One day in 1951, when Nobel Laureate and physicist Fermi was discussing the issue of flying saucers and aliens with others, he suddenly said: “Where are they all?” This question led to the scientific thesis, Known as the “Fermi Paradox”.
In order to understand whether we humans are the only life in the universe, we have been “searching for extraterrestrial intelligence”-constantly accelerating the speed of building larger and more complex machines, and tirelessly exploring space. But nothing has been achieved so far.
If alien life does exist, why have we never found any clues about them?
Perhaps they have made a sound to us, and we have been listening intently. However, their information will never reach us, because their distance from us exceeds the so-called “cosmic horizon”-and this is one of the most convincing answers to Fermi’s paradox.
The most likely place to have extraterrestrial life
The universe horizon is a barrier between the “observable universe” and the “unobservable universe”, and the boundary between the two domains.
For us, the cosmic horizon is centered on our planet, with a radius of 47 billion light-years away. In this range, our telescope can observe everything (everything we already know), so we also call the universe within this horizon the “observable universe”. It is a huge space, filled with 1,022 stars, which are burning and giving dazzling light to countless planets. Of course, these rays of light also shine on our earth.
Outside this horizon, there is a potential and infinite universe, which we call the “unobservable universe”. Research on cosmic expansion tells us that this unobservable universe may contain another 1,080 stars. These stars are embedded with the stars around us to form a majestic and magnificent universe.
Except for one obvious feature, the “two” universes are basically indistinguishable-this feature is: the unobservable universe is the place most likely to contain extraterrestrial life.
The existence of the universe horizon is because the speed of light propagation has an upper limit-light travels at a speed of 300,000 kilometers per second. Although it is very fast, it is already the limit. The farther away the light is, the longer it will take to reach us. Therefore, the farther the celestial body is from us, when we see it, we see its earlier appearance. For example, when you look up at a star 1,000 light-years away, what you see is what it looked like 1,000 years ago, not what it looked like at the moment.
This relationship between time and distance can explain why our universe is only 13.8 billion years old, but our universe horizon far exceeds it (as mentioned above, the radius of our universe horizon is 47 billion light years) ). Moreover, the horizon of the universe is still growing. As time goes by, the light from distant celestial bodies will eventually reach us, enabling us to discover them through instruments.
Celestial bodies are always far away from us
Unfortunately, as our cosmic horizon becomes larger and larger, our “event horizon” becomes smaller and smaller.
The event horizon of the universe is similar to the event horizon of a black hole. Beyond this limit, we will not be able to communicate with any objects, nor can we affect any objects.
A galaxy may be within the horizon of our universe-we may be amazed that it has so many mature stars-however, it will eventually exceed our horizon of the universe because the expansion of the universe will push it away from us further and further.
This expansion seems to be faster than light, and it is controlled by the charming “dark energy”. Dark energy, the name itself sounds a little mysterious and sinister. We have been trying to understand what it is and why it can expand our universe so fast. However, it remains mysterious so far.
In the end, the worlds that we can observe but never reach are taken away from us by the ever-expanding universe. After billions of years, they will also be beyond our horizon. In the more distant future, the current “observable universe” will shrink to only local galaxies: some rotating objects bound by gravity will become invisible a few light-years away. In contrast, at this moment, we live in a world of abundance.
Why can’t find extraterrestrial life
American astrophysicist Tomonori Totani used the cosmic horizon to solve the problem of “Fermi Paradox” in a study.
In fact, “the doctrine of the spontaneous generation of life” is an unacceptable viewpoint. But what is surprising is that all the creatures around us that we see were produced by non-living matter at some point in the earth’s turbulent history. In the observable universe, the probability of this happening seems very small. But what if in a larger universe with 1080 stars? Will this be easier for people to accept?
Although it is rare for life to occur naturally on our planet-the only place where life is produced that we currently know, it may be common and common outside of our universe. Our observable universe seems too small to find more life.
This means that, on the one hand, human beings are still unique examples of life in our observable universe, and are within the fixed boundaries of the event horizon; on the other hand, this is nothing special, because there may be counts outside the horizon. An unclear planet, where life lives and multiplies.
Somewhere in the universe, there are civilizations that we have never seen before, and there are “aliens” whose language is like a mantra to us, but there is no contact between us and them. There are fascinating things beyond the observable range of human beings, but these things will always be unknown to us.