Search found 2201 matches

by thoughtfully
Tue Feb 16, 2016 9:42 pm UTC
Forum: Science
Topic: LIGO Gravity Waves: Questions and Answers
Replies: 49
Views: 9268

Re: LIGO Gravity Waves: Questions and Answers

Another way to look at this is simply as a consequence of the Big Bang happening everywhere, without a preferred location. You look out into the sky, in any direction, and if there's nothing in the way, you can see all the way to the Big Bang. In EM, there's the hot plasma from in early Universe blo...
by thoughtfully
Mon Feb 15, 2016 11:54 pm UTC
Forum: Science
Topic: LIGO Gravity Waves: Questions and Answers
Replies: 49
Views: 9268

Re: LIGO Gravity Waves: Questions and Answers

It's the same idea as with the microwave background from the surface of last scattering, only 380k years or so earlier.

Incidentally, there's also expected to be a neutrino background signal.
by thoughtfully
Tue Feb 09, 2016 10:42 am UTC
Forum: Science
Topic: Wendelstein 7-X
Replies: 43
Views: 8789

Re: Wendelstein 7-X

Fusion reactors are a bit different because the reactant is physically separated from the reactor. There's not very much heat transfer by conduction, as I understand it. Still, there's quite a lot of neutron flux and thermal radiation getting out.
by thoughtfully
Mon Jan 25, 2016 9:14 pm UTC
Forum: Science
Topic: Landing rockets upright is unnecessary?
Replies: 61
Views: 13897

Re: Landing rockets upright is unnecessary?

I like digging up old threads. I'm sure seven won't mind.
by thoughtfully
Fri Jan 22, 2016 8:44 pm UTC
Forum: Science
Topic: electromagnets motors and resistance question
Replies: 3
Views: 2001

Re: electromagnets motors and resistance question

Sometimes the windings themselves provide a significant resistance. They can be very fine, long wires.
by thoughtfully
Thu Jan 21, 2016 9:06 pm UTC
Forum: Science
Topic: Landing rockets upright is unnecessary?
Replies: 61
Views: 13897

Re: Landing rockets upright is unnecessary?

A possibilities come to mind. To land gently enough to prevent damage, you pretty much have to use thrust. parachute landings are a not-so-gentle affair. If you are going to use thrust, your thrust needs to line up with your center of mass, or you will go tumbling around. Landing horizontally also m...
by thoughtfully
Thu Jan 21, 2016 3:09 am UTC
Forum: Science
Topic: Theory of black hole composition
Replies: 50
Views: 7596

Re: Theory of black hole composition

Do you know of published work by physicists on the idea that inflation always occurs in the neighborhood of the event horizon and prevents any infalling objects from reaching it (or reaching the spot where an event horizon would otherwise form, Not exactly what you're looking for, but I recently po...
by thoughtfully
Tue Jan 12, 2016 3:25 pm UTC
Forum: Science
Topic: The Argument from Contingency
Replies: 43
Views: 8247

Re: The Argument from Contingency

It's also possible that our universe was spawned from a (always existing, hence necessary) Multiverse.

But philosophy and language and ideas are meta-things, so one should take care when applying them too broadly to "reality".
by thoughtfully
Thu Jan 07, 2016 10:49 am UTC
Forum: Science
Topic: What's up with avocados?
Replies: 22
Views: 4297

Re: What's up with avocados?

There is a thread concerning chocolate and raptors lurking around somewhere. The main problem is that the prey has to withstand a much higher concentration of toxin than the predator. Alternatively, they could keep it in a pouch attached to their belt, but clever raptors could discard the pouch befo...
by thoughtfully
Wed Jan 06, 2016 5:06 pm UTC
Forum: Science
Topic: What's up with avocados?
Replies: 22
Views: 4297

Re: What's up with avocados?

