# Thread: Does time dilation affect physical aging?

1. To use an example from the Wikipedia entry on time dilation:

'In theory, and to make a clearer example, time dilation could affect planned meetings for astronauts with advanced technologies and greater travel speeds. The astronauts would have to set their clocks to count exactly 80 years, whereas mission control – back on Earth – might need to count 81 years. The astronauts would return to Earth, after their mission, having aged one year less than the people staying on Earth.'

Would the astronauts in fact have physically aged 80 years wheras the people on Earth would have aged 81? It seems unlikely but if that is the case then could humans extend their lifetimes by taking elongated return trips to deep space?

Thanks

2.

3. Yes.

The astronauts would age one year less than the people staying on Earth.

But a human could not extend his own lifetime by taking an elongated high speed trip to deep space. He would still experience all the years of his life as if he had stayed at home. His own body would still age at a rate if 1 year per year, for him. But when he returned to Earth, many more years would have passed. He would be able to literally travel into Earth's future.

But if he was going to die at the age of 80, he would still die at the age of 80, having experienced 80 years.

4. Many thanks.

So all I need to do is book a very long return trip and I'll get to see the world cup final in 2150. Knowing my luck it'd be cancelled:

'What do you mean it's cancelled...I don't care if it's snowing, do you know how far I've travelled to get here?....no, not from the hotel..'

5. Originally Posted by Citadel
Many thanks.

So all I need to do is book a very long return trip and I'll get to see the world cup final in 2150. Knowing my luck it'd be cancelled:

'What do you mean it's cancelled...I don't care if it's snowing, do you know how far I've travelled to get here?....no, not from the hotel..'
Not to mention the expense. If you traveled at 99% of the speed of light, you could return in 2150 in only 19 years of your own time.

The energy needed per kilogram to reach 99% of the speed of light is 1.5x10^11 kwh. The average price per kwh in the US is 12 cents, so this works out to 1.8 billion dollars per kg. And that's just to get to that speed. To make a round trip you have to get up to that speed, slow to a stop, get back up to speed for the return leg, and stop again after returning. each of these steps take that much energy, So you are looking at something like 7.3 billion dollars per kg. ( And to be quite frank, these numbers are highly optimistic as they don't take into account the practical aspects of such a trip and how they will inflate this cost greatly. )

So if I were you, I might plan on going on a diet, and above all, pack lightly!

6. Originally Posted by Citadel
Would the astronauts in fact have physically aged 80 years wheras the people on Earth would have aged 81?
I think it's important to understand why the two ages are different. It seems to be a common mistaken view that motion somehow physically affects clocks and the aging process. This is not the case. The twin-clock "paradox" is most easily understood by considering the journeys in four-dimensional spacetime. There are two points and two different paths between them. The people on Earth travelled the direct straight path between those two points¹ while the astronaut travelled a less direct curved path between these two points. Four-dimensional spacetime has geometric properties just as ordinary three-dimensional space has geometric properties. In three-dimensional space, the shortest distance between two points is a straight line, so it is obvious that a person who takes a less direct path has travelled further than a person who takes the direct path. In spacetime, for journeys in a predominately time direction, which means that the speed is less than the speed of light in a vacuum, distance travelled is measured by the time according to a clock that takes the journey. So in the twin-clock "paradox", the astronaut has travelled less distance in spacetime than a person who has travelled the direct route. In three-dimensional space, it is the direct route that is shortest, so why is it the astronaut's path that is shorter? This is due to a peculiarity of the geometry of four-dimensional spacetime compared to the geometry of three-dimensional space. It is this peculiarity that results in the speed of light in a vacuum being the same for all observers. Nevertheless, in spite of the difference between the geometries of four-dimensional spacetime and three-dimensional space, the twin-clock "paradox" is the result of the simple geometric fact that the distance between two points depends on the path between them.

¹ Actually this is not true if earth's gravity is considered, but in the twin-clock "paradox", it is ignored.

7. I have a question; what sort of effect would be noticed locally when an object with the mass of a regular golfball traveling at 99% the speed of light passes through the neighborhood?

8. Was it sliced or hooked?

9. Originally Posted by scoobydoo1
I have a question; what sort of effect would be noticed locally when an object with the mass of a regular golfball traveling at 99% the speed of light passes through the neighborhood?
Due to what? The object's gravity? Not at lot. Even at 0.99c, an object the mass of a golf ball would not produce a significant gravitational influence. However, in general, a moving mass produces what is known as "gravitomagnetism", which is the gravitational analogue of magnetism, and is responsible for frame-dragging in general relativity.

10. Originally Posted by KJW
Originally Posted by scoobydoo1
I have a question; what sort of effect would be noticed locally when an object with the mass of a regular golfball traveling at 99% the speed of light passes through the neighborhood?
Due to what? The object's gravity? Not at lot. Even at 0.99c, an object the mass of a golf ball would not produce a significant gravitational influence. However, in general, a moving mass produces what is known as "gravitomagnetism", which is the gravitational analogue of magnetism, and is responsible for frame-dragging in general relativity.
I was thinking something along the lines of whether there will be any rippling effects in the neighbourhood caused by an object traveling at those speeds. Since I'm not well studied in the subject, I figured I ask it to get a better picture.

