31–40 of 57 posts
Potentially a stupid question - How can the universe get "colder"? Does it just mean that the average energy-per-square-meter (or whatever unit) is less? If so, wouldn't that mean that saying "less dense" and "colder" mean basically the same thing at that scale? Maybe I'm asking something stupid and obvious, but I keep thinking that energy can't be destroyed, ergo, there's exactly as much energy (and thus heat?) as b…
This kind of science has always been hard for me to integrate. Thinking as a Bayesian, these arguments seem to be meant to influence my "prior" over possible initial states or natures of the universe. I'm not accustomed to that. I'm used to science presenting me with evidence meant to influence my "posterior". I can handle that.
Consider what the alternative would look like. You retain both your original prior and every piece of evidence you've ever seen, then recompute all of it each time you need the current value? No. That doesn't pass the intuition test either. What you now think of as your prior on the Universe is not actually the belief you held at birth. You've updated dozens or hundreds of times during childhood, and each time you discarded your old "prior".
Footnote: you do retain some of your recent evidence, for smoothing purposes. For more information, investigate how Bayesian networks incorporate time: http://en.wikipedia.org/wiki/Dynamic_Bayesian_network
Potentially a stupid question - How can the universe get "colder"? Does it just mean that the average energy-per-square-meter (or whatever unit) is less? If so, wouldn't that mean that saying "less dense" and "colder" mean basically the same thing at that scale? Maybe I'm asking something stupid and obvious, but I keep thinking that energy can't be destroyed, ergo, there's exactly as much energy (and thus heat?) as b…
Potentially a stupid question - How can the universe get "colder"? Does it just mean that the average energy-per-square-meter (or whatever unit) is less? If so, wouldn't that mean that saying "less dense" and "colder" mean basically the same thing at that scale? Maybe I'm asking something stupid and obvious, but I keep thinking that energy can't be destroyed, ergo, there's exactly as much energy (and thus heat?) as b…
Less dense implies colder, as the volume is not constant, but expanding. Temperature and density are different things though - one is how much energy something has, the other is how far away from other things it is. Related, but different. With respect to destroying energy - energy converted into matter is 'colder'. There's not the exact same amount of energy - it's not that it can't be destroyed, it must be conserve…
That was really informative, thanks.
Man, physics is cool.
Sometimes I think I was born too soon. To think the new knowledge we well discover with in the next 100, 200, 1000 years is really exciting. I wouldn't be surprised if in the next 20-50 years with all the genetic engineer going on one could live for ever. Of cause as long as you can afford it.
I envision a world where, due to technology and science, everyone stops aging after 25. A clock will be constantly visible on your forearm and time will be the only commodity in the world, in which you'll get paid and make payments in. After the age of 25, you'll get 1 to 75 years of "time" deposited in your account. The clock on your arm will decrement by default as time passes, and increase/decrease as you earn/spe…
I envision a world where ...
Earlier quoted context omitted.
This plot doesn't make any sense.
Time is the ultimate currency. Gold is only backed by the agreement of its scarcity; otherwise, it has no value (outside its physical usefulness as a material). Fiat currency is only backed by the confidence of a nation; otherwise, it has no value. Time is a currency that's backed by your life. It is as real as it gets.
The scarcity of Gold on the other hand is very real. Gold is limited and while it is possible to synthesize gold, the cost of doing that is great and does not scale.
Which is why I think the world you mention is impossible: we cannot even stop the piracy of music. Artificial scarcity is not sustainable. Once all the people will be able to live forever, they will live forever. What makes you think these "clocks" will be unbreakable?
And even if the technology will be perfect, do you really want to have on your hands a huge angry mob of people with less than 24 hours to live? Good luck with that ;-)
Yes, that function may hold outside your observable space, but it may not. We can't simply state as fact the predictions that come from assuming that this function applies outside our observable space.
Potentially a stupid question - How can the universe get "colder"? Does it just mean that the average energy-per-square-meter (or whatever unit) is less? If so, wouldn't that mean that saying "less dense" and "colder" mean basically the same thing at that scale? Maybe I'm asking something stupid and obvious, but I keep thinking that energy can't be destroyed, ergo, there's exactly as much energy (and thus heat?) as b…
Less dense implies colder, as the volume is not constant, but expanding. Temperature and density are different things though - one is how much energy something has, the other is how far away from other things it is. Related, but different. With respect to destroying energy - energy converted into matter is 'colder'. There's not the exact same amount of energy - it's not that it can't be destroyed, it must be conserve…
Potentially a stupid question - How can the universe get "colder"? Does it just mean that the average energy-per-square-meter (or whatever unit) is less? If so, wouldn't that mean that saying "less dense" and "colder" mean basically the same thing at that scale? Maybe I'm asking something stupid and obvious, but I keep thinking that energy can't be destroyed, ergo, there's exactly as much energy (and thus heat?) as b…
Less dense implies colder, as the volume is not constant, but expanding. Temperature and density are different things though - one is how much energy something has, the other is how far away from other things it is. Related, but different. With respect to destroying energy - energy converted into matter is 'colder'. There's not the exact same amount of energy - it's not that it can't be destroyed, it must be conserve…
http://blogs.discovermagazine.com/cosmicvariance/2010/02/22/...
tldr: "Energy isn’t conserved; it changes because spacetime does."
Earlier quoted context omitted.
Less dense implies colder, as the volume is not constant, but expanding. Temperature and density are different things though - one is how much energy something has, the other is how far away from other things it is. Related, but different. With respect to destroying energy - energy converted into matter is 'colder'. There's not the exact same amount of energy - it's not that it can't be destroyed, it must be conserve…
How does converting energy into mass make it "colder"? If you have 1 protons worth of energy in a volume, and you have 1 nonmoving proton in another area with the same volume, isn't there the same amount of energy in both regions? Or is it "colder" because you can't have a region with energy and nothing else, it must be something like kinetic energy, which gives heat?