The universe is everything we know that exists like us humans, the planets, the stars, the galaxies etc. The universe has a possibly infinite volume, due to its expansion. There are probably at least 100 billion galaxies known to man in the universe, and about 300 sextillion stars. The diameter of the known universe is at least 93 billion light years (1 light year = 9.46×1012 kilometers or 9.46×1015meters) or 8.80×1026 meters. According to General Theory of Relativity, space expands faster than the speed of light. Due to this rapid expansion, it is not brief whether the size of the universe is finite or infinite. The expansion of the Universe is due to presence of dark energy, which is found to be 73% and dark matter (23%). There is only 4% matter found. However, even though the universe is huge and massive, it has a very small density of 9.9 ×10-30 gm per cubic centimeters (excluding stars, planets and any other celestial body). There are about 1 ×1080 (1 followed by 80 zeroes) atoms in the Universe.
The universe fact file
- Coldest place ever:- Boomerang Nebula (-272.15oC)
- Coldest place in the Solar System:- Triton (Neptune’s moon)(-237oC)
- Hottest place in the Solar System:- The Sun (6000oC) or Venus (if it comes to planets)(462oC)
- Hottest temperature known:-Infinite degrees centigrade (Temperature achieved by Big Bang)
- Biggest star :- VY Canis Majoris
- Biggest galaxy :- Abell 2029 cluster
- Biggest planet in Solar System :- Jupiter
- Biggest planet ever :- TrES 4-b
- Nearest black hole to Solar System :- Cygnus X-1
- Nearest galaxy to Milky Way :- Andromeda Galaxy
- Nearest star to Sun :- Proxima Centauri
- Farthest object in the universe :- UDFj-39546284
History of the Universe
There were many theories put forward by different scientists over the years. However, the currently accepted theory is the Big Bang theory, which was found by astronomer Georges Lemaitre, and further studied by astronomers from around the world. Experiments such as the LHC (Large Hadron Collider) is also held to prove the Big Bang theory. According to the theory, 15 billion years ago (or 13.5 billion years approx) there was a huge explosion called the Big bang, thus forming a phase known as the Planck Epoch phase . As time passed , the explosion cooled down, thus forming the universe. The universe still expands today, at a alarming velocity.