Which part of sky are astronomers now zeroing in to catch alien signals?

In an effort to find extraterrestrial life, scientists have started to observe a region in the core of our galaxy — which is dense with stars — to detect a specific type of signal which only intelligent aliens can produce, reported Reuters Wednesday.

The region was previously ignored as the scientists have earlier focused on a narrowband radio signal type in a limited frequency range or on single unusual transmissions.

According to the scientists Wednesday, "the new initiative focuses on a different signal type that perhaps could enable advanced civilisations to communicate across the vast distances of interstellar space."

The pulse signals have repetitive patterns in which a series of pulses are repeated every 11 to 100 seconds and spread across a few kilohertz, similar to pulses used in radar transmission.

The scientists maintained that the search involves a "frequency range covering a bit less than a tenth the width of an average FM radio station."

Akshay Suresh, a Cornell University graduate student in astronomy said: "The signals searched in our work would belong to the category of deliberate 'we are here' type beacons from alien worlds."

"Aliens may possibly use such beacons for galaxy-wide communications, for which the core of the Milky Way is ideally placed. One may imagine aliens using such transmissions at the speed of light to communicate key events, such as preparations for interstellar migration before the explosive death of a massive star," Suresh added who is also a lead author of a paper published in the Astronomical Journal.

The efforts to find aliens is called the Breakthrough Listen Investigation for Periodic Spectral Signals (BLIPSS), which is a collaboration between Cornell, the SETI Institute research organisation and Breakthrough Listen, a $100 million initiative to search for advanced extraterrestrial life.

Astronomer and co-author Vishal Gajjar of the SETI Institute and University of California, Berkeley, said: "In the realm of searching for extraterrestrial intelligence, or SETI, we embark on a journey to detect signals from technologically advanced extraterrestrial civilisations."

Gajjar also added: "However, the nature of these signals remains a mystery, leaving us uncertain about their specific characteristics. Hence, it becomes crucial to explore a diverse array of signals that are unlikely to occur naturally in the cosmic environment."

How scientists are searching for aliens?

Using a ground-based radio telescope in West Virginia, BLIPSS has focused upon a sliver of the sky less than one-200th of the area covered by the moon, stretching toward the centre of the Milky Way roughly 27,000 light years away. A light year is the distance light travels in a year, 5.9 trillion miles (9.5 trillion km).

Suresh maintained that this area contains about 8 million stars. 

If extraterrestrial life forms exist, they presumably would populate rocky planets orbiting in what is called the habitable zone, or Goldilocks zone, around a star — not too hot and not too cold.

The scientists in the various monitoring efforts passively scan for signals of alien beings and do not actively send their own signals advertising our presence on Earth.

"In my opinion, the transmission of 'we are here' type beacons comes with the danger of potentially inviting aliens with unknown intentions to the Earth," Suresh remarked.

"Deliberate transmissions to potential aliens from Earth should be considered only if by global consensus humankind deems it safe and appropriate," Gajjar said.

"In my personal opinion, as a relatively young species on the grand cosmic scale, it would be prudent for us to focus on listening and investigating before embarking on deliberate transmissions," Gajjar said.

"Furthermore, it is crucial to recognise that sending signals on behalf of the entire Earth raises political and ethical considerations. Presently, it would not be appropriate for a single country or entity to make decisions on behalf of the entire planet."

"Thus far, we have not come across any definitive evidence. However, it's important to note that our exploration has been limited to a relatively small parameter space," Gajjar said.