Why UNLIMITED Exponential Growth of Pigeons would DESTROY the Universe!

[Steel]

I think we can all agree that any question that involves infinite pigeons is not physical, but as long as no one claims to actually be doing science here then we're all good. I think this is conversation worth having!

[Green Baron]

I certainly do agree.

A mass out of nothing, growing exponentially for an infinite time will form an infinite mass in infinite time. We ignore physics here at least for the initial impetus (the first few pigeons so to say) because, were physics valid, the process would never come into being. A mass (better: energy) doesn't come out from nothing.

At what time exactly shall we switch on physics again and how much of it ?

 

Edited May 4, 2017 by Green Baron

[kerbiloid]

Didn't the whole Universe mass appear out of nothing?

Why disallow pigeons to create their own Universe?

[Green Baron]

1 minute ago, kerbiloid said:

Didn't the whole Universe mass appear out of nothing?

Afaik not. The inflationary phase is the interesting time frame. Don't ask me details, but when i last read about it it all made sense somehow :-) Search for false vacuum, higgs field, these kind of things. Ignore that singularity thing.

1 minute ago, kerbiloid said:

Why disallow pigeons to create their own Universe?

They may commence.

:-)

[kerbiloid]

Though, I bet on rabbits.

[vger]

Unlimited exponential growth of ANYTHING would destroy the universe.

[ProtoJeb21]

To clarify (again):

This thread is showcasing what would happen if the context of the problem would actually be true. With the exception of how you would get all those pigeons, this completely follows the rules of physics. This includes the birds becoming a star. Like I said in the OP, it has to do with mass. All those pigeons so close together would be exerting a gravitational pull. A single bird does have gravity, although it is millions if not billions of times weaker than that of a planet or asteroid. But 424 octillion pigeons WOULD create a large enough gravitational field to pull them together. As the amount of pigeons rapidly grows, the area would be more and more crowded. They could eventually get compact enough to squish together. As the minutes pass, the ball of squished pigeons would increase in size until it is large enough to have its own gravity, swallowing all appearing pigeons. That's how they would become a star: wait a bit for all the birds to smoosh into an object heavy enough to sustain nuclear fusion.

@vger Yes, rapid exponential growth (like tripling something every minute) would eventually lead to universal destruction if there was an infinite amount of whatever is growing at that rate. I just posted the example with the pigeons because of how horrified I was when I ran the numbers.

[Steel]

8 hours ago, ProtoJeb21 said:

...As the minutes pass, the ball of squished pigeons would increase in size until it is large enough to have its own gravity, swallowing all appearing pigeons. That's how they would become a star: wait a bit for all the birds to smoosh into an object heavy enough to sustain nuclear fusion.

Interesting question: would the mass actually become a star as we know it?

At the end of the day pigeons (like most life) are mostly oxygen and carbon, which (a) require enormous pressures to fuse and (b) fusion of these only occurs toward the end of the life cycle of a massive star. So does this mean that when it does eventually fuse would we end up with a multi-solar mass star that appears as if it's quite late on in its life cycle?

[Green Baron]

I kindly ask to revisit stellar evolution. Stars are made from hydrogen. Red dwarfs slowly fuse their hydrogen if i remember correctly. Is carbon fusion involved at all ? I'd rather attribute it to red giants ?

 

Fusion is a very fragile process. Needs stability over millions of years and the right mixture, pressure and temperature. Carbon fuses (if it fuses during stellar evolution) in a hull that slowly moves through a stars atmosphere.

[Not citable] All the water in the pigeon bodies will moderate the process i don't think any fusion can start at all. Also the explosion like emergence of pigeons will not guaranty the stability needed. Furthermore i'd expect the pigeons not to have enough density to collapse into something supermassive. So the ball will probably just grow superluminal for eternity. Since the premise ignores physics and keeps doing so during the whole process we can safely keep ignoring it and accept superluminal expansion [/not citable].

:-)

 

Edited May 5, 2017 by Green Baron

[Steel]

Carbon- and oxygen-burning does happen in the cores of very large stars once they get towards the end of their hydrogen and helium stores. But I think you might be right, by the time you accumulate enough mass to start carbon or oxygen fusion, the mass would probably just collapse further into some form of degenerate matter.

Edited May 5, 2017 by Steel

[kerbiloid]

If KSP were calculating also vessels gravity, not only planets, this could be an achievement: make a self-gravitating Kerball (ball of Kerbals).

Edited May 5, 2017 by kerbiloid

[Steel]

25 minutes ago, kerbiloid said:

If KSP were calculating also vessels gravity, not only planets, this could be an achievement: make a self-gravitating Kerball (ball of Kerbals).

Im not sure anyone would ever get it, sadly not many people play KSP on supercomputing clusters

[Green Baron]

Off topic, just a sidenote: Orbiter does so. It calculates mass distribution of a vessel to determine different levers that force a vessel in a bound rotation and so on. Orbiter also takes account of perturbations in earths gravitational field. The resource specification is lower than that of ksp, Orbiter uses quite sophisticated algorithms and is programmed in c++.

The math orbiter uses is described in several pdfs that come with it.

