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Relativity question re. Voyager spacecraft


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Given that the passage of time appears to slow for objects traveling at speeds relative to us.

The assumption therefore is that the time recorded on either of the voyager spacecraft is now different to the present time on earth.

Voyager 1 approx 17.4 km/s

Voyager 2 approx 16 km/s

Can anyone work out what the time difference is?

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I haven;t done any serious calculations, but the Lorentz factor for those speeds are 1 / (sqrt(1- (17/300)^2)) +- 1.00161 which is approx 0.16%.

So if the journey was say 10yrs = 3650 days = 87600hrs then the time diff would be 141hrs!!

Not insignificant at all!!

Someone correct me pls.

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Not sure, I think its more like 17.6 days difference in 30 years according to cygnusx1's calcs.

But time would only have slowed for Voyager from our perspective not from the perspective of a stowaway for whom time would have passed as normal...

Very confusing lol

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I haven;t done any serious calculations, but the Lorentz factor for those speeds are 1 / (sqrt(1- (17/300)^2))

The equation is OK, but you've missed a few zeroes off the speed of light.

It's 300,000 kps, not 300. :D

Redoing the equation I get a value of 0.0000016%, which over 30 years comes to just over 1.5 seconds.

(Assuming I haven't made any mistakes as well). :D

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That's more like it S2. Just to throw another spanner in the works, the Voyager probes used gravity slingshotting (if that's a real word) as an aid to achieving the distances required so its velocity has not been constant, but compared to the speed of light, these differences would be very insignificant.

Steve..

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Thanks S2 and Paxo :D

It's a minor difference then but a difference all the same.

It does make for a good example of how little the effect is even when we think of what we would class as a relatively high speed spacecraft.

/wonders what is the highest speed craft out there at the moment and what it's time difference would be in 30 years.

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Yeah, the time effects on current spacecraft really are rather minimal as their speeds are relatively low compared to the speed of light.

The bigger problem for anyone stowed away on board would most likely either be lack of oxygen or lack of suitable toilet facilities :grin: (sorry, being silly!).

They are getting there though. It's the v/c ration which is interesting here really. Time effects become interesting when v/c is of the order 1/10. So currently the veolcities are about half way to getting interesting. If they double their velocity and get over 30,000km/s we'll actually have some interesting relativistic instruments. Not quite warp factor though! :lol:

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  • 3 weeks later...

A very interesting thread. I'm not stupid (honest), but this whole time and relativity thing, still twists my melon ! :shock: :shock: :shock: :scratch:

You're not alone. You can include me too :shock: :) I'm reading Einstein in Love, by Dennis Overbye, and there are quite a few well written paragraphs about the way Prof. Eistein was reaching his conclusions about relativity, throughout the 10 years before he actually worked out the famous equation. But I'm still getting around the all concept :scratch:

It's been quite a discovery, for me, to find that

the theory of Relativity had been around for quite a few years, having been first thought of by Jules Henri Poincaré. He lost interest on the topic as time went by, keeping the field wide open for Einstein to develop the theory further.

The next book that it's waiting on my shelf to be read is Nigel Calder's Einstein's Universe .

I haven;t done any serious calculations, but the Lorentz factor for those speeds are 1 / (sqrt(1- (17/300)^2)) +- 1.00161 which is approx 0.16%.

...

Is that the formula Cygnus?

I'd like to try a few calculations as that would probably give me a better idea quantitatively. I think...I hope so :lol:

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It's already interesting. It's off course according to where theory predicts it should be. No definite answers to why either as far as I'm aware.

John

Yes, I've been reading about that. Most peculiar.

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At the last astro society meetingthe talk was given by a Professor of UCL (I think)

He explained that so far Einstein has proved to be 100% correct except for the voyager anomally.

He likened it to the fact that we can work out the trajectory of a cricket ball using Newtonian physics and it will be good enough (99.99% accurate) for us to know where to go to catch it. But the result of the GR with give us the other 0.01%.

He has the voyager eroor could be that GR is 99.99% accurate but when we understand abit more about gravity and can study gravity waves etc we can refine GR just like GR refined Newtonian physics.

Cheers

Ian

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I wonder you know if it couldn't be something much more mundane.

We don't actually know the exact mass of the planets perfectly, we haven't found ALL the members of the solar system (when you think about things like the Oort Cloud, and the kazillion asteroids knocking about the neighbourhood), there's stuff like the solar wind blowing through space and all sorts of other variables going on.

I personally think there's a little bit too much confidence going on in our understanding on the gravitational effects impacting Voyager, and if we were to know them precisely and able to input every variable into a supercomputer we might just find it's just where it was supposed to be.

Just my hunch anyway! :)

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I'm amazed that some one isn't saying the anomaly in voyager's path is down to dark matter :nono: . Or even proves it's existence. Actually given that the reason for that is also related to gravity anomalies it make one wonder .

John

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I thought time was also distorted by large bodies in the universe as well as the actual travelling speed? i.e simply passing a planet slightly distorts time

I thought thats what I heard, but I might be wrong. Brilliant question about the voyger craft though

Matt

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I like your website Vega, and that reminds me that mine needs a big re-do :oops:

I thought time was also distorted by large bodies in the universe as well as the actual travelling speed? i.e simply passing a planet slightly distorts time

...

Matt

Why does it distort time?!? :scratch:

Though I'm thinking more in terms of a curved space. Or if one were to draw 4 axes for length, depth, height and time, then Time would vary.

I'm just rambling :lol:

By the way, is this the official Relativity thread? So, that I know where to rumble along on this topic since I'm reading a bit about it :shocked:

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Really glad I caused some thought :shocked:

Trying to get my head round this stuff but it's taken me about 2 months to read 130 pages of Brian Greene's Elegant Universe and I've realised that I need to get a newer version as this one was published in 2000! gah! Need to start again lol

As for the gravity question. Isn't it the acceleration (not speed) of voyager that's causing any anomaly rather than the gravity / space-time warping caused by a heavy body?

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Carol

I was too young to remember the landings, but I was told that the landing was manual as the ground was too rocky where the original site was planned and that they only had a few seconds left of fuel when Neil put the lander down.

Cheers

Ian

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