We talk a lot about time in daily life. The present, past and future, quickly and slowly. Planck time at one end, and infinity in the other. We have got advanced technical ways to measure time, and strange relativistic effects of it. But what exactly is time? The question is not often discussed. How does it work? What creates it, and how does it occure?
I think I can answer these questions in a simple and understandable way. A way which to me seems quite clear. I will explain my view, and can promise you some new ideas, and I'm sure you will give it a second thought.
Matter and time
These first words might seem obvious, but still ....
Let us first state that you yourself, your physical body only exists in the form and shape it has right now. How it was last year is history. The wound you had, the nails and your hair... Hairstyling has changed, nails replaced and the wound healed. It was something that existed then and which through chemical, mechanical and other processes gradually has changed in shape to become something new today, although most of the body remains the same. That time moves on, is actually a bad description, which creates some confusion. What's happening is that matter change constantly in the present. The faster the changes, the faster time....moves on ... in that order. History is something that exists only in our memory. Future only in our imagination. The present is a simultaneously position, speed and direction of all matter in the universe. The temperature of the matter represent its time. Our journey and speed together with selestial objects through space, represent time and developement of the universe. Maybe I should give some more explanation to this ...
Matter have to be one-unambiguous. This means that the universe only can exists in the present. Matter as it has been, the past form of the matter, is no place out there today. Not in another dimension, as antimatter, or in parallel universes. Neither is the future form of matter. But anyway ... the present is still not completely without any extension of time. This extension of the moment has the shortest period of time, possible in physics. This time, Planck-time, is the smallest possible subdivision of time who is permitted by the principle of uncertainty. This small extension is anyhow, essential to safeguard the moments, movement and direction of the matter, and the continuation of these to the next moment. The elementary particles that make up matter in the universe, has by this a tiny, tiny extent in time and space. This extent is small, but it surely is an extent. The particles are stretched out in their direction of speed. This extent is larger for matter who have more internal thermal energy, and thereby fast internal motions. If the particles had no extent, we only had a static matter without any time or change. By this we can tell that extent of matter in space has a direct connection to time.
Speed of time
We can not immediately observe that everything in universe is happening at the same time. This because the speed of information always is limited. But not the less it happens all at once. There is no timeline. It only exist in our imagination. The flow of time, or rather, the velocity of time, are different at different places. The information who have been exchanged between different locations, however, can at a later point in time, make it difficult to agree on what actually happend when.
Some might believe that the flow of time had continued even if the universe had not existed. This is probably due to the fact that we never have experienced anything else. Whatever we do, if we are bored, have fun, are busy or asleep, we experience that time inexorably is moving on. It's not possible to experience anything else. It is therefore difficult to imagining anything else but flow of time. Maybe as difficult as imaging how it's like to be dead...millions of billions of years.
But ... .. if everything was frozen. Where all processes and even the atoms had virtually stopped. Haven't we been into a state where the universe so to speak, only existed? Where metal could have been in contact with acid without corroding, where radioactive material emits no radiation, no events, impossible to observe or to say whether time exist or not. Where everything is dark and cold ... frozen. It would be exactly like time stood still.
However, this is an impossible scenario. We therefore modify it a little bit, and say that we can isolate a few atoms, we cool them down to a millionth of a degree above the absolute zero. Virtually all movement of atoms stops. (This was in 2001, conducted at Harvard University by the danish proffessor Lene Westergaard Hau. If we had considered the atoms in this state, we would have observed that things happen more and more slowly. One can rightly say that the time of these atoms are in the process to a halt. But what about the time outside these isolated atoms? If time has past outside, it's likely to think that the time inside also have done so. Time is everywhere. Isn't it ?
No, it's probably not. Time speeds are not universal and the same everywhere. It is definitely a local phenomenon.
If different things have different time speed, it does not mean they can not coexist in the same room.
They are not invisible or insensitive to each other.
They will not go into different dimensions.
Look around you ! Everything you see around you actually exist with Diff-time speeds right now!
