humility

I was reading through machine learning methods when I had a thought, "Wasn't some of these how the body programmed its cells?"

 Like with the Thymus
The Body continouly produce T-Cells then runs them through examples of the various cells in the body and examples of remembered bad cells.
If the T-cells attack a good cell or don't attack a bad cell, they are recycled
That sounds to me like the same method used for basic machine learning.

Is machine learning called something different when done by the body?

On 10/14/2020 at 8:34 PM, swansont said:

An appreciation of the magnitudes involved, which would come from doing some calculations of the energies of these processes.

To be honest I could never quite grasp how to comprehend electricity. Amps, Watts,  Volts, Watt hours, Quads, I can never quite figure out what does what or means what. So when I read that there are 3 trillion wattseconds of energy in the tides, that doesn't sound like a lot to me. I just thought "Thats just 30 million lightbulbs at one time, thats a very small number. But a single Tidal Turbine Produces 25 gigawatts a year,  thats 79 watts a second,  so you would half the amount of tidal energy in the oceans after just 19 million turbines built. Which is a lot, but there is more than enough space in the oceans for them. There are already over 300k wind turbines in the world and those can only go in very specific locations."

But I think the responses largely solved my curiosity regardless.

So I was thinking about how long the earth core will remain molten and the how much power is produced by the earth's core compared the amount of energy earth receives from sunlight and what would happen if geothermal energy was overused, pretty straight forward, the earth's core solidifies and that led me to thinking about tidal energy, which is powered by the moon rotating around the earth. And what happens if tidal energy is overused. The tide ceases. But then I thought "Hmm there has to be something else being used up, otherwise that would just be providing far too much energy considering the moon's orbit won't finish decaying for billions more years.  Can it really be a constant energy source for that long?"

So what am I missing here?

Actually yes I think it does. Thanks!  Im going to have to go back and reread a few books with this in mind. 

I dont mean the dictionary definition. I mean, well, it seems sometimes that the word information is used in a very special sense in physics.  Does it have a special meaning or is my perception off?

18 hours ago, studiot said:

OK so when a thing moves, something is different.

So asking the question what is movement means exploring what is that something that is different.

It also involves being able to distinguish anything different that is not movement.

 

Do you agree ?

 

 

I have a colour changing lightbulb that changes colour from red to green to blue and abck again when I switch it on

But the lightbulb stays in its socket and doesn't move.

 

So colour changing is change but it is not movement.

 

Do you understand this?

 

 

Since you are having trouble with a shadow moving, perhaps we should conside the hands of my bedside clock.

 

They go round and round on the clock face.

 

So do the hands move?

But does the clock move on my bedside table?

 

So what changes and what doesn't?

 

 

Sorry, this is too annoying and you missed the point of my question anyway.

18 hours ago, DrP said:

Things are complex when trying to define reality - the words are well defined. It can take a while to get your head around it if you don't have a background in science maybe? This is why children are taught language, mathematic, history, science etc in schools - to prepare them for later life. They aren't taught about spacetime as far as I am aware because it is quite complex and not need for early life as a human being in society. They just learn about 'gravity'. After learning languages, maths, history and sciences (physics in this case) they can if they choose to go on to study in much more detail at degree, masters or doctorate levels at university.  The question of motion and how it relates to spacetime and GR and the likes is the kind of thing you might get to study doing a pure physics or astrophysics degree  - probably year 2 or 3 after you have been prepped and taught enough physics to fully get your head around the stuff and the maths.  Sorry that feel 'it is a lot of effort' to get your head around the definitions - this is why people spend many years studying the subject.

 

Who do you mean by 'you' here? One of our members or science in general?  As I said above - it can take years of study for someone to understand it well enough to be able to answer questions about it to a level where the institutions feel they are worthy of an academic degree. What is your academic background? Do you expect to ask a simple question about movement and have the whole of physics wrapped up in a few lines of text as a reply? The answer can come in many different levels....  you could write a book about it getting deeper and deeper explanations as you get more detailed knowledge about the subject.

 

Im not really paying attention to who exactly Im talking to. I lose track once I get into a concersation. As Thats not really important. So you being whomever I was talking to. 

And I expect you to notice when Im applying concepts to the wrong words and to correct that, instead of assuming Im using the right words.  Because we just wasted an entire page of discussion because I was calling spacetime just space and no one apparently noticed that, instead kept trying to point out the definition of space instead of pointing out that space and spacetime were two different concepts.

I honestly thought space and time were literally the same thing and the words, space, time and spacetime were interchangeable. Because thats just one of the wierd things science does. 

