Question about Big Bang

[alokmohan]

You are thinking in terms of classical physics.Read elemetary thing on theory of relativity and you may agree.

 

[search]

Hello Oscar1<br /><br />In general (throughout the scientific community) the Big Bang is percieved as the moment at which the laws that govern the Universe were created. However There is a difference between Big Bang moment 0 and Big Bang moment 0+X.<br /><br />Meaning that scientists have been able, using different methods, to go back in the timeline of events. However it is impossible to recreate certain conditions which they believe it may have existed in the very beginning. So the theories they create must correspond to mathematical models and then they search for prove (Hubble, Cosmic Background Radiation, etc...).<br /><br />Sometimes they find a prove but then later one something else comes on and disproves it. The reason "the before" is not much of a subject is because then the applicable laws were probably very different and we do not have mathematical models for them. It does not mean there was nothing (in the literal sense of nothing) we just would not be able to explain it. <br /><br />Imagine this:<br /><br />A detective is investigating a crime that ocurred at the Big Bang moment (he thinks?) 13,7Billion years ago, however nobody really nows the precise location, murder weapon and motive and the only thing he has is the Universe area to search for evidence? That is what scientists are doing.<br /><br />Now imagine the detective is actually blind from birth (has never seen before) and someone shows him the Universe on a picture and asks: Can you tell me from that picture who is the killer? Obviously this detective cannot answer because he does not recognise pictures. He does not have this kind of "law" to get the information. That is asking what happend before the Big Bang.<br /><br />But believe it or not there are already scientific minds working on this. We do live in special moment in time. <br /> <br />Read the following website. There is on the top right corner a webswitch so you can choose either basic or advanced information on the same subject:<br /><br />

 

[oscar1]

Yes I do, and in fact I support the anthropic principle (at least the weak one). You and I are posting here, therefore, we have no alternative but to agree that we 'are'. Before the 'we are' we 'were to be', and after the 'we are' we 'once were'. Shake that, and you'd spoil the cup of coffe I am currently enjoying! <img src="/images/icons/wink.gif" />

 

[oscar1]

I quite accept that we are not able to look beyond the Big Bang, but I don't find that unability sufficient to argue that there is an absolute nothing there. In fact that suggestion (the claim that there is an absolute nothing) contradicts the claim that we cannot know. <br /><br />When I read "A Brief History Of Time", I came to the conclusion that scientists may very well often offer us nothing more than card houses. What I mean is that where Hawkin mentioned that he entered into a bet regarding Black Holes yee or nee existing, he thereby virtually admitted that all the very rational theories built around that Black Hole, would mean ziltsch if Black Holes later appeared not to exist. <br /><br />We do indeed live in a special moment in time, but I can imagine many a forebear of us having said or thought the same. I go for "I find it all fascinating" rather.<br /><br />

 

[alokmohan]

Kip Thorne says in p 525 of his book on black hole,inter alia,:In 21st century we may expect following developments, Gravitational wave detectors will soon bring us oservational map of black hole. ........ most likely sooner orlater some insightful physicist will discover and unveil the laws of quantum gravity ,in all their intimate details. With those quantum gravity laws in hand ,we may figure out precisely how our Universes space time came into being ,how it emerged from the quantum foam and froth of big bang singularity.We may learn for sure the meaning or meaninglessness of of the oft asked quesion "what preceded the big bang".

 

[oscar1]

I am very happy about that, because this means that I can have a fair number of cups of coffee still, before someone discovers that they don't actually exist. <img src="/images/icons/wink.gif" /><br /><br />I must say that that sounds pretty reasonable though, be it that I would have liked it even more if he had included somewhere in this: ".., or that gravity waves do not exist".

