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Question of the Week / Re: QotW - 23.12.08 What are black holes made of?

« on: Yesterday at 23:38:34 »

What are black holes made of?

Black holes are essentially places, not objects. The interior of a black hole is just more spacetime, just like outside, except more curved. If you fell into a large black hole, you'd notice no particular change as you crossed the event horizon. You could go on with you day as usual. All events inside a black hole are causally in the future of events outside, so there would be no way to affect anything outside.

The spacetime curvature would result in a tidal effect which gets stronger the closer to the singularity you get. For small black holes and other dense objects (such as a neutron star), the tidal effects would be fatal as you get anywhere close to it, let alone cross some event horizon. Hence my reference to a large black hole above where the tidal effects are not so noticeable even after crossing the event horizon.

If Escape Velocity is above 186,000 miles/sec, does a Single Photon start to get Stretched?

It really makes no sense to talk about any velocity over c. There is no escape velocity from a black hole, not even greater than c.There is no meaning to a photon getting stretched. Sure, it has a wavelength, but that is frame dependent, and photons and everything else would behave pretty normal at (and beyond) the event horizon, per the first postulate of special relativity which says that the laws of physics are the same in any inertial frame, and spacetime at an event horizon is locally Minkowskian (flat), so the physics of inertial frames very much does apply there.

Zer0, the escape velocity is determined by the gravity experienced at the launch site,

Escape velocity is a function not of the gravity experienced (how much you weigh there), but rather the relative gravitational potential.  So for instance, escape velocity of Earth is about 11.2 km/sec, but from the surface of Uranus you might weigh about 10% less but the escape velocity there is 21.4 km/sec, nearly twice that of Earth. The difference is that the gravitational potential on Uranus is lower than it is on Earth, assuming each is the sole object being escaped respectively.

Escape velocity has little to do with black holes since the concept is meaningless for one. There is no escape, at any speed and any acceleration. It would literally be trying to travel to the past. You just can't go that way.

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New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 05/12/2023 23:55:47 »

we have to accept that space is infinite, unless anyone has an alternative that doesn't require the Supernatural.

There are a lot of alternatives that don't require the supernatural.
How do you explain (without supernatural) the existence of this been-there-forever universe you propose. Sure, you avoid the whole [nothing, then later something] issue, but you still need to explain the something. It's not a science problem, but rather pure philosophy. So science doesn't need to answer it, but a belief system does.

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Physics, Astronomy & Cosmology / Re: Quantum Entanglement and Interstellar Communication.

« on: 02/12/2023 19:29:57 »

The particle is measured by applying a magnetic field.  The measurement will detect if the spin is up, aligned with the direction of the field or if it is down, aligned opposite of the field direction.  Therefore the orientation of the lab frame is not important.

It is the orientation of the field that is important. That defines the axis of measurement. It has nothing to do with choice of abstract coordinate system (lab frame).

This is not correct.  The particles are no longer entangled.  When 2 particles are entangled they have the same wave equation.

Good point. The wave functions (at least that concerning their spin) are different now. Other parts (wave function of position say) were never the same, even though they were spin-entangled. You can't say that two entangled particles millions of miles apart are equally likely to be found at a given location.

  When one of the particles is measured the wave function collapses and now the particles are no longer described by a single wave equation, now both of the particles are described by different wave equations.

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Physics, Astronomy & Cosmology / Re: Quantum Entanglement and Interstellar Communication.

« on: 02/12/2023 17:54:05 »

A couple of clarifications, based on my limited knowledge of the issue.

We will assume that the property we are going to look at is the spin of the particles.
The 2 particles are separated by 10 million miles.  Each location has a detector that will measure the particles spin direction (up or down).

We are measuring the spin relative to some particular axis. Only if both measurements use the same axis will the measurements be fully correlated. If perpendicular axes are used, there will be no correlation. If something between is used (45 degrees say), there will be partial correlation.

5.  Once either particle is measured they are no longer entangled.

Sort of. The measuring system is effectively entangled with the unmeasured particle, which is why you can know what the measurement will be if it ever gets done. I think if you measure a particle along the same axis twice in a row, you'd get the same result, so in that way of looking at it, the two particles remain entangled, but the entanglement is now restricted to the axis that has been chosen, so a subsequent measurement along a perpendicular axis isn't going to be correlated with the unmeasured particle.

6.  Once you measure the orientation of your particle you instantly know the orientation of the other particle.

You instantly know the outcome of a measurement of the other particle along the same axis, regardless of if it has already been done or will be done (a frame dependent distinction). The far guy of course knows none of this, so from his point of view, the outcome is still totally random.
Anyway, your wording implies that the unmeasured particle actually has a spin orientation, which most interpretations deny.


