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This is the worst analogy I have heard in a long time. It's even bad for physics journalism.
And the subtitle says "timescape", which immediately clues me into what the theory is about, instead of "time zone" as in the title.
While it is possible that relaxing the homogeneity assumption is needed to resolve the tensions observed among different cosmological measurements, it is also worth noting that supernovae are a quite messy tracer, because we don't really understand their explosions well enough. So a lot of things are just empirically calibrated. We are also now limited by systematics when using supernovae for cosmology.
> We are also now limited by systematics when using supernovae for cosmology.
Could you say more about this part? I don't know what that means.
For every sort of measurement, or constraint derived from data, you have uncertainties related to random noise (either related to do measurement error, or sampling error caused by finite number of objects in your sample). But you also have systematic errors, for example, if your measurements are biased in some way.
For supernovae, we know that the galaxies in which they explode are different in different redshifts, so it is possible there are effects that make supernovae brighter or fainter in different redshifts that have nothing to do with dark energy, but instead are related to chemical composition of stars. This is an example of systematic effect that can affect any cosmological measurement using supernovae. People try to control for those, but at the moment the uncertainty on cosmological parameters from SN is dominated not by random component of the error (i.e. related to number of SN), but the systematics and our ability to constrain them.
type IA Supernovae have ~the same energy output because of the chandrasekhar limit. can you elaborate on how stellar composition affects TIA output?
Currently we don't even know if type Ia is merger of two WDs, or accretion from a normal star to a WD.
Also the light-curve of the Ia SN is determined by the specific decays of various elements (Nickel and so forth). The ratio of those elements will depend on initial abundances. Also even the exact detonation of the WD depends on whether it' carbon-oxygen etc.
Very helpful, thanks!
Can Vernor Vinge please spend just one day not being right about everything?
Or Poul Anderson's Brainwave (1953), in which the Earth finally leaves a part of the galaxy which inadvertently made thinking hard. And everything with two neurons to rub together gets smarter, not just humans. Essentially, we evolved in what Vinge would later call "The Unthinking Depths" (if memory serves) to deal with the strain.
Came here to say the same thing - this is uncanny.
In some of his novels - most notably A Fire Upon the Deep (from 1992), he imagines the galaxy as divided into concentric zones, each with different physical laws and limits on intelligence and technology. These are referred to as "Zones of Thought," each affecting the potential for intelligence and technological development.
It's not a perfect match, as I think the new theory refers to relative time based on the density of matter at a given location.
Part of me wonders if this analogous to the "watched pot never boils" issue. Wander into the wilderness to do magic...
Deepness in the sky is top 5 scifi. Great programmer tropes hidden in there.
Others:
- first bobiverse book (followed by all the rest)
- permutation city (next: diaspora, etc)
- Diamond age (so relevant now with spread of LLMs)
- count to a trillion (A cowboy lawyer mathematician takes enough drugs to invent antimatter tech)
I've read two of his books and loved them. Which is relevant here?
The "fire upon the deep" series describes zones where the speed of light differs, causing deserts from which escape is difficult, did to the slow speed at which ships must travel.
I think in those stories the speed of light is the same but the speed of thought differs. Close to the center of the galaxy you cannot be very smart and faster than light drives don't work, if you get too close to the edge you get victimized by those things that Yudkowsky is worried about. There's a certain range in which you get space opera.
The most obvious way to change the speed of thought is to change the speed of the electromagnetic signals (light) that produce them. Ignoring the current known laws of physics, of course.
It's both, the farther you get from the center of the galaxy technology can be more complex, the speed of light is higher, and computation can be faster.
I think he is dead, there is little he can do now?
Dang. I hadn't heard. RIP.
What I don't get about this timescape theory, is what is the mechanism for time passing faster in the 'voids'? Or equivalently, what makes time pass slower along the edges of the voids?
Is it supposed to be gravitational time dilation? (e.g. 'low is slow') Surely this can't have an effect of this magnitude (a 2x speedup in the voids)? As I understand it gravitational time dilation only has significant effects (like the 2x slowdown) in the strong gravitational region regime, around black holes etc.
This is timescape cosmology’s inhomogenous universe hypothesis [1] that competes with ΛCDM’s cosmological principle [2].
In the homogenous cosmology there is the parameter Ω which determines if the universe is flat or not. Observations seem to show that Ω = 1, but if Ω>1 it will collapse back into a black hole and if Ω<=1 it expands forever.