According to Wikipedia, there's a theory that the target dispersers were extinct megafauna.
by thoughtfully
Sat Jan 02, 2016 3:13 pm UTC
Forum: Science
Topic: Friction and Normal Force (Load)
Replies: 6
Views: 2923

Re: Friction and Normal Force (Load)

Another way to see this is that you can't really disregard adhesion. Adhesives optimize a property that's always present, just to a lesser degree under the usual conditions.
by thoughtfully
Wed Dec 30, 2015 2:25 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2962
Views: 730986

Re: RELATIVITY QUESTIONS! (and other common queries)

That's the case for pretty much any black hole these days. The CMBR is 2.76K, but the emission from a stellar mass BH is way under that (*), and the huge ones at the centers of galaxies are even less. (*)The Hawking Temperature for a minimal stellar mass BH (3 solar masses) is 2.06e-8 K. The mass of...
by thoughtfully
Mon Dec 28, 2015 7:49 pm UTC
Forum: Science
Topic: How does two black holes orbit each other?
Replies: 14
Views: 2594

Re: How does two black holes orbit each other?

In any case, having an extreme or near-extreme Kerr black hole at the center of our solar system would almost surely result in some degree of excitement... Hell yeah! Naked singularities! How sexy is that? Of course, what would probably happen in reality is Quantum Mechanics would intrude to preser...
by thoughtfully
Thu Dec 24, 2015 8:57 pm UTC
Forum: Science
Topic: How does two black holes orbit each other?
Replies: 14
Views: 2594

Re: How does two black holes orbit each other?

What you describe corresponds roughly to the L4 and L5 Lagrange Points, although what counts as stationary depends on your reference frame.
by thoughtfully
Thu Dec 24, 2015 6:08 am UTC
Forum: Science
Topic: How does two black holes orbit each other?
Replies: 14
Views: 2594

Re: How does two black holes orbit each other?

Also, black holes don't have to be that massive. They generally start out being less massive than the star they formed from, for instance, since that star lost most of its mass when it exploded. A black hole can actually have any mass at all, if it's concentrated into a small enough volume. It's tho...
by thoughtfully
Wed Dec 23, 2015 3:12 pm UTC
Forum: Science
Topic: A question about tea
Replies: 18
Views: 4666

Re: A question about tea

Neil_Boekend wrote:
PAstrychef wrote:So steampunk is the way of the future!

So Mutant Chronicles is a prophecy? I really don't want it to be.

[aussieAccent]
That's not steampunk.
This is steampunk!
[/aussieAccent]

I guess it's a bit dystopian, too, alas.
by thoughtfully
Tue Dec 22, 2015 7:01 am UTC
Forum: Coding
Topic: Evidence-Oriented Programming
Replies: 9
Views: 5270

Re: Evidence-Oriented Programming

ucim wrote:Making it easy to do the easy stuff could make it harder to do the hard stuff.

This is Microsoft's business model, and why we hate strongly dislike them.
by thoughtfully
Mon Dec 21, 2015 5:52 am UTC
Forum: Coding
Topic: Evidence-Oriented Programming
Replies: 9
Views: 5270

Re: Evidence-Oriented Programming

Yeah, "for" is awful. I can still remember the moment when I suddenly grokked it, back when I was a wee protoprogrammer.

I'm a few weeks into learning Scala. It reads like Perl sometimes, but it isn't a language for a total novice, either.
by thoughtfully
Fri Dec 18, 2015 3:47 pm UTC
Forum: Science
Topic: Could we save the sun?
Replies: 18
Views: 3488

Re: Could we save the sun?

Well obviously, transforming bits into hard copy can entail any number of engineering challenges. That's a problem for the printer makers, though.
by thoughtfully
Fri Dec 18, 2015 10:19 am UTC
Forum: Science
Topic: Could we save the sun?
Replies: 18
Views: 3488

Re: Could we save the sun?

Even if we could save the sun, where would we get a hard drive big enough to hold it? I can come up with a lossy algorithm that would suit most purposes and only require a handful of floating point values. Mass and age, plus metallicity if you want to get fancy, will reproduce all the features that...
by thoughtfully
Wed Dec 09, 2015 2:36 am UTC
Forum: Science
Topic: A question about Dyson Spheres
Replies: 13
Views: 2869

Re: A question about Dyson Spheres

The inability to expand beyond the Dyson sphere would be a bit like considering the star as the core of a much bigger star with a heavy envelope of matter holding it down. Pressure and heat goes up, possibly igniting new sorts of fusion reactions. A lot is going to depend on how heat is conducted th...
by thoughtfully
Mon Dec 07, 2015 2:23 pm UTC
Forum: Science
Topic: Could we save the sun?
Replies: 18
Views: 3488

Re: Could we save the sun?

