Ask any question you want about Physics

originally posted by: KrzYma

originally posted by: stormbringer1701
www.extremetech.com...

so if there are no gravity waves does that mean Einstein was wrong WRT his model for gravity? gravity waves are a prediction of relativity and gravity is one of the things we still do not understand. we can describe it; even characterize its effects mathematically both with newtonian mechanics and relativity;but both Einstein's prediction and the QM expectations have failed to materialize.

gravity is an illusion, and not a discrete force or some space twist.

electric force is the only one force in the Universe, magnetic force, which reconfigure space is the "time component" of it.

if gravity is an illusion you won't have any issue taking a long walk off a short pier.

Is the moon there when nobody looks?

originally posted by: itanosam
Is the moon there when nobody looks?

Well you may have intended some sort of quantum question on observer and observed; but let us assume that like wild boars nobody could look above horizontal to see the moon. we would still have tides, and subtler effects whether we looked up or not. therefore the moon is there even when you are not looking at it.

Valid points, but the ccd artifact, I may have to procure a digital camera and look see if I can produce this band.
a reply to: ErosA433

originally posted by: ImaFungi
The space-time fabric which warps cannot be nothing.

Nothing cannot warp. What is the theory as to what exists, which warps, in the presence of mass?

See the theory of general relativity. Einstein said space has properties, but no substance. I know this causes your brain to melt down but it's still our best model today. Maybe someday we will have a deeper understanding.

And then the theory of graviton, is a virtual particle that 'comes into existence from nowhere' as a mass interacts with the unnamed unthought of 'substance which warps in the presence of mass'?

Relativity is a theory, graviton is hypothesized, not a full theory, and in fact we have a hard time incorporating gravitons into existing theories. They are not part of the standard model. We think we know some properties of gravitons if they exist. We think a graviton would be spin-2, massless, and travel at the speed of light, and they would mediate gravitational force the way photons mediate electromagnetic force (photons are also massless and travel at the speed of light). Who told you gravitons were virtual? They are hypothetical so we don't know if they exist, but if they do exist that would mean they are real particles since a virtual particle isn't really a particle.

originally posted by: itanosam
Is the moon there when nobody looks?

We may not know where an electron is when nobody's looking, but nobody has to look at the moon for it to be there. Stormbringer's point about the tides is a good one, you'd still see those even without looking at the moon.

originally posted by: Nochzwei
Valid points, but the ccd artifact, I may have to procure a digital camera and look see if I can produce this band.
a reply to: ErosA433

Not all CCDs are equal. Some include electronics intended to limit charge spill or "blooming". If you really want to duplicate that artifact in the video, it would be best to get the same type of camera used in that video, so you'll have the same type of CCD with the same characteristics.

a reply to: Nochzwei

easiest place to see it is in the live view if you point it slighylu away from a very bright object... so the exposure is not being set by the object, but say, something darker in the background. You will very likely see this kind of blow out, as said though, not all are born equal.

my D610 doesn't experience it when taking photos, the processor on board will deal with alot of it, plus the dynamic range on that sensor is extremely high in comparison to a hand held camera or a camera phone.

a reply to: Arbitrageur

I understand more about the fundamental nature of gravity than you.

originally posted by: Nochzwei
Did you watch the videos in my thread?

Nothing happens in the video worth talking about. Except if someone could create anti-gravity why wouldn't they show something levitating in a vacuum?

originally posted by: ErosA433
a reply to: Nochzwei

easiest place to see it is in the live view if you point it slighylu away from a very bright object... so the exposure is not being set by the object, but say, something darker in the background. You will very likely see this kind of blow out, as said though, not all are born equal.

my D610 doesn't experience it when taking photos, the processor on board will deal with alot of it, plus the dynamic range on that sensor is extremely high in comparison to a hand held camera or a camera phone.

Lol I can afford something like Nikon or Samsung hand helds. dont know what suppressions are incorporated though. You and arb brought up valid points, though I don't necessarily agree with your conclusions.

originally posted by: ImaFungi
a reply to: Arbitrageur

I understand more about the fundamental nature of gravity than you.

