Our search for technosignatures – clear signs of advanced civilizations beyond Earth – takes many forms. Many are driven by the famous Drake equation, which attempts to estimate how many technological civilizations there are in the Milky Way. However, there’s a big fat question mark at the end of that equation in the form of a variable intended to account for the “longevity” of a civilization. And to be clear, that doesn’t mean how long the civilization itself survives. It simply means how long it actively creates a signature that is detectable by our current technology. A new paper, available in pre-print on arXiv from Oxford astrophysicist Brian C. Lacki, argues that, since the chances of us overlapping in time with any such civilization are miniscule, we’re much more likely to find the ruins of a “dead” civilization – and, surprisingly, the best place to do so might be in our own solar system.

A fundamental part of this argument is driven by Earth’s own history. Up until now, SETI has focused on receiving “passive” signals from beyond the solar system, typically in the form of radio waves. However, even on Earth, our own “window” of sending radio signals into the vastness of space only lasted for around 100 years. We are actively eliminating most wide-broadcast radio signals in an effort to improve our communications infrastructure. So, in other words, even our own civilization isn’t bothering to maintain what minimal intentional broadcasts we were producing 50 years ago.

Instead, the argument goes, it’s better to find “passive” technosignatures, such as relics that require literally no upkeep and can last for billions of years. That would eliminate the need for “constant maintenance” of a radio transmitter or high-powered laser, and would make us much more likely to find the types of civilization that could, at least at one point in time, support that.

Fraser discusses our current search for technosignatures.

So what would such a “passive technosignature” look like in practice? Dr. Lacki breaks them down into three categories – diffusers, occulters, and glinters. From our perspective, occulters would be visible from its unnatural dimming pattern, which would appear similar to a transiting exoplanet, but clearly not the same. Glinters, on the other hand, feature gigantic mirrors that can focus or reflect starlight over thousands of light years, appearing as anomalous “lens flares” near their host star. Diffusers scatter light nearly isotropically, creating a faint signal that might reflect an unusual color or polarization.

Any of these systems is entirely passive, and requires no active role from their creators whatsoever. However, simply building enough of them will indeed require some form of maintenance. A Dyson Swarm is certainly within the capabilities of the types of civilizations being considered in this paper, but maintaining the orbital mechanics of such a swarm does involve active intervention, even though it’d be much less than an active radio transmitter.

Without such support, the components that make up the Dyson swarm would inevitably be drawn together via gravity, eventually colliding and creating what Dr. Lacki calls “technograins”. This destruction could even be accelerated by a “chain reaction” effect similar to Kessler syndrome here in Earth’s orbit, with each additional collision creating yet more debris to create yet more collisions. Do this enough times and even an alien megastructure can be ground down to micron-scale dust.

Fraser talks technosignatures with Dr. Jacob Haqq-Misra

Once small enough, these technograins might gain a trip out of its host solar system by a solar wind that overcomes the star’s gravity holding it back. These motes of dust are then free to roam the galaxy, escaping any long term confinement to their host star. That’s where the other interesting idea from Dr. Lacki’s paper comes in.

Our solar system isn’t stationary in comparison to the galaxy. As it orbits the Milky Way, it routinely sweeps through interstellar material, some of which might be made up of pulverized technosignatures. Even if that material swept into our galaxy billions of years ago, inactive worlds like the Moon could preserve it from that original time all the way down to now. In other words, researchers could screen Moon dust for signatures of extinct megastructures.

Ultimately, what the paper points out is that we don’t need bigger and better space telescopes to continue our search for technosignatures. Instead we might be able to find it by sifting through the regolith on our closest neighbor. And if we do find any, it will bring new meaning to the phrase “dust to dust” – since there will be a completely different form of intelligence handling the dust that came from a completely different civilization.

Learn More:

B. C. Lacki – Dust to Dust: Prospects for Passive Technosignatures as Relics of ETI

UT – Galaxies with High Radio Emissions Could be Home to Many Advanced Civilizations

UT – Breakthrough Listen Releases its one-of-Everything “Exotica” Catalog

UT – The SETI Institute Releases Technosignature Report on 3I/ATLAS

A celebration of the New York Knicks’ NBA championship ended in tragedy for a Canoga Park woman this weekend after police officers fatally shot her dog, sparking public outrage.

A video circulating on social media shows a woman sobbing in the hallway of an apartment complex, hugging her dog, who was wearing a New York Knicks T-shirt, as six L.A. police officers stood by.

“The Knicks just won a championship, we were so happy,” she yells out, petting her dog.

Shortly after, the video shows her yelling out the name Jeremiah. Her family said she was yelling out the name of her son, who was on the phone in a video chat with her when the shooting happened.

The Los Angeles Police Department said in a written statement that the shooting occurred Saturday shortly before 9 p.m. in the 7500 block of Jordan Avenue.

Police said officers responded to a call about a “screaming woman” and were directed to an apartment unit.

“The officers contacted the resident in the apartment unit; while speaking with the resident, a large dog was by her side barking at the officers,” the statement read. “The officers asked her to secure the dog, and the resident closed her door momentarily. She re-opened the door, and the dog exited the apartment.”

LAPD said officers shot the dog when it charged at one of them.

In the video, neighbors can be heard angrily admonishing police officers for killing the dog while the woman, identified as Marie Marseille, held the animal, crying.

Marseille could not immediately be reached for comment.

In a phone interview with The Times, the dog owner’s sister, Vanessa Marseille, said the family was shocked and devastated over the shooting death of the dog, Jameson.

“We just don’t know why it happened,” she said. “What’s more scary is that those shots could have hit her or anyone. It was reckless.”

Marseille said her sister told her that she was closing the door when Jameson got out and was shot multiple times.

“It’s just tragic,” she said.

Marseille said her sister was born and raised in New York and left for California in 2014 for work.

Two years ago, she said, her sister purchased Jameson.

“He was the oldest of seven puppies,” Vanessa said, recalling. “He’s quiet and energetic.”

Vanessa said the dog was always with her sister or nephew.

“Every time on FaceTime with Jeremiah, he’s always walking the dog,” she said. “When he takes my sister to work, Jameson is in the car, wagging his tongue.”

At home, she said, her sister and Jameson had their own routine.

“Before he eats his food, they pray together,” she said. “That was her second son.”

The Los Angeles Police Department said no officers were hurt in the incident, and the Force Investigation Division is investigating the shooting.