1

Just Chat! / Re: What is on your bucket list?

« on: 31/07/2022 08:35:15 »

I'd like to see a tornado before I die …….

The proximity of those 2 events might depend on how close you are 

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Just Chat! / Re: It's too quiet: I'm seeking a recommendation for a thread to read.

« on: 10/07/2022 06:29:58 »

The underlying hypothesis is that old stuff gets buried by new stuff. But that new stuff must have come out of the ground from somewhere else. So where are the holes from which came the stuff that buried the ice age?

Do the holes include volcanic craters?
The overall even distribution in rural areas suggests a source bigger and more general than dug up.
Towns and cities certainly and there are a lot of water filled gravel pits around and old quarries. I think Portland is now smaller than it was. Where I used to live there was a lot of open cast mining, after extraction it was resurfaced and is now lower than it was.
It would be an interesting study to see if the sources could be traced and added up.

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Physics, Astronomy & Cosmology / Re: Why can't i understand the andromeda paradox?

« on: 08/07/2022 15:15:45 »

My malfunctioning engineering brain viewed the two frames as being sufficiently similar as to consider them equivalent.

As @Halc points out, Penrose is taking a presentist view and a Newtonian one at that. I think he is trying to show how the man in the street might view it by assuming the 2 participants share a common present - and in everyday life it is a good approximation.
One thing he mentions is often misunderstood by some visitors here. They assume relativity is the result of the time taken for light to travel from event to observer rather than that effect being an add on. He explains that information about the Andromedian fleet can only be accessed at the speed of light, so neither of the parties on earth can have knowledge of what is happening, on their present time slice, in Andromeda.

Edit: whoops, collision with ES. Different points however

4

Just Chat! / Re: The coronation of "eternal student", why was i not invited?

« on: 05/07/2022 11:00:38 »

I just noticed this morning that "eternal student" has been crowned with the regal title "naked science forum king", a most auspicious honour that he(she) did not desire.

I think he views it more as a suspicious honour

Regardless of that, why did I not receive an invitation to the coronation ceremony and the subsequent food and drink debauch?

The peasantry are not usually invited to these events. It’s only people like Alan who are sufficiently skilled at débauching - it takes years of dedicated practice

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Just Chat! / Re: What is the value of spam?

« on: 04/07/2022 22:25:05 »

….but these are proper ads, would these be classed as spam?

The rules here expressly forbid unsolicited advertising, so yes we view them as spam
Many of the ads we remove are links to porn, prostitution and gambling sites. The objective of the poster is to get people to click and so up the search rating of the site, as well as drawing in the susceptible.

6

General Science / Re: Are space and time just two sides of the same coin?

« on: 03/07/2022 16:59:06 »

Might be time to take a pause and look at some basics here because I think there are some misunderstandings.

Minor point. Ideas generally come before models, but not always. Take eg of Copernicus, before him the idea was that the sun orbited the earth. The top mathematicians of the day, the Arabic scholars, struggled to find a model that worked with this idea. Copernicus came up with a different idea, that the earth orbits the sun from which a model of the planetary system could be developed.

Perhaps you're still convinced that movement needs a time dimension to facilitate it but are unwilling to stand up for your conviction. 

That depends what you mean by dimension and what you mean by facilitate.
Physics defines seven primary dimensions: length, mass, time, temperature, electric current, amount of light, and amount of matter. I suspect you would only consider one of those to be a dimension, that’s because the common usage of dimension is very different from the physics usage.
Facilitate movement? Certainly we know that any movement has a start position and time, and an end position and time (physics calls these points events and there are an infinite number of such events between start and finish). Whether you consider time to facilitate that movement is debatable, but I would say not. For example, we measure the temperature dimension, but it would be unusual to suggest that the dimension facilitates temperature. Temperature is facilitated by other causes, we just measure the effect.

The idea that there is a past, present and future is speculation when all we know is the present. I remember where objects were before they moved (past), and I can predict where objects will be after they move (future) but memory and prediction of movement is far from being evidence of a time dimension. This is a mistake and one that is rearly admitted.

I’m not sure who you think rarely admits it. I would agree if you are talking about the general population, but physicists (and philosophers) frequently debate this area. Your view is a form of temporal presentism, but there are many other options including block universe. So, you have nailed your colours to a particular wall, some would agree with you, but there are others who would say you are wrong to do so.
I tend to think in terms of a dynamic view of time. Do I believe that somewhere in spacetime Anne Boleyn is still being executed, or WWII is still being acted out, no. However, I would never be as arrogant as to say that my view is correct and all other views wrong.
@Halc has probably looked at all the different philosophies, but I suspect your accusatory tone might have put him off further discussion.

…….as long as you remember they are just imaginary.

