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DrJoePesce

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Mar 31, 2020
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Happy Tuesday All!

I wanted to give you a little astronomy gift, a virtual backdrop from the National Science Foundation. Others are available if this doesn't do it for you! :)

Since SR (Special Relativity) is in the mix....

Perhaps you have a far better handle on some of this and can help me (us).

Of course we'll use a spaceship A (with Alice) being observed from E (Earth with Ed). [I could be in error on all of these, admittedly.]

1) Ed sees Alice's clock run slower. He adjusts for the time it took for the light from her clock to reach him, and her clock is still slower.

2) Alice does the same and sees that Ed's clock is running slower.

3) When Alice and crewmates return to Earth, however, her clock will demonstrate that her travel time consumed less time (i.e. time dilation). This is consistent will all known experiments, that I'm aware. Some say this is due to a symmetry break since Alice was the one who experienced acceleration/deceleration. Is this the mainstream view?

Also, there is a math equivalence for time dilation found in length contraction, which came along shortly before Einstein's remarkable paper. But, the only known objective evidence I've ever heard that supports this as something physical has to do with the flattening of particles at CERN (or similar facility) that greatly favors length contraction over time dilation. Is there any evidence for contraction that can't be explained by time dilation that you're aware?
Happy Thursday Helio! Isn’t relativity a blast? I was going to reply directly to your post, but then found this terrific article: https://www.scientificamerican.com/article/time-and-the-twin-paradox-2006-02/ which, I think, gets to all your points.

Dr Joe
 
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DrJoePesce

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Hi Dr Joe. My sincere thanks for the most informative reply, containing references within references. I apologise for straying beyond the strict realm of science but, as you are well aware, time travel is SF screaming for clarification.

I have given an answer to the grandfather paradox. By Occam's Razor, it is preferable to assume that you (present) cannot visit your own past, because 'you' are already there in a different 'now', and your future self cannot coexist with your 'then' self, as you were not there at the time. This is instead of inventing multiverses (a non word, in this context at least). Simpler than inventing multiverses, which (inventing), presumably, is open to billions of people through history - not to mention possibly other creatures, all instigating their own scenarios. Could get a bit crowded, especially for the BLOCK model. I won't mention the BLOCK problem of predetermination ;) .

Quote
There is comfort in subsuming your sense of individuality to a larger sentiment of prescription and predetermination.
.— Jia Tolentino, The New Yorker, 1 Nov. 2019
Quote

Anyway, thanks again. I shall keep my headaches to myself, at least for some considerable time to come. :) :) :)

Cat :)
Hi Cat – don’t keep your headaches to yourself! That’s why the forum is here (even if I may not be an effective analgesic!).

I think I agree with you about the grandfather paradox. Although I think the non-mathematical explanation in the attached article is intriguing (I haven’t explored the math).

Dr Joe.
 

DrJoePesce

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Hi Joe,

Another question from me. Do we know for sure what's inside black holes? We know that inside neutron stars there are neutrons. Could it be there are also neutrons inside black holes ? In this article they discuss that black holes spin close to speed of light due to conservation of momentum. May be if our sun would spin at these speed it's gravity well (or spacetime) would also be spinning as fast, trapping the light within. Can we be sure that the black holes are not just neutron stars with more spin?

Thanks
Suneritz – great questions! First, we DON’T know what’s inside black holes (that is, inside the event horizon). Obviously, the stuff that fell in, and its mass (or mass equivalent for the photons). But how is it arranged? (Presumably within the singularity, but maybe not.) This is the great unknown, and the existing laws of physics can’t help us.

As for the article: In the thought experiment/example, shrinking the Sun to a 3km radius makes it a black hole, and produces all the extremes that come with that.

If we could spin the Sun, as is, at relativistic speeds (ignoring all the reasons why that would be difficult or even impossible), we still have a gravitating mass with 1x the mass of the Sun. So, no, it wouldn’t trap light. And that would also negate the more rapidly spinning neutron stars being black holes.

The extreme gravitational field of the black hole comes from the extreme gravitational well caused by 5+ solar masses in a space with 0 physical dimension (the singularity).

By the way, the rate of the (currently) fastest-spinning pulsar (so, a neutron star) is 716 times per second. (https://www.nrao.edu/pr/2006/mspulsar/) Assuming typical neutron-star diameters, this is about 24% the speed of light. Some neutron stars are really spinning!