If the concept of time is ment to have any meaning at all, it must be accseptable to say that where there is no movement, interaction or changes, there of course, where time has no influence, the time stands still. We then got the point of absolute zero temperature that is corresponding to the absolute zero time.
When calculating this point temperature, we measure temperature and energy of the matter. When decreasing the energy we make new measurements. We then get a graph for temperature / energy. On this basis, one can determine where there is no more energy left, the point of absolute zero temperature.
The same must apply to time.
Speed of light
If a photon, in our cooled modified case, moved some distance from A to B, we would know something about the time in there. The photon must spend some time at travelling the distance, but the time for the surrounding frozen atoms had not, until they had an interaction with the photon. How much time, depends on our definition of time.
Our second has been defined as the time Cesium 133 needs to oscillate 9,192,631,770 times. If we measure time by using supercooled Cesium 133 too, it will take a looong time before one second has passed.
The speed of light, c = (B-A) / t, where t is time. The c will become small if t is large. That the time is nearly put to a halt, will be OK for this small system.
Note that if a "person" in this system could see this light, the speed of light to him would seem natural, but for a person outside, speed of light would seem very slow.
For a group of atoms in a chemical reaction, the temperature is crucial to the chemical speed it happens by. It will then be natural to conclude that the speed of the particles determines how fast they will interact with the environment. Every elementary particle has it's own local time, and therefore its own chemical reaction rate. This is what we daily refer to as the temperature of the matter. The internal movements of matter is desided by the amount of it's thermodynamic energy, and therefore this energy is the time factory it self. But this is only at the atomic level.
The 3. law of Thermodynamics : "When the temperature of matter approaches absolute zero temperature, all the thermodynamic processes stops.
It seems that we have not understood some of the consequences of how it affects the time it self. As an example, photons move a certain length over a period of time. It must therefore have an impact on the speed of the photon, when the time of the material the photon interacts with, changes.
Its not a true that all chemical reactions changed speed equally in relation to temperature, because chemical reactions may have complicated patterns, so there are several things that affect the reaction time. But it is so, that any chemical reaction progresses more rapidly when the temperature increases. Even atomic clocks that contains the most stable crystals we know, must be kept at the correct constant temperature for optimum accuracy.
Time at different levels
Until now I've been talking about time at a atomic level. But what about the speed of time that affect the movement in universe. The time that is relative to the gravity we know, and the earths rotation. The time beeing affected when a spaceship moves very fast, as we heard about in Einsteins special relativity.
For the stars, planets, comets, gas and other objects which is a complex quantity of atoms, time will apply at a higher level. At this level it will be the speed of the objects in space that will affect the time of the system. This system consists of all complex masses in the universe. If the speed of a celestial body increases, there are two main ways it affects time.
One is that it simply will take less time for interaction to take place. This interaction may consist in transmission of torque and sling effects coursed by gravitation and direct hits.
The second way is that a body tumbling through space at high speed might (!) generate increased gravity of their environment coursed by Gravitomagnetic Londonmomentet. It will thus be able to transfer energy to the neighborhood by contributing to increased time rate. This will increase the rate of interaction and developement of the universe. The development speed is equivalent to the chemical reaction rate at the lower level.
The theory of special relativity supports this by telling that time rate of the surrounding universe, is rising in relation to one that moves very quickly in relation to the universe. However, one of the theory assumptions, is constant speed of light. (Or in other words: It's the effect it will give to time, length, energy and gravity when light, that is one of these several physical parameters that are all relativately bounded to each other, have been chosen as a constant.)
In this way, time have multiple levels. Celestial bodies in our universe have their speeds, and thus its own local time. Within these bodies, we find atoms and molecules which have their speeds and thus their local time. We can then estimate that inside atoms we can find other levels, as well as maybe our universe is a part of something larger which in turn has its speed and time.
The time for the atoms and the time of the universe we know can affect each other. As an example, a gas cloud contracts, and increase the temperature at atomic level to form a star that lights up. Core fusion processes then make influence at the development of the universe by radiation pressure, explosions, and more.
