1

Physiology & Medicine / Re: What kinda diet or diet medicine is good for someone without a thyroid?

« on: Today at 09:30:03 »

I am assuming that your doctor:
- has prescribed thyroid hormone replacement therapy? (And you are taking it regularly?)
- is regularly monitoring your thyroid hormone levels, and adjusting your dosage appropriately?

Gaining weight sounds like your thyroid hormone levels may be a bit low?
See: https://en.wikipedia.org/wiki/Hypothyroidism
...then see your doctor!

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Physics, Astronomy & Cosmology / Re: What's a black hole made of?

« on: 13/10/2018 01:17:54 »

The illuminous region around the BH's gravitational field represents it's external boundary

There is a region called the "photon sphere", which is outside the event horizon (at 50% greater radius). If you emitted a flash of light here, you would see a series of light echoes as photons from the flash repeatedly orbit the black hole.

Light emitted within the photon sphere eventually finds its way into the black hole.
By itself, the photon sphere does not emit any light, so you could not call this region "luminous".
However, matter in an accretion disk around a rotating black hole is subject to severe shear forces, which does emit a lot of light (including infra-red at the outer parts, and X-Rays at the inner edge).
See: https://en.wikipedia.org/wiki/Photon_sphere

The illuminous region around the BH's gravitational field represents ... is a reflection of the incoming light striking a mass.

If there is no infalling matter (eg from a closely-orbiting companion star) then there is no mass between the photosphere and the event horizon (...if you ignore the hypothetical, microscopically thin, microwave-shifted skin of star matter that fell into the event horizon when the black hole first formed).
For a black hole that is not actively consuming matter, there is no luminous region around it.

This reflection is similar to what occurs on a star, The cooler substrata below the star's surface creates a barrier that the hotter corona reflect off of. During a coronal () we see the cooler substrata mass.

I am not sure what "coronal" event you are talking about - maybe a Coronal Mass Ejection, or the Corona that is visible during an eclipse by the Moon?
But in any case, the density of the corona is so low, and the corona's total light output is so low that it is only visible from Earth's surface during a total solar eclipse. (Space telescopes can see it at other times using a coronagraph - but they don't need to battle Earth's atmosphere...)

Apart from solar eclipses, all that we see of the Sun is the lower layers of the Sun's atmosphere - the photosphere (not to be confused with the photon sphere around black holes!). We don't need to wait for some special coronal event to see it. The photosphere is not solid, and it tends to absorb light rather than reflect it.

The photosphere has almost a black body spectrum of around 5500C, overlain with fine emission and absorption lines from elements in the Sun. It does not reflect the spectrum of the corona (which has a temperature in the millions C).
See: https://en.wikipedia.org/wiki/Photosphere

3

Physiology & Medicine / Re: Why does time appear to slow down when we have an accident?

« on: 12/10/2018 10:57:38 »

The psychologist David Eagleman decided to put this to the test by dropping volunteers off a 150-foot high tower.
They had a specially-designed wristwatch to test whether the brain sped up at such times - but it didn't.
See: https://www.livescience.com/2117-time-slow-emergencies.html

4

Physics, Astronomy & Cosmology / Re: What's a black hole made of?

« on: 09/10/2018 10:04:07 »

Light trapped by this monopole's singularity gravitational force also is without a wave dynamic, because of the monolithic nature of the monopoles gravity (no waves). So, with no Light waves...

This post seems to be suggesting that there can be no light waves within a black hole (ie no light and no photons)?

One tool used by physicists is the "light cone", a volume of space within which light could propagate in a given time.

And physicists are happy to draw light cones at any position outside a black hole's event horizon - and even extrapolate across the event horizon to predict what might happen inside the event horizon.

The results within the event horizon are weird to our eyes - for example, time and space axes appear to be interchanged.
- However, there is nothing that prevents light from propagating - providing it propagates towards the singularity at the center of the black hole
See: https://en.wikipedia.org/wiki/Light_cone#In_general_relativity

5

Physics, Astronomy & Cosmology / Re: What's a black hole made of?

