Want to Know What Time Is?

I do not con­sider my­self to be smart enough to an­swer a ques­tion that re­mains unan­swered since thou­sands of years:

What is time?

Nev­er­the­less I will an­swer that ques­tion now. I am ask­ing ev­ery per­son smarter than me to ex­plain to me, why my an­swer must be wrong. More so: There may even be some very ba­sic math­e­mat­ics be­low. I am very keen to find out why this math­e­mat­ics is ei­ther wrong or ir­rele­vant – or sim­ply stupid. It sure is!

I define time as the amount of in­for­ma­tion available for a given phe­nomenon.

If there is a lot of in­for­ma­tion, then the phe­nomenon is con­sid­ered to ex­ist for a very long time. If only lit­tle in­for­ma­tion is available, the phe­nomenon is con­sid­ered to ex­ist for a very short time only.

For ex­am­ple, if a guy called Join Doe is trav­el­ing from Ber­lin to Moscow, there might be at least two bits of in­for­ma­tion about this:

  • John Doe is in Berlin

  • John Doe is in Moscow

If there is no other in­for­ma­tion available, then the phe­nomenon is very short lived, mean­ing John was trav­el­ing at max­i­mum speed. That could be the speed of light.

But there might be more in­for­ma­tion available: John might take a stop in Minsk, be­cause he loves a most beau­tiful Be­larus girl at that place. It just means, that his travel speed is much slower. Far from the speed of light in this very case! So there is more time be­tween his de­par­ture in Ber­lin and his ar­rival. It might even hap­pen, be­cause he is so very much in love with this girl, that he will never ar­rive in Moscow. In that case, the amount of time be­tween de­par­ture and ar­rival is in­finite.

Time Tcan thus be seen as func­tion of the dis­crete amount N of available in­for­ma­tion: T(N) We know that for any N_1,N_2 with N_2 > N_1there will always be T(N_2) > T(N_1).

(But apart from that I do not re­ally know a lot about the func­tion T(N).)

Please note that by this defi­ni­tion there is no di­rec­tion as­so­ci­ated with time! So, time does not re­ally tell us if Johnny starts his jour­ney in Ber­lin or in Moscow. We can only be sure that he was in Minsk, and that he was hav­ing a great time there, wish­ing to stay for ever with the girl. (Maybe she also re­ally cares a lot about him!)

Things are get­ting more in­ter­est­ing, if we – for ex­am­ple – con­sider a black hole. As we know by the the­ory of rel­a­tivity, time “is slow­ing down” a bit, the nearer you get to a black hole. Now, let us look at John Doe again: Imag­ine this guy is get­ting re­ally close to a black hole. (There is no rea­son what­so­ever to com­pare his re­la­tion­ship with his girl to a black hole or find any other similar­i­ties or even more vul­gar com­par­i­sons re­lated to her.) Just imag­ine that John is at­tracted to the black hole just as he is at­tracted to his girl friend. The nearer he is get­ting to the black hole, the lesser are his chances to es­cape. A black hole squeezes a lot of mat­ter into a tiny space, in­creas­ing its grav­i­ta­tional field and de­creas­ing time in com­par­i­son to other peo­ple lucky enough to stay farer away from the black hole. (Still, please no com­par­i­sons to the girl friend!)

If John fi­nally reaches the cen­ter of the black hole, there will be no more doubt about his very lo­ca­tion. No longer will he be in Ber­lin! He will not be in Moscow, nor in Minsk. No mat­ter how of­ten we would re­quest his po­si­tion, we will always be sure that we could find him in the cen­ter of the black hole. Thus the amount of available in­for­ma­tion about his po­si­tion has reached in­finity, the un­cer­tainty about his where­abouts has reached 0, and thus time will now longer flow. Time will stand still, and there will be no time at all at the cen­ter of a black hole.

As you can see, we can ex­plain the be­hav­iors of time in a very strong grav­i­ta­tional field, even with­out the nasty com­plex­ity of gen­eral rel­a­tivity.

Let me give you an­other ex­am­ple: The dou­ble-slit ex­per­i­ment, seen from the view­point of quan­tum the­ory. As we know, get­ting in­for­ma­tion about a quan­tum sys­tem always im­plies do­ing an ex­per­i­ment, and the re­sults will vary de­pend­ing on their prob­a­bil­ities. The more ex­per­i­ments we do, the more in­for­ma­tion we will get about the lo­ca­tion of a par­ti­cle. Some very smart peo­ple would most likely say, that the Schröd­inger equa­tion col­lapses with each ex­per­i­ment, mean­ing that a prob­a­bil­ity wave will turn into some (triv­ial) in­for­ma­tion about some­thing. What­ever that means, it is ob­vi­ous to us that in­for­ma­tion pops up in ex­change of a cer­tain amount of un­cer­tainty that we are loos­ing on the way.

We con­sider time to be just the sum of all the in­for­ma­tion gath­ered dur­ing ex­per­i­ments.

In par­ti­cle physics, the path of a par­ti­cle is some­what in­de­ter­mi­nate. No mat­ter how many ex­per­i­ments we do, we will only end up with an ap­prox­i­mate path of the par­ti­cle. OK. But if we re­peat the ex­per­i­ment un­der the ex­act same con­di­tions, we might end up with a com­pletely differ­ent path, only de­pend­ing on some prob­a­bil­is­tic rules de­ter­mined by the maths of quan­tum physics.

But with our un­der­stand­ing of time that does not re­ally bother us any longer. There is no or­der in time. Time does not flow from 0 to in­finity, always in the same di­rec­tion. It is just the sum of all the in­for­ma­tion that we can gather. And that does not need to be the same all the time!

Now you know what time is!