Hacker Newsnew | past | comments | ask | show | jobs | submit | zycon's commentslogin

Density is mass divided by volume. Volume of BH is defined by event horizon.

Singularity is a result of applying a theory of relativity in a case where we know relativity doesn't work, so it's unlikely it's real.


> Volume of BH is defined by event horizon.

The event horizon is a three-dimensional null hypersurface, though, encompassing a four-dimensional spacetime "volume". You are probably referring to the two-dimensional apparent horizon, which depends on the spatial slicing.


There's a hypothesis that Ordovician-Silurian extinction cca 450 milion years ago, one of the big five mass extinctions, was caused by a GRB.


Is there any data to back this up? (not attacking, just genuinely curious, i love learning about mass extinctions)


Only extremely circumstantial evidence. Some guesses about which species died off vs being protected, some climate change signatures that are consistent with a high UV burst.

About the best you can say for it is "you can't prove it didn't happen". Which, given that it was half a billion years ago, may be the best you can get. There isn't a real smoking gun.

The leading hypothesis is more that a long-term climate change caused secondary effects in a vicious cycle. We know the climate change was happening; there's very strong evidence. But it's not clear exactly what caused it or exactly how it led to mass extinction.


No, and the idea is widely derided by paleontologists because it's pretty much untestable.


Would the Earth shield one side of itself? If yes by how much?


Seems like that would only help if the duration of the blast was less than 24 hours


Rotation around the axis doesn't expose the northern hemisphere to the southern sky, nor vice versa.


That depends on the orientation with regard to the poles. If the source were directly over a pole, only fifty percent of the planet would be directly exposed. If it were over the equator, however, the whole planet would be, if it were a magic GRB that lasted way longer than usual.


Or perhaps more like 12 hours, as half of the Earth would be exposed instantly.

But even then it depends on whether it's the direct radiation that's the issue or something more indirect (atmospheric changes, etc.)


The longest gamma ray bursts only last a few minutes.


Just how many nines reduction from peak intensity after a few minutes are we talking? Because I'd imagine 0.01% of a nearby gamma ray burst would still be bad news.


doesn't this depend on the blast's origin relative to the Earth's axis?


It will affect atmospheric chemistry. It will produce a ton of NO2 and make atmosphere unbreathable without equipment.


I imagine that killing half the planet is enough to send the "lucky" half into chaos and collapse.


So the upside is that anything that can get through 10k km of rock is very unlikely to interact with anything on the other side (eg neutrinos)


Czech Republic data from ÚZIS report from 27.11.

New covid cases:

13736 - nonvaccinated, no previous covid

6579 - vaccinated, no previous covid

493 - nonvaccinated, already had covid

185 - vaccinated, already had covid

Current covid hospitalizations:

3302 - nonvaccinated, no previous covid (607 in ICU)

2777 - vaccinated, no previous covid (264 in ICU)

44 - nonvaccinated, already had covid (3 in ICU)

46 - vaccinated, already had covid (3 in ICU)

Source: https://twitter.com/dostalondrej/status/1464533409515114502 a report for the Czech MPs and senators from the Institute of Health Information and Statistics of the Czech Republic (ÚZIS)

The data speak for themselves.


Unless that is corrected for the age of the patients it won't tell us much. In particular, older patients are more susceptible to COVID, and also more likely to have been vaccinated, and similarly for patients with compromised immune systems.


The stats in Zürich Switzerland are very similar.

Even though it shows natural immunity is strongest as one would expect one can not risk getting covid being unvaccinated as we can see from the same stats.

In Switzerland at least you are given a certificate if you have recovered from covid just as you would get one for vaccination.


You can also get 3 month long certificate based on positive antibody test that is an improvement upon EU side where you can only get 6 month long certificate based on previous positive PCR test result.


The Swiss win again. Why this country is so much more reasonable compared to others? I want in!


This data is completely useless to draw any conclusions.


[flagged]


> NONE of vaccination pushers can explain deaths among people who had vaccines.

Vaccines are imperfect. They are particularly imperfect when given to patients with impaired immune systems. This is neither unexpected nor reason to think vaccines are not a good idea. Please do not resort to the Nirvana Fallacy! https://rationalwiki.org/wiki/Nirvana_fallacy


But it allows downloading and executing interpreted code. See paragraph 3.3.2 of Apple Developer Program License Agreement.

So you can have significant portion of your app in say javascript, which you can update OTA.

E.g. react native apps have most of their functionality in js and can use services like code push to update themselves without app store and it doesn't violate Apple ToS.


Czech Republic (EU member) data protection regulator is aware and ruled that if user has cookies enabled in his browser, that's enough and user gave cookie consent. If user doesn't want to have cookies stored, he can block them in the browser.


A simple off/on switch does not provide a sufficient level of control over cookie policy. It's reasonable to want to allow first-party cookies on certain sites, especially where they're needed for site functionality. But block third-party tracking cookies, or even block all cookies on others.

Cookie control/policy in browsers needs to become more sophisticated than what we have today.


Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: