razor) and is testable unlike dark matter.
The only real existence of dark matter is the fact that galaxies are moving too fast. Other than that we have nothing.
Astrophysicist map out the galaxies and throurgh estimatives of what they saw they can give an aproximate number of stars on a given region. Taking into acount the average mass of each star the mass of the aglomerate can be estimated ...[text shortened]... is days. But on archiv there are some articles on it if you want to take a closer look.
14 Feb 08
1 edit
Originally posted by kbaumenYou may have to go beyond Wikipedia to find out about this stuff. Try sticking MOND into Google.
Thanks. The only thing that's written there is that it attempts to explain galactic rotational curves without invoking dark matter and in some cases it reduces to MOND. There is no description on how the theory attempts to explain it. However, it seems to me that one must know a lot of math to understand TeVes (Tensors is what I'm mostly afraid of) and I'm just going to start calculus after about a year. I just started trigonometry. (11th grade)
Don't fear the math! Einstein was crap at math and did as little as possible if he could get away with it. He only forced himself to learn tensor calculus when he needed it to convince the other physicists that general relativity worked.
14 Feb 08
Originally posted by KeplerFrom what I can see there is as much evidence for one theory as there is for the other.
From what I can see there is as much evidence for one theory as there is for the other. The people who favour MOND don't explicitly say how gravity works at low accelerations and those that favour dark matter haven't a clue what it is. I currently favour MOND (TeVeS actually) because it is simpler than dark matter (Occam's Razor) and is testable unlike dark matter.
I'm not sure to what do you mean by this. The evidence is the same since both theories came as an explanation of the same physical phenomenom: abnormally large acclerations. The difference between both theoriesis that dark matter interacts via gravity, and gravity is more or less a well explained and understood physical interaction; while MOND says that F=ma is just an approximation and says that the real law is the one that makes things appear as they appear and so everything is right.
"How convenient! Now please tell me what this real law is."
"I can't tell you"
"Why not?"
"Because I don't know what it is, but I do know that with it everything is right"
"Right" *raises eyebrow*
You see the problem? I'm not taking sides int this but both hypothesis are shady but MOND do seem to be even shadier. This is of course a question of personal taste which one you like best and decide to work, but I know I don't like neither.
And I think that saying that MOND is more simple (simpler has a negative connotation from what I know of english) is really arguable. But if one takes into account all possibles candidates for darkmatter and no consensus being found I kinda agree with you.