Making the Sun lighter and longer lived is the simple answer that needs the least ongoing maintenance and doesn't involve interstellar haulage.
It isn't without its own problems, though!
by thoughtfully
Tue Dec 01, 2015 3:09 am UTC
Forum: Science
Topic: The end and beginning of the universe
Replies: 13
Views: 2485

Re: The end and beginning of the universe

It's got nothing to do with the writer's problems relating to the subject. Readers want protagonists they can relate to. HAL or similar beings won't ever be the heroes of popular fiction, regardless of how peaceful, benign, or otherwise virtuous their civilization is, even if it's written convincing...
by thoughtfully
Sun Nov 29, 2015 4:20 pm UTC
Forum: Science
Topic: The end and beginning of the universe
Replies: 13
Views: 2485

Re: The end and beginning of the universe

The trouble with White Holes is there are only bright when being fed a stream of matter on their Dark Side. I think that breaks the symmetry with the singularity at the Big Bang (unless the progenitor star is enough, I suppose), and I believe there are some other, more subtle arguments. Black Holes ...
by thoughtfully
Tue Nov 24, 2015 2:19 pm UTC
Forum: Science
Topic: Why is work independent of time?
Replies: 7
Views: 2839

Re: Why is work independent of time?

Work can depend on time, it's just buried in the force term, where maybe it isn't so obvious That's what I thought, but when I asked my professor he was adamant that work is independent of time. When you calculate it with force and distance, it is, in the sense that you can have the same F and d wi...
by thoughtfully
Mon Nov 23, 2015 2:22 pm UTC
Forum: Science
Topic: Gravity-temperature musings by Toffo
Replies: 162
Views: 29929

Re: Gravity-temperature musings by Toffo

This old post may help with understanding energy.
viewtopic.php?p=1794223#p1794223
by thoughtfully
Sat Nov 21, 2015 9:58 am UTC
Forum: Science
Topic: GR, the SM, SUSY, ST, and QM -- some general questions
Replies: 5
Views: 1946

Re: GR, the SM, SUSY, ST, and QM -- some general questions

With the the exception of GR, QM is part of all these things. QFT is basically field theory plus special relativity plus QM. Particles are localized bumps in, for example, the electron field. The Standard Model is a collection of QFTs that are the best experimentally verified framework of known phen...
by thoughtfully
Thu Nov 19, 2015 9:15 pm UTC
Forum: Science
Topic: Why is work independent of time?
Replies: 7
Views: 2839

Re: Why is work independent of time?

You can always have constant thrust, too. Ignoring any change in mass, one has d = a*t^2/2 F = m*a d = F/m/2 * t^2 Holding d constant, one can see the relationship. Work can depend on time, it's just buried in the force term, where maybe it isn't so obvious. There are a lot of ways to express work o...
by thoughtfully
Thu Nov 19, 2015 3:42 pm UTC
Forum: Science
Topic: Why is work independent of time?
Replies: 7
Views: 2839

Re: Why is work independent of time?

The work done is equal to the force times the distance over which the force is applied , not the distance traveled, which is after all, unbounded when there are no dissapative forces. Your distance equation need two terms, one with uniform acceleration, and one with uniform velocity. I'm not going t...
by thoughtfully
Wed Nov 18, 2015 6:34 pm UTC
Forum: Coding
Topic: The "IT DOESN'T WORK!" thread
Replies: 1963
Views: 572099

Re: The "IT DOESN'T WORK!" thread

How is your backwards compatibility broken? The easiest, least ugly thing to do is rename one of the files. You could import the renamed file and then assign that to the name "config". Would this work? import fooconfig as config config.configure() If your project has a complicated director...
by thoughtfully
Wed Nov 18, 2015 11:36 am UTC
Forum: Science
Topic: NASA reports net gain of Antarctic ice
Replies: 56
Views: 7875

