The universe is like a lonely place.
We know that an intelligent civilization (yes, civilization) is possible-we prove it-. Finding signs of other civilizations in the Milky Way galaxy is not so easy, but we have free tools. Based on our own technology, we can estimate the signals that alien technology may emit and search for them.
These signs are called techno signatures, and our efforts in the search for extraterrestrial intelligent life (SETI) revolve around them, especially at radio wavelengths.
“One of the great advantages of searching for techno signatures by radio wavelength is that they are sensitive to signals emitted from thousands of light-years away and consume less power,” said the University of California, Los Angeles. Astronomer Jean-Luc Margot said. Angels told Science Alert.
“For example, our search can detect Arecibo planetary radars over 400 light-years away, and can detect transmitters that are only 1,000 times more powerful than Arecibo. This is a trivial matter of advanced civilization. It’s an improvement. It’s all the way to the center. It’s a galaxy. The amount of galaxies that can be sampled by wireless search of techno signatures is huge. “
Margot and his team recently searched for technical signatures using the Green Bank Telescope, a powerful radio telescope in West Virginia.
In April 2018 and 2019, with a total of four hours of observation time, they reduced to 31 sun-like stars around the galactic plane and detected a total of 26,631,913 candidate techno signatures.
A closer analysis of the data revealed that all of these candidate technical signatures were generated here on Earth.
However, the methods used to process these data identify potential alien techno signatures and pin them from background humming or ping of artificial radio noise (so-called radio frequency interference or RFI). This is an important step to bring out. Navigation technology, satellite technology, mobile phones, microwave ovens, aircraft, communications; we are constantly immersing our surroundings in high frequency radiation.
“RFIs have the potential to obscure extraterrestrial signals,” Margot said. “The RFI makes the job more difficult because it detects tens of millions of signals per hour in the telescope, and we need to make decisions about every signal. Is it artificial or extraterrestrial life? Is it a body?
“It’s much easier to detect only a few signals. Fortunately, the algorithm can automatically classify over 99.8% of the signals.”
The team has made some improvements to the data processing pipeline, improving sensitivity and signal detection rates, and the filters used to automatically classify RFI signals in the data, excluding them as alien technical signatures. did.
As Margot pointed out, these filters correctly flagd 26,588,893 (99.84 percent) of the signal as an artificial RFI. Even if you process a very large number, you still have a lot of data to process. In this case, it was a 43,020 signal.
Most of these remaining signals were within the known RFI range and were classified accordingly. It left 4,539 signals as the most promising alien techno signature candidate. These had to be carefully and visually inspected-and everything was ultimately determined to be of human origin.
“If the signal is detected in multiple directions in the sky, we can be very confident that it is artificial,” Margot said. “Extraterrestrial signals from emitters at interstellar distance are detected in only one direction.”
The result is not unexpected. Searching for 10 million stars, a much larger sample of stars earlier this year, showed no signs of alien technology. But that didn’t really matter. Or at least not the only point.
First, Margot uses SETI data processing as a tool for training students at UCLA.
“We’ve been searching as part of the SETI course we teach at UCLA every year since 2016. This course seems to be unique not only in the United States, but probably around the world,” he explained.
“Students collect terabytes of data from known or suspicious planetary systems, collaborate on data processing pipelines, search for technical signatures in the data, and publish the results. Students acquire important skills. Witnessing to do is the most satisfying. Of this important search. “
The team’s sophisticated pipeline also revealed some issues with previous attempts to process SETI data. More specifically, we try to quantify how many transmission civilizations may exist in the Milky Way galaxy. Their results show that these estimates can be up to 15 times lower because the data processing pipeline “cannot detect some of the signals designed to detect”.
“We have implemented a signal injection and recovery analysis tool that can quantify the efficiency of the data processing pipeline. This efficiency must be taken into account when limiting the number of civilizations to send.”
The team pipeline has some limitations. If the two signals intersect, the algorithm only gets the signal with the highest signal-to-noise ratio. You may also miss a faint signal to high levels of background noise. This means that signal recovery may be reduced in areas of high signal density.
Overcoming these limitations could be the focus of future work. But it’s a rewarding job. RFI is a problem for all radio astronomers, not just SETIs, making it impossible to make some measurements from Earth. Therefore, scientists are looking for a radio telescope behind the moon. The moon acts as a natural cushioning material against artificial radio interference.
And, of course, it could detect something-slightly but not zero-.
“Search may answer one of the deepest scientific questions of our time: are we alone?” Margot told Science Alert.
“All life on Earth is associated with a common ancestor, and the discovery of other forms of life revolutionizes the understanding of our life system. At a more philosophical level, it is of humankind in space. It will change the perception of position. “
The study was accepted Astronomical Journal, And available on arXiv.
This article was originally published by ScienceAlert..Read the original article here..
Astronomers detect millions of signals from intelligent civilizations: us
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