Science tells you that alien cultures must exist, but most people choose not to believe it.

The search for extraterrestrial life and cultures has been ongoing since October 4, 1957, when the first satellite was launched.

In the last century, the search for outer space has made significant breakthroughs on the physical level, but before we explain why science has discovered about outer space, speaks of our eyes.

Many people think that what they see in their eyes is real, so they will admit that this thing is real, and what is invisible to their eyes is regarded as non-existent. However, if the scientific theory is utilized, there is a big misunderstanding in this cognition, because people's eyes can see things are too limited, and the site is not necessarily the reality.

The frequencies of the electromagnetic spectrum are classified from low to high as radio waves, microwaves, infrared rays, visible-light, ultraviolet rays, X-rays and gamma rays, and their corresponding wavelengths decrease from kilometers to the diameter of an atomic nucleus.

The current scientific understanding of electromagnetic waves is that the spectrum is infinite and continuous. In other words, the limit of long waves is seen as equal to the size of the universe.

So from this point of view, we're in a universe where electromagnetic waves are everywhere. Visible light is just a small part of the electromagnetic spectrum. So when we need to examine the universe and the civilizations in outer space, we must take a longer view and think bigger, not just in the current frame.

Because the human eye can see very limited, so in order to expand the exploration of outer space, researchers have had to build large-scale observatories and telescopes on the ground and in space for nearly 100 years, the most famous of which is the Hubble Telescope.

Hubble is a visible light space telescope orbiting the Earth. During its 31 years of service, it has provided countless facts about the universe in the observable universe. The three most famous images are Hubble Deep Field, Hubble Ultra Deep Field and Hubble Extremely Deep Field.

The three deep space-related images were made in 1995, 2004 and 2012. They refresh our knowledge again and again, and tell us what it is supposed to be outside the universe.

Passed in 1995, the Hubble Deep Field is an image of a small area of the sky taken by the Hubble Space Telescope. The location is located between 40,000 and 100,000 light-years from Earth in the constellation Ursa Major.

The area was initially undetectable to the naked eye. After 324 exposures over 10 days, Hubble found 3,000 galaxies in this shadowy region.

Taken in 2004, the Hubble Ultra Deep Field, HUDF, a small portion of the constellation Fornax, show an area of 3 square arcminutes, or just 12,700,000 time the size of the entire sky. And that very minute area contains about 10,000 galaxies.

So based on the uniform distribution of galaxies in the universe, we can estimate that there are approximately 100 billion galaxies in the observable universe.

Most recent Hubble eXtreme Deep Field, XDF, focuses on a small portion of the previous ultra-deep Field. Combining nearly a decade's worth of data, Hubble has finally created a composite image of very concentrated space.

The result is a galaxy 13.2 billion light-years from Earth. The farthest we've ever seen in outward space, and the dimmest galaxy in the image is only 10 billionths of the lower limit of visible light.

To put it simply, if there are 100 billion galaxies in space, there are about 10^25 planets in those galaxies. I should warn you, however, that this is only in the visible-light range, and we can calculate the number of planets. Nevertheless, in the vast universe, the invisible spectrum is the most mysterious part.

So statistically speaking, alien life and alien cultures must exist, but we humans are currently limited in our ability to actively find them.

One might say, so what if there are foreign civilizations out there? So what if we humans could be found? Now we have not yet explored the human beings themselves, how can we have time to care about things outside the earth.

There is true to this, but it is not entirely accurate. In my opinion, it would be better for us if we could find some advanced extraterrestrial civilizations.

After all, their technology is more developed than ours, and they have gone through all the holes. At least, they can let us tread less thunder on the road ahead. For example, should we develop artificial intelligence or not?

Well, this phase of the exploration article is here, like to see this kind of exploration article partner also please give the author a point of concern and praise, I will work harder to write a good article to provide you with.