[Bored chemist]

Could a force (2 ug or so) equal to the weight of a single dust particle really twist and turn Cavendish's iron rod?

Of course it could.
Why would it not?
Someone clever enough to know what they are talking about could even calculate the angle it turns it through.
https://en.wikipedia.org/wiki/Torsion_constant

[alright1234 (OP)]

Could a force (2 ug or so) equal to the weight of a single dust particle really twist and turn Cavendish's iron rod?

Of course it could.
Why would it not?
Someone clever enough to know what they are talking about could even calculate the angle it turns it through.
https://en.wikipedia.org/wiki/Torsion_constant

A force equivalent to a dust particle (2ug) probably would not twist and turn a string of dental floss.

[Bored chemist]

A force equivalent to a dust particle (2ug) probably would not twist and turn a string of dental floss.

I gave you a reference earlier which lets you find out how far it would twist it (depending on other stuff like the length of the beam and the string + the stiffness of dental floss).

Why not calculate it?
(If you like, you can get a grown up to help you)

Just to help you out a bit, I weighed  5 metres of dental floss. It has an apparent mass of 0.42 grams.

[alright1234 (OP)]

I did this little thing to add to everything else. What do you think? I'm since working on it and will add some more as I am growing up.



Newton's gravity equation is applied to an astronaut with a mass of 50 kg in the space station that is 249 miles (400,727 m) from the surface of the earth. The distance r which represents the distance from the center of the earth to the space station is,


r = (earth's radius) + (height) = (6.371  x 106 m) + (.4  x 106 m) = 6.771  x 106 m.......................69


Using the distance for r (equ 70) in Newton's gravity equation forms,



F = (G m1 m2)/r2  = (6.7 × 10-11) x (50kg) x (6 x 1024kg) / (6.771  x 106m)2 ≃ 438.4 N or 44.7 kg.....................70


According to Newton's gravity equation, a 50 kg astronaut in the space station forms a 44.7 kg gravitational force pointed at the earth. The centripetal force CF is used to justify the weightlessness of an astronaut in the space station is calculated,


CF = mv2/r = (50 kg)(7672 m/s)2/ (6.771 x 106 m) = 437 N or 44.56 kg................................71


The gravitational and centripetal forces form an equilibrium that produces the massless astronaut yet when a force is applied to an astronaut outside the space space and the astronaut propagates at a velocity of 50 mph in the direction opposite to the angular velocity, the described astronaut does not propagate towards the earth which proves the gravitational and centripetal forces do not function for a 50 kg astronaut propagating around the earth. Also, the space stations is orbiting the earth at approximately 250 miles above the surface of the earth. The 450 ton space station cannot orbit the earth at a height of 1000 miles above the surface of the earth which proves the gravitational and centripetal forces do not function for the space station at the height of 1000 miles. In addition, the centripetal force for a 50 kg mass on the surface of the earth propagating around the Sun is calculated,


CF = mv2 /r = (50kg)(30,462 m/s)2 / (1.5 x 1011 m) = .31 N............................................................................72


At 12:00 am (midnight), the centripetal force produced by the 50 kg mass on the surface of the earth propagating around the Sun is .31 N pointed away from the earth which represents the decrease in the weight of the 50 kg mass yet at 12:00 am (noon) a .2908 N ( v = 29,648 m/s) centripetal force would be pointing in the direction of the earth that would represent a .6 N weight variation every 24 hours which are not experimentally observe and proves the centripetal force does not function for a 50 kg mass on the surface of the earth propagating around the Sun.

[Bored chemist]

What do you think?

I think you should put it somewhere else and answer the question I asked in this thread.

[Bored chemist]

a 50 kg astronaut in the space station forms a 44.7 kg gravitational force pointed at the earth.

No.
The Kg is not a unit of force.

when a force is applied to an astronaut outside the space space and the astronaut propagates

Google translate didn't help me with that.
Would you like to try again?

[alright1234 (OP)]

What do you think?

I think you should put it somewhere else and answer the question I asked in this thread.

It is not physically possible to detect a 2ug force in 1797.

[alright1234 (OP)]

a 50 kg astronaut in the space station forms a 44.7 kg gravitational force pointed at the earth.

No.
The Kg is not a unit of force.

when a force is applied to an astronaut outside the space space and the astronaut propagates

Google translate didn't help me with that.
Would you like to try again?

The said astronaut is weightless and propagates in any direction when a force is applied yet according to the gravity theory using the centripetal force there is an equilibrium between Newton's gravitational force and the centripetal force which does not exist.