Dr. Joe
 

DrJoePesce

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An initial skim suggests cosmic rays accelerated inwards are bad at 10M km and very bad at 2.5M km. I have a base at Moon #16 and out as okay for Van Allen radiation but still moderately dosed by synchrotron radiation from Jupiter.
A base procedure assuming some in situ abilities:
1) Manned landing at Moon #16 with RF ion engines. Take off, accelerate fast inwards using RF engines. Cut them before inner Jovian system physics disrupts them.
2) Slow down with rockets. Land on Callisto. Not differentiated from being a 3d checkerboard of rock and ice. Meteorites will have smashed through the ice cube and stuck. Over time, they will have sunk not too far; only to the underlying rock. Here lies 3x the metals of Triton harvestable.
3) Melt through the ice with lasers. Collect the meteorite fanned out brecchia pieces. Crush them, melt them, sift them. Make ice armour for the trip back. Armour the ship.
4) The rockets that landed also need to use Callisto in situ ice propellant as rocket fuel. Make rocket fuel from the ice. Make Ions. Potentially leave ion engines on surface.
5) Lift off from Callisto using rocket fuel. Then potentially leave rocket engines in orbit.
6) Either use existing RF engines, or ferried from outer Moon RF engines, to accelerate fast in the particle and plasma soup of Callisto distance (at least with micro-meteorite armour as shielding). Radiation might cease these engines but meteorite hits will certainly obliterate most rocket fuels.
7) Cut the engines. Eventually begin a slow RF ion burn landing on Moon #16 with ions, metal ore, igloo ice. Evaluate health effects of synchrotron radiation for a potential retreat outwards.
I really like your ideas Phillip Huggan! Note that while metals would make a great radiation shield, water is likely sufficient (and much lighter).

Meteorites that have impacted these ice satellites will have indeed penetrated the surface and are probably studding that crust. It’s likely these satellites have sub-surface oceans, so if the impactors penetrated deep enough they would sink beyond reach.

Energy source: We would be quite far from the Sun at this point, so I suspect we can’t rely (wholly, at least) on solar energy but would need nuclear reactors (probably).

More things to ponder!

Dr. Joe
 
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Catastrophe

"There never was a good war, or a bad peace."
Dr Joe, "don’t keep your headaches to yourself!"

Well, if you are inviting me . . . . . . :) :) :)

May I ask whether you have any 'scientific' views on time travel? Obviously, we are not in a position to enact experiments, or to falsify conclusions (if we had any conclusions).

Albert Einstein once wrote: People like us who believe in physics know that the distinction between past, present and future is only a stubbornly persistent illusion. Time, in other words, he said, is an illusion. Many physicists since have shared this view, that true reality is timeless.

The time line model can be rather appealing, until you hit predetermination. That could easily encounter the "forbidden" rule, so I will only say that a fixed time line has serious implications. "What wrote the book?" might be a bad place to start, causing more than serious headaches.

But, could there be an "open" time line, maybe something akin to how we see our travelling "now" (if it exists?). We can see our past part of the time line, and some constraints on the variables which apply to the future, but we don't need the BLOCK model for that. Maybe the world line can accept some degree of fuzziness? Maybe the nature of the time line cannot accommodate any fuzziness, and then we drift into dreamy semantics. Maybe last Thursday is just as real as this moment, and the arrow of time is even more unforgiving. Grrrrrrr I will save that stuff for my next novel ;) .

Anyway, I will "cut the cackle" and just ask whether you can envisage a time line which does not depend on predestiny? I mean this, I suppose, in the context of a BLOCK model. Can any such model have any credibility in the way that the big bang gives problems very closely approaching t = 0, where we are stuck with words like (e.g., division by zero) infinity? If I understand correctly, there is some difficulty with a singularity (if such exists). Is, in fact, the BLOCK model falsified by its dependence on predetermination?

Cat :)
 
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Happy Thursday Helio! Isn’t relativity a blast? I was going to reply directly to your post, but then found this terrific article: https://www.scientificamerican.com/article/time-and-the-twin-paradox-2006-02/ which, I think, gets to all your points.
Thanks much, Dr. Joe, for that great article. I've seen this before, Paul Davies, IIRC.

My hang-up seems to exist within the following claim in that article:

"As the traveler reaches the star, he reads his clock at eight years as mentioned, but he sees the homebody's clock as it was six years ago (the amount of time it takes for the light from Earth to reach him), or at four years (10-6). So the traveler also views the homebody's clock as running at half the speed of his clock (4/8)."

Upon arrival to the star, notice that the 10 years of time expired by the Earth clock is the amount of time our travelers will agree with as having expired, less the 6 years of travel (hence 4 years net). This, however, means the travelers would not have observed a slower time rate for the Earth clock. Although this fixes the paradox, it does so by slight of hand, IMO. The challenge I have is that the in relativity, both will argue the other's clock is slower. Either the Earth clock is seen as slower or it's not. To claim 10 Earth-years have elapsed (less 6 = net of 4) seems awkward, at best, for me at least. If the travelers really would see Earth clock running slower, the net time should be less than 4 years net. Seeing 4 years on the Earth clock by the travlers is admitting to the Earth clock having never run slower... I think. :)

It's a head-scratcher for me, but I do appreciate the article. :)
 

