Time Dialation and Biological systems

[Ryan_m_b]

I have read various articles on relativity and and am happy with the idea of FORs. However I feel somewhat under pressure from the science community to just accept the idea without question - especially counterintuitive issues.

No idea where you are getting that feeling from, certainly not here. I can't find any examples of someone admonishing you for questioning and plenty of people trying to help you to understand. To suggest otherwise is to be a severe distortion of the facts and would be quite insulting.

This evokes suspicion in the layman who then looks for chinks in the armour of theoretical science and then what does he find out? He finds out that science, for quite sometime now, has not been able to reconcile the theory of the everyday world with the theory of the very small in a theory of everything which subsequently begs the question wether certain parts of scientific theory has not been fudged over so as to speak in order to make other parts of theory work.

Yes science is incomplete, if it wasn't we would have stopped. This is not a hidden fact but a foundation of modern scientific enquiry. You're framing this as though there is a conspiracy amongst scientists to cover up the fact that we don't know everything, I'm sorry but like most conspiracy theories it's all in your head.

Thank you both for your input - its much appreciated. Its just I have received conflicting info from different scientists such as: When traveling at the near speed of light every would come to a virtual standstill. Cheers until later.

Only from the perspective of someone in another frame of reference. Put it this way:
Alice and Bob are sitting in spaceships at rest relative to each other. Alice fires up her engines and blasts away, measuring her speed relative to Bob to be .9c. Bob looking through his spaceship's telescope will see everything on Alice's ship happening slowly; the clock will tick slower than his, her breathing will be slower, heart rate etc. However for Alice nothing has changed. Time seems to pass exactly as it did when she was at rest.

 

[indirachap]

No idea where you are getting that feeling from, certainly not here. I can't find any examples of someone admonishing you for questioning and plenty of people trying to help you to understand. To suggest otherwise is to be a severe distortion of the facts and would be quite insulting.

No insult intended. By pressure I mean not pressure from scientists on this board but pressure from science in general on the layman to conform to conventional scientific thought.

Only from the perspective of someone in another frame of reference. Put it this way:
Alice and Bob are sitting in spaceships at rest relative to each other. Alice fires up her engines and blasts away, measuring her speed relative to Bob to be .9c. Bob looking through his spaceship's telescope will see everything on Alice's ship happening slowly; the clock will tick slower than his, her breathing will be slower, heart rate etc. However for Alice nothing has changed. Time seems to pass exactly as it did when she was at rest.

"However for Alice nothing has changed". Is this phrase not pure supposition? Surely for Alice everything has changed. Bob can see that Alice is virtually frozen in time by traveling at the near speed of light. Supposing that biological systems are affected by time dialation, Alice by being virtually dead would not percieve anything like normality and would not even if she were functioning normally

The question is (a) what is the actual physical state of Alice's biological system when Bob saw her through his telescope and (b) does this violate some basic a priori principles of life as we know it. If the answer is yes, then surely science is irrational?

 

[Ryan_m_b]

No insult intended. By pressure I mean not pressure from scientists on this board but pressure from science in general on the layman to conform to conventional scientific thought.

I'm not going to dispute that you feel that way and I can't really comment on it more without knowing more about your background.

"However for Alice nothing has changed". Is this phrase not pure supposition? Surely for Alice everything has changed. Bob can see that Alice is virtually frozen in time by traveling at the near speed of light. Supposing that biological systems are affected by time dialation, Alice by being virtually dead would not percieve anything like normality and would not even if she were functioning normally

From Alice's point of view nothing has changed. Even from Bob's perspective she is not virtually dead, he could record his observations of her and play them at a faster speed and she would seem to behave exactly as she was when they were stationary.

The question is (a) what is the actual physical state of Alice's biological system when Bob saw her through his telescope and (b) does this violate some basic a priori principles of life as we know it. If the answer is yes, then surely science is irrational?

Alice's biology is behaving in exactly the same manner as it was before she accelerated away, just slower from Bob's perspective. There is nothing inconsistent here.

 

[phinds]

The question is (a) what is the actual physical state of Alice's biological system when Bob saw her through his telescope and (b) does this violate some basic a priori principles of life as we know it. If the answer is yes, then surely science is irrational?

YOU ARE NOT LISTENING !

