Gravity and Weightlessnes

In between abusing pieces of steel and other materials I digressed into writing this book which is available free of charge in pdf form.

Thanks Jim added the link so those interested might find the download:

Gravity & Weightlessnes

John

Thanks both

... I have downloaded it [complete with the weightless ‘s’ that must have drifted away]

MichaelG.

You're right Could this be a sign?

Executives don't mess with toy trains*. If they did BR might have made sense.

Tim

PS * yes, I know this is about gravity, but look at the title of the Website.

Edited By Tim Stevens on 16/03/2021 17:57:27

The book introduction summarises the issue. Einstein used the example of a person in a lift to illustrate that one does not feel constant velocity, but feels acceleration. I am sure Einstein was well aware of the limits of his example. Unfortunately not everyone who studied his little book on Relativity was able to appreciate those limitations.

Designers of flight simulators are well aware that the human body is most sensitive to changes in acceleration and is not so sensitive to steady acceleration. That is why simulators use jerky movements accompanied by visual cues to fool the passenger. The rams are allowed to relax slowly, which requires slight accelerations to which the passenger is insensitive.

We feel acceleration through our feet or other part of the body which is in contact with the applied force. Gravity acts throughout the body. Therein lies the distinction which the book hopes to illustrate.

The Researchgate articecle is cut down. The complete book is available from Open Library part of the Internet Archive, and also on our own website swarfology.com.

What is gravity? Would I be right in saying science dodges the question by simply defining a force to be anything that causes movement? In which case, although forces obey the same rules (i.e. their properties can be measured, and they have fields), they could all be different. Gravity, magnetism, electrical and the others might have a common cause, but I don't think there's a complete theory or explanation yet?

Without understanding the maths, I was happy with Einstein's proposition that mass puts a dent in the space-time continuum, allowing the orbit of this satellite to be calculated.

But I think the maths is just a model. It doesn't prove 'space-time' really exists, only something like it obeys the same rules. I don't pretend to understand it. If space-time exists, then what is 'space' and what is 'time'? My head hurts!

Dave

what is 'space' and what is 'time'?

...and time drops to zero with velocity

More weirdness I was trying to understand recently:

Light has no mass and therefore cannot be affected by gravity. Light can only travel in straight lines in a vacuum except that the matrix it is travelling straight within may be 'bent' by gravity. Therefore the model concludes there has to be some underlying matrix we choose to call space/time or subspace or whatever. Unless it's all a convenience and light can indeed be bent by gravity despite havng no mass...

More confusing was that the 'Big Bang' accelerated the constituents it created outwards (while having assorted interactions between them on that journey) yet the assorted bodies created are confounding expectations by continuing to accelerate away from each other and expanding total universe(s). The implication being that space/time has a repulsive force within it. A weak repulsive force within space/time would imply an antigravity effect? Which by its nature cannot coelesce to a powerful antigravity force in the way gravity does?

pgk

Here’s a rather surreal ‘gravity related’ story from the News, **LINK**

https://www.smithsonianmag.com/smartnews-science/spherical-neutrino-observatory-submerged-underwater-worlds-largest-freshwater-lake-180977252/

MichaelG.

Jim in respect of fooling the senses, I visited the Museum of Science and Industry in Chicago many years ago whilst working near Chicago. They had an excellent exhibit of coal mining, access to this exhibit was via a lift located on the top floor of the building, when the lift descended there were what appeared to be “windows” in the lift and on the outside of these “windows” were scenes scrolling past that gave the illusion that you were in a pit cage descending hundreds of feet into the bowels of the earth. When you arrived and stepped out you were for all intents and purposes in a working coal mine, a brilliantly constructed exhibit, and the elevator really tricked the mind. Dave W

Like Ady1, what is space and where is it?

Thanks for these.

Time is like money. - It's difficult to find enough of it.

Space is what gets filled with junk. It is difficult to locate, especially if one is carrying something heavy.

The Chicago Museum is indeed excellent. The example quoted illustrates why Mathematics, and careful, repeatable experiments, form the foundation of Physics and Engineering.

There is obviously a mass of information in this thread!

Must read it all, when the time can be found .

Howard

Edited By Howard Lewis on 18/03/2021 17:16:34

Dave W's posting on lifts and coal mining reminds me of a simple question:

You are decending by vertical lift into a very deep coal mine and the only light is from a safety (Davey/Stephenson) lamp. The rope fails and the cage free falls to the bottom of the shaft. What happens to the light from safety lamp before you die?

JA

Comment: This has everything to do with gravity and weightlessness

Edited By JA on 18/03/2021 18:17:09

Thanks for the link Michael. What bothers my simple mind is ...

The modules occupy an area of 17,657 cubic feet,

Sam

Not just your simple mind, Sam ... mine too

MichaelG.

.

Edit: ... but I lost the will to investigate any further when I saw the ‘cookie settings’ hurdle required to look at the linked item: 

“ The modules occupy an area of 17,657 cubic feet, reports Igor Bonifacic for Engadget. “

Edited By Michael Gilligan on 18/03/2021 18:55:34

Michael, In not grasping the implications of 'Cookie Settings', I wasn't game enough to include the second part of the sentence.

Jim, I must take this opportunity to acknowledge the many stories in your website **LINK**

swarfology.com.

Most entertaining and very much to the point.

Cheers,

Sam