Re: NASA reports net gain of Antarctic ice

Yeah, gotta love those alpha emitters. So cuddly (and occasionally warm)! But do not take internally :)
by thoughtfully
Wed Nov 04, 2015 2:37 pm UTC
Forum: Science
Topic: NASA reports net gain of Antarctic ice
Replies: 56
Views: 7875

Re: NASA reports net gain of Antarctic ice

If I reach far back into the dusty corners of my mind that contain high school physics class memories, I seem to recall that the concave shape of water in a container was due to the nature of water adhering to the sides of the container, working against gravity. In the absence of gravity the water ...
by thoughtfully
Tue Oct 20, 2015 1:21 pm UTC
Forum: Science
Topic: Sun as final storage for radwaste?
Replies: 134
Views: 27963

Re: The sun as a nuclear waste incinerator

There's a thread on this already, your answers can be found there.
by thoughtfully
Sun Oct 18, 2015 11:58 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2962
Views: 730986

Re: RELATIVITY QUESTIONS! (and other common queries)

If the universe evolves to a state of total entropy, doesn't that imply that all information has been lost? The information isn't lost, anymore then it's lost when a set of encyclopedias is burned. So I was just thinking about an accelerating expansion of the Universe while I was reviewing my post....
by thoughtfully
Sun Oct 18, 2015 7:23 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2962
Views: 730986

Re: RELATIVITY QUESTIONS! (and other common queries)

A few related questions... I can have a stab at these. Why is it implicit in quantum theory that information is never lost? This has to do with Unitarity , which is basically the requirement that all probabilities of possible outcomes add to one. That's not a great explanation, I know. The Wikipedi...
by thoughtfully
Sun Oct 11, 2015 1:34 am UTC
Forum: Science
Topic: Quantum vacuum and relativity
Replies: 6
Views: 2017

Re: Quantum vacuum and relativity

Rather than the Doppler effect, I prefer to think of Unruh Radiation as the Equivalence Principle equivalent of Hawking Radiation, if that helps. Also, if it doesn't help. What a stupid expression :) If you want some math, I posted an uncommented CAS session once just as a demo for mathomatic. It us...
by thoughtfully
Tue Oct 06, 2015 1:56 pm UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2962
Views: 730986

Re: RELATIVITY QUESTIONS! (and other common queries)

As someone pointed out in another thread, different frequencies of light travel at different speeds (otherwise you couldn't split light with a prism?). So... how? I thought all massless particles travelled at the same speed in a medium, but it seems that's not quite the case. This only applies in a...
by thoughtfully
Mon Oct 05, 2015 1:25 am UTC
Forum: Science
Topic: Miscellaneous Science Questions
Replies: 2962
Views: 730986

Re: RELATIVITY QUESTIONS! (and other common queries)

The no-hair theorem only applies to classical black holes. It's a theorem, a logical inevitability of its premises (General Relativity). Adding quantum mechanics changes the premises.
by thoughtfully
Thu Sep 24, 2015 1:52 am UTC
Forum: Science
Topic: Nuclear explosion powerplant
Replies: 31
Views: 6310

Re: Nuclear explosion powerplant

The blast will heat up anything it's passing through, ionizing a lot of it. Also, x-rays (and some gammas). Gawdawful buttloads of x-rays. Atmosphere is going to be leaking in, unless herculean efforts are made, or it's off-planet. You'll have your plasma. Containment is a solved problem. It's under...
by thoughtfully
Thu Sep 24, 2015 12:55 am UTC
Forum: Science
Topic: Nuclear explosion powerplant
Replies: 31
Views: 6310

Re: Nuclear explosion powerplant

Hey, I see you have loads of hot plasma there. Why not use some of these babies , maybe inline with steam generators. I'd just use a relatively small number of bombs in Orion type lifters to place solar power stations in orbit and beam the power back to earth using microwaves. There are some nutty p...

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