Jzz

May 10, 2021
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Also, there is a math equivalence for time dilation found in length contraction, which came along shortly before Einstein's remarkable paper. But, the only known objective evidence I've ever heard that supports this as something physical has to do with the flattening of particles at CERN (or similar facility) that greatly favors length contraction over time dilation. Is there any evidence for contraction that can't be explained by time dilation that you're aware?
Many physicists cherish the hope that there is some kind of secret code in both special and general relativity that will return everything to normal and that will rationalize all results. Unfortunately, this just does not happen. Relativity is based on the fact that both time and space are mutable. The general theory of relativity explains gravity as a distortion of space (or of the spacetime continuum) caused by the presence of matter or energy. A massive object generates a gravitational field by warping the geometry of the surrounding spacetime. And it is all based on the slender, insubstantial and illogical assumption (postulate??) that the speed of light is immutable. For decades this fact that the speed of light was constant only because both time and space were underwent change was shrouded in mystery. The general assumption was that the speed of light was the speed limit of the Universe further everyone thought of the speed of light (through a vacuum) as some kind of benchmark of precision. The speed of light was constant, it could never vary. What a crock!

Therefore, according to relativity, time does dilate and lengths contract (or expand) depending on your frame of reference. It is not something that is just a perception. Think of the twins paradox, it is something tangible.


Of course we'll use a spaceship A (with Alice) being observed from E (Earth with Ed). [I could be in error on all of these, admittedly.]
The third thing that comes to mind is that Ed and Alice are fine for the rarified atmosphere of theory, in practice take two planets 4 light years apart with a 10,000 km wide kilometre between them, wouldn’t a 1000 commuters be plausible at any one time (one space travel became well established that is) ? The point is that that 10000 km wide corridor would be split up into 1000! different pieces. Where is there room for sentient life in such a scenario. 1000! Is a number that is bigger than all of the atoms in the Universe!

The fact that has to be faced is that relativity is not real, it is the imaginary world created by a brilliant mind for his own indulgence and which others bought into because there was, at the time no viable alternative. Today such an alternative does exist in the form of GAT, a new aether theory that has all the answers. Read The Electromagnetic Universe:

 
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Hi Joe,

Thanks for detailed and mainstream explanation on my last question. Another quick question while it’s not busy. If you could run an electric wire around Moon (or Mars) in a geo stationary orbit and pass an electric current (superconducting due to vacuum) could that wire become an electro magnet? If it could, would the core of the rotating body underneath start producing electric current (like an electric generator), which could give off substantial enough magnetic field, which could protect the surface below from dangerous radiations like an “umbrella” would, which by the way looks like an interesting ancient device.

Thanks
 
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Special relativity only tells us that the relativistic time t' of the moving frame observed in the stationary frame (relative to the observer) becomes shorter than the relativistic time t of the stationary frame:

t' = t/γ

Nothing else. It is a wrong interpretation that the clock on the moving frame ticks more slowly than the clock on the stationary frame. We know a physical clock does not directly count relativistic time but counts the cycles of its oscillation system and the number of cycles in special relativity equals the relativistic time divided by period. As period is relativistic time and should behave like relativistic time, the period p' of the moving clock should be shorter than the period p of the stationary clock:

p' = p/γ

which makes the number of cycles N' of the moving clock equals the number of cycles N of the stationary clock:

N' = t'/p' = (t/γ )/(p/γ ) = t/p = N

That is, clock time is absolute and independent of the reference frame, completely different from the relativistic time which is just a mathematical variable without physical meaning.

Therefore, based on such a fake time, special relativity is wrong.
 
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Regarding the twin paradox in special relativity, the traveling twin's biological age is the product of relativistic time and his aging rate. The aging rate of the traveling twin is getting faster than the aging rate of the twin on the earth similar to the frequency of the moving clock shown above. The relativistic effect of time dilation and aging rate of the traveling twin cancel each other to make their product always the same as that (i.e. the biological age) of the stationary twin. Therefore, even in special relativity, you will never see that the traveling twin becomes younger after a space travel.

Similarly, all so called relativistic effects will never be shown on any physical process.
 

Jzz

May 10, 2021
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Nothing else. It is a wrong interpretation that the clock on the moving frame ticks more slowly than the clock on the stationary frame. We know a physical clock does not directly count relativistic time but counts the cycles of its oscillation system and the number of cycles in special relativity equals the relativistic time divided by period. As period is relativistic time and should behave like relativistic time, the period p' of the moving clock should be shorter than the period p of the stationary clock:
My advice is to be careful about clocks. Even a clock on the top floor of a high rise building will run faster than one on the ground floor. This is an experiment that has been tried numerous times, but it is probably due to the effects of gravity rather than General relativity.
 
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My advice is to be careful about clocks. Even a clock on the top floor of a high rise building will run faster than one on the ground floor. This is an experiment that has been tried numerous times, but it is probably due to the effects of gravity rather than General relativity.
Yes, it is true that gravity can slow down atomic clocks and can also make pendulum clocks tick faster, but it just influences specific physical processes just like the influences of temperature which can be corrected through calibration. It can not make time go faster or slower. All so-called relativistic effects are misinterpretations.
 
