Is there evidence that aliens have visited Earth? Here are the conclusions of the US Congress hearings on “Unidentified Aerospace Phenomena (UNP)”

The United States Congress recently held a hearing on the US government’s information on “unidentified aerospace phenomena.”
The last such investigation took place more than 50 years ago as part of a US Air Force investigation called Project Blue Book, which examined reports of sightings of Unidentified Flying Objects — UFOs (note the name change).
The recent hearings were the result of a provision, attached to a 2020 COVID-19 bill, that required US intelligence agencies to produce a report on UNPs within 180 days.
The report appeared last June.
Why would governments be interested in UNPs?
An interesting hypothesis is that UNPs are alien spacecraft visiting Earth. This is a concept that is getting a lot of attention, as it has been popularized for decades in sci-fi movies, but also through accounts of Area 51 and alleged audience sightings.
Another, far more prosaic hypothesis is that governments are interested in unexplained aerospace phenomena, especially those in their sovereign airspace, because they may represent technologies developed by a possible enemy.
Indeed, most of the discussion at the recent hearing focused on the potential threats posed by UNPs, on the assumption that they are man-made technologies.
None of the public testimony supported the conclusion that alien craft had crashed or visited Earth. The hearings included closed secret sessions that likely dealt with more sensitive security information.
There is no doubt that unexplained phenomena have been observed, such as in the images obtained by US Navy pilots (see video clip above) showing fast-moving airborne objects. However, supporting the hypothesis of the extraterrestrial origin of these objects requires much more substantial and direct evidence, allowing for a large-scale analysis using the tools of science.
The existence of life elsewhere in the universe is a fascinating question for science and society. Therefore, the search for extraterrestrial life is a legitimate action, which is subject to the same evidentiary criteria that apply to all of science.
A drop in an ocean

Scientists have used radio telescopes in extensive studies to search for “technosignatures”, that is, signs of hypothetical technological civilizations on planets in other parts of our galaxy (the Milky Way).
However, after decades of many teams of experts using powerful telescopes, sufficiently large regions of our galaxy have yet to be observed.
If we consider the Milky Way to be equivalent to the Earth’s oceans, then all our efforts over the past few decades would be like taking out a random amount of water that fits in a swimming pool in search of a shark.
Besides, we’re not even sure sharks exist, and even if they did we don’t know what they’d look like or how they’d behave.
While I believe, almost certainly, that there is still living somewhere on the trillions of planets in the universe, the size of the universe is an issue.
What would it take for extraterrestrial contact?

The vast volume of the universe makes it very difficult to achieve interstellar travel, receive signals, or communicate with any potential distant life form (at least according to the laws of physics as we know them).
Speeds are limited to the speed of light, which is about 300,000 km per second. Even at that speed, a signal takes about four years to travel between Earth and the nearest star in our galaxy, which is four light-years away.
Furthermore, Einstein’s theory of special relativity tells us that, in practice, the speed of a physical object such as a spaceship will be less than the speed of light.
Also, signals get weaker in proportion to the square of the distance they travel. At interstellar distances, this is an important limitation.
Consequently, for planets hundreds or thousands of light-years away, the travel time is probably many thousands of years. And any signal coming from civilizations on those planets is incredibly weak and hard to detect.
Hiding the crash of an alien ship on Earth?
Can we believe that aliens have already crashed on Earth and that the US government has covered up this fact, as Republican Congressman Tim Burchett claimed in his reaction to the hearing?
For airlines belonging to the International Air Transport Association, the risk of a plane crash is about one in a million. This begs the question: can we believe that an alien spaceship, which can travel for thousands of years across interstellar distances, is more robust and better designed than our airplanes?
Let’s just say that this hypothetical alien ship is a hundred times better made. Consequently, the risk of an accident would be one in a hundred million.
So for there to be an alien wreck hidden in Area 51, then a hundred million visits by alien ships would have been required. That’s 2,739 extraterrestrial visits per day, every day, for the last 100 years!
So where are the aliens? According to what was shown above, there should constantly be spaceships around the Earth.
With all the radars constantly scanning space, the billions of cameras on cell phones, and the hundreds of thousands of amateur astronomers photographing the sky (as well as professional astronomers with powerful telescopes), there should be plenty of evidence, really good, in the hands of the general public and scientists, not just governments.
It is most likely that the UNPs presented in the “evidence” was staged or caused by natural phenomena that we do not yet understand.
In science, Occam’s Razor is still an excellent starting point: the best explanation is the simplest explanation consistent with the known facts.
Until there is much more and much better evidence, let’s conclude that aliens haven’t visited us yet. However, I hope at some point that evidence will exist.
Until then, I will continue my search for them in the sky vault.