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.
Tutorial: Shaping the Universe, Gravity and the four forces of nature;.
- Thread starter paddoboy
- Start date
exchemist
Valued Senior Member
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 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
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
exchemist
Valued Senior Member
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.)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
Ahh c'mon now q-reeus, surely your not offended by the smart arse remark?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.
The river analogy is just that, an analogy, and iirc, all accurately, more or less said the same thing...
Totally uncalled for and yes obviously offensive. The cure - refrain from such abusive language. Choose to be civil - all the time.
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.
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.
If you say so...I will certainly follow your own generally change from the offensive.
But you have! ever since you started here and followed me over to that other place.
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.
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.
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
According to Lawrence Krauss, the quantum foam is the nothing that we, spacetime, and everything arose from.
Never was nothing. Always COULD have been nothing, but NOTHING is a state which didn't happen
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.
The greatest question, along of course with the 'are we alone" question, is will we ever have an observable QGT.
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
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