Stephen Hawking - Turns Out That You Can Escape A Black Hole
- Thread starter Dryson
- Start date
And yet, no mention was made of the big bang, merely the subsequent expansion of the universe. If you have some alternative explanation for redshift why not share constructively?
That's not an explanation. It looks more like evasion and an inability to support a claim with real knowledge. Why not at least just invoke Hubble and use words like "redshift" or "Type 1a supernovas" instead of coy responses?
Thank you, JWPlatt.
I knew which "evidence" psCargile was referring to, but he obviously missed my point about not confusing data with conclusions. Redshift is the data. That it is thought to be caused by the Doppler effect is the conclusion (the assumption, really). PurpleBuddha made the same mistake in referring to the "CMBR" as a conclusion. I don't know if either of these posters is a professional astrophysicist with degrees and training, but I do know that these topics are contentious among professionals in the field. I just happen to be curious enough to look into the alternatives.
For those interested, there are alternative explanations for the cosmic microwave "background" and redshift. On the latter, take a look at Halton Arp's book Seeing Red. It contains a wealth of data that's not addressed in pop science documentaries and books. Arp was a respected astronomer—until he started pointing out the problems with redshifted objects. Then the situation became worse than with Galileo—it wasn't his detractors who refused to look through the telescope. They blacklisted him so that he couldn't look through the telescope anymore. That alone has got to make one curious.
I knew which "evidence" psCargile was referring to, but he obviously missed my point about not confusing data with conclusions. Redshift is the data. That it is thought to be caused by the Doppler effect is the conclusion (the assumption, really). PurpleBuddha made the same mistake in referring to the "CMBR" as a conclusion. I don't know if either of these posters is a professional astrophysicist with degrees and training, but I do know that these topics are contentious among professionals in the field. I just happen to be curious enough to look into the alternatives.
For those interested, there are alternative explanations for the cosmic microwave "background" and redshift. On the latter, take a look at Halton Arp's book Seeing Red. It contains a wealth of data that's not addressed in pop science documentaries and books. Arp was a respected astronomer—until he started pointing out the problems with redshifted objects. Then the situation became worse than with Galileo—it wasn't his detractors who refused to look through the telescope. They blacklisted him so that he couldn't look through the telescope anymore. That alone has got to make one curious.
The tunnel effect causes them to evaporate, though very very slowly.
Even better, the black hole would end up in an explosion of light, more powerful than a supernova.
Yes, I've never seen this addressed by any popular astrophysicist/cosmologist. The implication is always that a black hole stays a black hole until it completely "evaporates." But I always think there must be a symmetric tipping point. Acquire enough mass, black hole. Lose enough mass, not a black hole and there's a potentially sudden release of compression.
The yield of an evaporating black hole is equivalent to about 5 teratons of TNT (2.0 × 10^22 J) -- big but 22 orders of magnitude smaller than a supernova (2 x 10^44 J).
https://en.wikipedia.org/wiki/Hawking_radiation#Black_hole_evaporation
Black holes turning into white holes is predicted by loop quantum gravity (apparently):
http://www.nature.com/news/quantum-bounce-could-make-black-holes-explode-1.15573
https://en.wikipedia.org/wiki/Hawking_radiation#Black_hole_evaporation
Black holes turning into white holes is predicted by loop quantum gravity (apparently):
http://www.nature.com/news/quantum-bounce-could-make-black-holes-explode-1.15573
I can't take the time to read the book for the purpose of a forum post, but I did go read the wiki on Arp, intrinsic redshifts, and non-standard cosmologies which takes only a few minutes. So yeah, I'd recommend doing at least that before offering coy answers.
In a paragraph here...
https://en.wikipedia.org/wiki/Non-standard_cosmology#Redshift_periodicity_and_intrinsic_redshifts
...the claim is flatly stated that "The controversy was laid to rest by the 1990s when evidence became available that indicated quasars were actually the ultra-luminous cores of distant active galactic nuclei and that the major components of their redshift were in fact due to the Hubble flow," apparently because of a much larger dataset than Arp had available.
Science should never claim itself as being right, so my mind is open, but while mistreatment of the man makes him sympathetic, it does also not make him right.
Yeah, I also thought that debate had been settled over two decades ago but people keep trying to revive its rotting corpse while claiming some grand conspiracy.
It's snark. I used to get all brainy back in my twenties, twenty years ago with all kinds of supporting links and quotes from books off my shelf, but now I'm all out of damns to give. Metryq can believe whatever; I'm not going to entertain anyone with facts or opinions that must be known prior in order to argue against.
At any rate, before any of the current black holes turn into white wholes, it'll take a time so long that we need an exponential of an exponential to represent it. I don't remember the exact number but it was impressive to look at.
Here is a good article on black holes and how one was created.
Tiny particles of light (photons) are sometimes ejected back out, robbing the black hole of an infinitesimal amount of energy, and this gradual loss of mass over time means every black hole eventually evaporates out of existence.
How interesting that a black is created from light photons, a sun as well as being destroyed eventually by the same source that created it. It creates itself but can be destroyed by itself yet can never truly defend itself against itself.
http://physicsworld.com/cws/article/news/2008/mar/06/artificial-black-hole-created-in-lab
http://www.seeker.com/first-ever-black-hole-created-on-earth-1764728472.html
In this article I found something interesting when the images are compared to toilet paper on a stand up dispenser in the bathroom.
