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Postuar nga NS-6 datë 12 Nëntor 2005 - 06:11:

the world of physics and astronomy

ashtu sic kam bere tek mjeksia edhe ketu po hap nje teme ku mund te jene shrimet ne anglisht per ti dhene mundesi edhe atyre qe kane problem me shqipen qe te mund te marrin pjese...si dhe per te shtuar ndonje artikull qe mund ti beni thjesht copy-paste ne menyre qe ta lexoj gjithkush...nese eshte artikull i gjate ose ndajeni ne me shume postime ose shkruajeni nje pjese dhe jepni linkun per tjetren...

Postuar nga darke datë 12 Nëntor 2005 - 17:21:

miremengjes scientic moderator

Here I bring my question. Would it be possible that a space could fill up with light at a point that no more light could fit in that space???

This is - to make my question more clear -, a space with light; you put more light and you continue adding light. Would exist a point in the time where you couldn't add more light into that space???

Waiting for answers

Postuar nga Fizikanti datë 15 Nëntor 2005 - 18:30:

Re: miremengjes scientic moderator

Citim:
Po citoj ato që tha darke
Here I bring my question. Would it be possible that a space could fill up with light at a point that no more light could fit in that space???

Light does not fit in a space. Light is made up of massless particles (photons) which move (at the speed of light ).

This is - to make my question more clear -, a space with light; you put more light and you continue adding light. Would exist a point in the time where you couldn't add more light into that space???

Waiting for answers

Space with light, hmmm. When you say a defined region in space, it could be open or closed space. If it is open then you could not "fill it up" with light, as light would just pass through. If it is closed then light would be absorbed, reflected, pass through the material defining this region in space. So as you see my friend the question does not make much sense. I hope though, that I make sense to you.

But keep wondering though, this is how people come up with new ideas.
PS: try to learn a little bit about the subject in question (light) before raising questions (makes it easier to explain).

Postuar nga Fizikanti datë 15 Nëntor 2005 - 18:32:

this was my quote, sorry for inserting it in the wrong place.
Light does not fit in a space. Light is made up of massless particles (photons) which move (at the speed of light ).

Postuar nga darke datë 15 Nëntor 2005 - 23:32:

Citim:
Po citoj ato që tha Fizikanti
this was my quote, sorry for inserting it in the wrong place.
Light does not fit in a space. Light is made up of massless particles (photons) which move (at the speed of light ).

could we say in this case that a "finite" space can be filled up with an "infinite" amount of light?

PS: if we would have to learn everything before raising questions, we would be MONKEYS still

Postuar nga Fizikanti datë 16 Nëntor 2005 - 07:48:

Citim:
Po citoj ato që tha darke

could we say in this case that a "finite" space can be filled up with an "infinite" amount of light?

PS: if we would have to learn everything before raising questions, we would be MONKEYS still

Light can NOT fill up anything. Please learn what light is, then we can discuss about implications and speculations. I think it is basic knowledge.

With regard to the last quote, this is was what I said:
PS: try to learn a little bit about the subject in question (light) before raising questions (makes it easier to explain).
Where did I express that you must learn everything!

You kids, so much to learn and so eager to try and impress everyone.

Postuar nga darke datë 18 Nëntor 2005 - 22:52:

Citim:
Po citoj ato që tha Fizikanti

Light can NOT fill up anything. Please learn what light is, then we can discuss about implications and speculations. I think it is basic knowledge.

With regard to the last quote, this is was what I said:
PS: try to learn a little bit about the subject in question (light) before raising questions (makes it easier to explain).
Where did I express that you must learn everything!
You kids, so much to learn and so eager to try and impress everyone.

First of all, I have to say that your last message has been truly dissappointing. Just know that my ignorance is compared to your prepotency. Thanks God we are not in the times when I would probably loose my head for saying "incongruences" or for not knowing something "basic" for others.

Please, don't bother yourself trying kids -like me- to understand Phisic affairs. For nothing in the world I wanted to waste your time. Anyway, I will continue wondering about the answers that you gave me in your first message:

According to the "basic knowledge" I remember that light is explained by two theories: In one hand, as a corpuscular phenomenon and in another hand, as an electromagnetic wave. Well, you say "light can not fill up anything" but you didn't say any conclusive reason. Also u said: "If it (space) is closed then light would be absorbed, reflected, pass through the material defining this region in space”. It makes me wonder why??? That space can’t be covered with a special “impervious” material, to reflect the light inside without any loss??? Something like optic fiber???; furthermore I don’t believe that light can’t be isolated into an empty “closed” space and to see what happens there.