As stated previously by me and others, Alice experiences NOTHING untoward. Everything is perfectly normal to her. Time dilation is an artifact of frames of reference. It is NOT experienced by the Alice, it is observed by Bob. It is an artifact of relativity. Get over it and move on.

EDIT: I see Ryan beat me to it (and with less vehemence )

 

[Dale]

I feel somewhat under pressure from the science community to just accept the idea without question

This is an absurd comment. We are not asking you to accept the idea without question. We are asking you to accept the boatloads of experimental evidence that supports the idea:

http://www.edu-observatory.org/physics-faq/Relativity/SR/experiments.html

It isn't science applying pressure on you to change your way of thinking, it is nature. Yes, our classical/intuitive worldview is hard to relinquish, but it has been experimentally disproven. Nature simply doesn't work in the way you want it to.

 

[Dale]

"However for Alice nothing has changed". Is this phrase not pure supposition? Surely for Alice everything has changed. Bob can see that Alice is virtually frozen in time by traveling at the near speed of light. Supposing that biological systems are affected by time dialation, Alice by being virtually dead would not percieve anything like normality and would not even if she were functioning normally

You are currently traveling at .9999999 c in some reference frame. Do you notice anything abnormal? Are you virtually dead?

The question is (a) what is the actual physical state of Alice's biological system when Bob saw her through his telescope and (b) does this violate some basic a priori principles of life as we know it. If the answer is yes, then surely science is irrational?

(a) Alice is "actually" slowed down IN BOB'S FRAME. (b) no it doesn't violate any principles of biology. I already explained to you in great detail why not, but it seems that you either did not understand the answer or you understand it but don't want to acknowledge it.

 

[ghwellsjr]

...
If a spaceship travels from Planet Earth to a Plant X and back at the near speed of light would the clock onboard the spaceship run considerably slower than the clock at the spaceship station on Earth? If the answer is yes would this not mean that the crew lived their lives onboard in actual slowmotion - indeed a virtual standstill?

I have read various articles on relativity and am happy with the idea of FORs.

...
"However for Alice nothing has changed". Is this phrase not pure supposition? Surely for Alice everything has changed. Bob can see that Alice is virtually frozen in time by traveling at the near speed of light. Supposing that biological systems are affected by time dialation, Alice by being virtually dead would not percieve anything like normality and would not even if she were functioning normally

The question is (a) what is the actual physical state of Alice's biological system when Bob saw her through his telescope and (b) does this violate some basic a priori principles of life as we know it. If the answer is yes, then surely science is irrational?

Let's say Bob stays on Earth and Alice travels at high speed toward Planet X where Carl lives. In the FoR where Earth and Planet X are both at rest, Alice will be experiencing time dilation. When Bob looks at Alice through his telescope, he sees her in slow motion. However, when Carl sees Alice take off through his telescope and start her journey toward him, he sees her in fast motion. Furthermore, when Alice looks back at Bob on Earth, she sees him in slow motion and as she looks ahead at Carl on Planet X, she sees him in fast motion. All these different observations from different points of view are not what we call time dilation. You have to make a distinction between what is observed by different observers and what is assigned by the specified Frame of Reference.

Now let's consider a different FoR, one in which Alice is at rest while she is "traveling" toward Planet X. Now Alice is experiencing no time dilation but both Bob on Earth and Carl on Planet X are experiencing time dilation. They are the ones that are traveling at near light speed and are "virtually frozen in time", as you like to say.

But again, as Alice looks back at Bob on Earth, she sees him in slow motion and as she looks ahead at Carl on Planet X, she sees him in fast motion, just as before. And when Bob looks at Alice, he sees her in slow motion and Carl sees her in fast motion. The selected FoR has no bearing on what observers see.

So if you are really happy with the idea of Frames of Reference, then you should have no problem understanding that time dilation is relative to the selected FoR and has nothing to do with what observers see.

Do you understand all this? Do you have any questions?

 

[indirachap]

Thank you ghwellsjr and everybody else for their kind replies.

[Do you understand all this? Do you have any questions?]

I am unhappy about the idea that Alice would have aged less than Bob on her return to Earth. Does this not violate some basic a priori principles of biology?

 

[Dale]

Does this not violate some basic a priori principles of biology?

No, it does not.

 

[Nugatory]

I am unhappy about the idea that Alice would have aged less than Bob on her return to Earth. Does this not violate some basic a priori principles of biology?