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Disproving special relativity

In Newtonian mechanics, we have Galilean Transformation between two inertial reference frames:

X' = X - vT
Y' = Y
Z' = Z
T' = T

where v is the speed of the origin of the inertial reference frame represented by Galilean spacetime (X', Y', Z', T') relative to the origin of the inertial reference frame represented by Galilean spacetime (X, Y, Z, T).

We can prove that clock time is the same as Galilean time T:

Since clock time Tc is defined by the number of cycles N of a physical periodical process:

Tc = N/k

where k is a calibration constant and equals 9,192,631,770 for a cesium atomic clock.

The clock times Tc and Tc' of two clocks attached to the inertial reference frames defined by Galilean spacetime (X, Y, Z, T) and (X', Y', Z', T') above are

Tc' = N'/k
Tc = N/k

where

N' = T'/P'
N = T/P
P' is the period of the clock on (X', Y', Z', T') and P is the period of the clock on (X, Y, Z, T).

As in Newtonian mechanics, time is absolute, we have P' = P and thus

Tc' = N'/k = (T'/P')/k = (T/P)/k = N/k = Tc

which means the time shown on the moving clock is always the same as the time shown on the stationary clock, i.e., the clock time is absolute and independent of the reference frame. If we choose k = 1/P, then

Tc' = Tc = N/k = (T/P)/k = T (1/P)/(1/P) = T

That is, in Newtonian mechanics, clock time is the same as the absolute Galilean time.

But Einstein uses Lorentz Transformation to introduce a new set of space and time (called relativistic space and relativistic time) which is mathematically equivalent to the redefinition of space and time:

x' = γX'
y' = Y'
z' = Z'
t' = (1/γ)T' - (γv/c^2)X'

where γ = 1/sqrt(1 - v^2/c^2), (x', y', z', t') is the relativistic spacetime coordinate system with the same origin and same directions of space axis's of the Galilean spacetime (X', Y', Z', T'), and v is the speed of the origin relative to the medium of light, aether. When v = 0, relativistic spacetime (x, y, z, t) becomes the same as Galilean spacetime (X, Y, Z, T):

x = X
y = Y
z = Z
t = T

Yes, Einstein has the right to introduce new spacetime, but he must also change the design of clocks to adapt to his new relativistic time. In reality, the principle of physical clocks have not been changed according to relativity and thus clocks still measure the absolute time. The change of the definition simply means the newly defined relativistic time is no longer the physical time measured with physical clocks. Thus special relativity is wrong.

The absoluteness of clock time can also be shown by physical clocks in special relativity. For example, we can use the height H of a vertical pole to represent the physical time of a clock attached to the inertial reference frame (x, y, z, t) and (x', y', z', t') respectively. If the two clocks have the same physical time observed in (x, y, z, t), we have two events:

(x1=0, y1=0, z1=T1=H, t1=t)
and
(x2=vt, y2=0, z2=T2=H, t2=t)

which are simultaneous measured with both clock time (T1 = T2 = H) and the relativistic time (t1 = t2 = t). Now let's see the two events observed in (x', y', z', t'), which can be obtained through Lorentz Transformation:

x1' = γ(x1 - vt1) = -γvt
y1' = y1 = 0
z1' = z1 = H
T1' = z1' = H
t1' = γ(t1 - vx1/c^2) = γt

x2' = γ(x2 - vt2) = γ(vt - vt) = 0
y2' = y2 = 0
z2' = z2 = H
T2' = z2' = H
t2' = γ(t2 - vx2/c^2) = γ(t - v(vt)/c^2) = γt(1 - v^2/c^2) = t/γ

That is, the two events become

(x1'=-vγt, y1'=0, z1'=T1'=H, t1'=γt)
and
(x2'=0, y2'=0, z2'=T2'=H, t2'=t/γ)

They are still simultaneous measured with clock time (T1' = T2' = H = T1 = T2), but no longer simultaneous measured with relativistic time (t1' != t2'), which means clock time is still absolute in special relativity, different from relativistic time and thus relativistic time is no longer clock time but a mathematical variable without physical meaning. Based on such a fake time, special relativity is wrong.
 

DrJoePesce

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Dr Joe, "don’t keep your headaches to yourself!"

Well, if you are inviting me . . . . . . :) :) :)

May I ask whether you have any 'scientific' views on time travel? Obviously, we are not in a position to enact experiments, or to falsify conclusions (if we had any conclusions).

Albert Einstein once wrote: People like us who believe in physics know that the distinction between past, present and future is only a stubbornly persistent illusion. Time, in other words, he said, is an illusion. Many physicists since have shared this view, that true reality is timeless.

The time line model can be rather appealing, until you hit predetermination. That could easily encounter the "forbidden" rule, so I will only say that a fixed time line has serious implications. "What wrote the book?" might be a bad place to start, causing more than serious headaches.