Postuar nga Fizikanti datë 18 Nëntor 2005 - 23:18:

Ok, maybe you would better understand if were in my position. It is pretty difficult to explain answers under "certain" conditions.
This (What light is) is something basic with respect to the discussion not with respect to me. You opened this discussion and as such it is expected that you know the basics of what we are trying to assert here. If you don't then it makes it difficult for others to explain their answers.
Here come some of the answers to what you wrote in the last message:

If you assume you have an enclosed vacum space, with material that is perfectly reflective (is possible) then the only way for the light to escape is through the same avenue that it enters. So you can not avoid this if you have an outside source. The only way to set up such conditions that you imply, will have to use an inside source. And if such then when light is produced will be absorbed again by the same material that is beeing used to released in the first place and will continue as such in a loop. So you can't "fill up" the space after all.
Does it make sense? Let me know...

Postuar nga freespirit datë 23 Nëntor 2005 - 07:33:

Ok. I have a question. I have a hard time understanding the multidimesions or imagining the simplest example. Can anyone help with that or recomend any good books that would give me some kind of insight.
thanks

Postuar nga Fizikanti datë 24 Nëntor 2005 - 17:32:

Re: hi

Citim:
Po citoj ato që tha freespirit
Ok. I have a question. I have a hard time understanding the multidimesions or imagining the simplest example. Can anyone help with that or recomend any good books that would give me some kind of insight.
thanks

One example used to explain the space curvature is to imagine the 3-D space as 2-D flat space and imagine that we can't see above (Z-Direction) only left/right (x-y direction). And everything is flat. Then the 4th dimension would be the Z direction but we have no way of explaining (at the moment). We think there are many dimensions, we can use mathematics to describe them but physically I do not know any model that describes the 4th dimension and above (not including Time as a dimension).
Hope this makes sense.

Postuar nga darke datë 25 Nëntor 2005 - 04:39:

Citim:
Po citoj ato që tha Fizikanti

If you assume you have an enclosed vacum space, with material that is perfectly reflective (is possible) then the only way for the light to escape is through the same avenue that it enters. So you can not avoid this if you have an outside source. The only way to set up such conditions that you imply, will have to use an inside source. And if such then when light is produced will be absorbed again by the same material that is beeing used to released in the first place and will continue as such in a loop. So you can't "fill up" the space after all.
Does it make sense? Let me know...

what would happen if we could get a mechanism that would allow to keep the light without any way out?

PS: thanks for your answer

Postuar nga Fizikanti datë 28 Nëntor 2005 - 18:45:

I will need some time to answer this, need to open some books and refresh my knowledge. This is a very interesting question. Answer is coming...

Postuar nga freespirit datë 29 Nëntor 2005 - 03:58:

Citim:
Po citoj ato që tha darke

what would happen if we could get a mechanism that would allow to keep the light without any way out?

PS: thanks for your answer

I do not think thats possible unless its a mechanism that sucks up the light or is a mechanism with a source of energy inside that produces light and built with walls that reflect the light back inside.
bye

Postuar nga NS-6 datë 29 Nëntor 2005 - 04:26:

what about black holes?if the light enters its "dead point" radius there's no escape any more!

Postuar nga freespirit datë 29 Nëntor 2005 - 04:49:

Citim:
Po citoj ato që tha NS-6
what about black holes?if the light enters its "dead point" radius there's no escape any more!

o.k but the original question is if it possible to fill up a space with light until its full, which is not. Maybe black holes could be analogy to the mechanism Darke refered but still we dont know what they are.
bye

Postuar nga Fizikanti datë 29 Nëntor 2005 - 09:05:

Citim:
Po citoj ato që tha NS-6
what about black holes?if the light enters its "dead point" radius there's no escape any more!

There is escape from black holes, they release all the mass as a very fast (near the speed of light) and very hot stream jet from the "two poles". I do not think that black holes draw parallel with the question raised, as other factors come into place like space curvature, black hole spin and it's mass. So we no longer can define a particular space as the space is bent to great extremes (even in closed loop).
Instead try to think of possibilities in terms of energy accumulated in the form of the photons in a closed space. Imagine what could happen if we keep adding photons?!

Postuar nga kontinenti datë 30 Nëntor 2005 - 11:01:

Sa gje e bukur eshte te shkruash anglisht!
Ehhhh...kulture hesapi.

Postuar nga darke datë 03 Dhjetor 2005 - 21:38:

Citim:
Po citoj ato që tha Fizikanti
Imagine what could happen if we keep adding photons?!

Yes!!! what would happen??

