How Big is the Universe?

The universe is big, but how big everyone who look at the uncountable numbers of stars thinks about it. We know that earth revolves around sun and the sun along with millions of other stars revolves around the center of milky way which along with billions of galaxies lies in the universe and the Universe is the totality of everything that exists, has existed, and ever will exist.The part of the universe that we can see, referred to as the observable universe, has a diameter of about 93 billion light years (28 billion parsecs). The universe is mostly empty space, close to a vacuum .

     The size of universe depends upon the factor that it is finite or infinite, we know that universe is expanding but can we know the current size of universe if it is finite? Astronomers measures how far is the galaxy by redshift, they don't worry about the distance as universe is expanding ever time. The more the redshift is the distant the galaxy is.

    For example, the galaxy we observed has a redshift of 7.5. Using this, we can determine distance by calculating how long the light has traveled to reach us.which comes out to be 13 billion years, so you might think that the galaxy is 13 billion light year away, As the universe 13 billion years ago is smaller than now. so it was actually closer at the time the light left that by using this we calculate the distance of the galaxy when the light came out from it which was only a short 3.4 billion light years away. But now the galaxy is much more farther than that as the galaxy has moved in those years because the universe is expanding. It is now about 29 billion light years away but we see it as 13 billion light years which is exactly 3.4 billion light years away when the light came out from it.29 is definitely more than 13 which is also more than the actual 13.

    It is bit confusing as light takes time to travel for example when we see a star at 13 billion light years away we are seeing it what it looked like 13 billion years ago. But today after 13 billion years the star has moved much farther away than we see it.

   As we can see at only a limited area of the universe we have no idea how big it is the most distant light we can see has a redshift of 1000.the distance is really really big, and through the years it is now much more distant.
   Universe is bigger than what we could imagine. The new research show that the universe is 250 times bigger than the observable universe . The universe which we can observe has a diameter of 93 billion light years. And if the research is right than the universe must be 250 times bigger than 93 billion light years. But do we know the shape of universe before knowing its size? Cosmologist believe that universe must be possibly look like
1) flat, like a Euclidean plane.
2) open, or curved like a saddle.
3) closed, or curved like a sphere.

 Today all we can do is imagination based upon some researches but don't forget only 500 years ago people used to think that everything in the universe revolves around earth.

Source of informations
An example used from here.
And some info from here
Image credit here