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A Question on Abiogenesis

Again, according to the Wikipedia article, the existence of virtual particles is questionable. But let's assume they exist. According to -- http://particleadventure.org/frameless/virtual.html --

"A result of the Heisenberg Uncertainty principle is that these high-mass particles may come into being if they are incredibly short-lived. In a sense, they escape reality's notice. Such particles are called virtual particles.
Nice and colloquial.
"Virtual particles do not violate the conservation of energy. The kinetic energy plus mass of the initial decaying particle and the final decay products is equal. The virtual particles exist for such a short time that they can never be observed."
They don't violate the law of conservation because they come from the vacuum energy. The energy does come from somewhere and it does go somewhere.
So, how is the (presumed) creation of incredibly short-lived virtual particles comparable to the (known) creation of the incredibly long-lived universe?

I am not thge one who made the link, quantum fluctuation is a real thing and if the BBE was postulated to be a quantum fluctuation then it becomes important.

You stated
Yes. Virtual particles are just a theoretical construct to explain what otherwise cannot be explained -- the same as the theoretical construct that the universe came into existence with no impetus.

Virtual partciles are more than a theorhetical construct, the production of particle pairs is observed in particle chambers.

Now the theory that the universe came about from a quantum fluctuation is a possible theory and it would be the impetous. Now impetus would be different from intention.
 
Virtual partciles are more than a theorhetical construct, the production of particle pairs is observed in particle chambers.
What "particle pairs" are you referring to? A positron/electron pair emerging from a photon collision wouldn't be an example of virtual particles. Did you have something else in mind?

I'd agree that virtual particles are more than a theoretical construct thoug. They are a theoretical construct that contributed to a very accurate theory.
 
Now the theory that the universe came about from a quantum fluctuation is a possible theory and it would be the impetous.
Okay, but doesn't it seem a tad mystical that the universe arose as the result of a quantum fluctuation?
 
Okay, but doesn't it seem a tad mystical that the universe arose as the result of a quantum fluctuation?

Not if quantum fluctuations can be described as a function of nature like organic chemistry or electricity.
 
According to -- http://news.bbc.co.uk/1/hi/technology/4530930.stm --

"The free online resource Wikipedia is about as accurate on science as the Encyclopedia Britannica, a study shows."
That's why you need expertise in a topic. The Wiki is flat-out unreliable on many subjects. It does not matter if it is "on average" on a par with an excellent encyclopedia. Remember that a guy with his feet in the oven and his head in the freezer feels comfortable "on average." Also, the BBC is not a scholarly source of information.
 
That's why you need expertise in a topic. The Wiki is flat-out unreliable on many subjects. It does not matter if it is "on average" on a par with an excellent encyclopedia. Remember that a guy with his feet in the oven and his head in the freezer feels comfortable "on average." Also, the BBC is not a scholarly source of information.

Wow, that is really beautifully stated, JJM.
 
What "particle pairs" are you referring to? A positron/electron pair emerging from a photon collision wouldn't be an example of virtual particles. Did you have something else in mind?

I'd agree that virtual particles are more than a theoretical construct thoug. They are a theoretical construct that contributed to a very accurate theory.

I have an old brain but I recall a collider picture that showed a high energy particle emiting two opposite particles that are then reabsorbed by the primary particle.

If this is bogus then i apologise to Rodeny and claim that I have an old brain.

Rodney I will say this:

If my memory is incorrect I apologise , I will check this out and make a more formal apology.
 
Okay, but doesn't it seem a tad mystical that the universe arose as the result of a quantum fluctuation?

It would be if you started with absolute nothing, not nothing that is called nothing because it is unknown.

First off theories are approximations of the way reality might work, not exact maps of reality. Second the quantum fluctuation is mostly speculative theory of the BBE until something definitive can be found out about it.

Mystical theory: There is nothing, like nothing, no energy, no space of any sort, no nothing. This nothing then gives rise to something through the process of *insert miracle here*, we can label this quantum gobbledygook.

Not as mystic speculative theory: the universe arose from a pontentialy preexisting something, we can not describe or observe this something. It could be like a black hole, it could be like an infinite recurrsion of expanding bubble universes, it could be alomost anything because it can not be tested or observed at this time. This possible undefined something might have given rise to the BBE and the observed universe through the process of quantum gobbledygook.
 
I wonder if there's some confusion here with the intermediary particles in Feynman diagrams? These are also 'virtual particles' but are unobservable (as to observe one would interact with it invadidating your Feynman diagram). I vaguely remember someone from SSC (that dates it) arguing that a virtual-W in neutron decay can't really be said to be real or not real as nothing other than the neutron that's decaying that can ever have any experience of it. I.e. whether a W actually appears or not is undecidable.
 
Rodney :
It appears that my memory was at fault, there is no evidence for the virtual particles expect that they make the equations work. So unlike quarks there is not even indirect evidence.

I was very wrong.

david
 
Again I join a 3 page thread not having had the time to read what has been posted. I see it has gone a bit off track. So forgive any redundancies and my redirection back to the thread topic if the topic has run its course.

If abiogenesis has occurred once, then in similar conditions given infinite time, it can occur an infinite number of times.

However, if the question is, did it occur more than once on Earth, excluding any events that shortly after died out, the definitive answer to your question can be found in genetic evidence.