PS: this is getting exciting

Postuar nga NS-6 datë 04 Dhjetor 2005 - 00:22:

well,keeping in mind that the closed space is still composed of other particles that will exchange these photons...great instability...the energy gathered will be extremely hard to controll...probably explosion at the end...am i right?

Postuar nga freespirit datë 06 Dhjetor 2005 - 02:00:

Citim:
Po citoj ato që tha NS-6
well,keeping in mind that the closed space is still composed of other particles that will exchange these photons...great instability...the energy gathered will be extremely hard to controll...probably explosion at the end...am i right?

Yeah and if we are talking about big spaces this could be a big bang. I think.
bye

Postuar nga Fizikanti datë 06 Dhjetor 2005 - 07:28:

Citim:
Po citoj ato që tha NS-6
well,keeping in mind that the closed space is still composed of other particles that will exchange these photons...great instability...the energy gathered will be extremely hard to controll...probably explosion at the end...am i right?

Well, assuming that photons are absorbed by the other materials (depending on material) then all the enrgy absorbed would translate into internal energy which would make the material reach high temperatures, meaning a breakdown of internal structure of material, solid changes to liquid then gas where the pressure would keep rising (since the space is closed and assuming is perfectly insulated, no energy losses) till force generated by the pressure would be bigger then the force used to hold this "closed" space together. At this point you could expect an explosion depending on how big the pressure build up is.
What if there is no material in this space? Vacum in which we add photons. Then the question would be; can photons interact with each other at high densities in the enclosed vacum?

Postuar nga NS-6 datë 07 Dhjetor 2005 - 03:41:

one moment here...where do these photons come from?and one more question: i have read that the empty space can be assumed as a space where matter appears and disappears...i mean an appearance and disappearance of matter and antimatter...if we consider this situation there will be an interaction...most probably i mean...otherwise i just dont have any idea by now...

Postuar nga Fizikanti datë 08 Dhjetor 2005 - 06:05:

Citim:
Po citoj ato që tha NS-6
one moment here...where do these photons come from?and one more question: i have read that the empty space can be assumed as a space where matter appears and disappears...i mean an appearance and disappearance of matter and antimatter...if we consider this situation there will be an interaction...most probably i mean...otherwise i just dont have any idea by now...

I know that today would be impossible to set up this experiment as it was mentioned previously it would be imposible for the photons not to be absorbed in the enclosed space. In this case we are trying to solve a "though experiment".
I also have read this prediction where matter and antimatter are formed from "nothing" or in vacuum. As far as I know this remains an unproven theory. A very interesting one that explain things that previously were not explain by any theory. I would like to draw your attention to this thought experiment only, what would happen if we keep adding photons to an enclosed vacuum space?

Postuar nga NS-6 datë 08 Dhjetor 2005 - 15:53:

as far as i know(and told me) photons do not interact with each other since they have no mass...i mean pachage of energy can not interact with each other.however i cant give any proven data on this "still remaining hypothesis for me"...so adding photons inside this empty vaccum space wont make any difference in terms of entropy(the system is isolated and no energy exchange with the outer space isn't it?),as the space is empty!!!
correct me if i'm wrong here!

Postuar nga NS-6 datë 09 Dhjetor 2005 - 04:38:

Citim:
Po citoj ato që tha Fizikanti

As far as I know this remains an unproven theory...

i read smth yesterday about this...in medicine there is a type of machine used in radiology,called PET (positron emmiting tomography),a last generation one i must say that uses this thing...photons with an energy greater than 1.02 MeV are trasformed into an electron and a positron which are captured by the machine and based on that trasforms the information gathered in an image...this phenomenon is called "effetto coppia" in italian...
this is what i have read!

Postuar nga Fizikanti datë 10 Dhjetor 2005 - 03:25:

I have posted this in another forum and got some interesting answers.
Photons would interact with each other if we were to have such conditions.
An example of this sort of photon-photon interaction is the creation of e+ e- (electron/positron) pairs out of the vacuum. If you put enough photons in a box, you'll exceed the Schwinger critical field, and you'll start to see electron-positron pair production in the box. So the pressure will rise and the box will eventually explode.
So that was the answer of the original question by darke. I hope you understand it.
Basically we start with massless particles and end up generating mass in the enclosed vacuum till presure rises beyond critical point.
Here is a link to other views regarding the question.
http://www.physicsforums.com/showthread.php?t=103186

Postuar nga NS-6 datë 10 Dhjetor 2005 - 04:20:

wowww...the discussion seemed really long there ...
ok!!!coming up with another question:
gravity!in which conditions it can be repulsive and (just in case),what is known about its nature?
i've heard physicians find it difficult to include it in the main formulas.

fizikanti,thanks for the patience and the time u spend to write these informations here...and forgive us if the questions have any problem!