Maybe also you are the kind of people that see pi and theorems as real as the rocks and trees. As you only see the rocks and trees as collections of measurements. And so you cant comprehend why one would want to differentiate a measurable pattern as less real than a rock or tree. That could also be adding to the confusion.

10 minutes ago, studiot said:

 

 

 

OK I did ask if you have a problem with English.

But you did not reply.

 

So let's take it very simply.

 

I am only answering your question what is movement?

 

So please cooperate.

 

Do you know what a Sundial is?

Do you understand that the shadow line on a sundial moves ?

 

yes, yes

So mass warps the spacetime field, which is like an object in that it is not merely a mathamatical or linguistic construct, the warping is called gravity, and space is just the measurement of distance and movement.

This is a lot of effort just to slot in the correct words. And you need to do a lot better at identifying when concepts are being applied to the wrong words if its such a big deal. 

10 hours ago, Strange said:

Space is just distances (in three dimensions). Would you call the distance between you and your coffee cup an "object"? 

 

I would yes, if that distance could be twisted so my cup and me touch.

So mass waes

4 minutes ago, Strange said:

The analogy is supposed to show how changing the geometry of the lines that the people are moving on can cause an apparent force between them.  Forget the "Earth" part of it and focus on the geometry of the lines of longitude.

You can certainly say that magnets curve the electromagnetic field. Which is a reasonable analogy for how mass affects the spacetime field.

Gravity doesn't curve space. Mass curves spacetime. One consequence of that is gravity.

If you want to to stick to a totally Newtonian approximation, that's fine.

I get the impression you don't really want to understand, so I won't put any more effort into this.

Space IS the measurement(s) of distance. That is all it is. And those measurements are changed by the presence of mass-energy.

So, not an object.

And not "warped by gravity".

 

Maybe it is a problem with words. So mass warps space, and spacetime is a thing that gets warped but space is just measurement?

Wait you calked it a spacetime field, so there a field isnt a mathamatical word so there IS an actual object like thing and its called the spacetime field.

And I do want to understand, You are just terrible at explaining and seem to keep contradicting yourself.

4 hours ago, beecee said:

Mass/energy acts on spacetime by warping/curving it. We feel that warping/curving as gravity....a spinning massive object like the Earth, will twist spacetime within its vicinity which we call frame dragging or the Lense Thirring effect. 

As I have just said, it is mass/energy that curves spacetime or mis-shapes it in someway [gravitational lensing, gravitational waves, Frame dragging] and we feel that as gravity. So gravity is simply geometry...the geometry of spacetime as dictated by mass/energy....or as a famous physicist named John Wheeler once put it, "Spacetime tells matter how to move; matter tells spacetime how to curve". 

Yes, it is a spherical object, or more correctly an oblate spheroid and the analogy by Strange is relevant. 

Also a point concerning gravitational lensing particularly,  light/photons will follow similar geodesics in spacetime.

So Space is like an object that is being warped by gravity?  And not just the measurement of distance?

I feel like you kerp going back and forth. Either space gets warped by gravity, or its a measurement of distance. I cant understand how it could be both.

Actually I see how it could be both, but it seems like you keep insisting space isnt something getting warped by gravity then saying it is.

5 hours ago, Strange said:

Space is just distances (in three dimensions). Would you call the distance between you and your coffee cup an "object"? 

It does require a new way of looking at things.

The curvature of spacetime caused by mass describes the way that the relative paths of particles moving forwards in time change in the spatial direction(s). 

As an analogy, imagine two people walking forwards, side by side, on a flat plane. Their paths will remain parallel over time. We can consider the direction they are walking as the "time" dimension (they are moving steadily into the future) and the distance between them as one of the space dimensions.

On the the flat plane, the distance between them doesn't change over time. Now put them on the surface of the Earth and have them both walk towards the North Pole (along lines of longitude). As they move forwards (in time) they get closer together. No force is acting on them, it is just a consequence of the curved geometry they are travelling in. You can consider them falling towards one another because of the gravity of the curved space-time they are in.

Your analogy doesnt work because earth is still an object. 

So one can say that magnets curve the space of other magnets then? Like those magnetic spinning toys that just keep spinning for years before running out of energy.

Also wouldnt it be better to just stop referring to space directly then? If you want to be super accurate with all terms, why say "Gravity curves space" instead of saying "Gravity pulls objects into hyperbolic arcs" Since its not actually curving space, its curving trajectories.

5 hours ago, studiot said:

Thank you for letting me know this.

The above quote is enough to see that you completely missed the point of my post.

I'm sorry if it was unclear, did you have trouble with the English or what?

 

I distinguish between all types of change and movement which is a special type of change.