But, could there be an "open" time line, maybe something akin to how we see our travelling "now" (if it exists?). We can see our past part of the time line, and some constraints on the variables which apply to the future, but we don't need the BLOCK model for that. Maybe the world line can accept some degree of fuzziness? Maybe the nature of the time line cannot accommodate any fuzziness, and then we drift into dreamy semantics. Maybe last Thursday is just as real as this moment, and the arrow of time is even more unforgiving. Grrrrrrr I will save that stuff for my next novel ;) .

Anyway, I will "cut the cackle" and just ask whether you can envisage a time line which does not depend on predestiny? I mean this, I suppose, in the context of a BLOCK model. Can any such model have any credibility in the way that the big bang gives problems very closely approaching t = 0, where we are stuck with words like (e.g., division by zero) infinity? If I understand correctly, there is some difficulty with a singularity (if such exists). Is, in fact, the BLOCK model falsified by its dependence on predetermination?

Cat :)
Thanks Cat! I'm afraid I'm not versed enough in this subfield to be able to reply definitively. I will try to do some research and respond later.

Dr Joe
 

DrJoePesce

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Hi Joe,

Thanks for detailed and mainstream explanation on my last question. Another quick question while it’s not busy. If you could run an electric wire around Moon (or Mars) in a geo stationary orbit and pass an electric current (superconducting due to vacuum) could that wire become an electro magnet? If it could, would the core of the rotating body underneath start producing electric current (like an electric generator), which could give off substantial enough magnetic field, which could protect the surface below from dangerous radiations like an “umbrella” would, which by the way looks like an interesting ancient device.

Thanks
Hi suneritz - keep the creativity coming. I think you would still need a liquid metallic core for this to work. So maybe on Mars, probably not on the Moon. You would also have difficulty keeping the wire in orbit (and I wouldn't want to be on the surface when it comes screaming in!). Also, I don't think the current we could generate would be strong enough to induce a current, or one that is strong enough to create a magnetic field.

As I read this and responded, I can't get out of my mind another concept that uses a cable (though for something completely different): the so-called space elevator idea. The jist of it is that you have a carbon-fiber cable (because that's the only thing that would be light and strong enough) extending from the equator to geosynchronous orbit and on which you launch satellites; bringing them up to geo like an elevator (and down too). It's a novel idea that would probably be possible in the not-too-distant future. It is another thing I wouldn't want to see fail, with 35,000km of carbon-fiber cable wrapping around the equator!

Dr. Joe
 
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Catastrophe

"There never was a good war, or a bad peace."
View: https://imgur.com/a/1ARPmm3


Hi Dr Joe,
A multi-part question, if I may, about singularities.
1. My understanding is that, at t = 0, physical laws break down, due to division by zero. I also understand that beyond this zero point, by a minute interval, big bang theory is pretty solid, and this is reassuring. Am I OK so far?

2. What is current official standpoint on such a (BB) singularity? Coming from (1), there are suggestions of infinite density, temperature et cetera. Am I correct in thinking that these infinite conditions are the result of singularity theory, and not essential prerequisites of the following BBT?

3. I preface this question by stating that I am not looking for support of any particular outcome. I have serious reservations about some possible outcomes.
Is there any scientific reason why a singularity might not be replaced by a nexus, as in the cyclic scenario 'big crunch' or super black hole -> nexus -> big bang, omitting the singularity? I do accept that there are serious questions with cyclic models, particularly in relation to entropy and the 2ndLoTs.

Cat :)

P.S. Thursday 24th March 05.20 GMT:

Further to my new thread "Some thoughts on antimatter"

4. Are we limiting our thinking on possible cyclic universes to recycling the 'same old' Universe phases/components in total negation of the fact that we really know nothing about >95% of the observable universe?
 
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Catastrophe

"There never was a good war, or a bad peace."
One more please Dr Joe - much closer to BB and conventional stance, I believe.

Is the idea still current in scientific circles, that there were (very soon after t= 0) very large amounts of matter and antimatter which mutually destructed, leaving just what we have now as 'ordinary' matter?

If so, then was it the mutual destruction of + and - what fuelled inflation?

Cat :)
 
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Hi suneritz - keep the creativity coming. I think you would still need a liquid metallic core for this to work. So maybe on Mars, probably not on the Moon. You would also have difficulty keeping the wire in orbit (and I wouldn't want to be on the surface when it comes screaming in!). Also, I don't think the current we could generate would be strong enough to induce a current, or one that is strong enough to create a magnetic field.

As I read this and responded, I can't get out of my mind another concept that uses a cable (though for something completely different): the so-called space elevator idea. The jist of it is that you have a carbon-fiber cable (because that's the only thing that would be light and strong enough) extending from the equator to geosynchronous orbit and on which you launch satellites; bringing them up to geo like an elevator (and down too). It's a novel idea that would probably be possible in the not-too-distant future. It is another thing I wouldn't want to see fail, with 35,000km of carbon-fiber cable wrapping around the equator!

