We are all familiar with the Hubble Telescope, one of the greatest cosmic telescopes of mankind to date.
It can clearly observe galaxies 13.4 billion light-years away from our Earth.
But whenever we all mention this distance, there is always a question: why can't we see aliens when it can observe 13.4 billion light-years away?
Today we will take a brief look at the Hubble Telescope.
The Hubble telescope can observe primordial galaxies 13.4 billion light-years away.
So far, it has been working for more than 30 years, has orbited the earth about 140,000 times, and has traveled a total distance of more than 6 billion kilometers.
More than 1.2 million observation missions have been completed.
Countless precious universes have been sent back to us human beings**.
What does it mean for the Hubble Telescope to observe galaxies 13.4 billion light-years away?
Everybody knows that. The speed at which light travels is 300,000 km/s.
The distance of 13.4 billion light-years means that the galaxy that Hubble is seeing at this moment is the galaxy 13.4 billion years ago.
The entire universe has only been born until now.138200 million years.
This means that the Hubble telescope can observe galaxies that were first formed in the universe.
So this has led many people to wonder why the Hubble telescope can't even be observed by aliens if it has such a powerful function.
This brings us to the characteristics of the Hubble telescope, which has an aperture of only 2About 4m.
Due to the limitations of this condition, even the use of the Hubble telescope to observe the distance from our Earth is 4Proxima Centauri, 22 light-years away, can only show the appearance of a bright spot.
If the Hubble telescope is pointed at the moon, the resolution is less than 100 meters.
Think about it, how can you see an extraterrestrial civilization in such a situation?
What's more, if extraterrestrial civilizations evolve to the point where they can use electromagnetic waves, then we need to detect them not only by optical telescopes, but more importantly, by relying on electromagnetic waves to detect extraterrestrial life.
Although the Hubble telescope can see far, it is according to the standards of our human life to look for aliens.
In order to evolve life like us, the corresponding planet must have a thick atmosphere.
If there are alien civilizations on a planet and they are wrapped in a thick atmosphere, then imagine that the Hubble telescope will not be able to photograph them through the atmosphere.
In addition, the universe itself is full of black holes, dark matter, nebulae, and other objects that hinder the propagation of light.
So for the Hubble Astronomical Telescope, these interstellar objects are a big challenge.
Thus, while the Hubble telescope can observe galaxies in the range of 13.4 billion light-years, it cannot clearly observe the specific features of a planet's surface.
So the best way to find extraterrestrial civilizations is to use radio telescopes. Perhaps one day in the future, mankind will develop more advanced cosmic telescopes.