IT don't call, send mail

A new approach in the search for life in space: sending spacecraft instead of radio waves

  
Is this the best way to search for life in space? The radio telescope in Arecibo.

It is possible that an alien spaceship, carrying a message to us, resides somewhere in the solar system, scientists write in the journal Nature.
To date, it has been considered that the best way to discover aliens is to search for radio signals, which can cover vast distances. Now researchers from the United States claim that sending a spacecraft into space is a much more effective way.
A recent probe looked at radio signals from 800 stars, but no sign of extraterrestrials was detected. The search for life in space advanced into the modern era in 1959 with the publication of an article by Giuseppe Cocconi and Philip Morrison of Cornell University in the journal Nature.
In the article, the researchers claimed that radio telescopes, which are built to monitor natural radio wave sources, can be used to search for alien signals. According to a certain estimation method, radio waves are the best way to transmit information at interstellar distances.
Furthermore, there are frequencies that make sense to use. The "Water hole" region is a calm region in the radio wave spectrum, where the emission line of the hydrogen atom stands out. Considering the connection between water and life, the waterhole area may be a spectral meeting place for different species.
Since 1959, many searches have been conducted, most of them in the area of ​​the water pit. Everyone brought up pottery. Experiments were also conducted, looking for laser flashes, which may also be an effective way to transmit messages from star to star.
Christopher Rose (Rose) from Rutgers University and Gregory Wright (Wright) from the Antiopi Society, both American researchers, present a new explanation for the lack of success in the search for extraterrestrial signals in the field of radio waves.
They claim that in many cases it makes more sense to send a spacecraft carrying a message to other stars than to send a beam of radio waves. For long messages, their "packaging" method is more efficient, as it requires less energy for each bit of information transmitted.
Their work reopens a line of research, neglected by the alien hunters. They thought that the energy needed to build and launch a "letter in a bottle" is much greater than the energy needed to transmit signals on radio waves.
The possibility of an alien spaceship hidden in our solar system is one of the staples of science fiction.
Arthur C. Clark used the idea in his 1951 book "2001: A Space Odyssey", in which an alien monolith is described, discovered on the moon. The book was the source of inspiration for the 1968 film, bearing the same name.
Maybe it's not science fiction after all.

translating:
Dikla Oren

A message to aliens? The radio waves are ineffective, it's better to send them a bottle

By Yuval Dror

A message to the aliens, sent aboard the Pioneer 10 spacecraft out of the solar system
The search for extraterrestrial intelligent life began more than 45 years ago, by scientists who concluded that the best way to communicate with aliens was through radio waves. For this reason, they argued, the radio telescopes on Earth should be used to try and listen for signals that might be sent to us from outer space and send our own signals to the stars.
The bad news is that so far no signal has been received. The even worse news is that apparently no aliens picked up the signals we sent their way. The particularly bad news is that a pair of American scientists claim that the method of communication based on radio waves is ineffective, and if we want to be sure that the aliens know we are here - it is better to send them a package.
The search for intelligent life in outer space is complex - no one knows if there is intelligent life outside the earth and even if it does exist, it is difficult to guess what means of communication would be useful to communicate with them. It is estimated that aliens will want to contact us through radio signals, but we do not know which direction our "ears" should be directed, to which frequency they should be tuned and if we will be able to decipher the messages when they arrive - if they arrive.
And what, then, is the best way to send radio signals to the aliens to announce that "we are here"? Christopher Rose and Gregory Wright, from the Department of Electronics and Computer Engineering at Rutgers University, tested whether the radio wave transmission method was good for the task. They published the results of their research in the journal "Nature". According to them, even though radio waves, laser rays and X-rays travel at the speed of light, the greater the distance they travel, the more they lose energy and scatter, and therefore the message becomes unclear. "Think of the beam of a flashlight," Rose tried to explain: "The intensity of the light decreases as you move away from the source."
In addition, from an economic point of view, the ability of humans to send radio waves in every possible direction is almost zero, due to the enormous energy that must be invested in sending radio rays into outer space. And what about the listening alien? If we transmitted the signal for five minutes and then stopped, who guarantees that precisely in those five minutes the alien is listening?
For these and other reasons, the team of scientists claims that if they were asked, they would suggest IT (from Steven Spielberg's film) - to write and not to call. Of course, IT's case was urgent and that's why he chose to call, and this is exactly Rose and Wright's claim. "The starting point of the previous works was to establish contact as quickly as possible. However, if we eliminate the need for speed, we come to the conclusion that the first contact with aliens will be made after they receive an actual item from us, such as a message in a bottle, and not an electromagnetic message."
According to them, a package sent into space is not "diluted" like radio waves over time. From a calculation whose value increases, it is possible to engrave all the information that exists on the surface of the earth on the surface of a cube that weighs one gram (provided that the engraving is done at the nanometric level). Although it will be necessary to ship the cube in a rigid, heavy and large package to protect it from radiation and the ravages of space, in the long run shipping will be cheaper and more efficient.
The two stated that it is likely that the aliens also understand this, and therefore it is possible that a similar message sent to us from the aliens is somewhere on Earth and we simply did not notice. This is of course the main problem with Rose and Wright's proposal, because who guarantees that the aliens will know how to open the box we sent them, pick up the cube and realize that all the human information is engraved on it? And in general, do we want to start our relationship with the outside world by throwing boxes on the heads of the residents?