beecee

 

 

i.e. when a large amount of matter falls towards a black hole it is heated and a large amount of it is blow away, often as polar jets.

I was expecting this to be about evaporation of micro black holes. Describing polar jets as a black hole exploding is just... very irresponsible journalism, frankly.

Yes, polar jets do not come from within the EH of a BH. Our best theoretical model says they are caused by spinning/charged BH's, where twisted magnetic field lines, whip matter up and fling it up and away before it ever crosses the EH.

Nothing means absence of anything which has physical properties

If any thing matter, energy ,force or anything else has physical properties it is not nothing.

Facts though are we, the Universe/spacetime are here....And unless some definition of nothing as detailed here...http://abyss.uoregon.edu/~js/ast123/lectures/lec17.html, has existed for an infinite amount of time, the something from nothing hypothesis[ https://www.astrosociety.org/publications/a-universe-from-nothing/ ] [ https://arxiv.org/pdf/1404.1207.pdf ] is the only scientific answer available.

 

3) What is space? it is just mathematical co-ordinate system or something else.

Putting it in layman's terms, space is what stops everything from being together, just as time is what stops everything from happening together, while spacetime is the multi-dimensional framework within which it is possible to locate events and describe the relationships between them in terms of space and time. The concept of spacetime follows from the observation that the speed of light is constant and invariant, Spacetime allows a description of reality that is common for all observers and Intervals of space and time considered separately are not the same for all observers.

Space is real, time is real and spacetime is real:

While spacetime is a non physical entitiy, it is just as real as any magnetic field is real.

In the case of many/most atheists, I suspect they don't consider the views of others have any validity precisely because they HAVE considered them (unlike many/most religious fundies), but I won't belabor it.

Plus of course any religious/supernatural view by definition is unscientific.

 

Why do you bring this up?

To show the great man's thoughts on the title of the thread and what he may have meant.

Yes it is absolutely right to say nothing can come from nothing . Mathematically if there is 0 before equal, after equal will also be zero. Your question is valid.

Again, one's definition of "nothing" is important here.....The cosmological Singularity from whence the universe and associated matter and energy arose from a fluctuation in the quantum foam....Is this pre BB quantum vacuum nothing?

Empty space that we may chose to examine is not really empty but filled with spacetime and seething with virtual particles popping in and out of existence.

The following link explains it much better then my own amateurish attempt...

http://abyss.uoregon.edu/~js/ast123/lectures/lec17.html

quote from the above link........

"With respect to the origin of the Universe, the quantum vacuum must have been the source of the laws of Nature and the properties that we observe today. How those laws and properties emerge is unknown at this time.

Quantum Fluctuations :

The fact that the Universe exists should not be a surprise in the context of what we know about quantum physics. The uncertainty and unpredictability of the quantum world is manifested in the fact that whatever can happen, doeshappen (this is often called the principle of totalitarianism, that if a quantum mechanical process is not strictly forbidden, then it must occur)".

You will probably enjoy this then

 

"Spontaneous creation of a universe from Nothing"

 

https://www.google.ca/url?sa=t&source=web&rct=j&url=https://arxiv.org/pdf/1404.1207&ved=0ahUKEwjJ9sHz06PUAhUK5WMKHUMfDVgQFggjMAI&usg=AFQjCNFktncVqDNaSYL7UGEvKza6EJFvUw&sig2=sZ9jc3WP3_sBHzsik7D57A

Thanks...Interesting.

https://en.wikipedia.org/wiki/Religious_and_philosophical_views_of_Albert_Einstein

One that has always been here is a lot easier to comprehend than one that came out of nothing.

You think so?

What is your definition of nothing?

Space and time, [spacetime] as we know them, did have a beginning and the matter that evolved via phase transitions and such, will also come to an end as far as we know.

Perhaps what some define as nothing, is what has always been there.

 

the ability to think means that there is something rather than nothing, and something cannot spontaneous appear out of nothing if nothing doesn't have at least one innate and eternal property.

Speaking scientifically, this "something from nothing" appears to be the only answer/solution, although as yet, it is still speculative.

What other scientific answer is there? An infinite universe? I see that as much harder to accept.

https://www.astrosociety.org/publications/a-universe-from-nothing/

 

 

Not really. There is a "zero energy universe" hypothesis.

 

However, there is no evidence that something can (or did) come from nothing, so the whole question seems moot. You might as well argue about what colour unicorn eggs are.

A correct scientific statement.

But I find the "universe from nothing" speculative scenario, not that hard to accept.

https://www.astrosociety.org/publications/a-universe-from-nothing/

Another relevant point in my opinion, and as mentioned earlier, is one's definition of "nothing"

http://iopscience.iop.org/article/10.1088/0143-0807/11/4/008/meta

Perhaps one day the advent of an observable "Quantum Gravity Theory" may shed more light on this so far rather interesting scientific speculation.

Would you agree it's just one proposed mechanism and may or not be correct?

 

That is always true in science. However, in this case, the waveform matched very precisely the predictions for a signal produced by the merger of two black holes. So, it could be something else that we know nothing about that just happens to look just like something we do know about ... or it could be what it appears to be.

Nice answer to a "query" which reminds me of remarks we often see outside of science that tend to deride same by the tired old "Ahh, its only a theory" jibe.