« on: 07/10/2018 22:29:18 »

(A Black Hole) cannot be made of normal matter.  That part is wrong.  Normal matter of that mass cannot support its own weight, and breaks down even before the black hole forms.

I think it is just a matter of grammatical tense here.
- We see mechanisms that form black holes from normal matter when a star implodes and/or explodes.
- However, once this matter approaches the singularity, normal matter should be torn apart - it's not clear what the components would be (eg would they be outside the Standard Model?)
- And once it reaches the singularity, normal matter should be mashed together - it's not clear what the result would be
- But really, we can't say much about what happens inside the event horizon of a black hole

Is a BH empty? If it rotates, the answer needs to be no.

We expect that most black holes will form with the angular momentum of their parent star, accretion disk or galaxy.
It is theoretically possible for a black hole to have near-zero angular momentum:
- If there was a merger of two black holes with opposite and equal angular momentum.
- Or transiently, if the black hole was tearing off the atmosphere of a nearby star which was orbiting in the opposite direction to the direction of black hole rotation.
- But I expect that most black holes would have considerable angular momentum

The black hole, is a singularity, it is comprised of unattached subatomic particles

A black hole singularity in general relativity is where all of the particles end up at a single point; all paths entering the event horizon end up at the singularity.

Some theories of Quantum Gravity may allow some quantum fuzziness about the "single point".

But Quantum Gravity is not yet sufficiently mature to assert that "it must be composed of subatomic particles that are not congealed in a structure".

a chiralty gravitational effect

Gravitational waves are polarized.

Once 3 gravitational wave observatories were online, it was possible to detect the polarization of gravitational waves.

The first one was: https://en.wikipedia.org/wiki/GW170814

But I don't understand  "a chiralty gravitational effect".

6

Physics, Astronomy & Cosmology / Re: How many black holes are there in the Universe?

« on: 07/10/2018 21:57:47 »

...an argument I've been honing over time... I'll post an explanation as a new post in this thread as soon as it is written.

Merger of black holes (or merger of two neutron stars to form a black hole) is mainstream science, based on scientific observation of the real world.
See: https://en.wikipedia.org/wiki/List_of_gravitational_wave_observations

Questions about black holes belong in the "Physics, Astronomy & Cosmology" section of the forum.
However, a proposed explanation of the structure of the cosmos based on black holes belongs in the "New Theories" section of the forum.
@scherado, I recommend that you post your explanation there instead. 

7

Physics, Astronomy & Cosmology / Re: How many black holes are there in the Universe?

« on: 07/10/2018 09:47:36 »

It is thought that there is a supermassive black hole in the center of (nearly) every galaxy.
See https://en.wikipedia.org/wiki/Supermassive_black_hole

Supernova of a large star is very likely to produce a black hole. It is thought that there are about 30 supernovas per 1000 years in our galaxy, but ancient astronomers have only reported about 3 every 1000 years.
- One possible reason for the discrepancy is that the black hole swallows the star before it can emit the massive burst of superheated gas that glows for months.
- A more boring reason may be that the ancient Greek philosophy that "the stars are unchanging" may have inhibited Europeans from reporting such events for many centuries. But Chinese astronomers were not under this illusion.
See: https://en.wikipedia.org/wiki/Supernova#Core_collapse

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Physiology & Medicine / Re: Other than THC and CBD, how much is known about cannabinoid treatments?

« on: 01/10/2018 22:20:04 »

to what extent is 'entourage effect' been studied?

The entourage effect seems to be more "magical incantation" rather than  "scientific evidence"..

As you say, CBD has very different effects than THC, and this has been well-researched. But it is harder to study minor components which vary greatly between strains of cannabis.