Leap from one level to the next is enormous. It's hard to say what, if anything, will correspond to what, at the different levels. But, if we compare the solar system with an atom, which at first glance may seem comparable, this seems to give the ratio 1 to about 10 ^ 44, which is a completely incomprehensible large numbers.
I was looking at the venerable TV channel National Geographic the other day. They mentioned that physicists had begun to look at the similarities between the universe at intergalactic scale and the world at atomic scale, witch was inconceivable and extremely unserious only a few years ago. But many things are comparable, like the huge empty space between the bodies, energy leaps, the core and the star, electrons and planets, spin, double and triple star systems. But there are also many things that are totally different. Quarks, quantized orbits, huge amount of different particles, different forces..... I've been looking for comparable objects from the two different "worlds", but its hard to find. At first, most people think of the solar system and the atom, I have tried to be creative and have landed at the idea that the universe might look like a vakuumfluktuasjon. That is the easiest because no one know what its like. But anyway :
Heisenberg: dt = h/2dE
The time, dt, goes to infinity if the energy of the fluktuation, dE, approaches zero: the universe may thus be a long life vakuumfluktuation! (Øystein Elgarøy and Maria Mouland Institute for Theoretical Astrophysics, University of Oslo)
How to test temperature influence at time, and its impact on the speed of light
I've designed an experiment to demonstrate how the photons speed depends on the temperature of the medium / matter they interact with. I have not succseeded yet, and probably never will, but anyway, I will tell how it works.
I do not think its realistic to belive that light have only one certain speed, the speed of light, c, in vacuum.
Therefore I think of a flash of light, such as a photo flash, as a shower of photons with slightly different speeds. These photons will not interact with all matter. The photons interact only with the matter who is whithin the limit of correct speed, given by the speed and temperature, relative to itself. These photons will "harmonize" in time and speed with this matter.
This may be the reason why we have found that the light exist at just one speed relative to ourselves. Even when two people are moving at different speeds relative to the light source at the same time. When you're moving towards the light source, you will harmonize with the slow photons, but if you moves away from the light source, you will be in harmony with the rapid photons.
How can this be ?
We can compare how the photon transfer energy to the electron with processes we know from our own solar system. If an object from outer space had passed through our solar system at extremely high speed, the object would probably pass through the solar system without leving much energy behind. Since almost all of the solar system is empty space, the chance of a direct hit with one of the planets or the sun is almost like zero. When the object's chance to make one of the planets changing orbit is at most, the speed of the object should be about the same as the planets in order to transfer energy by its gravity.
(With the model of gravity as we know it today, any transfer of mass inertia will lead to a slightly change of orbit. With a model of sine-gravity, however, the planets would be stable within certain distances around the sun. Sine-gravity will be featured at this site later.)
If the speed of the object is low, the relative speed between the object and the planet also would be to high for a good energy transfer, because the planets themselves is at a quite high speed. The object would just take a journey around our sun before it leaved us behind, and become likea a long-periodic comets.
Light from variable stars, and film/CCD wich is possible to vary in temperature, would serve as the active ingredients in such an experimental attempt. The light from a distant variable star is sent out periodically, or in great "waves" of photons corresponding to the stars periode. Every wave will contain photons with slightly different speeds. A bright star with short, regular periods and a long distance from us is the goal. Its magnitude also have to vary as much as possible.This would result in rapid photons from one period catching up with the slow photons from the previous one. This may let an observer at Earth be eable to expose photons from several periods from a single star at the same frame. The waves of photons from the different periods, however, will be at different speeds. The obsever who always is at about 37 deg.C. will with his only eyes just be able to obseve photons at the speed wich harmonize with his own temperature. But, by using a camera, he will be able to observe at different temperatures.
By varying the temperature of the medium(CCD/film) during an exposure, as an example, 1 minute, he might be able to capture several periods of this star in only one exposure. Thus, because the change in temperature of the medium when exposing, also will change the time of the medium, and then allow the medium to harmonize with several of the waves and their different speeds. But with photons of just one speed at the time.