Dr. Joe
Thanks Joe. If even it’s theoretically possible on Mars, I’ll take it. :)

I was also wondering if the opposite can be done. For example, could we (temporarily) suppress planet Venus magnetic field? Then Sun would strip away it’s dangerous atmosphere (like it did with Mats) so people could move in there after magnetic field is restored again. To implement it, may be the same approach with the wire to generate a magnetic field except we need to create antimatter (positrons) current inside Venus core so it would destroy it’s regular electron current. Is this how antimatter works, and would there be a. significant energy released endangering the planet? Thanks
 

DrJoePesce

Verified Expert
Mar 31, 2020
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View: https://imgur.com/a/1ARPmm3


Hi Dr Joe,
A multi-part question, if I may, about singularities.
1. My understanding is that, at t = 0, physical laws break down, due to division by zero. I also understand that beyond this zero point, by a minute interval, big bang theory is pretty solid, and this is reassuring. Am I OK so far?

2. What is current official standpoint on such a (BB) singularity? Coming from (1), there are suggestions of infinite density, temperature et cetera. Am I correct in thinking that these infinite conditions are the result of singularity theory, and not essential prerequisites of the following BBT?

3. I preface this question by stating that I am not looking for support of any particular outcome. I have serious reservations about some possible outcomes.
Is there any scientific reason why a singularity might not be replaced by a nexus, as in the cyclic scenario 'big crunch' or super black hole -> nexus -> big bang, omitting the singularity? I do accept that there are serious questions with cyclic models, particularly in relation to entropy and the 2ndLoTs.

Cat :)

P.S. Thursday 24th March 05.20 GMT:

Further to my new thread "Some thoughts on antimatter"

4. Are we limiting our thinking on possible cyclic universes to recycling the 'same old' Universe phases/components in total negation of the fact that we really know nothing about >95% of the observable universe?
Hi Cat, Happy Monday. Great questions, as always!

1. Yes. But the division by zero is because the physical dimension, r, is zero (the universe is a singularity at time = 0).

2. Well, I guess it’s not a requirement to have a singularity for a big bang event, but if you run the movie backwards, as it were, you end up with a singularity. (The same thing you have in a black hole, just with more mass.) We only have one universe, so the big bang model only operates in one place. And so, because of this, I would say that, yes, a singularity is a prerequisite. But to me, by calling it a prerequisite seems to indicate the model is operating somewhere else (another universe, for example), and, of course, we don’t know anything about other universes (or even if they exist). (By the way, the big bang theory is the vernacular name for the favored theory/model of the universe. It should be called the inflationary model/theory, for reasons we get to in your other post, below.)

3. I don’t know enough to know whether the singularity could be replaced by something else. I also don’t know why you might want to or need to replace it. Speaking of big crunches: Problems with these models aside, it is highly unlikely our universe will cycle like this: big bang, recollapse, big bang. There’s just not enough mass/density to allow that. Up to 20 years ago, it was thought to be highly unlikely (because of the lack of mass), but now with dark energy (which is accelerating the universal expansion), it is even more unlikely to recollapse.

4. Apart from the unlikelihood of a cyclic nature of our universe, I don’t think so. Everything in our universe exists (whether or not we know what it is and understand it), so if we did have a cyclical universe, I don’t see why there would be problems with recycling matter/energy. Presumably the universe at the quantum level (and the forces/energy therein associated) would be the same from cycle to cycle. I suppose with each big bang event there could be minor fluctuations in forces and constants (mass of electron, for example). I hadn’t thought about this from the perspective of what differences (if any) might interfere with the cycle, and that is interesting. We could certainly end up with universes where the constants are tweaked such that atoms can’t form, or fusion can’t take place. Again, though, a cyclical nature of the universe is not on the cards for us.

Thanks for the thought-provoking questions! Dr Joe
 

DrJoePesce

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One more please Dr Joe - much closer to BB and conventional stance, I believe.

Is the idea still current in scientific circles, that there were (very soon after t= 0) very large amounts of matter and antimatter which mutually destructed, leaving just what we have now as 'ordinary' matter?

If so, then was it the mutual destruction of + and - what fuelled inflation?

Cat :)
Hi Cat – Yes, absolutely. Indeed, matter and anti-matter are coexisting up to about 1 second after the big bang. At about 1 second, all the matter and anti-matter particles annihilated each other…. Except, for some reason (not yet understood), for every one billion anti-matter particles there were one billion and one matter particles. When the billion matter and billion anti-matter particles annihilated, one matter particle remained (multiplied over many times, of course!). This occurred well after the inflationary period (which happened between 10^-35 second and 10^-24 second after the big bang; when the universe expanded by a factor of 10^50, going from the size of an atom to the size of a grapefruit).