Postuar nga Fizikanti datë 13 Dhjetor 2005 - 00:11:

NS6, it is a pleasure helping country man that are here to learn and engage in discussions. I have read some papers on antigravity, most recently from a russian scientist (Yevgeny Podkletnov) who promisses to have discovered the secret of antigravity. Not a lot of people have taken seriously his claims because has yet to dublicate the results of his first experiment. There are some new theories that look promising, like dipole anti-gravity (http://tachyonics.com/) and "Big spin" anti-gravity (http://www.antigravity.org/). The discovery of the anti-gravity will change our lives forever. Hope that it happens in our life time, we might get a chance to step on the moon and mars after all.

Postuar nga kontinenti datë 17 Dhjetor 2005 - 22:23:

SHume bukur, por, perse e shkruani ne anglisht? Po ata qe nuk dine anglisht, nuk kane te drejte te mesojne ide te reja, apo zbulime te reja, per teori te aprovuara e jo te aprovuara, gravitet e anti gravitet etj.
Kush ju detryron te shkruani ne anglisht?

Postuar nga NS-6 datë 18 Dhjetor 2005 - 05:51:

ket teme ketu e kam hapur me qellim qe darke te mund te merrte ndonje informacion sepse me kishte qelluar shpesh te flisja me te dhe te me pyeste per pune fizike dhe mjeksie...ashtu sic bera edhe tek mjeksia,bera edhe ketu...sidoqofte nese ke ndonje gje fare mire mund te hapim nje teme ose te kapim nje teme nga ato qe jane hap edhe pyet aty dhe shpresoj se do marresh pergjigje!zgjidh nje teme konte edhe fillojme e diskutojme andej,por ne kete teme do flitet ne anglisht per shkak te darkes!shpresoj se me kupton!
shnet!

Postuar nga kontinenti datë 18 Dhjetor 2005 - 11:11:

Po si mer, te kuptova drejte.
Por, problemi eshte se Darke eshte nje njeri i vetem, kurse te tjeret jane qindra. A nuk do shkonte me mire qe Darke te kishte nje teme dhe te bente pyetje atje?
Nuk eshte e hijshme te mohohet leximi i qindra vetave, per nje njeri te vetem.
Po qe se keni deshire te shkruani per Darke, nuk eshte gje e keqe, por, me poshte, nuk besoj se do jete lodhje qe ate qe keni shkruar ne anglisht, ta shkruani edhe ne shqip.
Mbi te gjitha kjo eshte gje e mire edhe per ju...lexoheni nga shume njerez.

Postuar nga NS-6 datë 18 Dhjetor 2005 - 18:14:

Citim:
Po citoj ato që tha kontinenti
Po si mer, te kuptova drejte.
Por, problemi eshte se Darke eshte nje njeri i vetem, kurse te tjeret jane qindra. A nuk do shkonte me mire qe Darke te kishte nje teme dhe te bente pyetje atje?
Nuk eshte e hijshme te mohohet leximi i qindra vetave, per nje njeri te vetem.
Po qe se keni deshire te shkruani per Darke, nuk eshte gje e keqe, por, me poshte, nuk besoj se do jete lodhje qe ate qe keni shkruar ne anglisht, ta shkruani edhe ne shqip.
Mbi te gjitha kjo eshte gje e mire edhe per ju...lexoheni nga shume njerez.

te thashe qe kete teme e kam hap me qellim per darken dhe cdo gje qe shkruhet ketu ka per synim ti vije ne ndihme asaj...nuk po mohohet leximi i qindra veteve,per me teper po stimulohet leximi nga te tjere i kesaj zone...fundja fundit jo te gjithe kane njelloj kohe.le te themi qe dikush ka gjetur nje info interesante dhe nuk ka kohe ta perkthej...mund ta shkrujae ashtu sic eshte ne keto lloj temash,pa humbur kohe si dhe duke treguar infon...nese bie rasti qe dikush ka ndonje gje rreth nje subjekti fizike ose astronomie mund ta kerkoje edhe ketu ose pyet dhe kur ti pergjigjen,informacionet mund ti marrin edhe nga ketu...une te thashe,nese ke pyetje ose ndonje gje shkruaje ose ne ndonje nga temat qe jane hap dhe besoj se fizikanti ose kush tjeter qe do dije ti pergjigjet ishallah do ta beje...nuk ka asgje ketu qe po bllokohet...do te dish per gravitetin dhe antigravitetin?ke nje teme pyetje pergjigje ne fizike dhe astronomi nese nuk gabohem...postoje aty dhe do gjehet pergjigja nese eshte.
shpresoj se kam qene i kuptueshem.

