It depends on how much matter it can attract in that period no matter how short it is.
There are apparently several formulae, all giving different answers!
One such is: t = (5120 * pi * G^2 * M^3) / (ħ * c^4)
https://en.wikipedia.org/wiki/Hawking_radiation#A_crude_analytic_estimate
(M = mass of black hole, G = gravitational constant, c = speed of light and ħ is the reduced Planck constant. The 5120 is unexplained, and many assumptions are made to arrive at the formula.)
According to this formula, a black hole of one solar mass takes > 10^67 years to evaporate - much longer than the current age of the Universe!
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You got me wondering about the Heat Death of the Universe, and a solar mass black hole WILL evaporate before then!
https://en.wikipedia.org/wiki/Graphical_timeline_from_Big_Bang_to_Heat_Death
https://en.wikipedia.org/wiki/Graphical_timeline_from_Big_Bang_to_Heat_Death
I read about the Heat Death of the Universe about four decades back, and all matter was supposed to transmute into the "most stable" element, lead. But according to that chart, there will be no protons and no black holes. Apparently, the only things that will be left are electrons and neutrons.
Lucky we are, living in a self healing universe.
Why it does not plug large leaks ?
How large, should be a BH to last ?
Could be the leaks have a purpose.
Beyond BH some fantasize White fountains. Could we, instead, imagine Big Bangs beyond Black Holes, this could result in a perfectly leak proof meta-universe.
I'm sure the know of the line but not so certain about the unit "cm" ;-D
I hope that on the record a more universal unit of time was used - e.g. a part of c. And the they didn't call c, "c" 🙂
//
Talking to ETs.
Trouble is, they certainly do not use the same units for length, mass, time, ampere.
We could give to ETs the value of a universal constant that has no unit.
There are few constants like this which are pure numbers.
A dimensionless universal physical constants, is the fine-structure constant α, which characterizes the strength of the electromagnetic interaction.
We could give the binary value, instead of digits for creatures with 10 fingers.
How could we tell ETs, that this number is this specific constant, the fine-structure constant alpha ?
Trouble is, they certainly do not use the same units for length, mass, time, ampere.
We could give to ETs the value of a universal constant that has no unit.
There are few constants like this which are pure numbers.
A dimensionless universal physical constants, is the fine-structure constant α, which characterizes the strength of the electromagnetic interaction.
We could give the binary value, instead of digits for creatures with 10 fingers.
How could we tell ETs, that this number is this specific constant, the fine-structure constant alpha ?
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It was - the hyperfine transition of neutral hydrogen!
There's a diagram showing the two lowest states of the Hydrogen atom. The transition from one state to the other provides the vital clock reference used in all the record cover diagrams and decoded pictures.
There are also illustrations of the proper waveforms of signals expected to be seen if the record is spun at the correct speed.
But allow me lay any further discussion to rest - there are no
aliens! 😆😍😀
M mchambin, I find it extremely unlikely that Extra-Terrestrials even exist!
Consider the unusual circumstances of our own existence!
https://en.wikipedia.org/wiki/Giant-impact_hypothesis
I am not too sure about this, but the debris from this collision caused 1 km high tides on our own planet. Being an inverse-cubed problem.
What I want to know from the Aliens, is if they have solved the Riemann Hypothesis.
I doubt it!
My current mathematical interest:
You can see where I am going here:
https://en.wikipedia.org/wiki/Regular_4-polytope
Into the Fourth Dimension of Spacetime! Well, somebody has to do it. 🙂
Consider the unusual circumstances of our own existence!
https://en.wikipedia.org/wiki/Giant-impact_hypothesis
I am not too sure about this, but the debris from this collision caused 1 km high tides on our own planet. Being an inverse-cubed problem.
What I want to know from the Aliens, is if they have solved the Riemann Hypothesis.
I doubt it!
My current mathematical interest:
You can see where I am going here:
https://en.wikipedia.org/wiki/Regular_4-polytope
Into the Fourth Dimension of Spacetime! Well, somebody has to do it. 🙂
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"I find it extremely unlikely that Extra-Terrestrials even exist!"
I feel the same way. It's a real hard sell in my book.
It doesn't help that there was a goon on the news this morning saying he had "spacecraft from other species" under oath. Sure you do buddy. Sure you do.
I feel the same way. It's a real hard sell in my book.
It doesn't help that there was a goon on the news this morning saying he had "spacecraft from other species" under oath. Sure you do buddy. Sure you do.
How stable are black holes of different masses?
Black holes evaporate by emitting thermal, blackbody radiation known as Hawking radiation.