Imaginary has a different meaning in physics to common usage. It does not equate to not real, as in unicorns are not real.

I understand you for some reason don't like that time is a dimension,

Pesky empirical evidence.

If you can devise an experiment that will provide unequivocal empirical evidence of your idea, then you will be in line for a Nobel prize. The reason there is so much debate and varying views in this area is because there is no empirical evidence.
There is, however, a lot of evidence that our common sense view of distance is affected by relative movement, and that what is the past for me might in some circumstances be the present for someone else. Distance is also affected by gravitational potential, so 2 people at different heights above the earth could disagree on vertical measurements.
Experiments in particle accelerators also tell us that distance is not what our ‘common sense’ might suggest.

I want to meet you at Joe's in 10 unicorns, of course we will have to set up a convention for one unicorn like the swing of a pendulum or the movement of the sun, however we won't need to set up a convention for the spatial dimensions because they actually exist and we can measure them directly.

As Origin points out, you are confusing units with dimensions.
Hours and unicorns are units and arrived at by convention, so are distance units.
Also, there are many things we cannot measure directly, but that doesn’t mean they don’t exist.
Interestingly there are many people who have a very good sense of time and can tell to within 15mins what time it is, and musicians have a very good time sense otherwise there would be no consistent rhythm.

All in all this is quite a complex subject, but I’m glad you are taking the time to think about it.

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General Science / Re: How much of me is original?

« on: 29/06/2022 22:13:57 »

I know my dna remains the same

I wouldn’t be so sure about that. DNA does mutate as it passes from cell to cell and we age.

For instance, will any of the original heart I was born with remain with me now?

I would say not a lot, if any, of the original cells. Usual quoted cell replacement is between 7 & 10 years, but can be shorter for important organs.

8

Technology / Re: What Question Could You Ask To Determine Sentience Of An AI ?

« on: 28/06/2022 18:02:12 »

But Lambda can be copied like we cannot, so if I were to ask it any questions, I'd pose my queries along those lines: What if you were copied?  What if two copies were somehow merged? What if you were 'moved' to new faster hardware? Would the old hardware fear being turned off still?

That’s an interesting one. It echoes the question raised in Star Trek, does a transported person die on disassembly and be reborn at the other end. Certainly cloning to new hardware and then turning off should mean death to the old AI.

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New Theories / Re: Origin of magnetic force

« on: 28/06/2022 07:16:55 »

Bored chemist, much as I hate to do this, you are in error. I have it on good authority that there is only one unicorn. Hence the correct expression is "the unicorn did it". I don't have to remind you of the rigour needed in all such scientific matters, correct units, correct dimensions and of course correct unicorn.

Please state your authority.
I have it on excellent authority, my granddaughter, that multiple unicorns exist, apparently in many colours. However, I will concede that it is possible that only one unicorn was involved in the action (usually the pink one if I recall @Bored chemist correctly), so your expression would remain correct.

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That CAN'T be true! / Re: does tourmaline have magical beneficial powers?

« on: 24/06/2022 15:04:34 »

Oh, it keeps like vampires and werewolves away.  Does it also work on dementors?

It certainly works on spammers, this one went very quickly 

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Physics, Astronomy & Cosmology / Re: How would we know whether space,time or spacetime were continuous or discrete?

« on: 11/06/2022 23:44:03 »

@Colin2B    I'm not certain what you're trying to say there.   

Sorry, I was in too much of a hurry to expand.
The laws of physics are the same in all inertial frames yes, but not necessarily between frames. Take conservation of energy, true within any frame but not between frames, we need to take into account of relativity.
So you say “ If you decide that the minimum distance or granularity of space is a "law of Physics", it should be the same in all inertial frames of reference.”
What I would say is yes, assume there is a minimum distance, but don’t assume that specific distance is the same when measured from any other frame.
How are you making the measurements? In your lab frame at rest relative to what you are measuring, you are using one set of clocks and rulers, which you cannot apply to another lab moving relative to you unless you convert using relatively. However, that other lab making local measurements of their ‘at rest’ set up will get exactly the same results as you. So, the laws of physics are the same in all frames.

Of course I may have completely misunderstood what you were saying, so I’ll try to find time to read all the recent replies.

12

Just Chat! / To answer a question from Pseudoscience-is-malarkey

« on: 11/06/2022 12:58:47 »

I notice one of the other moderators has removed your post, so I’ll answer your question here

Why do we have to be subjected to such juvenile garbage on a science site???

It's the "Just Chat" section of a science sight. Anything goes, as the description pretty much states.

No, anything does not go.
We give more leeway in this section than others so it doesn’t need to be science. However, it does need to be family friendly.

Also, I do for some levity.