Postuar nga eng_girl datë 19 Dhjetor 2005 - 01:23:

Interesante e gjitha kjo!
Faleminderit per postimet Dark, NS-6, Fizikanti e te tjeret

Postuar nga darke datë 25 Janar 2006 - 15:40:

Citim:
Po citoj ato që tha Fizikanti
If you put enough photons in a box, you'll exceed the Schwinger critical field, and you'll start to see electron-positron pair production in the box. So the pressure will rise and the box will eventually explode.
So that was the answer of the original question by darke.

wowwwww that's really interesting!! ... and freespirit would be right... this could be related with what we have learnt about the "begining" from the point of view of Religion? the first Big bang could have happenned like this, couldn't it?

Citim:
Po citoj ato që tha freespirit

Yeah and if we are talking about big spaces this could be a big bang. I think.
bye

Postuar nga Fizikanti datë 25 Janar 2006 - 17:34:

Citim:
Po citoj ato që tha darke

wowwwww that's really interesting!! ... and freespirit would be right... this could be related with what we have learnt about the "begining" from the point of view of Religion? the first Big bang could have happenned like this, couldn't it?

This has nothing to do with Big Bang theory. It is a whole different story how big bang might have occured or if it ever did. Most physicists believe that this has happened but it has not been proven yet. There are also other theories out there that explain how we got here, some of them plausible.
With respect to religion, it would be very ill advised to involve religion in the BIG BANG theory, as this scientific part of the forum would become philosophical at best.
Keep wondering...

Postuar nga darke datë 26 Janar 2006 - 13:58:

Citim:
Po citoj ato që tha Fizikanti

This has nothing to do with Big Bang theory. It is a whole different story how big bang might have occured or if it ever did. Most physicists believe that this has happened but it has not been proven yet. There are also other theories out there that explain how we got here, some of them plausible.
With respect to religion, it would be very ill advised to involve religion in the BIG BANG theory, as this scientific part of the forum would become philosophical at best.
Keep wondering...

what's wrong mixing disciplines??

Deleuze said once that the best encounters happen in the limit between two zones:p

Postuar nga Fizikanti datë 26 Janar 2006 - 17:32:

Citim:
Po citoj ato që tha darke

what's wrong mixing disciplines??

"Fizike dhe Astronomi" is the name of the forum which means Physics and Astronomy (just in case you did not know).

Postuar nga darke datë 17 Prill 2006 - 02:31:

can the light exert a force on the matter?

I was re-reading all this above, and another question has come to my mind. It's about the light again... since the light contents energy... can the light exert a force on the matter? when the light hits against an opaque object and it's absorbed, that energy must go to some place, where does it go?

Postuar nga Fizikanti datë 17 Prill 2006 - 18:29:

Yes

Light or photons exert a very small force on matter when they collide with it. Making use of this fact (conservation of momentum) many ideas have come to forefront on how to use it to build the next generation spaceship. The benefits are obvious:
1. No need to use propellant for acceleration.
2. Can reach very high speeds (predicted 1/10 the speed of light).
3. Clean.
4. Low risk level (with regard to propellant).

There are also disadvantages to this solution as you would need a source (the sun) which would have to be close enough (within solar system). A very large mirror would be required to obtain the necessary acceleration to make a mission feasible. Take a look at these websites for more info:

http://solarsail.jpl.nasa.gov/introduction/index.html
http://www.planetary.org/programs/p.../solar_sailing/
http://nmp.jpl.nasa.gov/st9/index.html
http://nmp.jpl.nasa.gov/
http://www.solarsails.info/web/index.html#missions

hope it helps

Postuar nga darke datë 27 Tetor 2006 - 00:16:

question

why a mosquito doesn't sink in the water and can walk in its surface?

Postuar nga eng_girl datë 27 Tetor 2006 - 02:41:

Re: question

Citim:
Po citoj ato që tha darke
why a mosquito doesn't sink in the water and can walk in its surface?

This is due to the surface tension of water, with a relatively high density. Also, mosquitoes are symmetrical; their body weight is equally distributed and supported by their legs (dont know the appropriate term). By the way, mosquitoes are not the only insects that are able to "walk on water".
I believe Da Vinci had a design of some sort of "floating shoes" to help human walk on water, but I'm not sure!

Trego 41 mesazhet në një faqe të vetme

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