Article: What technosignatures would interstellar objects have?

[Gary C]

"Since [Interstellar Objects] are still a relatively new discovery, despite their theorized existence for years, they are at the forefront of technosignature research. And the paper posits four different types of technosignatures astronomers might be able to find on one of them."

The article: https://phys.org/news/2025-09-technosignatures-interstellar.html

The original paper: https://arxiv.org/abs/2508.16825

 

[jdog]

"Since [Interstellar Objects] are still a relatively new discovery, despite their theorized existence for years, they are at the forefront of technosignature research. And the paper posits four different types of technosignatures astronomers might be able to find on one of them."

The article: https://phys.org/news/2025-09-technosignatures-interstellar.html

The original paper: https://arxiv.org/abs/2508.16825

A nice review of the science and observing options.

While work has begun on statistical treatments for these new and fascinating objects (e.g. Marceta 2023; Hopkins et al. 2025), and a small number of nearly unambiguous technosignatures may exist, we believe an ISO-specific scale for technosignature assessment is premature.

Any potential detection of technosignatures from an ISO will require the most stringent and detailed confirmation possible.

And I like how the article author points out:

One advantage of the techniques proposed in this paper is that all of the data needed to prove them would already be collected by telescopes doing other science to a relatively unique object. There's no required observational times or special equipment needed.

So unlike a lot of advocates of niche topics, they're not demanding a ton of additional public spending or the staging of a probe in interplanetary space, just some focused attention.

 

[Mendel]

1. "If an ISO moves quickly in a way that can't be explained by gravity, then it's likely due to some sort of thruster, and hence a technosignature."

2. "A second technosignature on an ISO would be unnatural spectra."

3. "Third would be a strange shape." e.g. a solar sail

4. "The final technosignature would be one of SETI's longest-standing practices—a transmission."

 

[Eburacum]

Number one is incomplete; ISOs, and any small object in space, can be affected by other forces, such as sunlight and outgassing.
The Yarkovsky effect is a result of radiation hitting one side of a rotating object, and subsequent re-radiation, causing deflections in various directions
https://en.wikipedia.org/wiki/Yarkovsky_effect
Another effect changes the orbits of dust grains, but has a tiny affect on larger objects too.
https://en.wikipedia.org/wiki/Poynting–Robertson_effect

 

[Mendel]

Number one is incomplete; ISOs, and any small object in space, can be affected by other forces, such as sunlight and outgassing.

It's incomplete because I only gave a very rough overview.
If you look the point up in the article or the paper, you'll find they have considered it. (The words "moves quickly" do a lot of lifting here.)
In effect, you're criticizing my overview for not being very detailed, i.e. for being an overview.

 

[Eburacum]

Apologies for that. But we can't let Loeb and his supporters get away with saying that only gravity affects interstellar objects; it wasn't true in the case of 'Oumuamua, or in the case of 31/Atlas.