Since I claim to know next to nothing about the fundamental nature of gravity, such a claim without any other context could easily be plausible. However in the context of your post history I must admit I don't hold high hopes you've discovered the fundamental secret of gravity, but if you have, please explain it.

First you might want to read this article by Einstein that discusses your previous line of questioning about whether or not empty space can have properties, or what exactly we mean by "empty space". Here's a short excerpt from it:

"Relativity and the Problem of Space" Albert Einstein (1952) English translation published 1954

It is indeed an exacting requirement to have to ascribe physical reality to space in general, and especially to empty space. Time and again since remotest times philosophers have resisted such a presumption. Descartes argued somewhat on these lines: space is identical with extension, but extension is connected with bodies; thus there is no space without bodies and hence no empty space. The weakness of this argument lies primarily in what follows. It is certainly true that the concept extension owes its origin to our experiences of laying out or bringing into contact solid bodies. But from this it cannot be concluded that the concept of extension may not be justified in cases which have not themselves given rise to the formation of this concept. Such an enlargement of concepts can be justified indirectly by its value for the comprehension of empirical results.

The assertion that extension is confined to bodies is therefore of itself certainly unfounded. We shall see later, however, that the general theory of relativity confirms Descartes' conception in a roundabout way.

If you don't have time to read the whole thing, this short quote from Einstein is an extremely condensed related idea:

" Physical objects are not in space, but these objects are spatially extended. In this way the concept “empty space” loses its meaning. "

However I think you'll have a better idea of what that means if you read the whole article. It's written for public consumption and isn't overly technical. He even discusses the history of philosophical ideas about space so he gave it a great deal of thought.

originally posted by: joelr

originally posted by: Nochzwei
Did you watch the videos in my thread?

Nothing happens in the video worth talking about.

Lol, are you blind

lots of anti-gravity occurring in this youtube video

It is a known affect - happens all the time, the other thing that occurs sometimes is well known and understood

dvxuser.com...

this page as a great explanation of other effects too.

originally posted by: ErosA433
lots of anti-gravity occurring in this youtube video

Actually the alternate hypotheses for the vertical artifacts were "weird radiation" or "light traveling faster than the speed of light":

originally posted by: Nochzwei
CCD artifact? Maybe. But I think the machine is generating some weird radiation that is hitting the camera detector or maybe the light from the bulbs is travelling faster than c due to time dilation.

At least this hoaxed Richard Feynman quote explains why the light from the headlights travels faster than the speed of light, though even if that was true (it's not) I don't see how that explains the vertical lines.



The ice-cube tray analogy seems to explain the vertical lines better.

originally posted by: joelr

originally posted by: Nochzwei
Did you watch the videos in my thread?

Except if someone could create anti-gravity why wouldn't they show something levitating in a vacuum?

for levitation, you will need to stop time completely and at this point the antigravity machine is no longer a part of this universe. so it will disappear and what happens to the space occupied by the machine? It may collapse in on itself and result will be goodbye planet earth and you and me oblivion.

originally posted by: ErosA433

lots of anti-gravity occurring in this youtube video

Lol nice one

My video at 4:52 you can see the purple band get stronger quite distinctly
a reply to: Arbitrageur

a reply to: Nochzwei
Yes but at 4:36 the purple band is even righter than at 4:52. There's not as much ambient light at 4:36, so more light from the light bulbs saturates the sensor. Then he backs up letting ambient light in, and the purple band gets fainter. I do see the sudden increase at 4:52 and I don't have an explanation but if I had to guess, it's so sudden it almost looks like maybe he flipped some kind of switch or changed some kind of setting on the camera.

a reply to: Arbitrageur

The initial difficulty arises with the word 'space' and its exact most specific definition and usage in these contexts and discussions.

