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How do they know it's the largest? They should rather say it's the largest known if anything.
by playingalong 2y ago
How do they know it's the largest? They should rather say it's the largest known if anything.
- John23832 2y agoI think that is pedantic and goes without saying. There are always unknown unknowns.
- eikenberry 2y agoYes and no. Scientists throw out these sorts of terms and know what they mean but the general population doesn't and doesn't get the ramifications of the real meaning. Just see how many people think that when a scientist says "the universe" that they mean the entire universe and not, as scientists mean, the observable universe. For general, "pop" cosmology those have very different meanings and lead to all sorts of bad thinking.
- Swizec 2y ago> Just see how many people think that when a scientist says "the universe" that they mean the entire universe and not, as scientists mean, the observable universe We once pestered our physics professor to explain what’s outside the universe. He finally said that’s a dumb question, the universe is definitionally everything, if we find anything beyond the edge of the universe, we’ll just call that universe too. Always liked that framing.
- tsimionescu 2y agoIn many contexts, "the universe" means "the whole universe [to the best of our knowledge]". For example, when scientists talk about the age of the universe or the start of the universe or the ultimate fate of the universe, they really do mean the whole universe, not just the observable universe.
- eikenberry 2y agoSo sometimes scientists are just talking out of their ass. They are people after all, so it should be expected sometimes.
- tsimionescu 2y agoNot really, the observable universe is a specific part of the universe we know of. We also know a lot of things about the parts of the universe outside the observable universe. In time, some parts of what is today the observable universe will become unobservable (since they are receding at an accelerating speed because of dark energy). That doesn't mean they will cease to be things we talk about when we say "the universe". Now, is it possible that some day we'll see new stars or something else coming from a completely unexpected direction, and discover that the universe also contains things that did not begin at the big bang? Sure, it's always possible, and our theories will change. But it's absurd to qualify each statement based on the possibility that new knowledge will come along at some point, when the same qualification always applies.
- eikenberry 2y agoObservation is a cornerstone of science and theorizing about something you cannot observe is interesting but not science. This is speculation about what might be outside the observable universe and that could lead to science disproving those particular speculations, but speculation is not science, it is philosophy.
- tsimionescu 2y agoObservation is not limited to direct observation. You can take what you're seeing with instruments, and extrapolate based on known laws, and you're still doing science. In fact, this is even more important to science than direct observation, which is extremely limited. By direct observation, I can't even tell if the earth was here yesterday, or at least a thousand years ago, even less so if it will still be here tomorrow. By the same token, when you look at certain characteristics of what you can observe of the universe, and you take the known laws of physics, you can find out a lot about the unobserved, and the un observable, universe.
- playingalong 2y agoWhile I understand there are unknown unknowns, in science you can sometimes prove that something cannot be smaller or something cannot be bigger. Because it would simply not be possible. Not sure if that's the case for DNA. And I am not talking about unknown unknown like some living organism using some other "substance" as the generic material.