All that said, the glove analogy (a classical example) still satisfies pretty much all of the above points. I separate the gloves in envelopes unopened, When one is opened, that person instantly knows the contents of the other envelope. It's a epistemological thing, not a metaphysical one. The glove system is classical, so metaphysically, there is in fact a left glove in this envelope and a right in the other. No superposition. We just don't know which is which.

Quantum systems go further than that. The EPR paradox showed that quantum entanglement cannot be classical like the gloves. I'm not going to attempt to explain that since I'd get it wrong. Look up the paradox or Bell's theorem if you want the detail. They are probably well beyond what Zero want's to know. They are beyond my capability to convey correctly without just copying text from a website.

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Physics, Astronomy & Cosmology / Re: QM puzzle: Is a measurement being made in the 2 slit experiement all the time?

« on: 30/11/2023 16:16:38 »

So the integral we'd be interested in, representing the total probability of finding the electron at the screen from  'then'/ that time  to  infinity  is finite << 1.   Specifically we can assume the electron would never be found at the screen, write it off and just fire the next electron.

Sounds reasonable

Anyway, we were talking about a lack of detection at the screen as being a lack of measurement:

Depends on your definition of measurement. In real life, measurement is epistemological. If the electron hits the lab wall, you're unaware of it and your epistemic wave function isn't altered by the event. In the sim, the sim would know that the wall was hit and the actual wave function would be altered, and the real wave function would collapse. The screen then also measures the collapse because the screen measures the wall; it becomes entangled with the wall state.

Well, that is still some measurement by the screen as far as I can see.

Yes, you know it missed, so the epistemic wave function is altered by the knowledge, even if it isn't 100% certain.

It is NOT at the screen at any time, although there are lots of other places it can be

Unless you're assuming a counterfactual interpretation, I think it a mistake to talk about where it is in the absence of measurement. But a lot of simulations do exactly that, so I suppose it depends how your sim is implemented. You know it missed, so the new wave function can yield odds of where it likely hit, and that's assuming that the lab is reasonably closed and it doesn't shoot off into space never to interact with anything, as so many photons never do.

Is it possible for a thing to exist despite the fact that it hasn't and will not in the future interact with anything else?

A matter of definitions. What does it mean to exist? There's conservation laws, so of course it exists. It merely lacks a location/momentum.

  Anyway.... there's always gravity which we don't tend to include in any Quantum Mechanics,   the electron is still providing some energy density and thus curving space, i.e. it is interacting with something else in some way (you would think).

For example, the electrons can encounter other particles and potentials en route to the barrier and/or screen.

Always wondered about that. Do they regularly do the electron-gun thingy in a vacuum to avoid that sort of thing?

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New Theories / Re: If there was one Big Bang event, why not multiple big bangs?

« on: 30/11/2023 02:05:16 »

If i was Never born,
i shall Never die...

My sister did that actually, so I suppose she is a counterexample to your statement.
She was about 5 months older than me.

How about the premise that life has always existed; has an infinite past as well as an infinite future.

Seems there would be a lot more life seen in places other than Earth then. There is a very viable proposal that Earth life did not originate on Earth, but even it doesn't go so far as to say it was always there. That violates all evidence.

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Physics, Astronomy & Cosmology / Re: QM puzzle: Is a measurement being made in the 2 slit experiement all the time?

« on: 30/11/2023 02:00:52 »

The question is:   Isn't the phosporescent screen always making a measurement?

Easy answer: Yes. More complicated: Yes, relative to the screen, just like the cat measures the poison bottle, so the bottle is not in superposition of closed/broke, but the bottle is still in superposition of those states relative to the lab observer. Copenhagen places a 'Heisenberg cut' at the boundary of where those states differ.

You seem to be asking if the electron misses the screen, is a measurement taken? Well, not by the screen (yet), but either the electron with interact with something else (and thus get measured by something else), or it never interacts, and is effectively nonexistent (according to any local interpretation at least).

Specifically isn't it possible that by constantly making a measurment, the phosphorescent screen ensures that the electron's wave function cannot collapse to the state where it would be at the screen?

Yes. The comment only applies only to interpretations where collapse is meaningful. You'd have to word it differently for others, but still, effectively yes.

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Physics, Astronomy & Cosmology / Re: Quantum Entanglement and Interstellar Communication.

« on: 28/11/2023 12:15:14 »

That's interesting, Halc. How would one go about demonstrating that such a particle is in a state of superposition?

I do not know the exact procedure to detect superposition of spin state, but I do know that it is a statistical thing, that it can be demonstrated only by doing the experiment repeatedly. So for instance, the photon might be in superposition of having gone through one slit and the other, but the measurement is the dot it creates on the screen which doesn't tell you anything, but 1000 dots creates an interference pattern (superposition) and 1000 dots creates a simple bell curve (not in superposition). The spin state is similar, so you'd need to have a lot of them.