It’s an intriguing thought that the energy from the particle annihilation was what caused inflation, but I think not (and I’m not sure there would have been enough energy to do that). Inflation is happening within the fabric of space, probably at the quantum-mechanical level. But the biggest argument for why this wasn’t the energy source? Because the acceleration of the universal expansion rate that kicked in about 1 billion years ago. This accelerated expansion is caused by the so called “dark energy”, and is probably related to, and by the same processes occurring during, the inflationary period, right at the beginning.

It's all quite amazing, isn’t it?

Dr Joe
 

DrJoePesce

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Thanks Joe. If even it’s theoretically possible on Mars, I’ll take it. :)

I was also wondering if the opposite can be done. For example, could we (temporarily) suppress planet Venus magnetic field? Then Sun would strip away it’s dangerous atmosphere (like it did with Mats) so people could move in there after magnetic field is restored again. To implement it, may be the same approach with the wire to generate a magnetic field except we need to create antimatter (positrons) current inside Venus core so it would destroy it’s regular electron current. Is this how antimatter works, and would there be a. significant energy released endangering the planet? Thanks
Hi suneritz! My answer is going to be a hand-waving one (I haven’t done any calculations – not even on the back of an envelope!).

I think suppressing a magnetic field is not possible (from being generated; certainly, we can shield from a magnetic field, but not planet-wide). I think the only way to suppress a magnetic field is to stop the dynamo and I suspect that’s not possible, even with advanced technology.

You mention positrons because you would presumably induce a current flowing in the opposite direction? I think if anything it would just flip the magnetic field, but, again, I don’t think you could stop the dynamo. By the way, you probably won’t need positrons – I think maybe protons would work. (Incidentally, protons and electrons flowing from the Sun are trapped in magnetic field lines, and they induce currents and affect the magnetic field locally, but not universally.) I also think it would be extremely difficult to work with antimatter like that, in any case.

Venus’s atmosphere IS being lost to space (certainly the current thinking is that the water vapor interacts with sulphur dioxide to form hydrochloric acid, and what was left is broken up by ultraviolet photons and driven off). It just that the rate is slow (and it’s being replenished from the surface (volcanos?).

Great questions!

Dr Joe
 
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DrJoePesce

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Speaking of magnetic fields, here is my Monday surprise for you: The latest from our new, beautiful, solar telescope -NSF's DKIST.


With a stunning high-resolution images of sunspots, and the magnetic field flux tubes visibly emanating from them.

1648475638226.png
 
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DrJoePesce

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When I was in graduate school, long ago, magnetic fields were poorly understood (and hard to understand). And they were usually invoked when one couldn't explain an observational finding: "Look at this strange behavior, it's probably caused by magnetic fields". Which was shorthand for, I don't know what this could be, we don't understand magnetic fields, let's use them as an excuse and move on!. The audience would nod wisely.

Now, thanks to new advances (like the NSF's DKIST solar telescope), and other astronomical observations (like these of the jet in M87: https://www.space.com/m87-black-hole-jet-double-helix-structure and https://www.space.com/first-black-hole-image-polarized-m87 ) we are starting understand and better explain astrophysical phenomena.

Dr Joe.
 
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Given that an object in a stable close orbit just outside the event horizon of a black hole will experience time dilation; then to a distant observer, will the orbital period appear to be slower than expected by purely Newtonian mechanics?
 

Catastrophe

"There never was a good war, or a bad peace."
Hi Dr Joe,

I have repeated questions and answers for clarity. Don’t worry, I have summarised it below. New in BOLD:

A multi-part question, if I may, about singularities.
1. My understanding is that, at t = 0, physical laws break down, due to division by zero. I also understand that beyond this zero point, by a minute interval, big bang theory is pretty solid, and this is reassuring. Am I OK so far?

Yes. But the division by zero is because the physical dimension, r, is zero (the universe is a singularity at time = 0).

1a. I am sorry, I should have cleared that my use of t = 0 here included an alternative scenario – namely the mid-point of a nexus (in that hypothetical scenario). Since I am open to thinking about (not necessarily supporting) such, I was making the point that the ‘OK part’ (BBT) can (according to this hypothesis) be considered irrespective of the precedent ‘singularity’, viz, separating the unknown beginning from the supported sequitur.


2. What is current official standpoint on such a (BB) singularity? Coming from (1), there are suggestions of infinite density, temperature et cetera. Am I correct in thinking that these infinite conditions are the result of singularity theory, and not essential prerequisites of the following BBT?


2. Well, I guess it’s not a requirement to have a singularity for a big bang event, but if you run the movie backwards, as it were, you end up with a singularity. (The same thing you have in a black hole, just with more mass.) We only have one universe, so the big bang model only operates in one place. And so, because of this, I would say that, yes, a singularity is a prerequisite. But to me, by calling it a prerequisite seems to indicate the model is operating somewhere else (another universe, for example), and, of course, we don’t know anything about other universes (or even if they exist). (By the way, the big bang theory is the vernacular name for the favored theory/model of the universe. It should be called the inflationary model/theory, for reasons we get to in your other post, below.)



