I don't grasp time dilation. I keep trying to find an explanation that makes sense to me, but it makes my head hurt.

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The mind is a weird and mysterious place

What I was alluding too was that you can bend (fold) a piece of paper in half, you can bend a thin sheet of metal or plastic into a curve, you can't bend fresh air or effectively nothing tangible.

Of course not. But gravity can warp and bend the space-time fabric. Euclidian geometry only works in a non-gravitational field.
However the geometry is different in space and actually looks like this when in a gravitational field.

That explain why photons that always move in a straight line (shortest distance) will to us appear to follow a curvature.
Example of gravitational lensing where you can see whats behind a galaxy.

I don't grasp time dilation. I keep trying to find an explanation that makes sense to me, but it makes my head hurt.

Here is one explanation without math.
https://www.youtube.com/watch?v=JwCYwte9NKg

There are many things that I do need to know and understand that I don't yet. e.g. women and American politics.

Well, you've had over half a century to do so, & still don't know? - ROFLMAO.

Well, considering I learnt the "Golden Rule" - Do Not P Off a female over half a century ago, puts me in the 01%. :-) Wonder if the Alien Females are similar to ours?

So, if I took a really fast spaceship to Alpha Centauri and came back in 10 years, many thousands of years would have gone by on Earth, and I would only be 10 years older?

And if I had a live webcam connection to earth the whole time, with a clock on the wall at mission control, I'd see the hands whizzing by on it's face?

I know experiments on earth and with the ISS have "proved" time dilation to some extent, but the above scenario boggles my mind.

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The mind is a weird and mysterious place

Just finished watching a fascinating DVD - Mission Control: The Unsung Heroes of Apollo. From Kennedy's 1st announcement to the actual landing took 8 years 56 days. In 287 days time, it will be the 50th anniversary of the landing.

I (back then at least) thought that by now (present time) we would be well & truly out there. Not that we would have met E.T. but the increased potential...

Short answer yes.
But the time dilation effect is hardly noticable unless you move very fast.
If the journey takes 10 years travelling at 68% of the speed of light, 20 years would have been passed on earth.
At 98% of the speed of light, 50 years would have passed.


When looking at your webcam you will see the earth clock going faster.

Time dilation is very real even in our daily life.

Each GPS satellite is updated every 24 hours. The update consists of corrected orbital parameters and clock corrections. These corrections are in a file that the software accesses and makes corrections to its state vector, which is used in the continuous transmission to ground users.
The atomic clocks on each GPS satellite run about 1 nanosecond per second slower than clocks on the ground. This is due to General Relativistic Gravitational time dilation. It may not seem like a lot, but remember that light travels about 1 foot per nanosecond, so an error of one foot per second could ruin your whole day.

Time dilation occur in two different situations.
When an object move at relativistic speeds and when objects are in a gravitational field.
A clock on an object below the earths surface will tick slower than one on the surface.
It's because there are two types of mass, inertial and gravitational.
https://en.wikipedia.org/wiki/Mass

Oops. Actually three types of mass:)
Inertial mass measures an object's resistance to being accelerated by a force (represented by the relationship F = ma).
Active gravitational mass measures the gravitational force exerted by an object.
Passive gravitational mass measures the gravitational force exerted on an object in a known gravitational field.

A clock on an object below the earths surface will tick slower than one on the surface.

I have to correct myself.
When moving a clock below the earths surface it will tick faster than on the surface.
When it's in the very center it becomes weightless because all the mass gravition around it cancel out.

If the journey takes 10 years travelling at 68% of the speed of light, 20 years would have been passed on earth.
At 98% of the speed of light, 50 years would have passed.

Ok, I was thinking along the lines of how long it would take to get to Alpha Centauri going the speed of say, one of the Voyagers, which would take about 80,000 years. If speeded up fast enough, so that the journey to there and back would only take 10 years, I was thinking based on time dilation, that a lot more than 80,000 years would have passed on earth. The reason I thought that way is because I was under the impression the effect of dilation was a lot greater.

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The mind is a weird and mysterious place

Perhaps it was the movie Cocoon for this, mentioned a little earlier on.

Anyway, getting a bit older myself, except for not blaming any time dilation here either.

You mean the 1%. I learnt that 70 years ago during the "terrible twos" with my mum. Doesn't mean you understand why females get peed off though. It's just a survival tactic.

No, I mean some men don't know how to deal with women & treat them as inferior &/or objects of pleasure. I very much doubt a 3 year old learnt much at that age. :-)

Wonder if the Alien Females are similar to ours?

Not brave enough to answer that one :-))

Honest enough. :-) Would you go if the alien ship was crewed by women only?

For theory of relativity challenged Setizens such as myself, I have found a time dilation calculator tool at the top of this webpage: https://www.dcode.fr/time-dilation#q2

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The mind is a weird and mysterious place

For theory of relativity challenged Setizens such as myself, I have found a time dilation calculator tool at the top of this webpage: https://www.dcode.fr/time-dilation#q2

Yes, I have even compared that with my own calculations.
What you realize is that rockets have to be fast. VERY fast. To notice any differences at all, you have to reach 30% of the speed of light. At very least if I would go!
If you want to travel for 10 years while at earth it's 20 years you have to reach 86% of the speed of light.
(Not 68% that I claimed earlier. Getting old:) )
Now how fast does Voyager travel to Alpha Centuari? About 16,000 m/s that is 0.0053% of the speed of light.
Just to notice any time dilation effects at all, rockets have to go 6000 times faster than that.

Thanks, Lynn :) I'd not thought of those additions.

I must say, when it comes to ignoring something, that really is a most intriguing way of doing it ;) Say there'll be a pm to prepare for, for which you do, and get one all about successes at a different distributed computing platform entirely ;) Maybe it's due to busy-ness...? I know I have that happen too sometimes.

I might be about the forums sort of more-or-less this week, but it's doubtful I will be after that for awhile - so you know... pm-away while I'm around if you want to.

@Michel448a

what if they have double of .... what you love the most on them ?

You mean like 4 eyes, that kind of thing...?

;)

It would be interesting.

Can we assume alien life-forms would be subject to evolutionary processes? I think I will for the moment. Then I'm going to imagine there would be some functional reason that would make such differences advantageous for them. Appealing to humans might not feature in that at all, and some of the reasons for duplication might not appeal to us either, so, you know... *look at no one in particular... because they already know who they are* be careful what you wish for ;)

If they're clothed in some manner, predicting what might be making them the shape they seem to be - could be fraught with all manner of misconceptions too. They might reproduce by budding-off (like the hydra for example...) y-e-e-e-s... and for those already struggling to understand women of your own species - I don't much rate your chances of understanding the female version of an alien one. But you never know! :)

I enjoy having my mind boggled by science, though. A lot. I like trying to understand it too. And I'm glad there are people here who are prepared to go out of their way to help explain it when some of us are stuck. So thank you :)

haha it depends what you like the most :D

You're a leg man... I can tell...

;)

Some only with their partner

Some without their partner

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Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?

I know I said I couldn't think of any movies with this story-line, and you mentioned Cocoon, Chris, but I never saw it; on the other hand, I just thought about Close Encounters of the Third Kind. Didn't the guy who saw the UFO at the beginning of the movie end up going on the spaceship and leaving his family?

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The mind is a weird and mysterious place

Didn't the guy who saw the UFO at the beginning of the movie end up going on the spaceship and leaving his family?

I think they'd already left him because he'd gone a bit... well, erratic I think is how wiki describes it.