I have tried to pick out the best stars, and presented them at this list. The column BRUKBARHET gives a number. Higher number means better for the purpose.
Konstel.
Stjerne
Type
Max
Min
Amplitude
Periode
Avstand
nødv.avvik c
Amplitude
periode
Brukbarhet
Dec
R.A.
mag
mag
mag
dager
l.y.
m/s
%
timer
(størst mulig)
grader
tid
Eri
ny
beta C
3,4
3,6
0,2
0,17790414
1000
146
50
4,27
325
04:36:19.1
-03:21:09
Tau
RW
EA
7,98
11,47
3,49
2,7688396
1400
1626
873
66,45
251
04:03:54.4
+28:07:33
Lac
DD(12)
beta C
5,16
5,28
0,12
0,1930924
1900
84
30
4,63
244
22:41:28.5
+40:13:32
Sgr
Y
C delta
5,25
6,24
0,99
5,77335
7100
668
248
138,56
220
18:21:22.9
-18:51:36
Sge
U
EA
6,45
9,28
2,83
3,380626
1400
1985
708
81,14
137
19:18:48.4
+19:36:38
Aql
FF
C delta
5,18
5,68
0,5
4,470916
7700
477
125
107,30
121
18:58:14.6
+17:21:39
Pup
V
EB
4,35
4,92
0,57
1,4544859
1600
747
143
34,91
74
07:58:14.3
-49:14:42
Cep
beta
beta C
3,16
3,27
0,11
0,1904881
760
206
28
4,57
54
21:28:39.5
+70:33:39
Cma
EY(15)
beta C
4,79
4,84
0,05
0,184557
1800
84
13
4,43
45
06:53:32.8
-20:13:27
Peg
gamma
beta C
2,78
2,89
0,11
0,15175013
480
260
28
3,64
39
00:13:14.1
+15:11:01
Mon
V637 (19)
beta C
4,96
5,01
0,05
0,1912
1600
98
13
4,59
32
07:02:54.6
-04:14:21
Sco
sigma
beta C
2,86
2,94
0,08
0,246839
940
216
20
5,92
29
16:21:11.2
-25_35:34
Sgr
U
C delta
6,28
7,15
0,87
6,744925
3400
1631
218
161,88
25
18:31:53.0
-19:07:30
Her
u(68)
EA
4,69
5,37
0,68
2,051027
1100
1533
170
49,22
23
17:17:19.4
+33:06:00
Cma
beta
beta C
1,93
2
0,07
0,25003
740
278
18
6,00
20
06:22:41.9
-17:57:22
Oph
theta
beta C
3,25
3,31
0,06
0,140531
590
196
15
3,37
18
17:22:00.5
-24:59:58
Oph
U
EA
5,84
6,56
0,72
1,67734617
810
1702
180
40,26
17
17:16:31.6
+01:12:38
Cet
delta
beta C
4,05
4,1
0,05
0,16113668
850
156
13
3,87
16
02:39:28.9
+00:19:43
Lyr
RR
RR ab
7,06
8,12
1,06
0,56686776
190
2452
265
13,60
14
19:25:27.7
+42:47:05
Cep
delta
C delta
3,48
4,37
0,89
5,366341
1500
2940
223
128,79
13
22:29:10.2
+58:24:55
Vir
FM(32)
delta Sct
5,2
5,28
0,08
0,07188
230
257
20
1,73
11
12:45:37.0
+07:40:24
Tau
lambda
EA
3,3
3,8
0,5
3,952955
1600
2031
125
94,87
10
04:00:40.8
+12:29:25
CrB
gamma
deltaSct
3,8
3,86
0,06
0,03
99
249
15
0,72
9
15:42:44.5
+26:17:44
Hya
eta
beta C
4,27
4,33
0,06
0,17
520
269
15
4,08
7
08:43:13.4
+03:23:55
Eri
lambda
beta C
4,22
4,34
0,12
0,701538
930
620
30
16,84
5
05:09:08.7
-08:45:15
Pup
rho
delta Sct
2,68
2,87
0,19
0,1408809
93
1245
48
3,38
5
08:07:32.6
-24:18:15
Sct
delta
delta Sct
4,6
4,79
0,19
0,1937697
160
995
48
4,65
5
18:42:16.3
-09:03:09
Del
delta
deltaSct
4,38
4,49
0,11
0,158
200
649
28
3,79
4
20:43:27.3
+15:04:28
Aur
KW(14)
deltaSctc
4,95
5,08
0,13
0,088088
100
724
33
2,11
4
05:15:24.3
+32:41:16
Tau
theta 2
delta Sct
3,35
3,42
0,07
0,07564
120
518
18
1,82
3
04:28:39.7
+15:52:15
Sco
my 1
EB
2,94
3,22
0,28
1,44626907
530
2243
70
34,71
3
16:51:52.1
-38:02:51
UMa
ypsilon
delta Sct
3,68
3,86
0,18
0,1327
80
1363
45
3,18
3
09:50:59.3
+59:02:19
Gem
omega
Cep
5,14
5,23
0,09
0,7282
930
644
23
17,48
2
07:02:24.7
+24:12:56
Vir
CU
