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Question of the Week / Re: QotW - 23.12.08 What are black holes made of?

« on: 06/12/2023 17:57:55 »

Zer0, the escape velocity is determined by the gravity experienced at the launch site, and most likely by the topology of the mass responsible for the gravitation. As regards what happens to photons that cannot escape the event horizon of a black hole I can't tell you as I don't know. A member such as Halc or Origin should be able to help.

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Physics, Astronomy & Cosmology / Re: Has E=mc2 been proved practically?

« on: 04/12/2023 20:10:38 »

Zero, the equation E=MCsq relates mass to energy. For a massless particle like a photon we use E=hF where h is the planck constant and F is the frequency. Theses symbols are not correct and I hope I am being clear, I can only find the reduced planck which is h/2pi.

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Physics, Astronomy & Cosmology / Re: Quantum Entanglement and Interstellar Communication.

« on: 01/12/2023 17:51:03 »

True enough, Zero. But the more you know the more you realise how little you know. Honestly if I could contribute more, I would without hesitation.

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Physiology & Medicine / Re: Does my mother possibly have ALS?

« on: 30/11/2023 15:59:39 »

While I sympathise with your difficult family situation nobody here can answer your question. As far as I know one of our contributors is a medic but diagnosis online is simply not possible. Wishing your mom all the best.

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Just Chat! / What do you think of copout 28

« on: 30/11/2023 10:47:29 »

Personally I think it is pointless regardless of whether one believes in global anthropogenic warming or not. The possibility of global agreement on anything is close to zero given human nature. The conference head will be uttering lofty aspirations while selling petroleum on the side!

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That CAN'T be true! / Re: What is "four times less"?

« on: 29/11/2023 20:58:19 »

Maybe it removes negative grease, so you end up with plates covered in gank?

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COVID-19 / Re: What is "long covid" and what different types are there?

« on: 28/11/2023 09:27:23 »

If I could answer some of the questions about postviral syndromes I could become quite wealthy-very little is understood. It is diagnosed based on a patient's symptoms, there is no test to do this. Look into the history of chronic fatigue syndrome. There are as many theories concerning the cause as there is in the case of ball lightning. It appears to involve subtle changes in the immune system, possibly t1/t2 lymphocyte dominance but as I said it does remain a mystery despite extensive research. It can range from relatively mild symptoms to incapacitating ones and again why this is so remains unexplained. Some patients improve over time and others do not.

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COVID-19 / Re: What is "long covid" and what different types are there?

« on: 27/11/2023 13:32:47 »

It is a postviral syndrome that occurs long after the initial infection has been cleared. Many viral and bacterial infections can cause similar problems, not just covid.

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Physiology & Medicine / Re: If two people with full blown AIDS have sex, is there a risk? Can it get worse?

« on: 23/11/2023 16:40:47 »

Well yes, if one is male and the other female then conception could lead to congenital aids in the offspring. Other than that, no. People suffering from full blown aids have a very poor quality of life and I would doubt they have the energy for such shenanigans.

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Physics, Astronomy & Cosmology / Re: Temperature and k.e. : Does a substance cool down if particles break apart?

« on: 11/11/2023 11:00:13 »

Hi ES, i'm shooting in the dark here as physical chemistry was one of my weakest disciplines(among many!): I suggest you analyse in terms of enthalpy, I would expect the temperature to go down and the pressure to increase. I now patiently await denunciation.  SCRAP that, no change in pdv, but I still think pressure will increase.

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Physics, Astronomy & Cosmology / Re: Why are some isotopes fissionable?

« on: 10/11/2023 14:33:47 »

U235 is fissile and u238 is fissionable. Fissile refers to an element than can undergo fission and release sufficient neutrons to enable a chain reaction. Fissionable refers to an element than can undergo fission but cannot sustain a chain reaction, due to insufficient neutrons being released. Why some elements are one or the other I can't tell you but I would suspect it is down to the neutron requirements of the favourable daughter nuclei. Most fissile elements have odd mass numbers but this is not absolute. Most of the energy in the big multi-megaton bombs derives from u238.

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Chemistry / Re: How to keep molten plastic in liquid state foor long

« on: 30/10/2023 13:20:41 »

Perfluoroisobutene is a breakdown product of decomposing Teflon(ptfe) and is extremely toxic and acts similar to the war gas carbonyl chloride(phosgene). As far as I remember it is more toxic than carbonyl chloride but I may be open to correction on this. The effect of these substances is pulmonary oedema and one drowns in one's own exudate.

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Question of the Week / Re: QotW - 23.10.27 - Why is the sea salty water, but lakes and river are fresh?

« on: 19/10/2023 20:23:07 »

Fresh water bodies are supplied by precipitation which is close to pure water with negligible salt content. Rivers run into oceans carrying small quantities of various salts leached out from rocks. Water evaporates from the oceans leaving whatever salts are present in the oceans and the evaporated water then becomes precipitation to start the cycle over again. Over time this process has concentrated the salt in the oceans.

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Geek Speak / Re: Complaint about Windows 11

« on: 13/10/2023 09:14:02 »

Hi, ES. Don't get me started, as they say. In my opinion, WINDOWS is a very poor operating system, and has been for a very long time. The last stable form of windows was windows 3.1, which was back in the early nineties. Stability is my main beef but I agree that changing things that don't need to be changed is utterly pointless and counterproductive.

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Physics, Astronomy & Cosmology / Re: What happens to the surplus electrons after an alpha decay?

« on: 08/10/2023 11:42:26 »

If one charges up any arbitrary item with either + or - and leave it undisturbed one will find the charge ebbs away as virtually all so called insulators do conduct to some very minor degree. A totally isolated alpha emitter, in vacuo, would, I expect, become highly charged over time and at some point might inhibit or slow the alpha emission(wild speculation).

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General Science / Re: Infinity...

« on: 30/09/2023 13:14:15 »

Thank you, Alan, for your generous acceptance of my correction. This is the way it should be and I wish it would also apply to some of our prolific nonsense posters.

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Physics, Astronomy & Cosmology / Re: Why isn't my salt water evaporating?

« on: 15/09/2023 20:13:10 »

Thanks, Evan_au. As I explained above I answered similarly in a more verbose but most likely less clear answer that evaporated.

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Just Chat! / Is the universe real?

« on: 06/09/2023 12:01:57 »

Recently I learned, through a conversation with Halc, that quantum theory says that one of the following statements must be false: (A) there can be no retrocausality and (B) counterfactual definiteness exists. The idea that either of these is false seems incomprehensible to me, on an INTUITIVE level. So what's going on here? I don't buy into these "simulation" ideas which in my opinion are just science fiction gone crazy. This will probably be too philosophical for Alancalverd though he is welcome to reply: Buddhism states that reality is an illusion- is it that too far off the mark? PS as I stated in another post I will be incommunicado for ~9days( sectioned under the mental health acts----no! only joking).

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Physics, Astronomy & Cosmology / Re: Does helium make all sounds higher pitched?

« on: 03/09/2023 21:08:41 »

I don't think so, Kryptid. The resonant frequency of the glass is determined by the physical properties and physical form of the glass. The larynx relies on gas properties, a bit like an organ pipe. Have look at organ pipes and how they work, with open and closed pipes influencing the frequency. There might be some slight effect with different gases.

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New Theories / Re: Dark Motion. Is it the answer to the Dark Matter and Dark energy problem

« on: 03/09/2023 18:25:35 »

Hi Origin, this is futile and I agree that the thread should be locked. The OP is plainly in a "black is white" mode.