Do you have Time

[NightOwl58]

Is time just relative to the viewer? Conscious of its effect of never going backwards. Everything is born, lives then dies then is recycled into something new.
I travelled to Alaska from the UK and I arrived at the same time that I left the UK. Similarly, do you lose time when traveling to Australia? If you could travel fast enough in either direction, faster than the rotation of the Earth could you time travel? Experiments on the space station have shown that you age less when in space.
Would our concept of time change if it were possible to be born on a different planet in the solar system e.g. one year on Mercury would last only 88 Earth days and on Neptune one year would be 165 Earth years. Is our measurement of time based on the daily rotation of the Earth and the time it takes to orbit the Sun. Similarly, Astronomers talk of light years, the time it takes light to travel any distance and by looking out at Galaxies and into the Universe we are looking back in time. In that case can we be sure that the objects we observe still exist today and if our planet is viewed from such distances would we exist in the eyes of extra-terrestrials. Is the speed of light an unbeatable constant?
When observing Exoplanets are, we are seeing them in the past and cannot be aware of their current condition. If we could travel to a potential life supporting planet would it still be there also if we got closer would we see a more up to date version. If the voyager probes sent out in the 1970s were intercepted by intelligent life forms, they would have a total misconception of our current technologies.
Current theories suggest that to the viewer time stops on the edge of Black hole, how weird is that. What is Time? It’s time to sign off and watch the rugby.
From NightOwl58

[stella]

" Astronomers talk of light years, the time it takes light to travel any distance"

No "light years" is a distance NOT a time.

[brian livesey]

Isn't time a register of change? If nothing changed, could we speak of time?

[NightOwl58]

Yes, from my understanding according to the NASA website the light year is a measure of distance but is based on the time it takes an energy packed photon travelling at 9,4605 x 10 to the power of 12 km/s per 365.25 Earth days a total distance of 6 million, million miles based on the Gregorian Calendar.

For example, our closest star Proxima Centauri is 4.3 light years away, so if we could travel at the speed of light it would take us 4.3 years to get there. It takes the Sunlight 8.3 minutes to reach the back of our eyes. So, if the sun suddenly stopped working, we would have just enough time to boil and eat an egg before freezing to death which is quite a sobering thought.

If our calendar was based on the Julian version or any other religious based versions, the definition of a year would be different, which makes our concept of time a total nonsense.
Still watching the Rugby
NightOwl58

[stella]

"travelling at 9,4605 x 10 to the power of 12 km/s"

That is NOT the velocity of light; light travels at 299792.458 km/s.

[David Frydman]

The second of time is also a made up unit.

I don't know how it is defined now, but there used to be 31,556,926.08 seconds in an average year.
This was rounded to 31,556,926 with leap seconds added when needed.
The year is not constant.

Multiplied by the velocity of light in a vacuum per second gives 9.460528 x 10 to the twelve kms for a light year.

The length of different years is hardly relevant, so the velocity is given in a second.

Another measurement distance is the parsec.
But even this may be variable as the earth's orbital size isn't constant.
But I suppose a parsec has a given definition.

As to time.
I haven't got enough of it, although sometimes too much.

A film from 2011 that I enjoy is 'Time', where time is a currency that can be bought and sold.
Normally people live to 26 years and then stop living.
An interesting concept.
The rich can live for centuries.

Regards,
David

[NightOwl58]

Thank you stella for the correction and David for explaining where I got the figure from. I do apologise. I was just having another bad hair day.
From
NightOwl58

[brian livesey]

In "western culture" we regard time as being linear, but not all cultures have perceived time in this way. If everything was "frozen in time", how could we say that time exists at all?
We come back to the idea of time being a mental construct to register change, and essential for survival. No change, no Time.

[mike a feist]

"Apparent passage of time" to the individual person increasingly accelerates as one gets older.
As a schoolboy, a week was ages, from weekend to weekend. A year seemed almost forever.
Now at the tail end of one's life, a year is here and gone like quicksilver through ones fingers.
I cannot believe that next month is November again! Regards maf.

[JohnM]

The arrow of time ie why time goes from the past to the future is on of the 12 or so unsolved problems in physics. The basic physics equations that involve time do not have a direction in them and are reversible but time does not seem to reverse. It could be related to The Second Law of Thermodynamics that in a closed system disorder always increases though that may be a circular argument as it involves the arrow of time.

There is also some doubt if The Second Law of Thermodynamics and The Law of Conservation of Energy that is related applies throughout the Universe according to some who understand this better than me. It is also not compatible with Quantum Theory or Relativity (I can't remember which).

If The Second Law of Thermodynamics does exist and is applicable to The Universe it is interesting to note that the 'Big Bang' must have been a highly ordered state and disorder has increased since. Interesting that whien the Universe was very small and thus Quantum effects were important that this was a highly ordered state.

Off to put an ice pack on my disordered head now !

PS your body and mind is a local reversal of the Second Order of Thermodynamics !

[NightOwl58]

Hi John,
Yes, I am as confused as you are, Brian like John I wish time would stop being in my latter years too.
David the time film is relevant today because rich people can pay for health care and healthy and organically grown foods avoiding the fish and chips and indian takeaways that i eat.
Waiting for the time when when the Universe disappears in to a puff of particles, I shall be at the restaurant at the end of the Universe with Douglas Adams.
From
NightOwl58

[David Frydman]

I once asked a girl 'Do you have the time?'

The answer was 'Not today'.

Regards,
David

[JohnM]

I once asked a girl 'Do you have the time?'

The answer was 'Not today'.

That reminds me of 'The Time Lady' who used to take the time from the clock at the gates of The Royal Observatory at Greenwich to the various clock makers working in the centre of London.

I presume on occasions she could well have given the same answer.

Fascinating to remember the world before the Electric Telegraph, The Telephone, Radio Time Signals & the internet.

Now we can all get the time to a few milliseconds.

[JohnM]

Above I posted "There is also some doubt if The Second Law of Thermodynamics and The Law of Conservation of Energy that is related applies throughout the Universe according to some who understand this better than me. It is also not compatible with Quantum Theory or Relativity (I can't remember which)."

I have now remembered it is there is no Universal Law of conservation of Energy. The person who made this statement is James Peebles who has been awarded the Nobel Prize in Cosmology today. If you want a challenging read buy a copy of Peebles Cosmology one of the standard university level texts.

Details at: https://press.princeton.edu/books/paper ... -cosmology