Science isn't just asking "what if...?" It's following up with "... and how could I demonstrate that?" The third step is then "how do I communicate that to others?"
In the domain of chemistry, there's a wonderful example of that in Michael Faraday's "The Chemical History of a Candle". YouTube's EngineerGuy (Bill Hammack) has a wonderful recreation of Faraday's public demonstration of these properties. It seems obvious and pedestrian now, but that's because Faraday introduced us to these concepts and convinced us, collectively, of their fundamental truth. He gives us the hypothesis, he gives us the observable consequence, and he then demonstrates that consequence. Six-part series starting here:
https://youtube.com/watch?v=RrHnLXMTOWM
I've already answered your question, as it happens:
Looking out in space is looking back in time. Numerous phenomena support very strong consistency of physical constants to all observable levels. lizknope mentioned on HN recently naturally-occurring fission reactions on Earth about a billion years old or so. Those provide direct physical validation of physical constants as well.
That is, we have zoomed out time, using telescopes, looking back in the Universe 13.772 billion years (9.2 billion older than the Earth's own age). And there's no observable change in any of the fundamental physical constants that we can detect over this range.
But since you've repeated the question twice: why do you ask?