For instance as concrete or mud or porridge dries it hardens.

And yes the hardening can be measured.

So there is change.

But there is no movement.

 

For movement I further distinguish between the movement of a material object such as a football.

and the movement of a non material object such as a shadow.

 

Does this help to move our discussion forward?

 

Nope, I still have no idea what you are trying to say. 

1 minute ago, Strange said:

Dreams can be influenced by external factors, so I suppose they are "actual things" by this definition.

In that case, our measurements of space and time (and the geometry relating them) are actual things because they are influenced by the presence of mass and energy, and by relative movement.

Gravity is a force we feel. That force is created by the geometry of space-time. 

Space-time is a set of coordinates that we use for measurement. The equations relate space, time and the thongs that influence them.

Whether any of those things are "real" is not something I can comment on.

This conclusion seems to contradict everything that has been said.

We have a model of how curving spacetime causes gravity.

We have no model at all of how gravitons could cause gravity. 

Up to you. The best alternative then is to go back to Newtonian gravity where gravity is just a force proportional to mass. 

There are probably some vocabulary words Im missing that is causing this confusion. 

My initial question was making the assumption that space is basically its own force. Because its always described as if it was some kind of object that we are just sitting in. An object that gets curved and twisted by gravity, torn apart by black holes, and of course science fiction likes using warping of space to do all sorts of stupid things.

But thinking of space and time as just the numbers used to describe the relationship objects have with each other.  Really strongly changes my perspective on everything.

And it means however the force of gravity works, its affecting objects directly instead of the emptiness the objects are sitting in. 

6 hours ago, studiot said:

No

 

Since you haven't given me a clue as to what you understand by I said, I don't have a clue and can't elaborate further.

 

So it is up to you?

As I understood it, You described how movement is measured then went on towards linguistical definitions of the word.

6 hours ago, Strange said:

They are the same thing. When you walk 3 metres from your chair to the door, that distance is not an "actual thing" (depending, of course, on what you mean by "actual thing"). And that distance is exactly that is being measured and used in the description of motion etc.

I don't think it is misleading. Although it might be more accurate to say that it is the geometry that relates our measurements that changes. But as those measurements are what define "space" and "time" (and their relationship) it is pretty much the same as saying that space-time is curved.

It is mass that curves space and time; one of the effects of that is the gravitational lensing of light around the Sun. Another effect is the apparent force that we call "gravity".

By actual thing, I meant sometjing that can be influenced by external factors.  You know, if you have a big block its a thing because you can push and pull it and do stuff with it. But if you draw a picture of a big block, then that isnt a thing. The paper you drew on is a thing, the paint is a thing, but the apparent block, although you can measure its color and size, isnt a thing. No more than a cloud that looks like a marshmellow is actually anything more than a cloud.

Ive always thought of gravity as a thing since it could be warped and affected. And it seems like you are saying spacetime isnt real. Its just a conviently related set of equations that make nice pictures. 

At least this explains gravitons, I did wonder how gravity could be caused by space curving and gravitons. But if space doesnt curve then that means its all just gravitons curving the path of the objects. Since its the objects being affected, not the space the objects are in.

Ill have to drop spacetime as a word I use.  

What does 'sec' mean? I assume you dont mean Secant and its not in the dictionary except as meaning very dry. 

On 10/15/2018 at 1:54 AM, Eise said:

.

I would say that space 'sec' does not exist, so you are right, we can't formally define movement as a change in position in space. But there are very practical ways to 'define' space. Take two objects in otherwise empty space: at least we can define a distance between these objects. And if this distance changes, we say the objects move in relation to each other. Now you can more and more objects, measure their distances and directions, and you get a kind of coordinate system that can be called 'space'. If most objects move slowly relative to each other the impression of the existence of space in itself becomes very strong. And then of course also the impression of (fast) movements relative to 

Time and space are definitely not the same. 

Wait... wait... so if the 'space' used to measure position and movement and time is not an actual thing, but just a placeholder so you can drop numbers into to measure where objects are in relation to each other.

Then that would mean that the space that gets curved by gravity, is completely unrelated to the space we move through?

Or that saying space curves was a misleading choice of words just to describe the change in relationship gravity had on objects moving.

In which case, if the sun's gravity wasnt curving space, how exactly did the light from stars behind our sun be visible even though they should have been blocked?

Should I create a different thread for that?

On 10/15/2018 at 2:11 AM, Markus Hanke said:

A geometric relationship between reference frames in spacetime. In the simplest case of inertial motion, two reference frames being in relative motion quite simply means that they are rotated by a (hyperbolic) angle wrt each other in spacetime. Motion is purely a geometric phenomenon.