 

[LN400]

This all made me think about a lecture about maths and models in school way back. The backdrop was: A patient with severe fever taking fever reducing drugs while the body temp was monitored. The model for body temp over time worked like clockwork over a day or so but when we ran it over a week, the body temp landed at negative Kelvin. Models are great just don't go beyond the limitation of your model. Same with speed. Distance over time which most would agree is speed, is plain ludicrous and not correct in the slightest at very high speeds. Know the limitation of the model's validity.

/topic detour

[p1t1o]

21 minutes ago, LN400 said:

This all made me think about a lecture about maths and models in school way back. The backdrop was: A patient with severe fever taking fever reducing drugs while the body temp was monitored. The model for body temp over time worked like clockwork over a day or so but when we ran it over a week, the body temp landed at negative Kelvin. Models are great just don't go beyond the limitation of your model. Same with speed. Distance over time which most would agree is speed, is plain ludicrous and not correct in the slightest at very high speeds. Know the limitation of the model's validity.

/topic detour

All of known science is a model. This should be taught more, to reduce the proportion of people that think it is ok to point out flaws in the models and because of that, accuse science of being worthless compared to their gut feelings.

[Green Baron]

Some models are better (in terms of approximating nature) than others.

A model that computes a negative body temperature of a life creature should be overworked or discarded :-)

Edited May 5, 2017 by Green Baron

[LN400]

2 minutes ago, Green Baron said:

A model that computes a negative body temperature of a life creature should be overworked or discarded :-)

A consequence of that is that the entire idea of speed being distance over time as we know it from car speedometers etc should be discarded, or that clocks should be thrown in the trash bin. It all comes down to limitation of application and approximations (how close is close enough for practical purposes). If you only want to monitor the body temp over a single day (for whatever reason) then the model we used would be just fine to use and there would be no need to discard it. If you want more than a day, then you need a better model.

[Green Baron]

Why ? Need more info to follow your thought, because v=s/t works quite well here. Am ready to throw it overboard if offered something better :-)

A no-go is to set rules as one likes, ignore, switch or bend them or apply the wrong to a given situation (like v=s/t to relativistic speeds to stay with the example).

Switching off physics to construct a situation and then on again in an area while leaving it off in an adjacent and then demanding a solution from physics for the "on-area" simply does not work. I wish that basic insight would become more common :-)

 

[Steel]

1 minute ago, Green Baron said:

Why ? Need more info to follow your thought, because v=s/t works quite well here. Am ready to throw it overboard if offered something better :-)

I think he's talking about what happens when you get relativistic.

[Green Baron]

3 minutes ago, Steel said:

I think he's talking about what happens when you get relativistic.

He cannot blame the model for being incorrect. It is the wrong one for the situation. Like using a soft-wood saw for corundum steel.

[LN400]

Think back at physics in secondary school or high school or whenever you had your first physics class.

"Lisa leaves home every morning to go to school" the teacher says, and draws on the blackboard two dots with a straight line between them. The dots are Lisa's home and school and the line is the road. Now that works like a charm to explain low speeds like we experience every day but no Lisa anywhere is a point, no house or school is really a small dot on a blackboard and no road is a straight line a millimeter wide. It was all a model constructed to highlight a particular issue. So is the formula v = d/t. It is a model that should not be taken outside its field of application.

Steel is correct. When you go relativistic, v = d/t breaks down to absurdities and you need a much more complicated model. 

EDIT:

My point is: Every model in science, or economics, or any other field, have limited fields of application. Take the model out of its limitation and it's no longer a good model.

Edited May 5, 2017 by LN400

[Steel]

1 minute ago, Green Baron said:

He cannot blame the model for being incorrect. It is the wrong one for the situation. Like using a soft-wood saw for corundum steel.

Technically it is incorrect. Even at low speed absolutely tiny amounts of time dilation and length contraction are happening which are not taken into account in Newtonian mechanics. The reason Newtonian mechanics still works is because they're so small that they can safely be ignored, but that doesn't mean it isn't happening.

[Green Baron]

No Lisa comes home and asks dad (a physicist) why he is doing such complicated things while life is so easy, the teacher has demonstrated. What should dad say ?

3 minutes ago, Steel said:

Technically it is incorrect. Even at low speed absolutely tiny amounts of time dilation and length contraction are happening which are not taken into account in Newtonian mechanics. The reason Newtonian mechanics still works is because they're so small that they can safely be ignored, but that doesn't mean it isn't happening.

Sir, i know that :-)

Edited May 5, 2017 by Green Baron

[Steel]

3 minutes ago, Green Baron said:

Sir, i know that :-)

Well then he can blame the model for being incorrect!

[Green Baron]

13 minutes ago, LN400 said:

My point is: Every model in science, or economics, or any other field, have limited fields of application. Take the model out of its limitation and it's no longer a good model.

Am totally blowing the same horn :-)

 

5 minutes ago, Steel said:

Well then he can blame the model for being incorrect!

No. The model v=s/t is for every day use in a car the right one. It is not the right one for running a clock in a satellite that needs exact time. He can blame only himself for not knowing about the right choice or knowing it but ignoring it.

Edit: post 1000 ! Yay ! So much wasted time

Edited May 5, 2017 by Green Baron