The "Twin" paradox..

[xelasnave]

You must all know this one..
Two twins ..one flys away at c and one stays at home... when they reunite their ages are considerably different...

it fascinates me:D..... and when I found this (article below) I felt my thunder had been stolen... some may recall my ramblings about it years ago and my logic to point out there was no paradox:screwy:... well seems someone has or at least approached the problem the way I felt it could be addressed:)... and yes using different reference frames... other than those being measured for age increments.. I used passing stars.. so is this fella right or not???

http://www.sciencedaily.com/releases/2008/07/080703140721.htm


alex:):):)

[xelasnave]

Help moderators... this was supposed to go in general chat..opps

alex

[DJDD]

hi, is this the right link? it looks like the one in the pulsars and gravity thread.


[this much better than working on a friday afternoon... :lol:]

[avandonk]

It has long been seen in fundamental particle Physics that an unstable particle (of known half life) at high velocity approaching the speed of light has a far longer lifetime than his/her twin at a slower speed.

A photon if it was conscious would traverse the known Universe in an instant as far as it was concerned!

Bert

[xelasnave]

Sorry I cant find it...

alex

[xelasnave]

http://www.sciencedaily.com/releases/2007/02/070214220824.htm

Have a go at that one
alex

[bojan]

This is an old hat, Alex..
Have a look at this explanation.
http://mentock.home.mindspring.com/twins.htm
Pure and simple.

This one is more complex, but essentially the same.. and yes, it is from wikipedia.. but not everything found there is bad :-)
http://en.wikipedia.org/wiki/Twin_paradox

[xelasnave]

Thank you Bojan I like Wikipedia particularly all the stuff they have in blue;)

alex:):):)

[xelasnave]

I notice in the first example the twins are brother and sister and that the sister aged more:).. so what would happpen if the twins were both girls???:shrug::rolleyes:
No let me work it out;):lol::lol::lol:.
alex:):):)

[avandonk]

You are a twit or a stirrer for that very stupid comment.

bert

[xelasnave]

We can start a list starting with those two

alex

[styleman333]

Alex

I always read with interest your ideas and theories and most of the times i can only slightly grasp what u are on about , but u get me thinking ..... You would be a great guy to sit and have a few beers with and discuss some amazing things . Keep it up mate

[Ric]

I'll second that styleman, count me in for a cleansing ale.

I was just trying to follow the Wikipedia explanation after a few reds. Hmmmm I'd better had another read of that tomorrow. All those maths formulas got a bit much for me.:lol:

[bojan]

Beer.. YEAH :-) I am in :-)

[xelasnave]

Beer the source of much wisdom...
She came back today another reason for beer..
alex

[xelasnave]

I have been thinking about this and particularly why I bother to think about it:P.

I find myself pondering upon a situation that one could reasonably say will never happen:)... the prospect of humans pioleting space ships that travel at or near C is not going to happen:D... so we are dealing with simply a mind experiement which is incapable of resolution.

I know there will be those who site the atomic clocks as proof of time dialiation and in that case well I guess there is proof that relates to atomic clocks:)... but not to twins one of whom flys away at or near C ;).... so until we can observe one twin leaving the planet at or near C there is no physical evidence of the paradox we wonder about:eyepop:.

alex:):):)

[kinetic]

Alex,

I'm seriously not in a league to enter into this sort of discussion as
it usually makes my head hurt :)

But isn't there anecdotal evidence of the time dilation thing
also in the observed clock differences of the Apollo missions?

I recall reading somewhere that the earth clock was different to
the on-board mission clock by the calculated amounts after their
very very low sub C journeys...?

Steve

[xelasnave]

Steve I think it was the great man himself who said something to the effect that any idea required that it be capable of being explained simply... and we have the razor demanding simplicity over complexity.

I certainly dont consider my grasp of any of this stuff as anything more than casual .... I raise stuff so folk can discuss things so it is great that you have taken the time to contribute your observations:thumbsup:.

There is observational evidence of time dilation there is no question about that...the differences are small but there seems no question that time differences have been observed ..........but my point was simply that there is little to be served talking about the twins and humans travelling at C because we are speculating upon an event that almost certainly will never take place...

so far as I can tell the energy to get even a grain of sand to travell at C is enormous...maybe all the matter in the Universe would need conversion to energy to make the space ship cruise at C.... so there will never be a direct observation of the events we wonder about;)...

alex:):):)

[Zuts]

Hi,

The twin paradox occurrs at speeds far less than C. It would take an infinite amount of energy to reach C so this is clearly impossible. However speeds less than C would certainly be achievable. In fact future astronauts would use the twin paradox to make interstellar travel possible. At 0.5C the time dilation factor is 0.86, the closer one gets to the speed of light the higher the time dilation factor. At 0.999C the time dilation factor is around 6. This means that the trip to alpha centauri would from the astronauts view only take a few months elapsed time.

I think in the future humans will easily be able to get to speeds up to 0.999999999999C which would give time dilation factors of a few thousand and allow for trips clear accross the galaxy in only a few days astronaut time.

Cheers
Paul

[Virgs]

Solar neutrinos are evidence that time dialation does work at velocities near the speed of light.

[xelasnave]

Well Paul that is pretty fast and the carbon footprint tax may can them doing it:D... but one thing I hate to tell you even at C a trip across the galaxy wont be a matter of a few days:eyepop:... at the speed you could fly across and back as far as our solar systen is concerned (approx) in about a day ...but I think we have a flight of some 30,000 odd light years to the edge of the galaxy and 70,000 light years the center to view Sagitarium A .. a fly by the Milky Way will take some 150,000 light years at C... and then we have to visit the next door neighbour... 2 million light years...

Even if we could manage to fly at 100 times C we will not get to go all that far.,, this is where sums can be fun... how fast to get to next door M31 in say a week... makes one wonder if Star Trek was really based on true stories... How fast would they have to travell to fly by the galaxies they do/have.

We are and will remain little specks of life wondering about other little specks of life:rolleyes:.

alex:):):)

[xelasnave]

Sorry Paul I missed the point didnt I ...you mean...if at or near C the astronaught will experience only a couple of days... the twin thing.

Sorry

alex

[Zuts]

The closer you go to the speed of light the larger the time dilation. The Galaxy is maybe 100,000 light years across. If you travelled at 0.99999999999C your time dilation factor may be up around the 100,000 mark. Therefore you could cross the entire galaxy in only 1 year. Of course this is one year as measured by clocks on the spacecraft. The actual journey time as measured by an external observer would be a bit more than 100,000 years. This is just the twins paradox restated.

This is why time dilation is important. It is impossible to travel at C or faster than C, but by getting as close to C as possible it is possible to cut the journey time to any point in the local group of galaxies say, to any time you want. One day, one hour or one year. So for example you could easily travel to Andromeda galaxy in an hour as measured by your biological clock. Of course during this hour over 2.5 million years would have passed on earth. However if you packed enough people into the spaceship then who cares. You could easily start a new colony when you got there.

The energy required to reach this speed is not that great either. If you accelerated at 1 Gravity continuously you would probably be close to a one hour elapsed journey time to Andromeda after about a year.

Cheers
Paul

[Zuts]

A 1 G acceleration which is really not that high, i.e you would feel like you do on earth, nothing like the G force required to leave the earth would after a year give a velocity of

60 by 60 by 24 by 365 by 9.8 = 310,000 kilometers per second or nearly light speed. If you accelerated for say 14 months at 1 G then you could be as close to the speed of light as you wanted, say 0.9999999999999999....C which would allow a trip across the visible universe in around 1 second (spaceship elapsed time) say.

Cheers
paul