[elminah]

Hello,

I was wondering why we can replicate imponderability by free falling an airplane (the standard way they do it). And why the force of gravity cannot be felt inside this airplane - why it does not keep the objects on the earth side.

[Boerseun]

Actually, you do!

The airplanes they use for these exercises can do it for between 20-30 seconds, then they reach their airodynamic 'terminal velocities' - and then they have to pull up again, gain altitude and repeat the process.

You, as a passenger, are accellerating with the plane towards the earth at 10m/s^2, which happens to be the speed at which the Earth pulls at you. So, you float in mid-air, with respect to the airplane. When the airplane reaches its 'terminal velocity', which means it cannot fall faster through the specific medium without a power assist, it stops accellerating. You, inside, are 'falling' towards the earth inside a tube of air which is falling with you (the atmosphere inside the plane). So your airodynamic terminal velocity would be measured against the air falling with you - and you're static with respect to it, until the plane reaches its terminal velocity. Then you'd start falling towards the cockpit. But at this time, the pilot have already pulled the craft up to gain altitude for the next 'hop'. They do this because in trying to maintain 'weightlessness' inside the aircraft by opening the jets is virtually impossible - there's no way to get the jets to accellerate at exactly 10m/s^2.

[elminah]

I see it like this:

It shouldn't be possible not to feel anything - the sensation of weightlessness this close to a planet should be impossible to obtain.
You should feel a drag - acceleration of the plane or the gravity.
What happens in reality is that the sensation in that kind of plane is identical to the one on the orbit. It's like you can consider that the earth is falling towards you.

[sanctus]

Well this is why you call it microgravity and not zero gravity (as gravity is still ver present).
The drag you feel until you have the maximum speed reached as Borseun pointed it out.

Originally Posted by elminah

I see it like this: It's like you can consider that the earth is falling towards you.

I'm not sure if you misspoke when you wrote this, but if you said that while an astronaut or engineer was present, I feel that they could give you a strong argument as to the opposite of that statement.

It’s to my understanding that weightlessness either in parabolic flight or in orbit is the same.

What’s bothersome are your visual references, one you’re in a padded cargo hold, the other the vastness of near space.
Skydiving is somewhat different….You were doing fine until you stepped off the plane weren’t you?

Nowadays, it takes a rocket of some design to lift objects into orbit.
Once that propulsion is gone that object starts to fall to earth.
Even your plane would start to fall. Though a ship based on Magnetic propulsion would fit the bill.

Now maybe, IF you were bigger than the Earth....Then the Earth would fall towards you.

[elminah]

Maybe i haven't explain properly.
The gravity force does not really exist - it does not manifest like a force.
You don't feel the drag like when you accelerate in a sports car.
Gravity is more like an inertial modification of things - when objects are close to a planet (large object) the inertial resistance to acceleration makes the object accelerate towards the planet without feeling any drag. Einstein explain this by curvature of space - but this is like saying that space really exist - like ether.
Curvature of space in my understanding is more like a guideline for movement - the movement of objects in proximity of other objects is different than the Newtonian linear movement (conservation of moment).
My understanding of gravity is like this - gravity is not a force, it's just a rule of how relative object movement occurs, possibly an illusion determined by another phenomena that we don't understand.

Maybe theories like the accelerated expansion theory should not be dismissed before a better explanation is found.

[Dracontes]

elminah: I don't know, but it seems to me you're confusing the normal (as in surface reaction), tensional and compressional forces one feels on the surface of a planet as a concomitancy of gravity and a hard substrate with gravity itself.

One's always being accelerated, it's only the ground that stops one from going any further. Lacking that, or having enough distance between the mass in question and oneself, one's accelerated to the fullest extent of the law (of gravity). That one feels weightless is just a consequence of one's sensory devices, habituated to a world were whole-body acceleration is trumped by sundry surfaces, thus having various resulting forces to sense. Those devices the vestibular system in the inner ear and the stretch receptors in muscles.

I hope that was helpful and sufficiently intelligible.

Chendoh: Looking at the equation, attraction in gravity is mutual, so it really goes either way (in a conceptual context), though for the average human falling from space, the movement of the Earth towards the hapless person, is nigh to inexistant due to Earth's inertia, while the inverse is a more harrowing prospect

[elminah]

Ok , I understand, but the problem remains - can you make a device to measure gravity pull (acceleration) that is independent from vision in space? ( some accelerometer for gravity). Relatively you can consider that no pull is happening, just the two objects are adjusting their trajectories according to the rules of inertial movement.
I think that when you accelerate in a spacecraft in space you can measure the acceleration, and feel it.

I am saying that maybe there is no acceleration to be felt or measured, only because inertia does work different from the way it was postulated.
This can be tested by measuring tension in large objects in space due to gravity differences. Is there any proof that this tension exist?

[Boerseun]

If you're in free fall, your feet experience a higher gravitational attraction from Earth than your head. Same when you're in orbit. If you're floating in the space station with your toes pointing at the Earth, your feet are literally in a lower orbit than your head, and hence will have to move faster than the top of your head in order to maintain the orbit. These small-scale tidal effects are microscopic in its effects, hence we call these and other gravitational artifacts in near-to-earth space 'microgravity'.

Originally Posted by elminah

Ok , I understand, but the problem remains - can you make a device to measure gravity pull (acceleration) that is independent from vision in space? ( some accelerometer for gravity).

There are already formulas and devices. I believe that is how engineers measure GForce.

Originally Posted by elminah

Relatively you can consider that no pull is happening, just the two objects are adjusting their trajectories according to the rules of inertial movement.

Irrelevant….For now.

Somehow you are mixing apples and oranges.....Well, maybe not so much ....I can see where you are going......

Originally Posted by elminah

I think that when you accelerate in a spacecraft in space you can measure the acceleration, and feel it.

GForce again….Have you ever seen videos of manned spacecraft launches?

NASA - Multimedia - Video Gallery

Originally Posted by elminah

I am saying that maybe there is no acceleration to be felt or measured, only because inertia does work different from the way it was postulated.
This can be tested by measuring tension in large objects in space due to gravity differences. Is there any proof that this tension exist?

We mite be talkin' 'bout the Dark side here.....ergs an mass......

Originally Posted by Dracontes

elminah: I don't know, but it seems to me you're confusing the normal (as in surface reaction), tensional and compressional forces one feels on the surface of a planet as a concomitancy of gravity and a hard substrate with gravity itself.

Agreed........

Originally Posted by Dracontes

Chendoh:Looking at the equation, attraction in gravity is mutual, so it really goes either way (in a conceptual context), though for the average human falling from space, the movement of the Earth towards the hapless person, is nigh to inexistant due to Earth's inertia, while the inverse is a more harrowing prospect

Originally Posted by chendoh

IF you were bigger than the Earth….

Originally Posted by Boerseun

If you're in free fall, your feet experience a higher gravitational attraction from Earth than your head. Same when you're in orbit. If you're floating in the space station with your toes pointing at the Earth, your feet are literally in a lower orbit than your head, and hence will have to move faster than the top of your head in order to maintain the orbit. These small-scale tidal effects are microscopic in its effects, hence we call these and other gravitational artifacts in near-to-earth space 'microgravity'.

, And in the Quantum realm we are reminded of MBH……..Mini or Micro Black Holes.

Bravo! my Boerseun Friend!

Magnetic momentum is next!