People ask many questions about the wonders of the universe. Even scientists do not have the answer to these questions, such as where do we come from, why are we here, and many more broad questions. But, there are questions that we do have some answers to.
What is the universe?
The universe is all of space and time and its contents, which includes everything from planets to galaxies, the contents of intergalactic space and all matter and energy. The size of the entire universe is still unknown but the latest figure estimates it to be 90.68 billion light-years across.
What is a light year?
A light-year is the distance light can travel in one year. Light moves at 300,000km/s. In one year, it can travel about 10 trillion kilometres.
How many galaxies are there?
A galaxy is a system of millions or billions of stars. Using mathematical models, astronomers can work out the number of “invisible” galaxies beyond the reach of telescopes, finding out that the majority are too faint and far away to be seen. According to the best estimates of astronomers, there are at least one hundred billion galaxies in the observable universe.
Are there other unknown living creatures?
According to the royal astronomer, Martin Rees: "Planets exist around many, even most, stars. We know that in our Milky Way galaxy there are likely millions of planets, which are in many ways like the Earth, with liquid water."
This could mean that there is alien life. We do not have enough knowledge to make a conclusion that we are the only living life in the universe. Out of the billions of galaxies in the universe, we have not discovered a planet with beings on it that are more intelligent than us humans.