# ANOTHER topic, another question - upwards acceleration

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#### c47man

• 90
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #30 on: April 14, 2011, 10:44:02 AM »
I don't understand how in one hand you claim that the universe is constantly accelerating, while in the other hand you reject the possibility of a non-accelerating fixed point of reference. Acceleration is a change in velocity, as we all know, and velocity, as has been mentioned, is a vector based measurement which requires a frame of reference to determine. How is it then that the universe can have acceleration, and thus velocity, while simultaneously asserting that there is no frame of reference? You argue that the Earth is the only frame of reference, and thus acceleration never approaches the speed of light because we're on it. The Earth is acceleration RELATIVE TO SOMETHING, but you deny that that something exists! Please help me out here, I must be missing something

Also, please explain terminal descent and why when an object in a perfect vaccuum is accelerated upwards it will always fall back down, even though basic physics indicates that it would maintain its acceleration upwards if UA, and not gravity, were to blame.

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#### Nolhekh

• 1669
• Animator
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #31 on: April 14, 2011, 11:07:10 AM »
I don't understand how in one hand you claim that the universe is constantly accelerating, while in the other hand you reject the possibility of a non-accelerating fixed point of reference. Acceleration is a change in velocity, as we all know, and velocity, as has been mentioned, is a vector based measurement which requires a frame of reference to determine. How is it then that the universe can have acceleration, and thus velocity, while simultaneously asserting that there is no frame of reference? You argue that the Earth is the only frame of reference, and thus acceleration never approaches the speed of light because we're on it. The Earth is acceleration RELATIVE TO SOMETHING, but you deny that that something exists! Please help me out here, I must be missing something
When an object accelerates, it applies a force on whatever it's carrying, regardless of what reference frame you're observing it from. But it's velocity relative to the thing that accelerates that doesn't change.  From a non accelerating frame of reference, the earth's acceleration would decrease as it approaches the speed of light relative to that frame of reference.  Time dilation prevents this decrease in acceleration from being experienced by those in the accelerating frame of reference.   Also think of this acceleration as causing a constant change in the frame of reference, this change allows the acceleration to be felt by those on the earth, even though their relative velocity stays at 0.
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Also, please explain terminal descent and why when an object in a perfect vaccuum is accelerated upwards it will always fall back down, even though basic physics indicates that it would maintain its acceleration upwards if UA, and not gravity, were to blame.
I'm not sure I understand this question.

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#### c47man

• 90
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #32 on: April 14, 2011, 03:03:55 PM »
When an object accelerates, it applies a force on whatever it's carrying, regardless of what reference frame you're observing it from. But it's velocity relative to the thing that accelerates that doesn't change.  From a non accelerating frame of reference, the earth's acceleration would decrease as it approaches the speed of light relative to that frame of reference.  Time dilation prevents this decrease in acceleration from being experienced by those in the accelerating frame of reference.   Also think of this acceleration as causing a constant change in the frame of reference, this change allows the acceleration to be felt by those on the earth, even though their relative velocity stays at 0.

How does time dilation, what I assume to be a perceptual effect, compensate for a decrease in acceleration?

Secondly, if we pick a fixed reference point 'R' at the location of earth at the beginning of UA, and apply UA to earth, the sun, moon, etc. and then observe their progress from 'R', the Earth would require greater and greater amounts of energy to maintain its acceleration, and eventually would require an infinitely great amount of energy, more energy than we know to exist in the universe, in order to continue accelerating. Seeing as how the earth has been demonstrated numerous times to be billions of years old, I can't understand how UA could be perceived as a better explanation than gravity.

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Also, please explain terminal descent and why when an object in a perfect vaccuum is accelerated upwards it will always fall back down, even though basic physics indicates that it would maintain its acceleration upwards if UA, and not gravity, were to blame.
I'm not sure I understand this question.

It was two questions. First, please explain terminal velocity during rapid descent. Second, if UA is universal, i.e. "everywhere", then why doesn't it effect us? If we accelerate a mass in a vacuum aiming straight up, the mass will always fall back down. If UA is in force here, the mass should continue to accelerate infinitely, and never return.

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#### Oracle

• 633
• RE'er with an open, but critical, mind.
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #33 on: April 14, 2011, 03:18:21 PM »
How does time dilation, what I assume to be a perceptual effect, compensate for a decrease in acceleration?

As you accelerate toward the speed of light, time dilation causes you to experience time at a slower rate such that the acceleration (your change in velocity per unit time) remains constant.  But there is also a space dilation in which distance is also compressed in the direction of travel based on your relative speed, which will directly impact your velocity.  Since your perspective is from the earth, and that is itself its own inertial frame of reference, you can assume that the starting time of any measurement t0 is initially at rest, or velocity is initially 0 from any measured point.

Secondly, if we pick a fixed reference point 'R' at the location of earth at the beginning of UA, and apply UA to earth, the sun, moon, etc. and then observe their progress from 'R', the Earth would require greater and greater amounts of energy to maintain its acceleration, and eventually would require an infinitely great amount of energy, more energy than we know to exist in the universe, in order to continue accelerating. Seeing as how the earth has been demonstrated numerous times to be billions of years old, I can't understand how UA could be perceived as a better explanation than gravity.

You got me on that too.

First, please explain terminal velocity during rapid descent.

The upward accelerating air would still cause resistance, which would act similar to a drag force against you if falling in a RE.  Have you ever seen the effect of a person being held aloft in a vertical wind tunnel?  the effect would be similar, thus causing a terminal velocity where your acceleration would eventually match that of the earths, but since you have different velocities, you still plummet to your untimely demise.... unless you have a parachute.

Second, if UA is universal, i.e. "everywhere", then why doesn't it effect us? If we accelerate a mass in a vacuum aiming straight up, the mass will always fall back down. If UA is in force here, the mass should continue to accelerate infinitely, and never return.

We are apparently shielded to UA by our close proximity to eh surface of the disk, this shielding would logically lessen as you got higher off the surface and began to feel more of the effects of UA causing you to feel less weight until you are suspended weightless as the sun and the moon are above the earth (roughly 3000 miles up at the equator).

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#### c47man

• 90
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #34 on: April 14, 2011, 04:25:14 PM »
Alright, you win on number 1 and 3 I'll take your word for the time/spacial dilation corresponding to our decrease in acceleration

Still though, it doesn't seem like a better explanation, especially since we have all of the data from space indicating gravity. And... round earths...

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#### Nolhekh

• 1669
• Animator
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #35 on: April 14, 2011, 04:28:43 PM »
Alright, you win on number 1 and 3 I'll take your word for the time/spacial dilation corresponding to our decrease in acceleration

Still though, it doesn't seem like a better explanation, especially since we have all of the data from space indicating gravity. And... round earths...

Agreed.  However, regarding the energy powering the acceleration, the universe is expanding at an accelerating rate, so really both theories require an unknown source of energy.  Physicists call it dark energy.  I don't know how it works myself though.

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#### Oracle

• 633
• RE'er with an open, but critical, mind.
##### Re: ANOTHER topic, another question - upwards acceleration
« Reply #36 on: April 14, 2011, 04:42:20 PM »
Alright, you win on number 1 and 3 I'll take your word for the time/spacial dilation corresponding to our decrease in acceleration

Still though, it doesn't seem like a better explanation, especially since we have all of the data from space indicating gravity. And... round earths...

I'm a RE'er myself, so don't look at me to try and explain UA and make is sound plausible, LOL.  Personally, I find the idea of gravity much more believable.