 

[search]

Usually as the threads evolves the initial question tends to be lost absorved into the black hole of other questions we create. In this case the initiator seems to have been gone himself since I did not see any further comment from him. <br /><br />If he decides to join us again that would be a great leap for the Hawking black hole theorie: not all information is lost and you can survive black holes. There was a conference he gave in Cambridge not so many years ago where he declared being ready for new fundamental changes of his 30 year old black hole model ( a bit like the example I gave on our estimate thread initiator and question) but this came without any mathematical foundation (as far as I know).<br /><br />You actually came back to the point through a different route (some sort of space-time travel) when you mentioned the black holes and reminded me where this all started from Heist the initiator of the thread "ants on the ballon and the possibility to circumnavigate the universe" and from down the thread "why we cannot know what happened before the Big Bang".<br /><br />Check this one out. Go to unsolved mysteries<br /><br />http://www.pbs.org/wnet/hawking/html/home.html<br /><br />Check also the questions and answers:<br /><br />http://www.pbs.org/wnet/hawking/html/ask.html<br /><br />P.S. Have some coffee ready for the reading. "It is fascinating" and do not believe when someone tells you "there is absolutely nothing out there" . Colombo, Gama, Cabral, Magellian, Vespucio, Cook would have stayed nicelly at home drinking the old "arabica" or tea and you could not be marveled with all the other tastes since there was no one out there brave enough to go and find other worlds and other possibilities. Just for coffee drinkers:<br />http://www.coffeeresearch

 

[oscar1]

Thanks. And since time is so relative, I put it that I spent three cups of coffee reading!

 

[alokmohan]

Gravity waves do exist.Thory of relativity is clear on this.

 

[oscar1]

I've got a few scars to show that I learned about gravity already early in life, but I just can't imagine there being 'gravitons' like 'photons with gripping hands attached'.

 

[derekmcd]

Gravity waves exist only in theory. They have yet to be verified through detection. The Ligo Observatory in conjuntion with Geo 600 are trying to do precisely that. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[search]

Well not completely true but not completely false. Evidence of gravity waves have been found and it deserved a Nobel:<br />http://en.wikipedia.org/wiki/Gravitational_wave#Detection<br /><br />But evidence is still not the real thing so through LIGO and GEO600:<br /><br />At the moment they are making sensitivity test runs at LIGO and still did not reached the required level but are getting better:<br />http://arxiv.org/PS_cache/astro-ph/pdf/0608/0608606.pdf

 

[derekmcd]

Semantics. I stand by my statement as still being completely true. I understand what you mean, however; although the shrinking orbits fit precisely with a mathematical prediction of Einstein's theory, it is still just theory until physically detected. Until then, the statement "gravity waves exist" is a false statement. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[alokmohan]

Theory of relativity forecasts that gravity waves exists.Like many other forecasts of relativity it may exist.

 

[search]

Absolutely. Semantics it is. Cognitive semantics dough.<br /> <br />"Gravity waves exist" is false but also true.<br /><br />The evidence or effects have been found but we never really saw it. They do exist but we cannot prove yet because we still need to perfect our instruments.

 

[oscar1]

When I imagine the barycentre of two masses to be somewhere in the emptyness between these two masses, I would have to imagine gravity waves/particles to flow to that barycentre, that can only be a barycentre after their arrival, before they can get on with the job of attracting stuff towards that barycentre. Perhaps I am seeing it wrong, but this is why I have great difficulty believing in gravity waves/particles.

 

[search]

Barycenter of moon and earth it is easy to find (1600km below earth surface) but when we talk about galaxies or clusters it is another story.<br /><br />here is an example of that:<br /><br />http://www.journals.uchicago.edu/ApJ/journal/issues/ApJL/v473n2/5120/sc2.html?erFrom=5018348993711718061Guest<br /><br />Summary:<br />"Both of these operations introduce important uncertainties in their results. On one hand, the center of a system of few (typically four) galaxies is not well defined. Beers & Tonry (1986) have shown that any possible inner galaxy concentration is washed out when the barycenter is used as the center of galaxy clusters. So, given = 1, MG94's core radius should be much larger than ours, and indeed it is 2.5 times larger (Fig. 1). On the other hand, it is not clear that groups should have a normalized common size and that Rmax should be a useful measure of that size. Instead, our results show that our sample of HCGs can be considered as a realization of a unique profile, and that the dispersion in Rmax arises from statistical fluctuations."<br /><br />Regarding gravity getting the job done only after their arrival here is a very interesting article:<br /><br />http://www.ldolphin.org/vanFlandern/gravityspeed.html<br /><br /><br /><br /><br />

