Let’s say you are a high-tech alien civilization that wants to communicate with other civilizations in the Milky Way galaxy. Where would you place your flashlight? Probably close to home, right? The Galactic Center, the crowded, fascinating region around the supermassive black hole Sagittarius A*, is one of the best places in the Milky Way to send broad, repetitive radio signals to anyone who listens.

A group of scientists led by astronomer Akshay Suresh of Cornell University claims to have found a way to look for these signals.

The Breakthrough Listening Research for Periodic Spectral Signals (BLIPSS) project is designed to search for and amplify strange pulsed radio emissions from the galactic center that could be messages from extraterrestrial intelligent organisms.

“BLIPSS demonstrates the software’s superior potential as a science multiplier for SETI,” Suresh explains.

The galactic center is a very dense place filled with stars of all kinds and thick clouds of dust and gas obscuring everything there. There are also natural objects that send repetitive radio signals. But it’s also quite diffuse compared to other parts of the sky; Statistically, it offers the greatest potential as the direction a habitable exoplanet is located, given the abundance of stars in the center of the galactic line of sight.

If we’re going to find an alien signal, this is one of the best places to look, but there are challenges. It is quite a monumental task to isolate an artificial signal from the natural cacophony of light emanating from the galactic centre.

Periodic pulse signals would be an inexpensive way to transmit signals across vast swaths of interstellar space. Here on Earth we use pulsed signals for applications like remote radar sensing and aircraft navigation, but they can be sent much farther if scaled up with sufficiently advanced technology.

BLIPSS uses the fast convolution algorithm, which is a highly sensitive search technique, to identify periodic signals. For example, scientists have used this in the past to look for a type of star called a pulsar that emits periodic pulses of light.

Suresh and colleagues tuned the fast folding algorithm to a different task. Parkes used BLIPSS for radio imaging of galactic center data collected by the SETI Institute’s Breakthrough Listen initiative, which performed 7-hour and 11.2-hour observations of the galactic center with the Murriyang radio telescope in Australia and Green. Bank telescope respectively.

BLIPSS used 4.5 hours of data from the Green Bank Telescope in the 4 to 8 GHz range.

To make sure it could detect the types of signals they were looking for, the researchers tested their software on pulsars, reducing the frequency range to less than a tenth of the range covered by an FM radio station with a pulse frequency. 11 to 100 seconds.

They did not find signals that matched the search parameters, but their efforts have demonstrated the effectiveness of their method and the team is confident they will use them for different search parameters in the future. Source