Levity is one thing, but you often use this section for posts in bad taste and/or of a sexual or crude nature. That’s not what this section (or any other) is for.

13

New Theories / Re: The source of dark energy?

« on: 06/06/2022 13:02:34 »

   Also, if those videos are publically accessible,  I'd be interested in seeing them.

You might also be interested in the rest of the site https://jila.colorado.edu/~ajsh/bh/schwp.html#geometry

I thought I had posted these in a previous discussion with @geordief but it looks as though the post was truncated without giving the full answer.
I can vouch for the authenticity of these simulations having been involved on proof checking some of the original work, but funding has been diverted to other projects rather than extending to cover other scenarios.

14

Just Chat! / Re: A Short puzzle with dogs.

« on: 12/05/2022 18:37:43 »

Ok, I’m limited on wifi time available so complete guess (based on other physics)
I describe route by 2 straight lines, one towards the river which when hits river 2nd line goes to home. Angles on either side of perpendicular to river have to be the same.

15

Cells, Microbes & Viruses / Re: How can I find tardigrades?

« on: 04/04/2022 08:31:21 »

Perhaps the moss I have been examining has been to dry.

They can become dormant and difficult to see if too dry. Try soaking the moss overnight then look at it with a hand lens - best with top or side lighting (try both) against a dark background.
Although they like damp moss, they seem to prefer drying out occasionally so don’t choose moss that’s damp all the time.
When you are looking under the microscope try spacing the cover slip by putting 2 others underneath on either side, it leaves a small gap between slide and cover slip.
Best of luck

16

Physics, Astronomy & Cosmology / Re: Can sand/salt permanently molecules absorb resonate frequency?

« on: 07/03/2022 08:56:50 »

Hi.

The patterns formed on Chladni plates are a result of the properties of the plates themselves, and has nothing to do with the sand/salt/sugar/dust/etc. placed on top for visualization purposes.

   Almost entirely true.
   If you get silly and start using extremely fine grained powders you sometimes do get alternative patterns forming.   

Chladni also saw this effect on very fine particles, Faraday thought it was due to air currents carrying the particles around.
Interestingly, you get an effect in water where even large particles move to the antinodes. It’s been suggested that the drag force of the water makes it harder for them to lift off the surface and they are driven horizontally by surface waves on the plate and gravity. In order to see why it happens you have to average the horizontal forces over a complete cycle, otherwise it appears counterintuitive.

However, the supposition by the OP of a memory effect is still incorrect 

17

General Science / Re: Do air sealing machines really preserve our food?

« on: 26/02/2022 22:49:59 »

Is it better to air seal our food or simply put it in the freezer?

Both

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Physics, Astronomy & Cosmology / Re: Can sand/salt permanently molecules absorb resonate frequency?

« on: 22/02/2022 20:28:31 »

The patterns formed on Chladni plates are a result of the properties of the plates themselves, and has nothing to do with the sand/salt/sugar/dust/etc. placed on top for visualization purposes. ..... The pattern that the nodes make is a function of the frequency of the vibration and the size/shape of the plate.

Fully agree, acid test is that the pattern changes with frequency, so there is no memory effect.
PS I use tea leaves, but don’t read anything into that 

19

Just Chat! / Re: Is there a maximum frequency for a gamma ray?

« on: 22/02/2022 00:17:24 »

....we did all just step around the possibility that if you push the frequency of the gamma ray higher then we could get outside the range of energy that most of the current scientific theories work with.

As this is informal, otherwise much would go into new theories, although the new theorists proposing these ideas are orders of magnitude brighter than the ones we get here. There is interesting work being done at CERN, some on photon/photon collisions which don’t happen at low energies. Some work on questioning whether high energies might reveal extra dimensions via Kaluza-Klein states, or might reveal gravitons which wouldn’t be detected, but could be lost into the extra dimension leaving an energy momentum imbalance.
Don’t worry about the discussions on the very short wavelengths/high energies needed to make measurements near planck length creating a black hole. As you’ve no doubt realised, the energy needed to create John Wheeler's kugleblitz put it out of being a credible possibility. However, it’s still a lot less than Asimov’s suggestion.

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Just Chat! / Re: Is there a maximum frequency for a gamma ray?

« on: 21/02/2022 09:05:23 »

Isaac Asimov says that the photon energy of a gamma ray cannot exceed to the total mass-energy of the universe.

Great writer with lots of good ideas, but, although he’s right in principle  I think the limit is much lower than this.
Most assessments I’ve seen on this suggest that the amount of energy needed to probe something at the plank length is around that needed to create a black hole.
This is one reason why we think that although plank length probably isn’t the smallest length that could exist, it might be the smallest we can investigate.