"universe"

If someone asks the question, are humans alone in the universe? I believe that most people would answer in the negative. In fact, the scientific community also generally agrees that there are a large number of intelligent civilisations in the vast universe, some of which may even be far ahead of our civilisation, and in order to better describe the technological level of intelligent civilisations in the universe, scientists have also proposed the concept of "Cosmic civilisation levels".

The energy released by nuclear fusion is actually an important basis for stars to be able to maintain their stability

The reason we don't see time travelers is actually because they are not in our timeline

Further research shows that this mysterious force accounts for 68.3% of the total mass energy of the universe, and it is because of this that it is able to overcome gravity and become the dominant force controlling the operation of the universe

In the past days, scientists have been working on the study of meteorites, and as the research continues, there is more and more evidence that life should originate from outer space

Intelligent life is rare in the universe, or perhaps it is just wishful thinking on our part. As mentioned earlier, just in the galaxy, there are hundreds of millions of planets that have the natural conditions to nurture life, so a reasonable speculation is that life has evolved on many planets, and even a number of planets have evolved intelligent life.

Everything we can see in the universe has an internal structure and they are all made up of smaller matter, so what is the smallest matter in the universe?

There are many rumors that Pluto is a terrible world, where the temperature is so low that no life can survive, and even if there is life, it may be some extreme virus, so how terrible and unusual is Pluto?

Whichever way you look at it, humans cannot be the only intelligent creatures in the universe. As far as we know, the universe has existed for at least tens of billions of years, so a reasonable speculation is that there is probably an advanced civilization in the universe that is hundreds of millions or even billions of years ahead of humans, and if that is the case, their level of technology is something that we humans simply cannot imagine.

NASA's Jet Propulsion Laboratory's Near Earth Object Research Center has such a database, which is called the "Fireball Database."