Musings from the toilet.
Image c is the natural of toilet paper when are rest.
Image a is the unnatural position when the toilet paper is pulled back the opposite direction
Tiny particles of light (photons) are sometimes ejected back out, robbing the black hole of an infinitesimal amount of energy, and this gradual loss of mass over time means every black hole eventually evaporates out of existence.
How interesting that a black is created from light photons, a sun as well as being destroyed eventually by the same source that created it. It creates itself but can be destroyed by itself yet can never truly defend itself against itself.
http://physicsworld.com/cws/article/news/2008/mar/06/artificial-black-hole-created-in-lab
http://www.seeker.com/first-ever-black-hole-created-on-earth-1764728472.html
In this article I found something interesting when the images are compared to toilet paper on a stand up dispenser in the bathroom.
Musings from the toilet.
Image c is the natural of toilet paper when are rest.
Image a is the unnatural position when the toilet paper is pulled back the opposite direction
Last edited:
An artificial black hole on Earth? Interesting.
You have to remember that it's a process, extremely slow. Something like a number with billions of zeros, if I remember correctly. It must be slower than one infrared photon every billion years!!! for a big ass black hole!
The power due to the Hawking radiation from a solar mass black hole = 9 × 10^−29 watts. That's about 30 orders of magnitude less than a 100 W light bulb. This miniscule power is emitted in all directions; there's no net thrust vector.
The effective temperature of a solar mass black hole is 6 x 10^-8 K, so the peak of the black body spectrum by Wien's displacement law is at a wavelength of 2.9 x 10^-3 / 60 x 10^-9 = 48,333 m or about 48 km (in the ELF or extremely low frequency radio band). The energy of a photon with a wavelength λ is h.(c/λ) where h is Planck's constant and c is the speed of light or 6.626 x 10^-34. (3 x 10^8 / 48333) = 4.1 x 10^-30 J. So a rough estimate of the number of photons emitted per second is 9 × 10^−29 / 4.1 x 10^-30 or about 22 photons per second.
The evaporation time of a solar mass black hole is greater than 2.1 × 10^67 years (the current age of the universe at 13.8 x 10^9 years). A black hole cannot evaporate until its effective temperature is greater than the temperature of the cosmic microwave background (CMB; currently 2.7 K) as more energetic photons from the CMB are falling in faster than the black hole can evaporate and the black hole actually gains mass. The CMB temperature decreases as the Universe expands so it will eventually cool to a temperature below that of the black hole and the black hole can start to lose mass by Hawking radiation.
The CMB temperature T for a Universe expanding with constant speed varies as t^-(2/3) where t = time so T(future) = T(now).(t(future)/t(now))^-(2/3). Therefore, t(future) = t(now).(T(future)/T(now))^-1.5 so the black hole can start to lose mass when the Universe is (6 x 10^-8/ 2.7)^-1.5 times older than at present or about 4.2 x 10^21 years. As this is much smaller than 2.1 × 10^67 years and the Universe's expansion is believed to be accelerating, the estimate of 2.1 × 10^67 years is good enough. An accelerated expansion might well result in a Big Rip well before then -- perhaps less than 25 billion years from now.
The effective temperature of a solar mass black hole is 6 x 10^-8 K, so the peak of the black body spectrum by Wien's displacement law is at a wavelength of 2.9 x 10^-3 / 60 x 10^-9 = 48,333 m or about 48 km (in the ELF or extremely low frequency radio band). The energy of a photon with a wavelength λ is h.(c/λ) where h is Planck's constant and c is the speed of light or 6.626 x 10^-34. (3 x 10^8 / 48333) = 4.1 x 10^-30 J. So a rough estimate of the number of photons emitted per second is 9 × 10^−29 / 4.1 x 10^-30 or about 22 photons per second.
The evaporation time of a solar mass black hole is greater than 2.1 × 10^67 years (the current age of the universe at 13.8 x 10^9 years). A black hole cannot evaporate until its effective temperature is greater than the temperature of the cosmic microwave background (CMB; currently 2.7 K) as more energetic photons from the CMB are falling in faster than the black hole can evaporate and the black hole actually gains mass. The CMB temperature decreases as the Universe expands so it will eventually cool to a temperature below that of the black hole and the black hole can start to lose mass by Hawking radiation.
The CMB temperature T for a Universe expanding with constant speed varies as t^-(2/3) where t = time so T(future) = T(now).(t(future)/t(now))^-(2/3). Therefore, t(future) = t(now).(T(future)/T(now))^-1.5 so the black hole can start to lose mass when the Universe is (6 x 10^-8/ 2.7)^-1.5 times older than at present or about 4.2 x 10^21 years. As this is much smaller than 2.1 × 10^67 years and the Universe's expansion is believed to be accelerating, the estimate of 2.1 × 10^67 years is good enough. An accelerated expansion might well result in a Big Rip well before then -- perhaps less than 25 billion years from now.
As much as I love Stephen, I think he's flat out wrong about a few things and black holes are one of them.