alfa CV
4,92
5,07
0,15
0,5206794
360
1189
38
12,50
2
14:12:15.7
+02:24:34
Sct
R
Rva
4,2
8,6
4,4
146,5
4300
28003
1100
3516,00
2
18:47:28.9
-05:42:18
UMi
gamma
delta Sct
3,04
3,09
0,05
0,143009
220
534
13
3,43
2
15:20:43.6
+71:50:02
Mon
U
RV tau
6,1
8,1
2
91,32
3800
19752
500
2191,68
1
07:30:47.3
-09:46:37
Cyg
V1624(28)
SX Ari
4,91
4,97
0,06
0,7
690
834
15
16,80
1
20:09:25.5
+36:50:23
Lyr
beta
EB
3,25
4,36
1,11
12,93578
210
50629
278
310,46
0,1
18:50:04.7
33:21:46
Two star trails compared to each other to see what is caused by turbulence, and what is not Trail and spectrum from Arcturus.This metod gives more information. Much more accurancy in tracking will be nesessary
The resulting photo may look like a star-trail that vary in intensity as the camera hits the different waves from thr different periods. Even if each period perhaps is at many hours/days. Interesting in this context is the research work that Proffessor Lene Westergaard Hau made about the speed of light and temperatures. By sending photons through a Bose-Einstein condensate, which was cooled down to a few millionths of a degree above absolute zero, she managed to slow down the speed of the photons so they practically stopped. My opinion is that she stopped the time of the condensate (!), And thereby she caught photons who had a speed that harmonized with the speed and temperature of the condensate. But she did also speed them up again. I hope (!) the laser beam wich was slowed down, was there all the time. Therefore she could select different photons with different speed all the time. It was the condensate who decided which ones.
NASA here is telling that various ground based telescopes around the world have been observing Gamma-Ray Bursts. GRBs consist of photons and is to find in the high energic part of the electromagnetic spectrum of radiation. (EMS) These bursts were sent out into space in the universe's early childhood. They are very old and distant and have traveled for about 7 billion years before they reached us. A speciality about these bursts is that they occur very suddenly, and declines fairly rapidly. The problem with the observations was that the same bursts have been received at different times. This should not be possible in relation to laws of physichs. The speed of light in vacuum is constant. Even if they had been observed at slightly different wavelengths. This could not be explained. The question was if there was something in the room, which delayed the EMS, and most at the high energic end of the spectrum. NASA sent into space an observatory, the Fermi Gamma-ray Space Telescope, who could observe these bursts. They observed the photons of different wavelength, and they did measure the difference in arrival time at 0.9 seconds. 0.9 seconds difference at a time of more than 7 billion years is almost impossible accurately. They concluded that this was "at once" and that theories about the space was uneven enough to affect the speed of light, could depreciated.