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Physics, Astronomy & Cosmology / Re: Quantum Entanglement and Interstellar Communication.

« on: 27/11/2023 20:25:14 »

.
Quantum Entanglement can NOT transfer Information Faster than the Speed of Light in a Vacuum.
Agreed?

Origin gave a better wording of this statement. There are non-local interpretations that posit faster than light causation in entanglement situations, but none of them suggest that this can be used to transfer information faster than c.

then can we Please discuss Q.E. further by choosing the Left/Right socks Analogy?

Socks tend to not come in left and right, but gloves do. So entanglement is a little like wrapping a pair of gloves in two packages and one goes to Mars. Once there, either person can open the package he has and instantly know the contents of the other no matter how far away. Nothing physical changes, and the mechanism cannot be used to send a message.

The analogy ends there. A glove in a box is a classical object in a classical state of being left or right, and the package only serves to prevent knowledge of this classical state until opened. In quantum mechanics, the particle-pair is not classical, but in superposition of being in either state (let's say spin up/down). One can perform an experiment on either particle to demonstrate this superposition state, all without actually measuring its spin. That can't be done with the gloves.

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Physics, Astronomy & Cosmology / Re: Are All The Planets Moving Away From The Sun Due To Sun Losing Mass ?

« on: 15/11/2023 17:07:57 »

What sort of effect does the friction of the solar wind have

I would think not very much since for the most part the force imparted is perpendicular to Earth's orbital motion.  The wind comes out and the magnetic field deflects it fairly equally to either side.

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Plant Sciences, Zoology & Evolution / Re: How Do Seeds Know Which Way Is UP ?

« on: 14/11/2023 17:44:59 »

A lot of seeds I've watched seem to germinate out of some predetermined end, which might be the 'down' side. Both stem and root (stem first) seem to emerge from the same end. The stem part curls upward due to gravity, and yes, plants pretty much rely on that.
I've not seen bulbs reorient themselves but do not assert that it doesn't happen. Some bulbs I've planted come with instructions as to which end to point up, but the typical daffydills and crocuses (croci?) seem to do just fine if you just throw em in the hole.

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Physiology & Medicine / Re: How Does The Placebo Effect Work ?

« on: 14/11/2023 17:39:07 »

If yes, then can the belief in getting better be achieved without taking a false treatment ?

It takes actual belief, something some of us cannot just conjure at will.
I know others that are very adept at making up an alternate reality, and then actually believing it. I have a harder time doing it.

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Plant Sciences, Zoology & Evolution / Re: Do Land Animals Hesitate When Entering COLD Water ?

« on: 14/11/2023 14:51:53 »

Some (many cats for instance) simply don't like to get wet. Plenty of dogs run right in and enjoy it. Tigers seems to like it. Sheep?  Who wants a wet sheep?  Probably not the sheep.

Going into water why?  To drink only requires to be at the edge. Crossing a river is needed sometimes, so a wildebeest goes right in, sometime to the point of going back and forth across the large body being crossed in search of their calves, hard evidence of 'bewild-a-beast' effect.

Seals and otters and such are water animals and don't count, and one might ask why they might or might not hesitate to emerge from the water.

Do you just go straight in ? or put your toe in first ?

I go straight in.

We went to a campground where the owner could not get his swimming pool certified for public use since it lacked a chlorine and a filtration system. It was approved only for use of himself and personal friends. So if you wanted in, you went and asked, and he'd ask if you were his friend. Say yes, and you could go in.
Think was, the pool was continuously fed by a mountain spring, so technically it was an artificial pond, and super cold. Most people were content on the uber-hot days to merely dangle their ankles in.  I would dive right in for the full shock effect of hitting water that was single-digit C at best.  Loved it, but didn't stay in there too long.

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Plant Sciences, Zoology & Evolution / Re: What Do the Spiders In My Garage Eat In Winter ?

« on: 14/11/2023 14:40:48 »

If they're active, they're probably finding warmth and food somewhere. They're quite capable of preventing their fluids from freezing.
Some species do a form of hibernation (diapause I think is the term) where they go dormant and wait for spring.
Some simply die, leaving egg sacks to repopulate the joint in the spring.

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Physics, Astronomy & Cosmology / Re: Are All The Planets Moving Away From The Sun Due To Sun Losing Mass ?

« on: 14/11/2023 14:31:18 »

Are All The Planets Moving Away From The Sun Due To Sun Losing Mass ?

