The Cosmological Constant, Lamda Cdm, And The Expansion Of The Universe

[A-wal]

You mean Einstein's model of gravity? It's called the general theory of relativity. There's three theories of relativity but they don't contradict each other, each builds on the previous one and general relativity is the most advanced so it's starting at the wrong end. You might be better off starting with Galilean relativity, then the special theory of relativity and then general relativity.

[CraigD]

Gravity cause length contraction and time dilation, so one way of looking at is is object following straight paths through curved space and time.

Correct, but

Orbits round the sun. The Earths revolution (spin) isn't caused by gravity.

There’s a terminology mistake here. In orbital mechanics, revolution is the term for gravitationally bound body’s motion around its barycenter. Rotation is the term for its spin around its axis of rotation. This distinction is muddied by using revolution as a synonym for rotation in engineering units like RPM, and not one to obsess over, but if you’re going to correct peoples usage of the terms, you’d best get them right! ;)

 

how does these Einsteins equations looks like ...

The Einstein field equations look like

[math]R_{\mu \nu} - \frac12 R g_{\mu \nu} + \Lambda g_{\mu \nu} = \frac{8 \pi G}{c^4} T_{\mu \nu}[/math]

Unfortunately for people like me with an introductory grasp of modern physics (I have a BS in Math, and lots of computer programming experience) , all the terms with the [math]\mu \nu[/math] subscripts in this simple-looking equation are tensors, the math of which is difficult. I can’t even start with it, and have never met anyone without a PhD who could.

 

I’d love to see you make a start at them, though, Messy, and post your progress in the forums. Good luck! :thumb_up

[messy]

haha ok this is a really advanced equation .. my mind right now is not capable of comprehending the complexities of such an equation ..

 

anyway i am planning to improve my maths slowly , maybe towards the end of finishing the HELM website , i might try to understand equations like these ...

 

 

thanks for all the replies ...

[A-wal]

There’s a terminology mistake here. In orbital mechanics, revolution is the term for gravitationally bound body’s motion around its barycenter. Rotation is the term for its spin around its axis of rotation. This distinction is muddied by using revolution as a synonym for rotation in engineering units like RPM, and not one to obsess over, but if you’re going to correct peoples usage of the terms, you’d best get them right! ;)

Doh!

[GAHD]

 

The Einstein field equations look like

[math]R_{\mu \nu} - \frac12 R g_{\mu \nu} + \Lambda g_{\mu \nu} = \frac{8 \pi G}{c^4} T_{\mu \nu}[/math]

Unfortunately for people like me with an introductory grasp of modern physics (I have a BS in Math, and lots of computer programming experience) , all the terms with the [math]\mu \nu[/math] subscripts in this simple-looking equation are tensors, the math of which is difficult. I can’t even start with it, and have never met anyone without a PhD who could.

 

I’d love to see you make a start at them, though, Messy, and post your progress in the forums. Good luck! :thumb_up

This is a good series of "lectures" to prime on that math, and why.

 

Heay Freezy, how's your mission from Zeus?

[Super Polymath]

I don't believe in string theory. I think that the lamda dark matter model is also unlikely. Look, we only know less than 10% of the existing particles that shape our reality, beyond that are a greater number of unknown waves or fields generated by these unknown particles and their unknown reactions, and over that exists a greater number of potential atoms, molecules, and exotic stellar bodies out there. You know, our quantum theory from our tiny CMB perspective is so limited that we can't safely even work out a theory that's even remotely accurate with pure math. That's insanity.

 

I don't believe reality is finite, and I don't believe that there is a cosmological constant, but instead a cosmological variable. Pixy dust,magic, there is a real theory challenging string theory and a "constant", this is called conformal cosmology.