Roughly 14 billion light years.
Yes. It is 13.7 billion light-years in radius in light travel distance according to Ned Wright's Cosmology calculator.
This is an area of active research... meaning, nobody really knows. The visible Universe has a radius of about 46 billion light-years. According to the "inflation" theory (basically, the modern version of the Big Bang theory), the total size of the Universe MIGHT be millions or billions of times bigger.
This is an area of active research... meaning, nobody really knows. The visible Universe has a radius of about 46 billion light-years. According to the "inflation" theory (basically, the modern version of the Big Bang theory), the total size of the Universe MIGHT be millions or billions of times bigger.
What?!! Radius cannot be measured in Newtons!
approximately zero
Universe
Hydrogen
Hydrogen.
Hydrogen.
My universe is believed to have a radius of approx 47 billion light years. How big is yours?
The universe is around 70% dark energy (a.k.a. empty space). The rest is mostly dark matter, with a few percent for ordinary matter. That is the current scientific model.
Yes, there are many galaxies in the universe. Some of the others are visible from earth.