Scientists have expanded the search for technologically
advanced extraterrestrial civilizations by monitoring a star-dense region
toward the core of our galaxy for a type of signal that could be produced by
potential intelligent aliens that until now has been ignored.
Efforts to detect alien technological signatures previously
have focused on a narrowband radio signal type concentrated in a limited
frequency range or on single unusual transmissions. The new initiative,
scientists said on Wednesday, focuses on a different signal type that perhaps
could enable advanced civilizations to communicate across the vast distances of
interstellar space.
These wideband pulsating signals for which the scientists
are monitoring feature repetitive patterns – a series of pulses repeating every
11 to 100 seconds and spread across a few kilohertz, similar to pulses used in
radar transmission. The search involves a frequency range covering a bit less
than a tenth the width of an average FM radio station.
“The signals searched in our work would belong to the
category of deliberate ‘we are here’ type beacons from alien worlds,” said
Akshay Suresh, a Cornell University graduate student in astronomy and lead
author of a scientific paper published in the Astronomical Journal describing
the new effort.
“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.
The effort, called the Breakthrough Listen Investigation for
Periodic Spectral Signals (BLIPSS), is a collaboration between Cornell, the
SETI Institute research organization and Breakthrough Listen, a $100 million
initiative to search for advanced extraterrestrial life.
“In the realm of searching for extraterrestrial
intelligence, or SETI, we embark on a journey to detect signals from
technologically advanced extraterrestrial civilizations,” said astronomer and
study co-author Vishal Gajjar of the SETI Institute and University of
California, Berkeley.
“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,” Gajjar added.
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 center 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).
This area contains about 8 million stars, Suresh said. 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, transmission of ‘we are here’ type beacons
comes with the danger of potentially inviting aliens with unknown intentions to
the Earth,” Suresh said.
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 in
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 recognize 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.”
No aliens yet have been detected in the monitoring efforts.
“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.
Source : Reuters
- Agencies
