What is time?

Today I read an article in the newspaper about an experiment to be done in a crater on the moon. The researchers want to install hundreds of small antennas to measure very faint waves created some milliseconds after the Big Bang.
Milliseconds after the Big Bang? Were there milliseconds after the Big Bang? What were "milliseconds" just milliseconds after the Big Bang? Who measured them and how?

I'm very interested in the phenomenon of time. We all experience time, it passes by, we grow older, we see the clouds passing by, the seasons, day and night, we travel over the time zones, we turn on the TV at the right time for the six o'clock news. It all seems so simple... the way we experience time. 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day, 365.25 days in a year, one year is one rotation around the sun.

So? What's the problem? Let's say I get myself a shiny spaceship, leave the earth, take a steady position relative to the sun, sit there, read all my books, listen to my entire CD collection. One day, exactly 365.25 days later, the planet earth passes by. All the people I know are one year older. And I? I didn't travel around the sun with them. Am I not one year older? Well, not if you look at my calendar, I took of one leaf a day, at each sunrise. But the sun didn't rise or set all year. But my clock kept on ticking, my biological clock kept on ticking. I might have created one heck of a jetlag, I might have lost my sense of earth time, my rhythm of day and night but nevertheless I've grown older, about one year older.

Einstein learns us that the speed of motion, especially very fast motion near the speed of light can seriously influence the speed of time. An atom clock aboard a fast space ship ticks at a slower rate than its twin clock on earth. Not according to its observers during the flight, but when it returns to earth, they no longer show the exact same time. So far our technology is not advanced enough to show the tiny difference in time between the wrist watch of an astronaut and your kitchen clock. But if we would be able to travel near the speed of light, the difference would be huge.

While I was standing still compared to the sun, the earth was still traveling at its normal speed of about 54000 Km/h around the sun and someone on the equator was spinning around the axis of the earth with a speed of 1666 km/h, not near the speed of light. So my clock would not be much off.

But Einstein is simple, very simple, compared to what scientist currently believe about time. It's some kind of boiling nothing, moving very fast in one spot and almost standing still in the next. Atom clock time is different from astronomical time and both are much different from international conventions time. On subatomical level time might even have several dimensions.

Back to the Big Bang. The theory is: our universe did not exist before the Big Bang, there was no time, no space, no mass, no matter, no light, no radio waves. There was this one singularity, a dot, a very heavy dot that somehow got triggered to explode. The explosion created a soup of energy that created particles that created mass that created stars that created the elements we see around us. And from that moment on our words time and space had a meaning.

But what meaning? What was the size of the newly created galaxy? I think it was exactly one galaxy wide, on galaxy high and one galaxy long.
How long did that newly created galaxy exist at any given moment? Exactly one galaxy lifetime, no matter which moment you pick.

To measure means to compare. One meter of rope is just as long as a stick that we call a standard meter. One Kg of sugar on a balance is just as heavy as the block of copper or iron on the other side of the same balance.
We've invented an awful lot of instruments to measure time. First we noticed the days, the full moons and the seasons. Then we started to look at the time it took a certain amount of water to evaporate from a jar, Huygens invented the ticking clock, currently the standard for one second is a very precise number of oscillations in a very precisely defined state of a very precisely defined atom (cesium 133).

At the moment of the Big Bang there was no standard meter, no block of copper on a scale, not even an atom. It would take quite a long time before the first Cs133 atom would appear. A long time, but compared to what? Who measured it and how?

By our every day standards there are exactly 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day, 365.25 days in a year. And one year is exactly one orbit around the sun. That's precisely 31557600 seconds per year.
By a number of causes the earth's orbit around the sun is not perfectly constant. In the times of the dinosaurs the year had a significantly other duration. I don't know if their year was closer to 20000000 of our seconds or closer to 40000000. Neither do I know how their year compared to the number of rotations around the earth axis that we call days. I do know that their year was exactly one rotation around the sun. And that it was exactly 4 seasons. Dinosaurs migrated just like our birds, their trees show rings just like ours.

Our year of 365.25 days is an observation, our day of 24 hours is a convention and our year of 31557600 seconds is a calculation. A measurement would be to compare the seconds of the clock on your wall to the seconds of a Cesium 133 atom. But how about that atom clock aboard that space ship? It had the exact same numbers of oscillation of its Cesium 133 as the atom clock on earth.

According to most astronomers our universe is expanding. But what if we would have been able to place some kind of virtual ruler into the Big Bang? Lets say we would have called the exact distance between the first two hydrogen atoms our yardstick? These two atoms would now probably be somewhere at the outer edges of our universe. One galaxy wide, one galaxy high and one galaxy long, where's the expanding universe?

The heat radiation of the Big Bang flew away from the place where it all started with the speed of light. The material that much later formed the mass of our solar system moved very slow compared to the speed of light. As far as I can understand it should be still flying away from us, not being able to ever turn around and fly back to our antennas on earth, on the moon or in a space ship. Such measurements do measure something, but what?

The lines between exact science and philosophy can be very thin.
There are a lot of questions in this blog and no answers. By the way please do not comment that the mean tropical year counts 365.24219 days and the vernal equinox year has 365.2424 days, I know. So my calculations are off some seconds. Time is a difficult matter,
oh no, it not matter,
is it philosophy?
is it science?
If you want to read more about it, see time in Wikipedia.