There are four factors that make planets change their orbital distance, and yes, the sun losing mass is one of them,

1) Tidal effects push the moon away, but they also make the Earth recede from the sun, at a rate of over 10 cm/year
2) The one you mention: About 2 cm/yr recession is due to the sun losing mass.
3) Friction: The Earth loses orbital energy due to friction (collisions) with meteors and such
4) Gravitational waves: The Earth/sun system pumps about 200 watts of energy away in the form of gravitational waves.

In the future, it seems likely that Earth will get swallowed by the sun when it grows. The 3rd line, friction, will win in the end. For planets from Mars on out, the 4th line will win in the end, but all four lines rely on the consumption of some limited energy source.

The solar mass thing effects the orbits of all planets in proportion to their distance. The tide thing in proportion to their rotation rate over their distance.  The tidal thing decreases as the planetary spin slows down, so it is temporary since its energy source is limited.
The friction thing is limited by the amount of free matter flying around between the planets. The planets slowly clean up the solar system.
The gravitational wave thing continues unabated and will eventually be the winner. Jupiter will eventually collide with the sun due to it getting closer through the continuous radiation of energy, similar to how black holes eventually merge.

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Physics, Astronomy & Cosmology / Re: Temperature and k.e. : Does a substance cool down if particles break apart?

« on: 11/11/2023 14:44:05 »

Energy is conserved, the container is insulated.

Insulate means here that the peas bounce off the walls (and each other for that matter) with perfect elastic collisions.

The temperature must fall to half it's initial value when the particles split into two. 

Yes, by your reasoning (and that given by BC) the energy is constant, but more/smaller particles with the same energy results in half the temperature.

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Just Chat! / Re: What is the purpose of "question of the week"?

« on: 10/11/2023 14:53:05 »

Is it open to normal replies or does it have some other function?

It is very much open to replies from any forum member. The purpose seems to be related to the non-forum parts of the site or the radio show. Listeners of the radio or podcasts can submit questions and supposedly one question each week gets posted, with the answer (which sometimes don't come from the posted replies) being part of some subsequent podcast or something.

The protocol is: Don't post a new topic here. Only official members of the shows should do that, not even the forum mods. The site software should actually have something that prevents new topics from being posted here. I regularly move out (or occasionally delete) topics that are posted here.
Many human spammers seem to gravitate to that QotW. The bots all seem to choose THE OFFICIAL BOOK, making them really easy to spot.

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New Theories / Re: What is non-returning twin paradox?

« on: 02/11/2023 20:46:22 »

That's what's described in the videos by Minutephysics, MIT OCW, and Harvard professor. Right BEFORE the turn around, the travelling twin measured that the earth twin is younger than him. Right AFTER  the turn around, the travelling twin measured that the earth twin is older than him.

No video was referenced. Where is this asserted?  What video, what timestamp?
In particular, exactly what measurement does the twin perform that lets him know this, all without presuming the answer to his measurement before he performs it?  If the video does not mention a way to actually measure this, then the claim falls flat.

No where does he say or even imply an absolute reference frame.  I'm at a loss to see where you came up with that idea.

That's a logical implication of Lorentz' relativity theory, which differentiate it from Einstein's special relativity.

Yes, LET has completely different premises than does SR, making it a different theory, or different interpretation at least. Funny thing is that the simplified method I explained at the beginning of this topic works in LET just as well as it does in SR. That's not true for most explanations.

As for 'the exact cause of the dilation' as the one topic asked, dilation isn't something that is caused. It can be explained by various methods, so there is no one correct explanation, and the existence of any one alternate explanation does not in any way invalidate the others.  You seem bent on finding the most convoluted explanation out there, with bonus points if it's actually wrong.

In Lorentz' relativity, A objectively ages less than earth observer or Alpha Centauri observer. A never measure/calculate earth/Alpha Centauri observers to age less than himself.

All this is blatantly false. LET neither asserts nor concludes any of these things. I'm not saying LET is wrong. I'm only saying you are.

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New Theories / Re: Would this allow for the detection of gravitons?

« on: 01/11/2023 00:46:08 »

The idea is to use two micro black holes, perhaps with masses on the order of the Planck mass.

Wouldn't such small black holes evaporate faster than any manipulation on them could be done?

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New Theories / Re: Split: What is my explanation for the differential age of the twin?

« on: 30/10/2023 20:22:59 »

Halc, as soon as a discussion starts to get relevant and productive, you run and hide, and try to make any information that you don't agree with disappear.

I only moved it (and deleted dup posts).  We can discuss it in two weeks (here, not in the main forums) when your vacation is over.
Three straight posts in the wrong place, despite warnings.

The contradictions were heavily discussed here
https://sciforums.com/threads/bell%E2%80%99s-spaceship-paradox-does-the-string-break.165916/

and you ignore them all, and refuse to answer many questions that directly identify the contradictions