The less massive a black hole is, the faster it evaporates.
A black hole the mass of our Sun would take 10^64 years to evaporate.
A simple formula to calculate the time for a black hole to evaporate is [10^64 x (mass of black hole/mass of Sun)^3] years.
A black hole the mass of the Earth would last 10^47 years while one the mass of the average human would last for just under a picosecond.
I asked Ethan: https://www.forbes.com/sites/starts...sk-ethan-when-do-black-holes-become-unstable/
;-)
You pin pictures of black holes, funnel universes, dark matter and anti matter and more on the walls of your kids rooms, but you were still not able to clarify whether "mass" "falls" "into" "bent" "spacetime" or "mass" "bends" "spacetime"-)
... the majority mutual reassurance by various methods as mainstream "scientists" who do not allow themselves to ask questions - and probably cannot answer them - is regularly experienced in this thread;-)
You pin pictures of black holes, funnel universes, dark matter and anti matter and more on the walls of your kids rooms, but you were still not able to clarify whether "mass" "falls" "into" "bent" "spacetime" or "mass" "bends" "spacetime"-)
... the majority mutual reassurance by various methods as mainstream "scientists" who do not allow themselves to ask questions - and probably cannot answer them - is regularly experienced in this thread;-)
A quick search reveals the geometrically obvious fact that the Terry's Chocolate Orange is orange-shaped! 😀
There are 20 segments, similar to those in a real orange, which are stuck firmly together at the centre
A sharp whack on the kitchen work surface is all that is needed to separate the segments prior to consumption.
If you are a fan like me, you will find it nigh impossible to desist from eating an entire Chocolate Orange in one sitting!
P.S. It's not Terry's, it's mine.
P.P.S. Did you know that the Chocolate Orange (introduced 1932) was preceded by the Chocolate Apple (invented 1926).
If they exist in the form they are envisaged.
A link I posted reminded me of more sci-fi. All substances have a critical mass. Boring book however throw in density via compression............ We do feel we know what happens with hydrogen as a for instance.
This paper mentioned a forthcoming one by 3 people to try and get a grip of any nuclear effects due to black hole formation. No signs of it.
A fairly common comment about black holes is that physics breaks down. The other paper pointed out that it breaks down again at a singularity as gravity is infinite.
While nosing around I noticed a sun sized star had gone nova - now that is not supposed to happen.
If the sun goes nova orbits don't change - a bit strange as mass will be lost and spread out over a wide area. Angular motion retained when that has happened. I wonder.
LOL This remains interesting
https://en.wikipedia.org/wiki/Olbers'_paradox
Do you have more information on this event? It is certainly not in line with how a nova is thought to happen.
A Nova involves a white dwarf star pulling matter off a companion star in a close binary system until a powerful explosion occurs on the white dwarf's surface. https://www.space.com/31608-supernovas-star-explosions-infographic.html
And a Sun sized star certainly can't go supernova - for that a star needs to be about 10 times the mass of our Sun.
The fact that the night sky is not completely lit up by the almost infinite number of stars and galaxies in the universe has become known as "Olbers' Paradox".
But basically, the sky is dark because there hasn't been enough time for the light to reach us from the most distant stars.
The first published solution to Olbers' Paradox is attributed to Edgar Allan Poe. In his essay Eureka, Poe says:
"Were the succession of stars endless, then the background of the sky would present us a uniform luminosity, like that displayed by the Galaxy - since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all."
It's interesting to note that Poe died 80 years before Edwin Hubble's discovery in 1929, so was unaware of the expansion of the Universe.
I agree with Galu.
In the course of my Mathematical investigations, I have eaten another two Terry's Chocolate Orange segments:
TBH, I am feeling a bit sick. But expect to recover.
To address AjohnL's concerns about our Type G Main Sequence Sun going Nova, I assure you it will not happen!
https://en.wikipedia.org/wiki/G-type_main-sequence_star
The Worst that can happen is our Sun will become a Red Giant. Long after we are all gone!
In the course of my Mathematical investigations, I have eaten another two Terry's Chocolate Orange segments:
TBH, I am feeling a bit sick. But expect to recover.
To address AjohnL's concerns about our Type G Main Sequence Sun going Nova, I assure you it will not happen!
https://en.wikipedia.org/wiki/G-type_main-sequence_star
The Worst that can happen is our Sun will become a Red Giant. Long after we are all gone!
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From earlier in the thread: Being an average star, the Sun will evolve into a red giant, eject a beautiful nebula and end up as a white dwarf.