The universe began with the Big Bang around 13.6 billion years ago. The Big Bang was a rapid expansion of the universe from a tiny single point. This hot expansion has continued since then, resulting in the expansion of the universe in every direction.Know More
At the time of the Big Bang, the universe and all of its matter was concentrated in a single point. As the Big Bang started, this matter was heated to very high temperatures and expanded rapidly.
Several scientific observations have convinced astronomers that the Big Bang theory is correct. One of the strongest pieces of evidence is called the cosmic microwave background, or CMBR. This is the remaining heat from the Big Bang that can be seen in all directions when looking into the universe. As the universe has expanded, the initially hot material has cooled, so that it now emits light as microwaves.
By looking at distant galaxies and stars, scientists have also discovered that everything seems to be moving away from the Earth. The further away a galaxy is, the faster it appears to be moving. This shows that the universe is still expanding, although there is debate as to whether this expansion will continue forever.Learn more about Universe
Although the ultimate fate of the universe is a largely debated topic, according to the University of Tennessee, in an open universe the universe will continue to expand forever. This is due to insufficient mass to cause the expansion to stop.Full Answer >
The no boundary theory of the universe likens the universe to the Earth, in that is impossible to find any boundaries traveling around the Earth or to fall off it. This is possible as a result of theorizing that prior to the Big Bang, the generally accepted laws of physics did not apply and that the concept of time as we know it did not exist.Full Answer >
Johannes Kepler's theories of the universe were notable for hypothesizing that the universe was created on April 27, 4977 B.C. and that the planets orbit in an elliptical pattern rather than a circular pattern. His theory superseded previous theories which postulated that planets move in circular orbits at constant speeds.Full Answer >
Whether humans are the only intelligent life to have evolved in the universe cannot be answered with certainty, but a probability can be assigned to the proposition. Accurately estimating the number of advanced civilizations in existence is done by assessing the number of opportunities for intelligent life to evolve and contrasting that with the improbability of various stages in the development of a civilization.Full Answer >