Since the universe as a whole is balanced I'm wondering if you're in the dense part of the timescape your fate is to wind up in a black hole.
If these filaments and spaces have enough gravitational differences to affect the flow of time, wouldn't we also be unable to resolve distant objects as their light would be bent slightly and repeatedly in a random fashion?
If it’s all a swirling spinning turbulent mess is there enough difference in relative velocity that we’ve had more or less time since the Big Bang than other places?
Finishing off above question…
Is that What this model is suggesting or is the uneven distribution of mass contributing too?
I think the idea is mostly about the distribution of mass influencing time flow.
oh come on! Can't we all just use UTC and get along?
I love the smell of vindication in the morning
Vindication of what exactly? The claims in your comment, e.g.
> if you have less time in an area (i.e. due to a gravity well, like Earth's) you can equally view it as more space
are so nonsensical (with all due respect), they are not even wrong[0].
You should do a collab with Deepak Chopra!
> Instead, the basis of the timescape model is that, in fact, we see in the universe around us today that there are giant cosmic structures, enormous filaments and walls filled with galaxies and galaxy clusters. And in between those filaments and walls we have giant voids of nothing.
Could explain we haven't found life elsewhere?
No. We’re only searching for life in a tiny area around the Sun within our galaxy, the Milky Way. To find life we first need to find planets, which involves looking at stars over extended periods of time to detect tiny dips in brightness (transit method) or tiny wobbles causing minute redshift-blueshift cycles (doppler shift method).
Those cosmic filament structures are on the scale of millions and billions of galaxies over distances far larger than the size of a single galaxy. We can’t even resolve individual stars beyond our Local Group of galaxies and still most of the stars within the Milky Way are too far to use our exoplanet detection techniques (2 of them mentioned previously).
Finally, to search for life we’ve been attempting to search for spectral absorption lines of the gases in the atmosphere of an exoplanet, which involves recording a spectrograph during the transit method. This only works for stars with their orbital planes edge-on to us so that we can actually detect the planetary transits and record enough light from them over time to see how the spectrograph changes during the transit events.
Who says we haven't?
We have absolutely no real idea what life will look like.
What if there are already organisms that are so large or small that we just can't comprehend them?
Also, the universe is likely so large that we'll never encounter life like us.
Are you proposing that atoms are organisms and/or that astronomical objects may be organisms? I feel like you are just inflating the meaning of “life” without justifying why.
Defining it properly is a very interesting problem, but I think this is an extremely active field of study. Saying “what if subatomic particles are actually living organisms” is not a productive line of thought.
"Saying “what if subatomic particles are actually living organisms” is not a productive line of thought."
Questions usually can be productive. To answer it, we have to look up and apply the (debated) definitions of life and atoms in our understanding clearly don't meet it.
But since we only know so very little when going really small or really big, I do say it is an interesting thought to give room for quark or dark matter based life, or the theoretical organism of a black hole.
We simply don't know and we will never know, if we think we already know.
It seems they are stating that life elsewhere may be vastly different than life on Earth.
How did you arrive at your understanding of the comment?
We did recently find something very promising https://www.bbc.com/news/articles/c39jj9vkr34o
As was discussed at the time, that news was overhyped. The finding is not strong evidence of life, it's strong evidence that we don't fully understand how that molecule gets formed. And the most recent news on that front is that the finding itself is being challenged.
Every finding gets challenged, and that challenge always becomes news. Trying to evaluate the progress of a scientific debate based on news stories is like guessing the record of a soccer team based on a couple of viral goal clips.
The scale here is "thousands of galaxies".
The problem with where's the other life is already enormous due to the size of our one galaxy.
> Could explain we haven't found life elsewhere?
Or maybe we just haven't looked very far at all.
Nor for very long.
The problem with quantum physics is that it's also a matter of interpretation.
It's like interpreting the body language: what you think could true only from your cultural perspective about people who share your culture.
I do not particularly agree with this. I don't think this analogy works.
Otherwise, what explains that there are those who say dark matter exists and build other opinions above it, and others dismiss its existence completely.
It means each is focussing on one subset of all the available observations. If three blind men discover an elephant and one gropes his trunk, another gropes a leg and a third gropes something else, they will come to very different conclusions about what an elephant is.
Well... that's just your cultural perspective, man.