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how does it know there isn't one further out past the observable universe? OR Does Webb actually see 100 percent of the entire universe?
by gremlinsinc 3y ago
how does it know there isn't one further out past the observable universe? OR Does Webb actually see 100 percent of the entire universe?
- jperras 3y ago"Further out past the observable universe" pretty much doesn't matter (hah), by definition.
- dylan604 3y ago[flagged]
- CuriousCosmic 3y agoBy definition if we can observe it (either directly or indirectly via the effects on stuff we can directly observe), it's part of the observable universe. If it's outside the observable universe then by definition it has no observable effect. Until technology improves to expand the observable universe to a degree that we can observe it or it does something that allows us to observe it (which adds it to the observable universe), then it doesn't really matter to us. In other words: If it's not part of the observable universe, it doesn't matter to us because we can't possibly know anything about it. However as soon as we discover something about it, it becomes part of the observable universe and now we can care about it because we know of it.
- _Microft 3y agoNo, it does not depend on our technological capabilities. The observable universe [0] of a point is defined as the space from which it is theoretically possible that a signal can reach it. So: every point in space has its own observable universe and it is not dependent on any technological capabilities. [0] https://en.m.wikipedia.org/wiki/Observable_universe https://en.m.wikipedia.org/wiki/Observable_universe Edit, excerpt from [0]: „The word observable in this sense does not refer to the capability of modern technology to detect light or other information from an object, or whether there is anything to be detected. It refers to the physical limit created by the speed of light itself.“
- meindnoch 3y agoLol, no. "Observable universe" is not a philosophical concept; it's a physical one with a precise definition: those parts of the universe that fell within our past light cone.
- bandyaboot 3y agoWhat you’re calling narcissistic is nothing more than taking as a given that an observer can’t go faster than the speed of light.
- xorbax 3y agoWe don't know the shape of the universe. There could be nothing further than what we observe. We, by definition, cannot actually know. The universe may simply wrap around itself. The universe may have finite real volume due to big bang inflation and it simply can't be approached Fact is, far enough in the future inflation will be such that our view is vastly smaller than it is now. Their universe will be smaller because there will be no way for them to access what inflation has put beyond light and causality.
- dotnet00 3y agoThey still don't matter from our point of view, since everything outside the hubble sphere is by definition completely causally disconnected from us due to moving away from us faster than light. The main value of these sorts of detections is towards probing the early ages of the universe and how quickly certain things formed, in which context, the idea of a larger black hole beyond the edge of the observable universe doesn't make much sense, since the edge of the observable universe is t=0 for the big bang (to be precise, the edge observable via photons is actually t=~370k years, the point where the universe cooled enough to be optically transparent, but theoretically we could look to t=~1 second if we could devise a way to detect relic neutrinos from the big bang).
- koheripbal 3y agoIt sort of does because it had an impact on the formation of our part of the universe in the beginning, sorry it is useful in understanding the formation of the universe
- doctoboggan 3y agoNo, by definition we only see the observable universe like you noted, but most people assume there is more out there beyond it. In fact, by the Copernican principle we should assume there is more out there, otherwise we happen to find ourselves exactly in the center of everything and can see exactly as far as light could have traveled in the known age of the universe. The title is a little unclear, but I read it as the most distant known supermassive black hole. This is the farthest one we've detected, but we can assume there are further ones (even some that may still be detected by Webb in the future)
- bradgessler 3y agohttps://www.pbs.org/video/how-much-of-the-universe-can-humanity-ever-see-bboivw/ https://www.pbs.org/video/how-much-of-the-universe-can-human... is a really fascinating video to watch about the observable universe. In some ways it’s depressing that humanity is doomed to only understanding what’s in our observable universe. I really hope we find some way around it.
- Mistletoe 3y agoIs there any reason to think what’s outside the observable universe is any different? It doesn’t depress me since we have plenty to see to get a good idea and sample size to know what exists. What does depress me is the idea that far in the future all people will see is our galaxy and not know others exist.
- koheripbal 3y agoYes, because what is outside of the observable universe is the light from the big bang and the time just after it
- ianburrell 3y agoThe light from big bang is inside the observable universe. It is the cosmic microwave background. We can’t see earlier because the universe was opaque before 378k years and any light from earlier stages was absorbed.
- dotnet00 3y agoI feel like contextually it's pretty obvious that it's simply comparing to what has been discovered thus far.
- nuclearnice3 3y agoYeah, although it's not my habit to bother with articles, I was bold enough to click this one and confirm you are correct. First sentence: "Researchers have discovered the most distant active supermassive black hole *to date* with the James Webb Space Telescope (JWST)."
- motoxpro 3y agoSorry. Are you saying that you only go on hacker news and comment on articles that you haven’t read?
- nuclearnice3 3y agoYes. Your phrasing is a little different than I would use, but I think you've captured the gist. I'm not seeking out articles I haven't read to comment on, but rather I'm here for the great aspects of our community found in the comments. I think this thread -- where a portion of the debate is about details of the headline answered by the first sentence of the article -- hints that many people are using a similar modus operandi. My mental model is - comments are more entertaining - comments are shorter - comments highlight the strengths and weaknesses of the article - comments expand the scope of the article and point at interesting related items
- Eldt 3y agoWell that's a problem
- motoxpro 3y agoI understand just reading the comments for all the reasons you mentioned, but how can you contribute to the discussion when you never took the time to understand what the discussion was about? It’s like debating the validity of what the 10th person said in a game of telephone instead of going to the first person to understand what the origin of the idea is. As the sibling said, that seems like a problem.
- cvoss 3y agoAdding to the answers of others, Webb can't see the whole observable universe. It has an upper limit on wavelengths that it can detect. Because older / further away light sources are more red shifted, at some point the really old / really far away stuff drops off the spectrum range that Webb can see. Here's a nice read [0] which tells me that the oldest things Webb can see are from T = 100-250 M years after the big bang. The light from the [matter around the] black hole in the main article originated at T = 570 M years. So it is plausible to me that an even earlier one will be spotted by Webb eventually. [0] https://jwst.nasa.gov/content/science/firstLight.html https://jwst.nasa.gov/content/science/firstLight.html
- acdanger 3y agoFirst sentence: “ Researchers have discovered the most distant active supermassive black hole to date with the James Webb Space Telescope (JWST).”
- mock-possum 3y agoIt doesn’t know, this is the most distant it has detected so far