[Kryptid]

It is not physically possible to detect a 2ug force in 1797.

https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/49/Argument-by-Repetition

[alancalverd]

Ignoring the incorrect 2μg, it is incumbent on those who find Cavendish's experiment incredible, to explain why it yielded a value of G within 1% of the current best measurements.

[evan_au]

he astronaut propagates at a velocity of 50 mph

For material things (like an astronaut or space station), it would be better to use "travels" rather than "propagates".

We use "propagate" for things like waves: ocean waves or electromagnetic waves. (I know, English is pretty random...)

the astronaut propagates at a velocity of 50 mph in the direction opposite to the angular velocity, the described astronaut does not propagate towards the earth

Let's put this in perspective:
- The ISS is travelling in a circular orbit at a little over 17,000 miles per hour.
- This example imagines an astronaut getting a kick of 50 miles per hour, relative to the spacecraft
- So the 50mph can almost be ignored - the astronaut is still travelling at 17,000 mph, and so the astronaut remains in orbit
- If you look at the astronaut's orbit in more detail:
- It starts at the same altitude as the spacecraft
- But the astronaut is now travelling at slightly less than orbital speed for a circular orbit, so the astronaut starts to drop towards the Earth
- She gains speed as she drops towards the Earth
- If you had a good telescope, and the astronaut had a bright light, you would see the astronaut "below" the spacecraft (closer to the Earth) and pulling ahead of the ISS
- When the astronaut arrives at the point opposite where she got her initial kick (around 45 minutes later, for Low-Earth Orbit), she will be lower than the original orbit, but faster than the original orbit.
- The astronaut will now be travelling slightly faster than orbital speed for a circular orbit, and will start to rise further from the Earth
- Around 45 minutes later, the astronaut will be back at the original altitude.

To summarise: With a 50 mph kick, the astronaut does travel closer to the Earth - but not by very much.
But they remain in an elliptical orbit (until atmospheric drag gets them down...)

...I am sure Kryptid or Halc could give you exact figures...

[Janus]

Also, the space stations is orbiting the earth at approximately 250 miles above the surface of the earth. The 450 ton space station cannot orbit the earth at a height of 1000 miles above the surface of the earth which proves the gravitational and centripetal forces do not function for the space station at the height of 1000 miles.

In order to orbit at a 1000 mi altitude and  and maintain a circular orbit, the ISS would just need to have an orbital velocity of ~144,38 mph rather than the 17,256 mph speed it has now.  Even if you were to move the ISS up to that height with its present orbital speed, it will still orbit the Earth, it will just be an elliptical orbit which swings out to over 5100 mi in altitude during apogee.  The mass of the ISS (being very small compared to the Earth's) has no measurable effect on this.

A balance between gravity and centrifugal force is not how orbits are explained. And trying to think of this in these terms will only lead to confusion.*  Orbits are not maintained by some delicate balance between these two.  The only time you would get such a perfect balance is with a perfectly circular orbit, which do not occur in nature. 
The play between gravity and the velocity of a satellite is just not that stringent.  Its only when you decrease the velocity to the point where the orbit get so low at it low point that it grazes the planet, or you increase it to escape velocity ( ~41% greater than the circular orbit velocity), would you have  problems with maintaining an orbit.

*Nor is it the reason for an astronaut's "Weightlessness".  He feels weightless relative to the ISS because both are free to act in response to the pull of the same gravity and are following the same free fall trajectory.

[Bored chemist]

It is not physically possible to detect a 2ug force in 1797.

Why not?
Aristotle knew how a long time earlier
"Give me the place to stand, and I shall move the earth."

[alright1234 (OP)]

It is not physically possible to detect a 2ug force in 1797.

Why not?
Aristotle knew how a long time earlier
"Give me the place to stand, and I shall move the earth."

This is similar to the LIGO that is said to detect a 10^18 m mirror displacement and Weber's gravitational bar that measured a 1662 Hz GW.

[Bored chemist]

It is not physically possible to detect a 2ug force in 1797.

Why not?
Aristotle knew how a long time earlier
"Give me the place to stand, and I shall move the earth."

This is similar to the LIGO that is said to detect a 10^18 m mirror displacement and Weber's gravitational bar that measured a 1662 Hz GW.

It is indeed similar.
It is correct and you don't believe it.

Why don't you actually do the maths and find out what the twist of the equipment would actually be?
Are you, by any chance, not actually competent?

[evan_au]

Weber's gravitational bar that measured a 1662 Hz GW.

You should say "Weber claimed to have measured Gravitational waves".

