I always get a feeling of existential dread when I read these kind of news.
Don't worry too much about it. In the end, everything will be nearly 0k.
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The universe is expanding faster than expected
41–50 of 242 posts
Re: The universe is expanding faster than expected
#42One thing that really frustrates me about cosmology, or at least popular science reporting and books, is a particular kind of lack of intellectual rigor. Specifically, even as a layman, it's clear that observation and model are being conflated. Cosmology is a science in the broadest sense of being a field of human knowledge, but it isn't a science the way that, for example, physics is. It would better be described as…
I think observation and model almost necessarily have to be conflated. What we really see is light hitting our retina, or if you want to go one layer further, nerve impulses in our visual cortex. Everything else is model.
So if we accept that everything is model, then what you are really advocating is using verbose descriptions in terms of a fairly established model rather than succinct descriptions in a more speculative model. Phrasing it like this makes it clear that there is a balance to be struck between pros and cons. Maybe we are erring on the speculative side, but you will have to make that case.
Re: The universe is expanding faster than expected
#43When this article talked about the ladder of standard candles, I started to wonder: when using the brightness of supernovae between near and far galaxies, what about intergalactic dust absorbing some of the light? Wouldn't that mess up the ability to just straighforwardly determine the distance from the brightness in a 1/r^2 way?
Yes, apparently that absorbtion of light by intergalactic dust is a well-known phenomenon called interstellar extinction.
There are various ways of accounting for it.
Re: The universe is expanding faster than expected
#44Time runs slower when you're young; but then as you age there's less time in each day. Perhaps it's the same for everything else that experiences time, from us to galaxies and universes.
This is because information in your brain is constrained by physics. It takes tangible time for signals to travel between neurons. When you're young, you're small, and the distances are shorter. As you age, you grow in size, and the signal length grows also. Thus as you grow you literally think slower; though hopefully, more effectively (wisdom). Your perception of time changes accordingly.
What you wrote has no basis in reality whatsoever. In fact, nerve conduction is slower in children than adults due to underdeveloped myelination.
Re: The universe is expanding faster than expected
#45Earlier quoted context omitted.
I appreciate your optimism. I tend to be optimistic about the future myself. But there is no law of the universe that everything will work out ok. Only if we make the right decisions as a species and we don't get unlucky. I'm quite apprehensive that the great filter lies ahead - that technology accelerates too rapidly compared to our wisdom and we end up nearly destroying ourselves. We're getting the ability to progr…
I think it was a joke about zero Kelvin.
I thought of it as being 0k as in empty of information. Kelvin is K but I like this interpretation more.
Re: The universe is expanding faster than expected
#46Time runs slower when you're young; but then as you age there's less time in each day. Perhaps it's the same for everything else that experiences time, from us to galaxies and universes.
This is because information in your brain is constrained by physics. It takes tangible time for signals to travel between neurons. When you're young, you're small, and the distances are shorter. As you age, you grow in size, and the signal length grows also. Thus as you grow you literally think slower; though hopefully, more effectively (wisdom). Your perception of time changes accordingly.
By age 2 your brain is ~80% of its final adult size, IIRC. So not sure if this idea is correct (but at the very least plausible and intriguing!).
I think the experience of time has something to do with focus. When you are young, or on lsd, your brain doesn't filter out all the signals and so time "slows down" as you suddenly need to process more. I know this is a well researched idea, just forget the actual terms for it.
Re: The universe is expanding faster than expected
#47Re: The universe is expanding faster than expected
#48When this article talked about the ladder of standard candles, I started to wonder: when using the brightness of supernovae between near and far galaxies, what about intergalactic dust absorbing some of the light? Wouldn't that mess up the ability to just straighforwardly determine the distance from the brightness in a 1/r^2 way?
I am not an astronomer, but I imagine intergalactic dust leaves a distinct fingerprint on star spectra that you can measure.
Also, these numbers always have error bars. They spend a lot of time coming up with sources of error and characterizing them in order to understand the data fully.
Re: The universe is expanding faster than expected
#49Earlier quoted context omitted.
This is because information in your brain is constrained by physics. It takes tangible time for signals to travel between neurons. When you're young, you're small, and the distances are shorter. As you age, you grow in size, and the signal length grows also. Thus as you grow you literally think slower; though hopefully, more effectively (wisdom). Your perception of time changes accordingly.
Yes that's an interesting aspect that I hadn't thought of. I do agree with the wisdom part. ;) I also like to consider the experience of time in relation to total life lived. e.g. A month to a five year-old is the equivalent of a year to a 60 year-old. So as we experience more time, we feel that time passes more quickly. Although I sure hope there is a plateau to it as we get older.
Not exactly a plateau. More like a singularity threshold.
Re: The universe is expanding faster than expected
#50A few years ago, a published article suggested an alternative to the universe expanding is increasing mass. Older objects increase their mass and therefore are red shifted. Why is this alternative plausible theory recieving such little attention? Edit: changed mass decay to increase in mass. I misremembered the theory.
Hm - but older from what perspective? Since light travels at c, aren't all journeys light takes instantaneous from the point of the photon? My understanding as well being that all known natural processes (like beta decay) are time-dilated at relativistic speeds.
Also, how would this jibe with the parallax-based observations mentioned in the article?