Sunday, June 4, 2023

News bits: The universe is going to evaporate; Etc.

Steven Hawking's famous hypothesis about black holes slowly evaporating has received an update. Assuming the hypothesis is correct, and it might not be, the whole freaking universe is going to evaporate in a short ~1 x 10124  years or thereabouts! Guardian Mag writes:
Hawking's revised theory Predict Universal Evaporation, New study

Stephen Hawking's most famous theory about black holes has just been given a sinister update — one that proclaims that everything in the universe is doomed to evaporate.

In 1974, Hawking proposed that black holes eventually evaporate by losing what's now known as Hawking radiation — a gradual draining of energy in the form of light particles that spring up around black holes' immensely powerful gravitational fields.

Now, a new update to the theory has suggested that Hawking radiation isn't just created by stealing energy from black holes, but from all objects with enough mass.

If the theory is true, it means that everything in the universe will eventually disappear, its energy slowly bled from it in the form of light.

"That means that objects without an event horizon [the gravitational point of no return beyond which nothing, not even light, can escape a black hole], such as the remnants of dead stars and other large objects in the universe, also have this sort of radiation," lead author Heino Falcke, a professor of astrophysics at Radboud University in the Netherlands, said in a statement. "And, after a very long period, that would lead to everything in the universe eventually evaporating, just like black holes. This changes not only our understanding of Hawking radiation but also our view of the universe and its future."  
According to quantum field theory, there is no such thing as an empty vacuum. Space is instead teeming with tiny vibrations that, if imbued with enough energy, randomly burst into virtual particles, producing very-low-energy packets of light, or photons.
We present a new avenue to black hole evaporation using a heat-kernel approach analogous as for the Schwinger effect. Applying this method to an uncharged massless scalar field in a Schwarzschild spacetime, we show that spacetime curvature takes a similar role as the electric field strength in the Schwinger effect. We interpret our results as local pair production in a gravitational field and derive a radial production profile. The resulting emission peaks near the unstable photon orbit. Comparing the particle number and energy flux to the Hawking case, we find both effects to be of similar order. However, our pair production mechanism itself does not explicitly make use of the presence of a black hole event horizon.
A cranky physicist at reddit poo-pooed the whole thing as a kerfuffle in a teapot:

At first glance this just means that the theory predicts gravitational fields can create radiation outside of event horizons. this is based on the Schwinger effect, which showed that radiation can be produced by electromagnetic fields. Reporters need to stop magnifying physics out of proportion. This was already *almost* predicted by naive use of the equiv. principle, which supposes that Unruh thermalization should exist in gravitational fields. However, Unruh radiation (production of radiation from the thermalization) hasn't been confirmed and until now Hawking radiation was the closest theory to actual Unruh radiation.

To that, another cranky physicist commented: Doomed ... doooomed I say!

Holy Schwinger, Schwarzschild and Unruh! To prepare for bumpiness ahead, I purchased self-defense technology protect myself and my family:


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Spin tyranny update: From the Russian Motherland, we get this uplifting story:
In Russian Schools, It’s Recite Your ABC’s 
and ‘Love Your Army’

The curriculum for young Russians is increasingly emphasizing patriotism and the heroism of Moscow’s army, while demonizing the West as “gangsters.” One school features a “sniper”-themed math class.

Teaching the wee tykes in Russia

A new version of the ABC’s in Russia’s Far East starts with “A is for Army, B is for Brotherhood” — and injects a snappy phrase with every letter, like, “Love your Army.”

A swim meet in the southern city of Magnitogorsk featured adolescents diving into the pool wearing camouflage uniforms, while other competitors slung model Kalashnikov rifles across their backs.
It is reassuring to know that humanity is definitely not not a collision course with peace, civility, tolerance, democracy or long-term sustainability. 


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Meanwhile, an observer opines over at the Capitalism v. Socialism reddit channel:
A very common argument for socialism that I have seen is ranting about how bad the US is.

But I don't think that makes much sense because many of the supposedly bad things the US does or has don't apply to many other capitalist countries (e.g. healthcare, wars, expensive college education, 2 party system etc.)

Often these are very US centric and specific elements.

More less socialists are saying they are unhappy with how the US is run, they want better healthcare and they hate their politicians.

But that does not justify socialism in any way as many other capitalist countries don't even have the same problems and socialism had rather poor outcomes so far.

So the rational response to this would be to fix issues in their own country instead of dreaming about an unrealistic socialist utopia that never existed.
I think that the commenter, u/Agile-Caterpillar421, makes a couple of good points.

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