It is now thought that he was mistaken; his 1960s equipment was not sensitive enough, had too narrow a frequency range, and was too subject to noise.
He claimed a rate of black hole mergers that were incompatible with estimates of how many black holes could be colliding.
https://en.wikipedia.org/wiki/Weber_bar#History

But this comment belongs more in the LIGO thread, because with 2015 technology, LIGO is sensitive enough to detect oscillating gravitational waves over a wide range of frequencies.

And this comment has nothing to do with whether Cavendish's equipment could detect static gravitational attraction in the 1700s.
Note that Cavendish was not measuring gravitational waves: that is an entirely different phenomena.

[Bored chemist]

 I still look forward to alright1234 explaining how the actual maths (which is older  than Cavendish) is, in some sense, wrong

[evan_au]

Cavendish's equipment could detect static gravitational attraction in the 1700s.
Note that Cavendish was not measuring gravitational waves: that is an entirely different phenomena.

I think there might be confusion here about the difference between static fields and propagating waves?

We can clarify the difference between static and propagating gravitational fields by comparing the history of static and propagating electromagnetic fields.
- Static electricity was known from ancient times in the form of lightning - a force of nature that could not be controlled.
- Similarly, the Earth's static gravitational field was known from ancient times because a dropped rock falls down - a force of nature that could not be controlled
- Static Electric fields could be produced on-demand by the ancient Greeks by rubbing amber on cat fur, for example. Thales wrote about this in 600BC.
- Static magnetic fields could be harnessed for navigation by using magnetic minerals to form a compass. Early examples date back as early as 1000 BC
- Newton's theory of universal gravitation explaining static gravitational fields (and planetary orbits) was published in 1687.
- Propagating electromagnetic fields in the form of light were known to ancient humans, but this is built into our DNA; the theoretical mechanism was not known until Maxwell's equations in 1864.
- Propagating electromagnetic waves were first generated and detected in a controlled way by Hertz in 1887. That set off a series of inventions that eventually spanned the Atlantic with radio waves, and today allows communications with space probes beyond Pluto.
- Propagating gravitational waves were first theorised based on Einsteins's general Relativity in 1916. He didn't think they would be detectable.
- Propagating gravitational waves were first detected by LIGO in 2015. This has already set of a series of inventions to improve the sensitivity and range of detectors.
- At present, we have no idea if or when or how humans will ever be able to generate a gravitational wave which is strong enough for humans to detect.

Conclusion
Static electromagnetic and gravitational fields were known from prehistoric times.
- Controllable static electromagnetic fields dates back to 600-1000BC; Cavendish's experiments with static gravitational fields in 1797 was the first time they were generated and detected in a controlled fashion by humans.
- Propagating electromagnetic fields went from theory to generation and detection in 23 years.
- Propagating gravitational waves went from theory to detection in a century, and we have no idea when we will be able to generate them.

The reason for the slower development of technologies around gravitation is that gravitational fields are about 10⁴⁰ times weaker than electromagnetic fields, so we can expect the equipment to be about 10⁴⁰ times bigger and more powerful (as an extremely rough order of magnitude!)

See: https://en.wikipedia.org/wiki/History_of_electromagnetic_theory#Ancient_and_classical_history

[alright1234 (OP)]

It is not physically possible to detect a 2ug force in 1797.

Why not?
Aristotle knew how a long time earlier
"Give me the place to stand, and I shall move the earth."

Show a a 2ug force is measured today in modern physics. Cav is directly measuring a 2ug force. I do not think that they can do it directly even today. Show a link if I am wrong.

[Bored chemist]

Well, it's a matter of definition.
https://www.newscientist.com/article/dn21651-worlds-most-sensitive-scales-detect-a-yoctogram/
That's a millionth of a millionth of a millionth of a microgram.
So you are wrong by a factor of about 1000000000000000000
which is pretty wrong.

If you mean a traditional "weighing machine" then, for less than the price of  a good new car, you can buy one of these.
https://www.mt.com/gb/en/home/products/Laboratory_Weighing_Solutions/Micro_Ultra_Balances/XPR_MicroBalance.html

An off-the-peg lab microbalance which will resolve down to 0.1µg

They aren't new.
When I started work in the late 80s we had a balance with that resolution.
It was an AD2Z. They  still pop up on eBay from time to time.
https://www.ebay.com/itm/Perkin-Elmer-AD2Z-Autobalance-/110888520605?_ul=AR
and, if you are interested, I have a copy of the manual.


Even a home made  balance can get you down into the microgram range.
https://erowid.org/archive/rhodium/chemistry/equipment/scale2.html


So the real question here is why don't you believe reality?