What if time only exists on earth

Is there extraterrestrial life in space

If it is believed possible that there are other technically advanced civilizations in space, how can we find out? In order to clarify the question, researchers have been trying to systematically receive extraterrestrial signs of life since the 1960s with so-called SETI projects. SETI is the abbreviation for “Search for Extra-Terrestrial Intelligence”, which could be translated colloquially as “Alien manhunt”.

The researchers use radio telescopes for this, some of which have receiving dishes several hundred meters in size. This makes them so sensitive that they could also pick up extremely weak radio signals. In the meantime, the Russian-born Silicon Valley billionaire Yuri Milner has also started the search for extraterrestrial intelligences. With his “Breakthrough Lists” project, he finances scientists who, in addition to radio signals, also search for laser signals.

Because even with this, technically highly developed civilizations could communicate over long distances in space. Despite all efforts, no extraterrestrial message has yet been picked up - with one potential exception.

The wow! - signal

On August 15, 1977, the astronomer Jerry Ehman evaluates the reception data from the radio telescope at Ohio State University and can hardly believe his eyes: In the printouts, a signal stands out from the usual noise: it is exceptionally strong and only covers a narrow frequency range, so like a radio station broadcasts only on a certain frequency. Jerry Ehman is so amazed that he writes “Wow!” On the printout, hence the name.

Did it come from aliens now? In theory, that could be true, but unfortunately the technology at the time was not sensitive enough. The signal was therefore too noisy to make a decision. It could also come from a previously unknown astronomical event or from Earth. But even these alternative explanations are not entirely convincing. No other signal of this type has been received so far.

The big filter

At the end of the last century the idea of ​​the "big filter" came up. It says that a lot of steps have to be overcome in order for a civilization to arise and then to live long enough to make itself felt in space: First there has to be a suitable planet, then primitive life has to arise on it, which then develops developed from the single-cell stage to multicellular cells.

From these animal-like beings would then have to emerge, who learn to use tools and who develop their mastery of technology so that they create a highly developed civilization. This would have to last long enough for it to invent the technology that allows it to communicate beyond its planet. After all, this civilization might even leave its home planet to expand into space.

Which of these is unlikely?

Each of these steps could be the “Great Filter”, a kind of barrier that prevents the emergence of galaxy-populating civilizations. Because if just one of these steps is extremely unlikely, that could explain why we haven't encountered extraterrestrial life yet.

Perhaps the emergence of primitive forms of life is extremely unlikely, or the use of tools or another step towards a civilization colonizing space. The last possible “filter” would be that technically advanced civilizations only have a limited lifespan because something causes them to inevitably self-destruct after a relatively short period of time.

Are we maybe destroying ourselves?

In our case it is not clear whether we have already made it with the emergence of intelligent life and have passed the “big filter” or whether the big hurdle is still ahead of us. Then our big challenge lies in not destroying our livelihood ourselves if we don't want to perish again soon.

The next generation of space telescopes could provide an answer to whether the “Great Filter” is already behind us or still ahead of us. Because if we catch many signs with them from other technically highly developed civilizations, that would be a positive sign. That would mean that we have already overcome the toughest step in the emergence of intelligent life. So we would have the potential to continue for a very long time.

But if we find primitive life on other planets without encountering technically developed civilizations at the same time, the conclusion would be depressing. That would mean that the emergence of life in space is relatively frequent, but that civilizations developing from it quickly self-destruct. Otherwise you would have to find a lot of them.