Looking at the Tree of Life website, there are three branches, only one of which contains multi-celled organisms. A brief discussion of the question of single or multiple abiogenesis events can be found here. There is direct evidence of gene transfer across species, we see many examples of it today. This makes analysis of the question complicated. Did life emerge once and go in three directions shortly after, or did life emerge 3 separate times and then exchange some genetic material?

To date, we have not found any lifeforms which do not fit in any of the three branches. This includes newly discovered extremophiles from various locations. I think collectively there is overwhelming evidence against panspermia hypotheses.

That doesn't mean continued abiogenesis or living organisms reaching Earth from space hasn't occurred. But it does mean if such events have occurred, these lifeforms are not being found. That suggests they cannot easily become established like The Day of the Triffids suggests. If you think about invading species, they have to exploit the resources more efficiently or have some other survival advantage over native species in order to invade.

We do have sufficient knowledge of genetics to have established the connection between lifeforms as diagrammed in the Tree of Life. There are many gaps (egad the gap word) and perhaps a few misplacements. But if you search around that website and the supporting citations you'll find it is far from being based on sketchy evidence. I think a fair number of people don't realize just how detailed the trail of genetic evidence is. Human migrations out of Africa as well as our ancestors going back to the first organisms is mapped in fine detail in our genes.
 
That's why you need expertise in a topic. The Wiki is flat-out unreliable on many subjects. It does not matter if it is "on average" on a par with an excellent encyclopedia. Remember that a guy with his feet in the oven and his head in the freezer feels comfortable "on average." Also, the BBC is not a scholarly source of information.
I find Wiki citations best for explaining the history or definition of something everyone might not be familiar with that you put in a post.

The citations from Wiki are usually there if the information is questionable. It's very useful on occasion to start at Wiki but cite the original sources when you are looking for something to back a debate position.
 
Rodney :
It appears that my memory was at fault, there is no evidence for the virtual particles expect that they make the equations work. So unlike quarks there is not even indirect evidence.

I was very wrong.

david
No problem. And, if by some one in a million chance, I should ever be wrong about anything, I'll apologize too. ;)
 
It appears that my memory was at fault, there is no evidence for the virtual particles expect that they make the equations work. So unlike quarks there is not even indirect evidence.
Why do you conclude that? I have been led to believe that the Casimir Effect is evidence that virtual particles exist. After all, it is the pressure from virtual particles that makes th plates stick together (because there are more virtual particles outside than between the plates).
 
So the universe sprung up from "an empty, dimensionless, timeless nothingness"? What was the impetus?
Impetus? Isn't that what Aristotle thought moving objects contain which keeps them moving until it gets used up, or something like that?

Then Galileo and Newton came along and said, no, it doesn't work that way. There's no such thing as impetus. But there doesn't need to be. Moving objects keep moving in a straight line at the same speed they were moving, just because. Except, if some force acts on them, like gravity for example, then they'll accelerate in response to the force.

Then Einstein came along and said, no, that's not the way it's works. Gravity isn't a force; it's merely curvature of spacetime. And objects follow geodesics in spacetime, just because.

The point is, a scientific theory doesn't just give the reasons why things happen; it also says what sorts of thing need a reason in the first place and what sorts of thing don't.

But this is obvious. One can always keep asking "why?" to whatever explanation anyone gives for anything. So it's not a reasonable objection to a theory that it doesn't give explanations for its axioms. We have to start somewhere.

If you're not satisfied with "the universe is here, just because", what sort of explanation for its existence would satisfy you? And why do you feel that the unexplained presuppositions on which your explanation is based are any less in need of an explanation themselves?
 
Why do you conclude that? I have been led to believe that the Casimir Effect is evidence that virtual particles exist. After all, it is the pressure from virtual particles that makes th plates stick together (because there are more virtual particles outside than between the plates).

I know that the effects of them are real but I thought that they had actualy shown up on particle chambers photos. They or some virtual effect do seem to be required for the equations to work. But it would appear from a cursory galnce that there is no direct evidence or indirect evidence. Such as the scattering studies which show that protons and nuetrons to appear to have quark like properties.
 
But this is obvious. One can always keep asking "why?" to whatever explanation anyone gives for anything. So it's not a reasonable objection to a theory that it doesn't give explanations for its axioms. We have to start somewhere.


As the comercial said "Why ask why?"

or a trainer I listened to "Don't ask why, ask what?"
 
I know that the effects of them are real but I thought that they had actualy shown up on particle chambers photos.
I believe they are too short-lived to show up in particle chamber photos.

But it would appear from a cursory galnce that there is no direct evidence or indirect evidence.
What do you mean by direct evidence? You do not see the particles in particle chambers, only their effects. I do not think you have anything else than indirect evidence for stuff smaller than atoms.
 
If you're not satisfied with "the universe is here, just because", what sort of explanation for its existence would satisfy you? And why do you feel that the unexplained presuppositions on which your explanation is based are any less in need of an explanation themselves?
I think older and now discredited cosmological models are much more consistent with a random universe than the now accepted model. For example, if we could not specify a beginning of the universe, it might be the case that it gradually came into existence over countless eons of time via countless random events. But now that we can rather confidently state that the universe began as a single dimensionless point of infinity density, its creation seems much more consistent with the idea of a non-random miraculous event.
 

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