Nothing is mentioned about the fact that the ground-based telescopes did not have the same result.
My opinion about this problem, is that the solution of this, is to find in the temperature of the CCD's. The cameras on Fermi, had probably very similar temperature. They where both in space, and on the same satellite. Perhaps it even was the same camera. The ground-based cameras however, had probably different temperatures, and therefore different local time speeds. They registered photons that harmonized with their own time rate. These photons had slightly different speeds through space, and arrived at different times.
Another aspect of this explanation of time, is that it makes the inflation period (the first 300 000 years after the big bang) a bit more edible. In those early days the temperature was so extremely high that it is beyond all our imagination. This made the universe expand by many times the speed of light. This can be done whithin the laws of physics because it is the very space it self that expands (?) My explanation is another. The speed of time was so high compared to what we have today, that it made it possible. The period of inflation was maybe very long. Perhaps indefinitely, if there was any big bang at all.
The balance of energy for the photons of different speed.
A natural question that arises is the conservation of energy. Would not the this require that the light source emit more energy than you receive?
The issue affects not the part that describes time, but the part that who is to detect the phenomenon.
This may be a problem, and may be not, but of course we have to ensure the conservation of energy. If we can't prove it, we at least have to give it, at this stage, a fair chance to exist.
One of the problems is that the information we obtain have to be extreamly accurate. What part of the consumed energy is actually emitted as EMS at the different wavelengths, and what is transformed to heat.
The uncertainties by measuring what is received by a medium is an other problem. This requires extremely accurate measurements of media such as the CCD chips.
On a CCD chip, one photon turn loose one electron, and one only. Such a pixel is "black and white" and the photon turn loose the electron regardless of how much energy the photon may exist of. If there is some spare energy, this will transform into, maybe, heating. It is not easy to know what turned into what. The same amount of energy is probably not needed to turn loose all the electrons from the CCD chip. I therefore believe that a unified accounting at least are not easy to achive.
Another reason is the amount of radiation who does not interact, and probably are not possible to measure. Neither from the source, or by the media. It's like looking for the Higgs particle.
One should also note the very small differences. As previously mentioned the gamma-ray bursts that have been travelling for 7 billion years, come forward with a time difference at nealy one sekund. It was not so in the case of Lene Hau's work. But there the amount of photons was very few. Maybe photons out in one end of an Gaussian distribution curve.
Solar cells are now able to transform about 16-18% of the received energy into electric power. (It is estimated to give 3 times as much as this by using nanotechnology in the future.) The sun can of course not be used in this context when you only know what is received in the harmonic area, and not what is actually sent out from the sun. But anyway .... in 2008-2009, I read somewhere (unfortunately not remember where) that someone who did research in connection with the solar cells had managed to get out more energy than what theoretically is possible. It was about 15%. They were shocked at the results and assumed that it was all about measurement errors, but until then, they had yet no explanation of how this could happen.
It also is reasonable to assume that there is EMS out there, wich has a speed that do not harmonize with temperatures at the media we uses. Noise at CCD-chips are a well known problem, and varies with the temperature of the chip. The noise is due to electronic heat, but may be thats a secondary reason. The light source that emits EMS are usually hot. These sources also have to be in harmony with the emitted photons. It is therefore likely to believe that one can receive more EMS with a hot medium. But it is not likely that this EMS is well stuctured.
Time travel?
Time as a word is used a lot, and most people have a superficial, unproblematic relation to the meaning of the word.
Most people will be content with time as something that just floats off in a steady stream. Some will find it satisfactory with what relativity tells, and others love to think about time machines, wormholes and parallell universes.
It seems that a lot of people have a kind of perception that the timeline for the entire universe is stored somewhere. And that we on our journey in life is traveling along this timeline. That we in a manner are evoking the moment when we are at that point on the line . This leads them to fantasies obout traveling forward or backward in time. Or rather a jump back and forth in time.
Or that old times can appear in different places where the room have been turned and twisted on. And that it is possible to get glimpses of vessels or people from the days of old. On a popular TV channel the other day, it was told that in the Bermuda Triangle, it may exist "The fabrick of time."