2a. This starts by following from (1). I do not understand (mea culpa) how ‘running the movie backwards is a valid scientific process. The fact that you use a euphemism alerts me. When you have a jump like inflation, followed by a gradual curve, followed by increasing expansion, what sort of a backward projection do you make, and how do you justify it? Do you have enough data to make any such projection? If (not a straight line but) a ‘flattish’ parabola (or such) were fitted to the data, might not those incredibly small intervals like 10^-35 (10-35) become more ‘believable’ intervals? When we do not understand >95% of the observable universe, how can we begin to even think of laying down what the Universe was close to t = 0, whichever version we choose? What sort of scales do you use when you make the projection? Is this published somewhere I can access?

Please pardon my queries. I am a great fan of Korzybski (General Semantics) = “the map is not the territory”, et cetera. Probing is my second nature.

BTW I believe (if we are to uphold the viability of language) we have to ban words like universes, except in such a context as “Observable universes depend on the location of the observer” There is one ‘Universe’ in my book. Either we urgently need some new definitions or cosmology discussions are going to fail in short order.

Finally, my use of the word ‘prerequisites’, I believe, is quite justified. Suggesting ‘other universes’ is abhorrent in my book. I was merely asking whether the well attested BBT was inseparable from the (in my humble view) questionable (metaphysics, not science) model.

My question was “Coming from (1), there are suggestions of infinite density, temperature et cetera. Am I correct in thinking that these infinite conditions are the result of the singularity model, and not essential prerequisites of the following BBT?” In other words, Can we not (hypothetically) have BBT without some sort of (imho) fictional singularity?





3. I preface this question by stating that I am not looking for support of any particular outcome. I have serious reservations about some possible outcomes.
Is there any scientific reason why a singularity might not be replaced by a nexus, as in the cyclic scenario 'big crunch' or super black hole -> nexus -> big bang, omitting the singularity? I do accept that there are serious questions with cyclic models, particularly in relation to entropy and the 2ndLoTs.


3. I don’t know enough to know whether the singularity could be replaced by something else. I also don’t know why you might want to or need to replace it. Speaking of big crunches: Problems with these models aside, it is highly unlikely our universe will cycle like this: big bang, recollapse, big bang. There’s just not enough mass/density to allow that. Up to 20 years ago, it was thought to be highly unlikely (because of the lack of mass), but now with dark energy (which is accelerating the universal expansion), it is even more unlikely to recollapse.



3a. In view of the adoption of ‘useful fudge factors’ are we really in any position to categorically rule out the word “cyclic”. Coming back to Korzybski, verbal plasters may only cover over the chasms in understanding, Maybe ‘cyclic’ evokes unhelpful connotations. Maybe we should be thinking of a Universe where mere words like ‘beginning’ and ‘end’ have no cosmic meaning. I think it is sometimes a failing, as well as a blessing, that homo sapiens insists on ‘knowing all about everything’. His quest for truth may result in his ignorance. Is the Universe, whatever it is, a closed system? And are we addressing only the <5%?



4. Are we limiting our thinking on possible cyclic universes to recycling the 'same old' Universe phases/components in total negation of the fact that we really know nothing about >95% of the observable universe?



4. Apart from the unlikelihood of a cyclic nature of our universe, I don’t think so. Everything in our universe exists (whether or not we know what it is and understand it), so if we did have a cyclical universe, I don’t see why there would be problems with recycling matter/energy. Presumably the universe at the quantum level (and the forces/energy therein associated) would be the same from cycle to cycle. I suppose with each big bang event there could be minor fluctuations in forces and constants (mass of electron, for example). I hadn’t thought about this from the perspective of what differences (if any) might interfere with the cycle, and that is interesting. We could certainly end up with universes where the constants are tweaked such that atoms can’t form, or fusion can’t take place. Again, though, a cyclical nature of the universe is not on the cards for us.



4a. Much of this was dealt with in 3a. I would like to reconsider the word ‘cyclic’. Maybe we should be thinking of a Universe where mere words like ‘beginning’ and ‘end’ have no cosmic meaning. They are just words we invented, and have no underlying reality. Mere ‘grunts of a partially evolved ape’, one might think.



So let me replace all of the foregoing with a somewhat shorter version.



We have a very adequate Big Bang Theory (more correctly, as you point out, Inflationary Model/Theory) which, however, is based on an insubstantial base where the division by zero (r) invalidates using the laws of physics.




I believe that the layman, looking at the suggested beginning – an infinitely small concept at infinite density and temperature, might find ‘bursting out of nothing rather less palatable than an honest admission that we do not know, and probably have no means of knowing, the ultimate precedent of inflation. On this occasion, might he not be correct?



Thank you for the most interesting responses, which I value highly, and for your time in considering what are, in fact, metaphysical questions.



Cat :)
 
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