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PBS SpaceTime notes the fine structure constant (~1/137) is dimensionless and ubiquitous in physics. As a result, transmitting that ratio would be a good and clear indication we are intelligent enough to have at least that much physics: https://www.youtube.com/watch?v=RCSSgxV9qNw&t=564s

This might be better than mathematical constructs which conceivably do not require technology, "just" thought to discover.

⬐ koyanisqatsi

But this constant is an artifact of our symbolic encoding of universal properties. What reason is there to believe that alien civilizations would encode physics exactly as we do and would recover the same constant?

⬐ jondeval

> What reason is there to believe that alien civilizations would encode physics exactly as we do and would recover the same constant?

There is no reason to believe the symbolic encoding would be the same. For example, if they evolved with 8 fingers instead of 10 they could be driven to encode their symbols in a base 8 system.

I think the point of the OP sharing the PBS spacetime video in this context is that we have reason to believe that the fine structure constant is truly constant throughout the universe. So if the aliens have the capability of measuring and reasoning about electron orbitals and their binding properties with nucleus, then there will likely be significant overlap between our mutual concepts of 'fine-structured-constantness'. Just made that word up. :-)

This would be independent of encoding scheme and independent of practical communication issues.

⬐ koyanisqatsi

Right but I can ask the same/similar question. Why would they have particle physics like we do? There are several degrees of freedom in existing mathematical theories of physics and I don't think there is a good reason to expect that electrons would be re-discovered in another encoding of physics by an alien civilization. The entirety of particle physics is contingent on a bunch of mathematical abstractions (e.g. group theory) so then the argument becomes that these abstractions are not contingent discoveries which then fixes the entire mathematical edifice to be the same across all alien life and civilizations.

It's an interesting thought exercise but I don't think there is any reason to expect mathematics to be the same across all potential life in the universe. Human mathematics is adapted to human evolutionary contingencies and the same would be true for alien mathematics, physics, and engineering. By definition of "alien" their mathematics would be alien to us and even if there were commonalities they would be very hard to uncover.

⬐ jondeval

I understand your point. And I completely agree that many of our chosen mathematical structures, and even physical models are contingent and likely accidents of history and sensory constraints.

I'm comfortable living with the tension between these two propositions: (1) The manifestation of laws of physics are real, measurable, spread across the galaxies, and essentially outside of our subjective experience. For example, I do believe that gravity and electrons are real ... not just real for me. (2) The way in which we interpret these physical realities is somewhat conditioned by the constraints and experience of being messy human animals.

⬐ HardlyCurious

Well, this was held up as a universal truth because it doesn't depend on units, and so those don't need to be defined... But we still can't just show them the image '1/137' and have them understand the characters and operations. Our presentation isn't universal.

And I would argue that showing the length of distance we use isn't fundamentally different than explaining which syntax we use for division.

⬐ Dylan16807

> But we still can't just show them the image '1/137'

You can dump energy into two frequencies. You're overcomplicating it.

The video suggests binary which is also pretty simple.

⬐ nine_k

Another good signal could be transmission at the frequently of free hydrogen times pi, or times e, or both.

The problem here is not even in the need to spend colossal amounts of energy to signal one's presence. The question is whether such advertising is a good idea if the civilization strives to survive; very likely it is not.