Medical regulatory authorities require a very high threshold of proof of safety and effectiveness before a therapeutic drug is approved.
This means that a therapeutic drug vendor must outlay a considerable amount of money to have just one compound approved. It is only in the case of lethal and resistant diseases like TB will multiple compounds be approved.

The costs are so high that a pharmaceutical company won't even bother unless they have patent protection, which won't be possible on a natural chemical soup like cannabis.

See: https://en.wikipedia.org/wiki/Entourage_effect

This team at Sydney University address the Entourage Effect:
https://sydney.edu.au/lambert/our-research/cannabis-research.html

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Cells, Microbes & Viruses / Re: Is the Y chromosome a mutated, shrunken X chromosome?

« on: 28/09/2018 11:12:33 »

Wikipedia suggests that the divergence of a single chromosome into X & Y chromosomes occurred something like 150 million years ago.
See: https://en.wikipedia.org/wiki/Y_chromosome#Origin

10

Physiology & Medicine / Re: Why do people punish themselves sometimes?

« on: 26/09/2018 11:04:01 »

I think that some people punish themselves so severely that they seek escape in addictions - to work, alcohol and other drugs, gambling, sex and/or computer games. Or watching TV, listening to music incessantly, social media or discussion forums (fora?).

11

Geology, Palaeontology & Archaeology / Re: What causes Earth's magnetic field?

« on: 23/09/2018 11:22:06 »

There is a metallic flow but that won't produce a magnetic field, either.

The energy source is the heat released by the liquid outer core slowly solidifying, causing the solid inner core to slowly expand over time. This heat release causes convection currents in the liquid outer core.

The magnetic field itself is produced by electrical currents in the liquid nickel/iron, produced by magnetohydrodynamic effects.

In laboratory experiments, two additional factors are needed to kick-start the dynamo:
- Differential rotation of Earth's solid inner core and the mantle
- a "seed" magnetic field (that may have come from the solar magnetic field?)

These effects have been reproduced in the lab using a model with liquid sodium instead of liquid iron. One of the more recent experiments is described here:

the temperature is well over the Curie temperature so the iron and nickel are non-magnetic.

Sodium is not ferromagnetic, and yet the effects are reproducible in the laboratory because the metallic flow and electrical currents are similar (just faster).

The Sun also displays a magnetic field -  the Sun is composed mostly of a plasma of Hydrogen and Helium; these elements aren't ferromagnetic either.

12

General Science / Re: If I wear ANY battery watch, in by a weeks time, the battery is dead. Why?

« on: 22/09/2018 01:50:20 »

A high level of iron (eg from haemochromatosis) will not affect battery lifetime.
https://en.wikipedia.org/wiki/Iron_overload

Could you have fitted an expensive zinc-air battery (usually used in hearing aids) inside a sealed watch?
- No air=no power

13

Physics, Astronomy & Cosmology / Re: Does gravity have an infinite range?

« on: 21/09/2018 12:12:38 »

Some random thoughts: The Big Bang theory suggests a period of Cosmic Inflation, where for a moment, space expanded faster than the speed of light.

Gravity travels at the speed of light (in a vacuum). So for the moment before Cosmic Inflation, all matter was in the gravitational field of all other matter. This situation did not hold after Cosmic Inflation, nor does it hold for parts of the universe that are now beyond our Visible Universe.

So I suggest that:
- All of the universe once felt the gravitational pull of the rest of the universe, back at the Big Bang
- This was possible because the universe was not infinite, right after the Big Bang
- The effects of gravitational events that occur today (like colliding black holes) will propagate outwards at the speed of light, but will never reach the edge of the universe, as that is a receding boundary. So in this sense, the effects of gravity will have an infinite range in the infinite future (but also an infinitely small effect)...

Caveats:
- I really don't understand unification of the 4 forces in the early stages of the Big Bang.
- I really don't understand how quantization of gravity will affect this

14

Just Chat! / Re: "like"...is there a study that explains the annoying use of this word?

