The principle dates back to Albert Einstein's theory of general relativity. This is called the cosmological principle.
In 2003 and 2004, scientists created the Hubble Ultra Deep Field, which in a million-second exposure revealed about 10,000 galaxies in a small spot in the constellation Fornax. To the best of Livio's knowledge, Hubble is the best instrument available for galaxy counting and estimation. Unlike Hubble it will use infrared light.
In 1 trillion to 2 trillion years, Livio said, this means that there will be galaxies that are beyond what we can see from Earth. The visible matter we see collects inside this scaffolding in the form of stars and galaxies.
Also, the universe is accelerating in its expansion. So the number of galaxies could even be greater than 200 billion, when considering other universes. All in all, Hubble reveals an estimated 100 billion galaxies in the universe or so, but this number is likely to increase to about 200 billion as telescope technology in space improves, Livio told Space. They may be nearly circular or so elongated that they take on a cigarlike appearance.
Elliptical galaxies contain many older stars, up to one trillion, but little dust and other interstellar matter. While it is interesting to count the number of galaxies in our universe, astronomers are more interested in how galaxies reveal how the universe was formed. If you held your thumb at arm's length to cover the moon, the XDF area would be about the size of the head of a pin.
Scientists are divided on just how galaxies first formed. As the early universe inflated, there are some theories that say that different "pockets" broke away and formed different universes. As the universe gets older and bigger, however, galaxies will recede farther and farther from Earth.
Most astronomers suggest that galaxies formed shortly after a cosmic " big bang " that began the universe some 10 billion to 20 billion years ago. Galaxies are classified into three main types: So if that single small spot contains thousands, imagine how many more galaxies could be found in other spots.
The Hubble Space Telescope orbits 600 km above the Earth and has been sending back the most amazing images of our universe since 1993. Fortunately, adaptive optics can now compensate for the twinkles.
This is where the concept of the "observable universe" — the universe that we can see — comes into play. Optical telescopes have been used for astronomical observation since the time of Galileo, but the technology has moved on significantly since then. Magee, and P.