Astronomers have so far discovered approximately 6000 external planets – the world of the orbit stars other than our sun. If this number already feels ridiculous, it is better to prepare for yourself: through induction, there can be hundreds of Billions From the planets in our galaxy alone. Some of them will be like the ground, although we are not yet known what this fracture is. However, with the total of this huge, even a small part can result in many housing planets.
For this reason, most scientists take the idea of life in other worlds seriously. Life arose here very quickly – effectively once the Earth cools enough for the port of the ocean – which means that it is easy to start as soon as the conditions are Clement. However, the timing of the appearance of high features dangerously, such as intelligence and technology, is a different question and often shortens us to speculation (though this is There were some interesting investigations). But let’s say that now, there We are Intelligent foreigners and technological civilizations there, somewhere in the Milky Way.
Can they discover us?
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Drafting this way, in the most general sense, the answer is “yes”. I mean that there is no physical reason because it was unable to build a massive telescope, one of which is much larger than any place currently, it will be able to take a detailed picture of a planet from a large years away from light years away. The engineering task may be great, but it is not Technically impossible. After that, it may be just seeing the city lights at night, for example, to confirm foreigners – that is, we, Because we will be strange they-It comes out.
In fact, it may be easier than that. A much smaller telescope does not need to dissolve the planet; You only need to monitor this well enough to see it becomes brighter and Dimmer because the city lights are spinning inside and out of attention may be good enough. And this “smaller” telescope should be only, oh, let’s say, hugely ridiculous instead by an overwhelming majority.
The reason for wondering about this is that it turns the text program as usually required, and this is how we Can be discovered they, Looking at our current technology level. We cannot know their level in advance, but we know our king – so it makes sense to assume that their technology is equivalent to our duties and then asking about the distance they can discover for us.
This task is really difficult. The space is large, and vast distances weaken even the most powerful civilizations. But we can use us as a template and work back to estimate the external boundaries of any listening between the stars on our loud world by foreigners who use a similar technology.
A team of astronomers, headed by Sofia, Sheikh from the City Institute, managed the numbers and published its results in Astronomical magazine. (Seti symbolizes the search for intelligence outside the planet.) Researchers looked at different ways to discover various technology, and the answer depends on an amazing way on any specific person who will be searched for any foreigners. Many of these ideas have been investigated individually, but this recent analysis is examined collectively and consistently to reach some new ideas.
One example of technology is the radio. Since its inception in the mid -twentieth century, City Focus on discovering artificial radio signals from space. It is easy to create radio waves and discovery, and it can pass a speed of light through the space between the stars that hardly hinder any gas and dust that may be on the way. This makes the radio almost perfect for galaxy range.
Astronomers divided radio signals into four categories: first, pointed but intermittent broadcasts into space, mainly messages “We are here”; Second, the deliberate and continuous targeted signals have been sent to our planetary investigations in the deep space that continue in the galaxy; Third, the ongoing signs in the direction of kidney, such as “leakage” of emissions from mobile phones, in addition to radio and television stations; And the fourth, signals of artifacts, such as low -energy descending links from our planetary investigations.
It is not surprising, signals can be discovered in the first category far away because the force involved in the transmission is the highest. The Sheikh and her colleagues estimate that it can be monitored in 12,000 amazing light years of Earth! This is a maximum, but several Bilon The stars lie in their size. If you want to find it, this may be the way to go.
Other methods are not practiced as well. For the second category, the maximum distance is similar to 65 light years, which still contains thousands of stars. Only the third category comes out to four light years, which is not even the closest star to the sun. (This star, Proxima Centauri, is 4.25 light -year -old). The fourth, which will include signals from our spacecraft, such as the Voyageer 1 probe, have a detection limit less than a light year. This surprised me in reality, given how weak the signal is now, when the spacecraft is “only” about 25 billion km away. Voyager 1 sending 23 watts It is already afraid of less than a billion billionAs we saw from our world!
It is clear that the radio is the way to choose for foreigners looking for the Earth. But there are other signatures.
One of the results of our modern civilization is a fingerprint in Jonah. Besides carbon dioxide, a few other chemicals were thrown into the air by the industry and other human resources. Changing our planet’s climate is not great, at the very least, but it makes a signature discovered from space. This signature can be particularly evident for the observer between the stars along the eclipse in our solar system, which is the Earth’s orbit around the sun: from this perspective, they will see that our planet passes in front of our star once every year, its light disrupts slightly. This is called transit, and it was the most successful way to discover external planets.
Such crossings can also be used to analyze the air in the world from a distance. Since the light of the stars (or in our case, the sun) passes through the upper atmosphere of the planet, some wavelengths of light will be absorbed by the molecules there, creating a mark of the species that can be measured. We are already doing it for some transit external planets with James Web Telescope (JWST). The proposed future telescopes such as the NASA Observatory in the Worlds Observatory aims to wipe the atmosphere of dozens of external planets that can resemble Earth and that may exist around the nearby stars (even if they do not wander, as shown in our solar system!).
In their new studies, astronomers focused on the SETI Institute on revealing a dimension of nitrogen dioxide, or not2A clear secondary product for burning fossil fuels. Looking at the current levels in the contaminated air, they found that we can discover this signature of 5.7 light years. Only Alpha Centauri is within this range, which limits the options of any foreigners to inhale us. However, it is an impressive technological achievement to be able to do this type of research at all.
Most other types of fare technosinoin are worse. JWST cloning can be discovered somewhere near the orbit of Neptune, infrared heat that stems from our cities, but this corridor is increasing cold. About 100 times from this distance, the visual shine of the lights of the Earth City will fade to black – but it is still much lower than our Next star.
It is easier to discover the laser and is already tested by NASA and the European Space Agency at the present time to communicate via satellite in space. However, in light of reasonable assumptions, the laser beam of concentrated light will be very dim that cannot be discovered from a distance less than six light years, which is not enough to be monitored even in the Bernard star, which is the second most stars system next to us.
The worst searches for technological artifacts outside the world include. For example, the Earth’s swarms of satellite change the amount of sunlight slightly in the blocks of our planet during the crossing, but it is not enough until it can be discovered from Mars. It suffices to say that if foreigners are close enough to see such things, there will be much easier ways to discover us.
All of these numbers come with a great warning that foreigners are not more technically advanced than we are. This may be very conservative because, after all, we are more advanced all the time. We continue to build larger telescopes, limited to budget and physics laws, and still finding and developing new ways to investigate the universe, such as the discovery of neutrons and gravitational waves. We have only done what “hadith” astronomy can be called for a century or so, and it is difficult to predict our place 100 years. The galaxy has been in billions of years ago. No one can say who shares it with us or what they use to explore. the truth He is There, transforming our search for foreigners from the inside to the outside – by looking from the outside – it is best to tell us how to find it.