No. Alice is away for five years, she ages fives years, celebrates five birthdays (assuming that she celebrates a birthday every 365*24*3600 seconds according to her wristwatch), her wristwatch records the passage of five years, if she brings a sample of radioactive material with a five-year half-life with her it will be decay by 50% during the journey. No paradox or contradiction there, she's just lived through five years and aged accordingly just as any other chemical, biological, physical, or mechanical system would age over five years.

Bob stays at home for ten years, ages ten years, celebrates ten birthdays, his wristwatch records the passage of ten years, his sample of the radioactive material will be 75% decayed because that's two half-lives. There's no paradox or contradiction there, he's just lived through ten years and aged accordingly just as any other chemical, biological, physical, or mechanical system would age over ten years.

It's just a bit surprising when they meet each other.

 

[Ryan_m_b]

I am unhappy about the idea that Alice would have aged less than Bob on her return to Earth. Does this not violate some basic a priori principles of biology?

What is an "a priori principle of biology"?

 

[A.T.]

I am unhappy about the idea that Alice would have aged less than Bob on her return to Earth. Does this not violate some basic a priori principles of biology?

Which principles of biology? All principles of biology have to be consistent with the more fundamental principles of physics.

 

[ghwellsjr]

Thank you ghwellsjr and everybody else for their kind replies.

[Do you understand all this? Do you have any questions?]

I am unhappy about the idea that Alice would have aged less than Bob on her return to Earth. Does this not violate some basic a priori principles of biology?

It seems as though you have no problem with the purely physical devices such as clocks ticking at different rates and that Alice's wristwatch would run slower while she is on the trip so that it accumulates less time, say, five years vs ten years, to use Nugatory's example, during the course of the trip, but you are concerned that our biological clock's would not be subject to the same effects of time dilation, is that correct?

 

[Surfether]

Can anyone prove that Time Dialation affects biological systems?

Time is purely a measure of a change of entropy. The pointers of a clock indicate, that from one moment to the next the entropy of the spring has changed. A biological system is in no way different. The beating of the heart and the lines around the eyes are measuring the change of entropy and give an arrow or direction to time. But here is a thought: The pointers of the clock, from its relative frame of rest, are communicating to the rest of the Universe, its state of entropy at the speed of light. Indeed the clock would continue to do so in darkness and without pointers. Biological systems also communicate their entropy state at the speed of light. Thus C is the speed of information communication, whether electro-magnetic in type, or some other form related to the exchange of entropy information with the rest of the Universe. It should not surprise us, therefore, that movement at high relativistic velocities will affect the way we perceive the changes of time and entropy of bodies in other frames of reference. The same applies if we are at rest and observing the half life of a very unstable particle moving close to C.

 

[indirachap]

Which principles of biology? All principles of biology have to be consistent with the more fundamental principles of physics.

Do they? Do all the principles of biology have to be consistent with the more fundamental principles of Quantum Mechanics?

 

[Ryan_m_b]

Do they? Do all the principles of biology have to be consistent with the more fundamental principles of Quantum Mechanics?

Of course they do, why wouldn't they? Just because quantum effects don't manifest on the macroscale why would you think that the moment an atom or sub-atomic particle becomes part of a biological system it suddenly becomes different?

 

[indirachap]

What is an "a priori principle of biology"?

I should imagine an a priori principle of biology would be the requirement that Planet Earth conditions (be they artificial or natural) be maintained throughout the lifetime of a biological system.

This would be particularly applicable when dealing with the passage of time.

 

[Ryan_m_b]

I should imagine an a priori principle of biology would be the requirement that Planet Earth conditions (be they artificial or natural) be maintained throughout the lifetime of a biological system.

This would be particularly applicable when dealing with the passage of time.

Two important things:

1) Look up the term a priori, it does not mean what you seem to think it does.

2) As has been repeatedly pointed out for the traveller and their biology the passage of time stays the same.

 

[indirachap]

Two important things:

1) Look up the term a priori, it does not mean what you seem to think it does.

2) As has been repeatedly pointed out for the traveller and their biology the passage of time stays the same.

1) I am quite happy with the term denoting "without research" or indeed "obvious"

2) Surely nowhere on Earth would a traveller return from a journey having aged less than the twin he left behind? Does this not violate the example of a principle of biology that I gave?

I must adjourn

 

[Dale]

Do they? Do all the principles of biology have to be consistent with the more fundamental principles of Quantum Mechanics?

