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, Reuters reported.

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, read the report.

“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, Reuters reported.

“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.

A North Korean satellite launch on Wednesday ended in failure, sending the booster and payload plunging into the sea, North Korean state media said, and the South’s military said it had recovered parts of the launch vehicle, Reuters reported.

The new “Chollima-1” satellite launch rocket failed because of instability in the engine and fuel system, state news agency KCNA reported.

The flight was the nuclear-armed state’s sixth satellite launch attempt, and the first since 2016. It was supposed to put North Korea’s first spy satellite in orbit.

It prompted emergency alerts and brief evacuation warnings in parts of South Korea and Japan. The notices were withdrawn with no danger or damage reported.

South Korea’s Joint Chiefs of Staff said on Wednesday the military was conducting a salvage operation to recover what is believed to be parts of the space launch vehicle. The military shared pictures of debris pulled from the water.

Officials from the United States, Japan, South Korea held a phone call, where they “strongly condemned” the launch, Japan’s foreign ministry said.

“The three countries will stay vigilant with high sense of urgency”, the statement said.

North Korea had said it would launch its first military reconnaissance satellite between May 31 and June 11 to boost monitoring of U.S. military activities.

South Korea last week placed satellites in orbit with a domestically designed and produced rocket for the first time, and China sent three astronauts to its space station as part of crew rotation on Tuesday, read the report.

The rocket plunged into the sea “after losing thrust due to the abnormal starting of the second-stage engine,” KCNA reported, in an unusually candid admission of a technical failure by the North.

Pyongyang’s National Aerospace Development Administration (NADA) will investigate the “serious defects” and take action to overcome them before conducting a second launch as soon as possible, KCNA said.

In data provided to international authorities, North Korea said the launch would carry the rocket south, with stages and other debris expected to fall over the Yellow Sea and into the Pacific Ocean.

Air raid sirens wailed across the South Korean capital of Seoul about 6:32 a.m. (2132 GMT Tuesday) as the city warned citizens to prepare for a potential evacuation. Later alerts said the city warning had been a mistake.

“I was so panicked. Nine-one-one lines were busy and the internet was slow,” said Lee Juyeon, 33, a resident in the city of 9 million who was preparing to shelter in a basement with her young child before learning it was a false alarm.

Calm quickly returned in Seoul, while South Korean stocks (.KS11) and the won currency traded firmer.

The Japanese government also issued an emergency warning over its J-Alert broadcasting system for residents of the southern prefecture of Okinawa to take cover indoors early on Wednesday morning.

It later said the rocket would not fly into Japanese territory and lifted the warnings.

On Tuesday, Ri Pyong Chol, vice-chairman of the Central Military Commission of North Korea’s ruling Workers’ Party, said ongoing joint military exercises by the U.S. and South Korea required Pyongyang to have the “means capable of gathering information about the military acts of the enemy in real time.”

The White House condemned a launch using ballistic missile technology and said in a statement it was assessing the situation in coordination with allies, Reuters reported.

Japan’s Chief Cabinet Secretary Hirokazu Matsuno said North Korea’s rocket disappeared from radar above the Yellow Sea and did not make it into space, and added the government had no further information to share now.

“We strongly condemn North Korea’s actions,” he said. Tokyo lodged a complaint to Pyongyang through diplomatic channels in Beijing, he said.

Before Wednesday’s launch, the U.S. State Department said any North Korean launch that used ballistic missile technology would violate multiple United Nations Security Council resolutions.

“Space launch vehicles (SLVs) incorporate technologies that are identical to, and interchangeable with, those used in ballistic missiles, including intercontinental ballistic missiles,” a State Department spokesperson said.

North Korea has attempted five other satellite launches, with two placed in orbit, including during its last such launch in 2016. Its capacity for constructing working satellites remains unproven, however, analysts say.

“To the best of our knowledge, North Korea has a very limited capacity to build satellites,” said Brian Weeden of the Secure World Foundation, a U.S.-based space policy and security organisation. “They have launched a couple of satellites before, but all of them failed immediately after launch or shortly thereafter and none of them appeared to have any significant capability.”

North Korea will launch its first military reconnaissance satellite in June for monitoring U.S. military activities, state media KCNA reported on Tuesday.

In a statement carried by the KCNA news agency, Ri Pyong Chol, vice-chairman of the Central Military Commission of the ruling Workers’ Party, denounced joint military exercises by the United States and South Korea as openly showing their “reckless ambition for aggression.”

U.S. and South Korean forces have carried out various training exercises in recent months, including what they said were the biggest joint live-fire exercises last week, after many drills were scaled back amid COVID-19 restrictions and hopes for diplomatic efforts with North Korea, Reuters reported.

North Korea’s Ri said the drills required Pyongyang to have the “means capable of gathering information about the military acts of the enemy in real time.”

“We will comprehensively consider the present and future threats and put into more thoroughgoing practice the activities for strengthening all-inclusive and practical war deterrents,” Ri said in the statement.

Nuclear-armed North Korea has said it has completed development of its first military spy satellite, and leader Kim Jong Un has approved final preparations for the launch, read the report.

The statement did not specify the exact launch date, but North Korea has notified Japan of the planned launch between May 31 and June 11, prompting Tokyo to put its ballistic missile defences on alert.

Japan has said it would shoot down any projectile that threatens its territory, Reuters reported.

“(North Korea’s) satellite launches incorporate technology that is almost identical and compatible with those used for ballistic missiles, and regardless of the designation used by North Korea, we believe that the one planned for this time also uses ballistic missile technology,” Japan’s Chief Cabinet Secretary Hirokazu Matsuno said on Tuesday.

A U.S. State Department spokesperson said on Monday any North Korean launch that uses ballistic missile technology, including those used to put a satellite in orbit, would violate multiple United Nations resolutions.

The launch would be the North’s latest in a series of missile launches and weapons tests, including one of a new, solid-fuel intercontinental ballistic missile last month, read the report.

Analysts say the satellite will improve North Korea’s surveillance capability, enabling it to strike targets more accurately in the event of war.