Traveling through wormholes for showing up in other places at other times are also a popular idea. Even among physicists.
Such performances of time stimulates curiosity and is well suited for movies and stories as they provide many opportunities for escapism. And that is perhaps the reason why they're so popular. It is easy to get confused when talking about time the way we do today. And our memory play us a trick. In our memory all our past is more or less saved. Many memories back until we were children exist in a timeline. In addition, we have plans and ideas about tomorrow. And we know many of the things that surely will take place in the future. Such as the weather, that the sun will arise, planets will move, that children will grow up, and people get older. We know that by looking at the stars in the sky, we can see millions of years back in history. That even the sun, we see as it was 8 minutes ago.
Movies have become a natural part of our life. They obvius have a timeline, and we can play forward and backward as we like. No wonder we may sence that past and future exist. But the reality is probably different.
We are always travelling into the future, but the line of history have to be unbroken and continuous. Matter act from the previous moment at all time, and can not do otherwise. If a jump in time was possible, matter would have to dissapear from one place, and appear in an other.So jumping forward or backward in time have to be impossible, even if it's boring. Simply because we can not break with the relationship between cause and effect. It is not compatible with one of the most important knowledge of nature, wich is that energy can neither be created nor destroyed, but only change in its form. But if a person wish to move faster into the future than the contemporaries around him, this may be possible simply by beeing frozen down to a lower temperature. This person would (if he had survived and been conscious during such cooling) experienced that everything around him had happend faster because his own body processeses would happend more slowly. He would see how people became older while he almost stayed the same. Today, there are people who have payed a lot of money for beeng kept frozen in liquid nitrogen, and hope to be thawed out in the future, and that is a good idea in the first place. But its a sad fact that all the cells in their bodies cracks when the water in the cells became expanding ice crystals. We know what happends with a cucumber that has been frozen. As it is frozen it is hard, but when it thawed the fluid will flow out of the broken cellmembrane so that it become soft and wet. But sometime in the future it may be possible to find a way to avoid the cells cracking. Today's freezing of people, probably is done against better knowledge, but when there is money to earn...
To travel backwards in time is extremely difficult. To do it relatively however, is not to hard. You simply have to heat your self up, and if you do survive that, you will be able to study the world around you in slow motion, but of course at a high price. A way to really travel backwards, is to be at a point A in time, and isolate in a room. Then let time flow until point B at time. It is nesessary to avoided any infuense from what's outside the room, even radiation. At point B, you can return to point A by reversing all the physical processes that have occurred from A to B. At point A you just have to rewerse the physical prosesses again to start all over. The tip of the day would be : do not breake a cup of coffe.
Funny implications
Some more delicate aspects of time travel are also available. One example is whats happend if you travel back in time without knowing exactly where to "land". Recalling that the Earth moves at about 30 km/sec in its orbit around the sun (as well as moves the sun so that we will never get back to the same place, in addition to the galaxy ...). By setting the time machine's clock at 100years backwards, one might be unfortunate if the current time has changed in just a few seconds at the time, and he harbor many miles out in space. Or for that matter, inside the earth. That could be very cramped and uncomfortable! But it's just a small problem ...... you're probably not born yet, and that will perhaps make the journey quite bouring. I will recomand not to kill your own grandfather. Not even if you dont like him. If he steal your money, set your hous on fire and kill your dog. Don't do it.
Travel through a wormhole is perhaps a bit too bold. Even if you could survive the spaghettification. Imagine how it is showing up at some random place in the intergalactic universe, and in addition have to start looking for a habitable planet around a star looking nice, perhaps located 500 light years away ...
I think we wisely can forget about time travel. If you are still not convinced, it is safer to let someone from the future visit you. You just have to invite them. Find a big solid rock at a place that is hard to avoid for the future population. Write your invitation by cutting letters in the rock and remember to give the time for a meeting in such a way that you can show up at that time. And...be there.....You'll never know !!