Imagine a 10 ft by 10 ft by 10 ft area outside of the universe (for sake of argument imagine this is possible) with absolutely nothing in it; Is there a word that exists that we can agree on can be used to refer to such an area?

Because it seems if I were to refer to it as 'space', you would then say; no it is not space, because space has such and such definition and the smart people said 10 ft by 10 ft by 10 ft area in the universe 'has physical attributes' (or something) and you would try to use such concepts then to say 'space' cannot exist outside of the universe (if there is nothing outside of the universe).

This is the initial problem with our discussions, understanding and usage of terms.

Invent me a word different from 'space', that equals; an 3d area of pure absolute nothingness.

I thought originally the term 'space' was conceptually utilized for such.

But then when it began to be thought; 'there seems to be stuff in the blackness between planets';

The word 'space' now means 'stuff'.

And so now if I say casually; outside of the universe there is likely 'black area of nothing', like original concept of 'space';

You break down right there, and cannot proceed to discuss my reasonable comprehension of reality.

originally posted by: ImaFungi
Invent me a word different from 'space', that equals; an 3d area of pure absolute nothingness.

I thought originally the term 'space' was conceptually utilized for such.

Nope. Space doesn't mean absolute nothing.

Michio Kaku explains his terminology for two kinds of "nothing" at 9:02 in the following video:

1. Absolute nothing (not space, no equations), which would be hypothetically outside our universe, which is really nothing.
2. The vacuum, absence of matter, but not really nothing. It's the kind of space in our universe. The segment is filmed in the world's largest vacuum chamber.


I think discussions about #1 absolute nothing are rare since we don't even know if "outside our universe" is a valid concept, as it's possible the universe is infinite. So normally when people talk about space they are discussing #2 the vacuum, which has properties, since that's the closest thing to "nothing" we find inside our universe. It's not really "nothing", just the absence of matter within the vacuum. Even after the giant vacuum chamber has all the air pumped out, the space inside is still affected by Earth's gravity.

originally posted by: Arbitrageur

I think discussions about #1 absolute nothing are rare since we don't even know if "outside our universe" is a valid concept, as it's possible the universe is infinite. So normally when people talk about space they are discussing #2 the vacuum, which has properties, since that's the closest thing to "nothing" we find inside our universe. It's not really "nothing", just the absence of matter within the vacuum. Even after the giant vacuum chamber has all the air pumped out, the space inside is still affected by Earth's gravity.

Is it possible an area of #1 absolute nothing, can exist in the universe? Even 1 by 1 by 1 picometer?


You say 'its possible the universe is infinite'.

Only in terms of temporality (known as eternity).

But regardless, just because the universe might be infinite, or lets say the universe is infinite (first of all I dont even know what you mean by that, but you must admit, at any given time, there cannot exist 'beyond finite' quantity of stuff. It is impossible at any given time, for there to exist in total a non finite quantity...it is a meaningless proposition)

Lets say the universe is infinite, in whatever terms you explain what that means;

That say nothing, absolutely nothing, about whether or not, or why not, there could exist 'absolute nothing' beyond it.

At all times, the quantity of energy that exists is a finite quantity, (the concept of infinite as in 'numbers that go on for ever, meaning, consistently increasing in quantity' cannot possibly exist in reference to energy, and say that at this or any moment in time, there exists a quantity of energy which equals 'continual increasement of all possible never reachable quantities of hypothetical energy quantities')

The reason this is important, the idea of 'area of absolute nothing'... is because';

Lets say the totality of something, matter energy, universe, exists in an absolute area of nothing;

That fact (which is the most logical potential for being the truth) may have very significant influence on the nature of how matter interacts with itself, and whether or not there are pockets of true absolute nothingness inside the universe.

The most likely truth about this topic of reality is that;

There exists a finite quantity of matter and energy (which cannot be created or destroyed, just moves and interacts and changes form) which is surrounded by (and which exists in/on/amidst) an infinite area; meaning infinite ft by infinite ft by infinite ft of #1 absolute nothingness.