Yes, definitely. Furthermore, as I explained previously, all principles of biology are governed essentially exclusively by EM, so biology must specifically be consistent with Quantum Electrodynamics.

 

[Dale]

2) Surely nowhere on Earth would a traveller return from a journey having aged less than the twin he left behind? Does this not violate the example of a principle of biology that I gave?

Please cite a reputable source that specifically identifies that as a principle of biology. I for one have never come upon such a statement listed as a principle in any of my biology texts, so I think it is not an accepted principle.

 

[ghwellsjr]

Do you agree that clocks dilate but your problem is just with biological clocks? In other words, would Alice notice that her clocks were running slower than her own perception of time?

 

[Ryan_m_b]

1) I am quite happy with the term denoting "without research" or indeed "obvious"

It is not a synonym of obvious, it means that the conclusion can be derived without physical evidence from experimentation. I challenge you to derive any information about biology without physical evidence from experimentation (of which your own sensory input would include).

2) Surely nowhere on Earth would a traveller return from a journey having aged less than the twin he left behind? Does this not violate the example of a principle of biology that I gave?

Actually they would have but by such a tiny amount it's inconsequential. The difference between an airport clock and an aeroplane clock after a journey is virtually undetectable. Essentially a it's because at no point would the traveller have accelerated to relativistic speeds relative to an observer.

 

[Mark M]

2) Surely nowhere on Earth would a traveller return from a journey having aged less than the twin he left behind? Does this not violate the example of a principle of biology that I gave?

Ryan, DaleSpam, and ghwellsjr have been re-iterating this to you over and over - in YOUR reference frame YOU feel time passing normally. ANOTHER observer in a different reference frame sees your time moving slowly, your body slowing down, and your clock ticking slower. But YOU always feel normally.

This is a fact. There aren't any 'principles of biology' that contradict this.

 

[BruceW]

2) Surely nowhere on Earth would a traveller return from a journey having aged less than the twin he left behind? Does this not violate the example of a principle of biology that I gave?

Even on planet earth, time dilation will have an effect. (As Ryan_m_b also said). If I ride about on a fast train all my life, then when I eventually stop and meet with my stay-at-home twin, then I will have lived for about a second less time than he has lived.

To put it another way, the space time interval of my journey will be less than that of my twin, because I have been accelerating around on the train. And the space time interval is the same as the time which has passed for that person, so I will end up a little bit younger than my twin.

 

[PAllen]

So let's suppose the world worked according to what indirachap suggests. Then, if someone else travels very fast near me, I notice that my clocks (both light and mechanical), and radioactive decay, slow down compared to my biological time perception. If no one else moves fast near me, this does not happen. !??

 

[DennisN]

Poppin' in, first time I post in the Relativity forum, I think, hi!

Biology is governed by physics, not the other way around (this does of course not mean biology as a science is less important).

indirachap, I have read the entire thread and I have a suggestion. Many years ago I struggled myself with accepting relativity, since I found it counterintuitive (speed of light as a basis, length contraction, time dilation etc). My road to accepting the theory was not straightforward, but these were some of my important steps;

"How I Learned to Stop Worrying and Love Relativity":

1. Learning the basics of the theory.
2. Questioning it on various grounds (counterintuitive, hard to grasp etc)
3. Checking how tests and experiments matched up with the theory (it beats Newton et.al.).
4. Learning more thorougly about the theory (and adding a little General Relativity too).
5. Trying to fit it into my worldview.
6. Accepting it.

I don't know at which stage you are, but here is one suggestion from me:

Forget about the concept of an absolute, universal time. There is no universal clock which governs everything. Thus, a clock ticking on Earth is universally "meaningless", it's only important to someone on Earth (and the same goes for "space", there's no absolute, universal space; there is spacetime).

If you can make yourself accept this, you might find that time dilation is not particularly counterintuitive. For person A, clock C_A shows time T_A, perfectly normal to person A. For person B, clock C_B shows time T_B, perfectly normal to person B. But this does not necessarily mean time T_A = T_B, as there is no time T_U = universal, absolute time. If there was a universal time, then we could adjust our clocks to T_A = T_B = T_U. Remove the absolute, universal time T_U, forget it, and set T_A ≠ T_B (yet, of course, T_A = T_B if A and B are at rest with respect to each other).

 

[ZapperZ]

The original question has been answered several times. This thread is done.

Zz.