Wow! A message from an alien civilization?

*This text was written by a TecMundo columnist; finally learn more.

On Monday, August 15, the astronomy community celebrated the 45th anniversary of one of the biggest and most intriguing scientific mysteries of the last century: wow sign!

Few questions in human history have swayed the collective imagination, “Are we alone in the universe?” As it is known, while activating, Wow! .

This story begins in the 1950s, when the era of radio telescopes exploded and the idea of ​​searching for signs of civilization outside Earth began to gain momentum, when these two realities intersected at a joint event.

In the universe, radio waves are produced by accelerated particles from natural sources such as very bright stars, planets, nebulae, pulsars, quasars and even black holes. On Earth, radio waves are more common from artificial sources such as radio towers and cell phones.

Many radio telescope observations focus on a very specific region of the radio spectrum consisting of a wavelength of 21,106 cm and a frequency of 1420.406 MHz. At first glance, these values ​​seem arbitrary, but this region is emitted by hydrogen atoms, the most common element in the Universe.

Therefore, if there is an intelligent civilization within our galaxy, there is good reason to assume it. Milky Way If he wanted to communicate, he could transmit a strong signal of the same frequency (or close to it) to the so-called hydrogen line.

Then the search was about to begin. In 1956, construction of a large radio telescope began: the Ohio State University Radio Observatory, affectionately called the “Big Ear.”

Big Ear, the size of three football fields, was equivalent to a parabolic telescope with a diameter of 52.5 meters. A flat, curved reflector covered with aluminum foil was set at altitude above the horizon and received radio signals at one end, while a parabolic reflector at the other focused the beam.

The telescope remained stationary and used Earth’s own rotation to scan a narrow circular path across the sky each day, so that every single part of the sky could be seen for just 72 seconds.

In 1973 Big Ear was assigned full-time to the SETI (Extraterrestrial Intelligence Search) program aimed at searching for intelligent life in the Cosmos, and 4 years later, Wow! detected between observations.

On August 15, 1977, American astronomer Jerry R. Ehman volunteered for the SETI project while performing routine manual analysis of large volumes of observations on the IBM 1130 computer, while examining the data collected on August 15, he found a series of signal strength and frequency values ​​that astounded him and his colleagues!

Jerry quickly circled the mark phrase on the printed page and said, “Wow!” scribbled his exclamation point. at its limit. It was a strong signal originating close to M55, a globular star cluster in the constellation Sagittarius.

The strength and physical properties of the signal showed no indication that it originated from a natural source in the Universe, raising the expectation that its source could be intelligent, raising the signal to the category of the best candidate for an alien signal. . already discovered.

Over the next few years, several attempts were made to re-record the signal by various radio telescopes around the planet, but none were successful: the signal was never detected again.

Therefore, astronomers have put forward several natural-source hypotheses to explain the detection, from the suggestion that the signal comes from a hydrogen cloud around two comets to bright stars near the spot in the sky.

Unfortunately, we may never know the true origin of Wow, unless the signal is detected again! And while its origins are thought-provoking (and even appealing to our imaginations), its origins cannot be said much more.

Anyway, we keep looking at the stars.

Nicolas Oliveira, columnist TecMundoHe holds a diploma in Physics and a master’s degree in Astrophysics. Professor and currently doing his PhD working with galaxy clusters at the National Observatory. He has experience in Teaching Physics and Astronomy and researching Extragalactic Astrophysics and Cosmology. He works as a scientific dissector and communicator for the dissemination and democratization of science. Nicolas is found on social networks as: @nicooliveira_.