11. Originally Posted by scoobydoo1
Originally Posted by KJW
Originally Posted by scoobydoo1
I have a question; what sort of effect would be noticed locally when an object with the mass of a regular golfball traveling at 99% the speed of light passes through the neighborhood?
Due to what? The object's gravity? Not at lot. Even at 0.99c, an object the mass of a golf ball would not produce a significant gravitational influence. However, in general, a moving mass produces what is known as "gravitomagnetism", which is the gravitational analogue of magnetism, and is responsible for frame-dragging in general relativity.
I was thinking something along the lines of whether there will be any rippling effects in the neighbourhood caused by an object traveling at those speeds. Since I'm not well studied in the subject, I figured I ask it to get a better picture.
The effects of a moving object are completely the consequence of the effects of the corresponding stationary object. One need only consider the frame of reference that is moving with the object and apply the relativity principle that the laws of physics are the same in all inertial frames of reference.

12. Originally Posted by Janus
Originally Posted by Citadel
Manythanks.

So all I need to do is book a very long return trip and I'll get to see theworld cup final in 2150. Knowing my luck it'd be cancelled:

'What do you mean it's cancelled...I don't care if it's snowing, do you knowhow far I've travelled to get here?....no, not from the hotel..'
Originally Posted by Janus

Not to mention the expense. If you traveled at 99% of the speed of light, youcould return in 2150 in only19 years of your own time.

The energy needed per kilogram to reach 99% of the speed of light is 1.5x10^11kwh. The average price per kwh in the US is 12 cents, so this works out to 1.8billion dollars per kg. And that's just to get to that speed. To make a roundtrip you have to get up to that speed, slow to a stop, get back up to speed forthe return leg, and stop again after returning. each of these steps take thatmuch energy, So you are looking at something like 7.3 billion dollars per kg. (And to be quite frank, these numbers are highly optimistic as they don't takeinto account the practical aspects of such a trip and how they will inflatethis cost greatly. )

So if I were you, I might plan on going on a diet, and above all, pack lightly!

Ok. So I weigh 65.2 KG if i'm wearing nothing but a smile to make my soullighter
So that's 65.2*7.3 billion = 475.96 BillionDollars.

I can buy a hat at the game (but i'll need about \$100 of gold just in case theyhave changed currency) and it's in summer so, snow notwithstanding, it's aT-Shirt, shorts, underwear (g-string prob saves a few hundred million dollars)and sneakers. I'm guessing about 1.2 KG of kit = 8.76 Billon + \$50 because i'm buying a David Beckham brand...

So it's costing me 483.76 Billion + \$150 in change to get there. I can sell myclassic retro T-Shirt for the tickets and buy a cheap football top from avendor with the change.

All I need to do now is see if a payday loan company will give me the money

13. Originally Posted by scoobydoo1
I have a question; what sort of effect would be noticed locally when an object with the mass of a regular golfball traveling at 99% the speed of light passes through the neighborhood?
Not quite what you are asking, but it shows the dangers of throwing balls around: Relativistic Baseball

14. Originally Posted by Strange
Originally Posted by scoobydoo1
I have a question; what sort of effect would be noticed locally when an object with the mass of a regular golfball traveling at 99% the speed of light passes through the neighborhood?
Not quite what you are asking, but it shows the dangers of throwing balls around: Relativistic Baseball
Yup, this was the kind of effect I had in mind. Thanks Strange.

But seeing that outer space being so vast, and matter aren't exactly as packed as what we have in our atmosphere, would a similar effect described in the link you've provided still take place when the golfball does come into contact with other matter, and will the effect be obserable to us on earth when it passes through our solar neighborhood?

15. Are their time travelers?

16. Stop posting.

17. Originally Posted by Hill Billy Holmes
Are their time travelers?
We are all time travellers. Unfortunately, it is a one way street (although there are lanes for different speeds of travel).

18. Originally Posted by Janus
Originally Posted by Citadel
Many thanks.

So all I need to do is book a very long return trip and I'll get to see the world cup final in 2150. Knowing my luck it'd be cancelled:

'What do you mean it's cancelled...I don't care if it's snowing, do you know how far I've travelled to get here?....no, not from the hotel..'
Not to mention the expense. If you traveled at 99% of the speed of light, you could return in 2150 in only 19 years of your own time.

The energy needed per kilogram to reach 99% of the speed of light is 1.5x10^11 kwh. The average price per kwh in the US is 12 cents, so this works out to 1.8 billion dollars per kg. And that's just to get to that speed. To make a round trip you have to get up to that speed, slow to a stop, get back up to speed for the return leg, and stop again after returning. each of these steps take that much energy, So you are looking at something like 7.3 billion dollars per kg. ( And to be quite frank, these numbers are highly optimistic as they don't take into account the practical aspects of such a trip and how they will inflate this cost greatly. )

So if I were you, I might plan on going on a diet, and above all, pack lightly!
I have to have my lipstick!!!!!

19. Originally Posted by John Galt
Was it sliced or hooked?
a DRAW!!!

20. Originally Posted by Hill Billy Holmes
Are their time travelers?
Well we live life, therefore we travel in time. Moot point!

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