# Tutorial: Shaping the Universe, Gravity and the four forces of nature;.

And again how does

30 kilometers per second (speed of Earth moving around the sun) square with

9.8 m/s2 (which I take, from the video, NOT the person falling speed, but the Earth speed moving towards the person who is in free fall)
The latter as a measure of acceleration (not speed) cannot in any sense square with the former which is speed = |velocity|. Apples. Oranges. Basic dimensional analysis.

I was under the impression in a eliptical orbit there is speed up and slow down regions

ie

The orbit of a planet is an ellipse with the Sun at one of the two foci.
A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time.
The square of a planet's orbital period is proportional to the cube of the length of the semi-major axis of its orbit.

https://en.m.wikipedia.org/wiki/Kepler's_laws_of_planetary_motion#:~:text=The orbit of a planet,major axis of its orbit.

So I don't think continually accelerating is correct

And again how does

30 kilometers per second (speed of Earth moving around the sun) square with

9.8 m/s2 (which I take, from the video, NOT the person falling speed, but the Earth speed moving towards the person who is in free fall)

Thanks

Well it is continually accelerating, but indeed in an elliptical path the rate of acceleration towards the focus varies. In my understanding "continually" means without ceasing, but does not necessarily mean at constant rate.

I don't think there is anything to square between g and the earth's orbital speed. Why would there be any connection?

Well it is continually accelerating, but indeed in an elliptical path the rate of acceleration towards the focus varies. In my understanding "continually" means without ceasing, but does not necessarily mean at constant rate.

I don't think there is anything to square between g and the earth's orbital speed. Why would there be any connection?
Not sure if my misunderstanding means posting at cross purposes

My understanding continually accelerating means continually increasing speed

Forget about the other for the moment

Not sure if my misunderstanding means posting at cross purposes

My understanding continually accelerating means continually increasing speed

Forget about the other for the moment

Not with motion in a circle, it doesn't. Acceleration is dv/dt, i.e change of velocity with time. Remember both acceleration and velocity are vectors, so they have both magnitude and direction. For motion in a straight line, acceleration requires an increase in velocity, but for motion in a circle the velocity is continually changing direction, not magnitude. (For motion in an ellipse, there is some of each.)

The old abusive paddoboy reemerges full bloom.
Ahh c'mon now q-reeus, surely your not offended by the smart arse remark?
Instead of hurling abuse, try and rationally defend 'dragged space/spacetime'. I have given a rational argument against it. What can you personally offer as technically meaningful rebuttal? Nothing, instead resort to..."I prefer the explanations of mainstream professionals thank you."
Yep, exactly, and that makes sense to me, rather then listening to your own continual whinging and whining re the validity of GR over many years.
Well some time back you got feedback from a number of GR experts and the only one out of iirc four who believed in 'moving space/spacetime was your goto guy Andrew Hamilton of 'the river model' fame.
The river analogy is just that, an analogy, and iirc, all accurately, more or less said the same thing...

Ahh c'mon now q-reeus, surely your not offended by the smart arse remark?
Totally uncalled for and yes obviously offensive. The cure - refrain from such abusive language. Choose to be civil - all the time.
Yep, exactly, and that makes sense to me, rather then listening to your own continual whinging and whining re the validity of GR over many years.
Here you go again. I point to both my own and others clear identification of at least one inconsistency in GR's foundational principles, and you stoop to calling that 'whinging' and 'whining'. Again - learn to respond civilly and accurately. A really big ask I know.
The river analogy is just that, an analogy, and iirc, all accurately, more or less said the same thing...
No they didn't. At least two others stated outright that space doesn't 'fall' like water flowing in a river/waterfall. And I (and writer of Wikipedia article) have shown where 'dragged spacetime' makes a wrong prediction. The 'ether' of spacetime looks the same in every local coordinate system. Michelson And Morley - late 19th century.

Totally uncalled for and yes obviously offensive. The cure - refrain from such abusive language. Choose to be civil - all the time.
If you say so...I will certainly follow your own generally change from the offensive.
Here you go again. I point to both my own and others clear identification of at least one inconsistency in GR's foundational principles, and you stoop to calling that 'whinging' and 'whining'. Again - learn to respond civilly and accurately. A really big ask I know.
But you have! ever since you started here and followed me over to that other place.
No they didn't. At least two others stated outright that space doesn't 'fall' like water flowing in a river/waterfall. And I (and writer of Wikipedia article) have shown where 'dragged spacetime' makes a wrong prediction. The 'ether' of spacetime looks the same in every local coordinate system. Michelson And Morley - late 19th century.
I can't really recall exactly, but I was not inferring as flowing like a river in particular...but certainly aligning with the bending/warping/twisting geometry in the presence of mass/energy.

Totally uncalled for and yes obviously offensive.
OK, after thinking some, and noting the less offensive nature of the banter between us, on both sides, I apologise. Being the first to break that "truce"?

OK, after thinking some, and noting the less offensive nature of the banter between us, on both sides, I apologise. Being the first to break that "truce"?
Thank you - apology accepted.

Not with motion in a circle, it doesn't

OK that's the part I was missing

Thanks

Busy right now with Trusted Assistant

Will come back when she stops bothering me

Cheers

Never was nothing. Always COULD have been nothing, but NOTHING is a state which didn't happen

Never was nothing. Always COULD have been nothing, but NOTHING is a state which didn't happen

According to Lawrence Krauss, the quantum foam is the nothing that we, spacetime, and everything arose from.
Our defining of nothing maybe at fault.
Nice video.

Point is of course, while all we can do is speculate at that time, that speculative scenario, makes far more sense then any supposed supernatural and/or paranormal myth.
The greatest question, along of course with the 'are we alone" question, is will we ever have an observable QGT.

So how does speed of Earth around the sun link up with free fall speed please?
The Earth is in free fall towards the Sun.

There's no link between the free-fall acceleration of objects near the Earth's surface and the speed of Earth around the Sun.

Does that help?

The Earth is in free fall towards the Sun.

There's no link between the free-fall acceleration of objects near the Earth's surface and the speed of Earth around the Sun.

Does that help?

Thanks but as per below

Not with motion in a circle, it doesn't. Acceleration is dv/dt, i.e change of velocity with time. Remember both acceleration and velocity are vectors, so they have both magnitude and direction. For motion in a straight line, acceleration requires an increase in velocity, but for motion in a circle the velocity is continually changing direction, not magnitude. (For motion in an ellipse, there is some of each.)

sorted as per my response

OK that's the part I was missing

Thanks

Busy right now with Trusted Assistant

Will come back when she stops bothering me

Cheers

But still thanks