Astronomy & Physics

The most important thing in the General theory of relativity, made by Albert Einstein, is that the time depends on space - with bigger velocity time goes slower. Even when velocity equals speed of light time stops. For example russian astronaut who spent two years from his life for living in space and orbiting around the Earth saved 1/50 second of his life, because on orbit his velocity was very high. Or the center of the Earth is two and half years younger than surface, because points on surface goes faster than points in the center. This discovery opens new capabilities in physics. Now we can easily exchange time for speed and speed for time. It will be useful in long space journeys in future. We can also make computer calculations faster. In one sentence: we can play with time. Funny is if I'd move with my computer with speed equal 99,7% speed of light I'd finish this post before 4 o'clock.

The universe is so big that we can't imagine it. Even with objects like stars and planets will be hard. But with a few examples of the biggest stars I will show you how the Earth is small.   We usualy see models of the solar system with sun two or three times bigger than planets. Truth is quite different. Volume of our star is 1,3 millions times bigger than volume of the Earth!   Do you think now the Sun is big? Is it big compare with the Rigel? Does Rigel is big compare with the Betelguese or Antares? This is moment when we can't understand scale of the universe.   It's not the end of star gigants. The biggest stars in the universe is UY Scuti and Canis Majoris. For example when the Sun would has 20 centimeters the UY Scuti would has 20 kilometers. In the universe is few sizes can shock us like the biggest galaxy, but for me difference between Sun and the Earth is enough.    

  In ancient China astronomers observed big star. There weren't any stars before. An intersting thing in this object was size. It was very big. But after two months the star mysterously vanished.   Few century later in this place in the sky european astronomers found out, using the biggest telescope in the world, very young mebla. They called it "The Crab Nebula". After fifty years astrophysicists took all photos of the Crab and after analize they calculated the nebula is getting bigger and bigger very fast.   Next researches, made with radiotelescope, showed that Crab emitate lot of radiation.   After 30 years were found out pulsars - big neutron stars. Pulsars born in supernovas and also emitate radiation.   Astronomers connected this all facts and described Crab as nebula with pulsar inside made from supernova.   This history shows how scientists works together despite different times and places in the world.

We have only our eyes and dark sky with stars, but we know how big is our galaxy and even how fast the universe expands. We also know what happened 10 billions years ago, of what Mercury's atmosphere consists and we calculated when the sun will become a white dwarf . We know it just from looking for shining points on the sky. Different occurrences in the universe are subject of the oldest one natural science in the history - astronomy. This name is made from two grecian words:"astron" - star and "nomos" - law. The aim of this science is find out about laws rules in the universe by...observing sky.     With astronomy and of course physics we can simply describe world around us. Do we need information about velocity of the Andromenda's galaxy? I think it isn't very important. But with better knowledge about the universe we will know why we are here.