I just always assumed that's what they were. As you look out at the Universe at large, eventually you come to a place that we are unable to see beyond. A resonant block. This is not only the farthest out we can see, not only the furthest back we can peer, but also the "smallest" form of the expanding Universe... but at that far out, the sphere of view has the largest area? So if you were the "Big Bang" what do you think your little singularity of creation would look as the view of it became the most inflated perception of the entire Universe we are capable of perceiving.... I always thought it was understood it might look something like a quasar... and they'd probably be all over the outer reaches of the Observable Universe. I mean even if they once were all connected and represented the whole of existence, I suppose the fractal expansion of space would break up the view and eventually diminish their apparent capacity, not because they shrunk, but because they just became less proportionate to a larger expanding Universe. Well, at least that's what I always thought.

Your thoughts from my perspective, seem more like confusion.

We see numerous Quazars [active galactic nuclei] at varying distances from us, and all when the universe was comparitively young.

This supports the theory that in early times, the SMBH's at galactic cores were in a "feeding frenzy", having plenty of matter of all type to gobble up.

It is also thought that at one time the Milky Way would also have been seen as a Quazar in the same sort of feeding frenzy.....That now has subsided after many billions of years of sweeping out a zone around our SMBH that is somewhat devoid of much of the matter that it once had and that obviously Quazars that we observe still do.

There are some new theories which say there was no Big Bang, but rather inflation.

The BB theory does include Inflation. In fact it is now sometimes called the BB/Inflationary model of the evolution of the universe.

There are though a few hypothetical models of the exact nature of Inflation, including "Eternal Inflation"

https://en.wikipedia.org/wiki/Eternal_inflation

To me _ I see the Universe as a big round body like the earth as an example and why would the Universe have a different shape, and we are parts of it.

So !~ my question << ''Is the Universe in Motion''/ and if so!~ what is the evident proof:

The Universe is not a big round body...The Universe is all of spacetime and all that spacetime contains.

The planets, Moons, Stars, and Galaxies are all in motion as dictated by gravity.

Over larger scales, the Universe is expanding.

The BB happened everywhere at the same time, because everywhere was contained within the singularity from whence the BB arose..... no center, no edge/s

When one says the universe is in motion.... don't they mean that the galaxies are all rotating and flying about around and through each other? That we can see by looking at the night sky with a telescope and the patience to watch and plot the movement of the stars and galaxies in the sky, no?

 

 

But if you mean the WHOLE universe as an item... then, how could you possibly know seeing as we can't even see the edge of it? And as swansont said - moving relative to what?

From what I understand at this time, we have no way to indicate that the Universe is rotating or not, unless with reference to the CMBR.

 

1. Suppose we had a triple planet system that orbit each other and of quite different masses. We could find an average clock rate for the system by checking how fast a cock runs at the surface of each. We could do the same thing for our galaxy or a volume of space with a radius of a hundred million light years. If we look at the clock rate for the Universe thirteen billion years ago when it's volume was much smaller it's clock rate would be slower than the clock rate for today's Universe. This brings up an interesting question. We all know that velocity is determined by dividing the distance traveled by time. If this is true then the speed of light in the early Universe would be greater than it is today. If we were to go back to just after the BB, say 10^-42 seconds then the speed of light could have been millions if not trillions of times faster than today a neat explanation for inflation.

 

The clock rate is always 1 second per second for anyone measuring it from that same frame of reference.

Time dilation, or the rate at which any clock ticks, will certainly change from the reference from someone in another frame of reference.

The fixed nature of the speed of light,"c" leads us to the solution [special Relativity] that it is space and time which is of a variable nature according to ones frame of reference.

The apparent clock rate of the Universe 13 billion years ago, from our perspective now, appears "slow" because of the constant finite nature of speed of light at "c".

Travelling to the stars! A dream!! But while certainly a dream, given the time, and providing we are able to avoid any cosmological catastrophies and our own follies here on Earth, many things that we may now deem impossible, may be possible in the distant future, providing it does not contravene known physical laws and general relativity.

I have a basic question that I've never actually seen answered in discussions of LIGO and gravitational waves: if these waves are warping space itself (actually spacetime), then all matter occuping that space will be warped to exactly the same degree that space is warped, making such warps in principle undetectable. So if an interferometer like LIGO, with two perpendicular arms, is set up to measure such waves, what is it actually measuring? Any distortion of the arms in the direction of the waves will not be detected because that arm(s) will be distorted to exactly the same degree that space itself is distorted. Help?

I'm only a lay person as far as science/Cosmology is concerned but I see it as rather easy to understand that gravitational waves, are simply a distortion of spacetime..... A wave passing through the aLIGO , will lengthen space-time ever so slightly along one arm of the detector, and compress it along the other arm...

Waves by definition have peaks and troughs and travel transversely progressively away from their source.

Also of course the two detectors in operation that detected these GW's, did so at different instances of time, albeit it in milliseconds apart.

Science is a discipline in eternal progress and while false positives from experiments do happen, scientists do learn from these false results...the BICEP2 experiment being a good example, where after further investigations and data from other experiments, the original results were falsified.

While science discussion boards such as this are great for discussions and opinions to be sounded out, the scientists at the coal face, are doing the hard yards.

Hi, I have only just registered on this form, so Hi again )

I am not an astronomer or scientist, just someone very interested in cosmology and who has read a great deal and been apart of another science forum.

As such, my thoughts and knowledge are in layman's language.

I prefer to say that what existed before the BB was "nothing that we can understand or that is covered by our models"

Whatever existed before the BB, if anything, is just speculation....nothing wrong with that though.

My favourite speculation of what was before the BB is a quantum foam, and that our Universe and the BB from whence it evolved started out as a fluctuation in this quantum foam...a bubble if you will.

Other bubbles and BB's could also be speculated to have existed also.

I suppose it must remain as speculative until at least we have a working observable testable quantum gravity theory.

I'm from Sydney Australia by the way...