Huh, that explanation creates a new and even wierder mental image in my head, where objects that are moving, arent actually in motion, but its more like space itself is moving them in those byperbola arcs in lazy circles around each other.

On 10/15/2018 at 6:21 AM, studiot said:

Thank you swansont, +1

 

Now we are back on topic I can offer my thoughts on humility's question "What is movement?"

 

We say that if we can establish a comparative scale, possibly but not necessarily numeric, for some parameter or colllection of parameters that a change occurs when repetive observations of the system under observation return different scale values, after taking due allowance for observational error and variation.

Movement is the change of a restricted set of these parameters. That is it is a subset of change.

It is then necessary to examine more closely what we will allow as acceptable parameters.
This introduces modifying words or phrases to cotrol this.

Mechanical movement (which I think hunmiltity means) restricts the parameter to a position in space applied to material objects.

But we should consider other uses of movement for instance of immaterial objects eg the movement of heat in a bar or the movement of the stock exchange (ie a graph).

Isnt that what Markus said? Am I missing something?

I was just wondering, what exactly is movement?  Like if we are all part of space, then what exactly is our movement within space? We can't move relative to space obviously, but what exactly is happening to space as we move?  Wow this is hard to explain. I have this weird incomplete picture in my head of space like a thick web of strings and when we move its like the mass of strings moves with us but pulls and sways on other masses of strings from other objects. Why strings instead of water I don't know, probably just my brain trying to picture einstein's sheet metaphor in 3d.

Point is I don't know how we move through space. I'm not even sure if space is an actual thing or just a word used as a placeholder.

Well maybe it'll be easier to explain if I explain why I started wondering. So I suddenly recalled that I read somewhere that time is literally finite and will eventually run out, but we won't notice as its running out will be a slowing and slowing down of time until the entire universe is frozen in a single moment.

So I thought huh, if time is a finite resource then that would make space finite as well.

And I thought if something is finite than it can probably be isolated. And I thought what would happen if you isolated a bit of space from all the other space. Would it vanish from perception, would say you isolated a person's space, would they have a period of time to live equal to the amount of space they take up or would they instantly freeze?

Then I thought well obviously two isolated bits of space can't move since space itself can't move otherwise space would be something you could move relative to. But then I thought but what actually happens to the space in a different bit when you move around, maybe you are moving relative to space when you move relative to an object. But then I thought wait but space and objects aren't the same thing. Objects are just in space. But then I remembered time  and space are the same thing and we are clearly a part of time. And then I realized I just didn't have a clue.

Okay well this answers most of my questions. Sorry about the slow response, this was a late night post when I couldn't get to sleep and I forgot about it by the morning.  So sea salt. How is natural evaporation in lakes different from forced evaporation by boiling?

I noticed that borax is naturally occuring in salt lake beds that regularily dry up and then refill. 

Google was useless so Im asking here, if I took salt,dumped it in a pot of water, boiled the water away, then refilled and repeated, would I eventually wind up with borax?

If light doesnt degrade, can be used as a power source and can even be slowed down and takes up no space so can be stored in infinitely dense concentrations. Why dont they make batteries out of light? Sounds like they have the technology to do it. And I cant imagine cost is a factor, light is free.

How can the universe be expanding if there is no edge? Its supposed to be expanding faster than the speed of light.

And when I say time I mean space/time. Since space and time are the same thing. There is no actual such thing as time or space I think. So whenever I refer to one or the other, Im referring to both.

Does space/time have energy.

Dang, and here I thought I solved all of the universe's problems.

What does long radiation decay into if you put it inside a flawed mirror?

And each bounce on the perfect mirrors would impart a small amount of energy. Sounds like a potential exploit to gain infinite energy. Just make the top of the box out of microscopic pistons. Then make a billion boxes.

If you put a photon inside a mirrored box, will it bounce forever?

Does time have energy? Like if you go to the edge of the universe and try to leave, time stops. So that suggests to me time in not infinite. So is time powered by some kind of energy? Which of the four forces make up time?

This made me wonder just now, does the equal and opposite reaction rule apply to light? Because thats a Newtonian rule but light is a quantum thing. And lots of Newtonian rules dont apply to quantum mechanics.

I dont think the ball would roll. It would just be dragged. And without the rolling motion the wheel won't spin. Because the magnet would have to just pull on the top edge of the ball, letting go as soon as that edge is no longer the top, repeat. For the ball to roll. And thats not how magnets work.

Like how if you try to play pool on a air hockey table, everytime you hit a ball in the center, it just skids along the table rather than rolling.