« on: 16/09/2018 22:30:57 »

Has "like" replaced "um" and "ah" as a thinktime filler?

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Physics, Astronomy & Cosmology / Re: What do explosions look like in space?

« on: 16/09/2018 04:27:31 »

does it develop into a flat planar explosion?

A planar explosion was shown so many times that it has become a meme.

But I think it may have to do with the limitations of early computer graphics systems - you have to trace far more particles to do a convincing 3D explosion than to do a 2D explosion.

However, "analogue" film makers did apparently make somewhat realistic-looking space explosions by filming an explosion from above - this angle hides the asymmetry of a rising plume of smoke that you get with explosions in air, and turns it into a spherically-expanding cloud of gas. I hate to think what this cloud does to your camera.

16

Physiology & Medicine / Re: has there been any big study to see if plastic is appearing in human feaces?

« on: 16/09/2018 03:36:14 »

There have been studies of BPA appearing in human urine, relating that measure of exposure to various medical conditions:
See: https://en.wikipedia.org/wiki/BPA_controversy#Asthma

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Physics, Astronomy & Cosmology / Re: What do strange quarks do?

« on: 13/09/2018 11:54:33 »

the neutron lifetime puzzle

I wondered why I kept seeing different figures for neutron lifetime.

Not the 9 second difference between beam and bottle experiments.

But the larger difference between half-life and mean lifetime...

18

Technology / Re: How do astronauts clean their teeth in space?

« on: 09/09/2018 11:35:30 »

Chris Hadfield set out to inform (and entertain):

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Physics, Astronomy & Cosmology / Re: What do strange quarks do?

« on: 09/09/2018 07:23:37 »

At one level, science avoids questions like "what are they for?" and "what do they do?".

Science can detect some patterns, like there a 3 "generations" of quarks (purple) and 3 "generations of leptons (in green):

Standard_Model_of_Elementary_Particles.png (93.91 kB . 375x359 - viewed 1179 times)

We are most familiar with the stable members: up & down quark and the electron. These are the left-most particles.
Sensitive detectors can identify neutrinos (which are always oscillating); practical applications of these is currently limited to peering inside the Sun and exploding supernovae. We can also detect muons from cosmic rays, but practical applications are limited to peering inside pyramids.

The rightmost particles are unstable, and quickly decay into the stable particles to the left.
See: https://en.wikipedia.org/wiki/Generation_(particle_physics)
https://en.wikipedia.org/wiki/Standard_Model

The other quarks have very high energies, and can only be created for an instant in our most powerful particle accelerators. These emulate the extreme energies that existed for a moment during the Big Bang, when these heavy particles would have been stable (for a moment).

So, while they don't do much today, they would have played an important part during the Big Bang.

Maybe some advanced civilisation may be able to create and utilise these other quarks, but we can't today.

Some physicists think that these more exotic quarks may be stable under the extreme pressures at the center of a neutron star, preventing the neutron star from collapsing into a black hole. That's why it's important for LIGO to "weigh" colliding neutron stars.

Some physicists speculate that there may be other generations at even higher energies than the 3 we know, but these would exist at such high energies that we can't produce them today.

20

Physics, Astronomy & Cosmology / Re: How do you steer a rocket following take-off?

« on: 08/09/2018 09:45:17 »

The optimum course is a compromise:
- the atmosphere is a real drag, so you want to go vertically to get above it as quickly as possible.
- attaining a stable orbit means that you need to be traveling horizontally at about 7.5km/second (for the ISS).
- so, in practise, they do more vertically at first, and then more horizontally later.

This has to be modified for air-launched space probes, which are already above most of the atmosphere when they are launched (eg at 50,000 feet), and already travelling horizontally. But they need a lot more altitude to reach space, and a lot more horizontal velocity to reach orbit.

Rocket motors are often mounted on gimbals, allowing the engine direction to be steered, which changes the direction of the whole spaceship.

Edit: Error pointed out by Chris...