 

[kmarinas86]

<font color="yellow">When I imagine the barycentre of two masses to be somewhere in the emptyness between these two masses, I would have to imagine gravity waves/particles to flow to that barycentre, that can only be a barycentre after their arrival, before they can get on with the job of attracting stuff towards that barycentre. Perhaps I am seeing it wrong, but this is why I have great difficulty believing in gravity waves/particles.</font><br /><br />The barycenter is an illusion. If you have two celestial objects they have a force tugging each other. The line along which the tugging takes place crosses the barycenter at all times in a two body system. The force does not come from the barycenter but from behind it. The barycenter is not a langarage point except if the two masses are equal. In the earth-moon system, the barycenter is closer to the earth and the langarage point (L1) is closer to the moon. Therefore, gravitational forces are not balanced at the barycenter of the earth-moon system. It's simply a point that exists through which the earth and moon attract each other.<br /><br />http://www.santafe.edu/~moore/orbit12.gif<br /><br />If you took eleven of these objects and determined the net force it has on the twelfth object, the line along the vector of net force would cross the barycenter and that twelfth object.

 

[bdewoody]

I have another question along these lines. Assuming the Big Bang theory is true and everything is moving away from this point of origin wouldn't there be as much matter moving in the opposite direction and therefore not observable from our reference point? <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[alokmohan]

Physics of macroworld is guided by other laws.Dont think in terms of clssical physics.In relativtic world. As one moves rulers shrink ,you gain mass ,clocks slow down.If you move at speed of light your mass is infinity.Time ceases to sxist.So first have elementary lesson on relativity.

 

[search]

Sorry alok. I did not get this one? Is this post for me? On which subject?

 

[SpeedFreek]

<font color="yellow"> Assuming the Big Bang theory is true and everything is moving away from this point of origin wouldn't there be as much matter moving in the opposite direction and therefore not observable from our reference point? </font><br /><br />Ahh. But everything is not moving away from a point of origin. On the large scale, everything is moving away from everything else. There is no point of origin, or centre of expansion.<br /><br />Try not to think of the BB as an explosion from a single point. Think of it more like a point appeared and inflated internally, and then everything inside it expands away from everything else inside it. The universe is inside the point, and cannot know what is "outside", since to that universe, there is no outside, everything is inside, and moving away from everything else. Someone observing proceedings inside this universe can only see the light or radiation from things that are as close to them in light years as the universe is old. So there is probably a lot of stuff unobservable, because we can only see 13.5 billion ly years in any direction (because light has only had that long to reach us).<br /><br />Allegedly. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#ff0000">_______________________________________________<br /></font><font size="2"><em>SpeedFreek</em></font> </p> </div>

 

[bdewoody]

Thinking about this stuff begins to make one's head hurt. <div class="Discussion_UserSignature"> <em><font size="2">Bob DeWoody</font></em> </div>

 

[v_for_vendetta]

I don't believe anything from here because first of all we only see the visible univerese and how do they know their calculations are correct and the shape and density I mean density could vary from area to area meaning diffrent things

 

[alokmohan]

Not for you.For bdwoddy.You can observe a thing and draw conclusion.This way science runs.There was recessation of galaxies .We infer at a certain point of time they were in a singularity.Singulrity is a term which came from relativitic maths.To appreciate big bang one has to know a dose of theory of relativity.In yhe macro world Newtonian physics fail.That gives rise to bizzare question:what was there before big bang.The first three minutes by weinberg may be of help to understand what was there big bang....question basesd on wrong notions.