1

Physics, Astronomy & Cosmology / Re: Could the universe be a simulation?

« on: 16/04/2019 20:35:56 »

If we were living in a computer simulation then there would inevitably be bugs in the system. It is impossible to eliminate all computer errors. These would be detectable. So what 'bugs' do we have in our universe?

Would they necessarily be detectable to the subprograms (us) within the major program? ie if the program is laggy and buffering, would we perceive a stop and start, or would it appear continuous and smooth within the running program?

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Physics, Astronomy & Cosmology / Re: Why are there different sizes of stars?

« on: 16/04/2019 16:10:15 »

A few points:

Yes, there is a minimum size required, but that minimum also depends on the composition of the star. Stars that are only hydrogen and helium (primordial stars) must be much larger than stars that contain some carbon, nitrogen and oxygen (as our sun does).

Stars don't necessarily stop growing once fusion starts. If there is enough matter around, it will continue to fall in to the star and continue to add mass, even after the star has ignited.

There are also some maximum mass limits, which depend on the composition and temperature of the star.

3

Chemistry / Re: How can we remove a polar molecule from a solution?

« on: 15/04/2019 14:33:22 »

ooooh! I know this!

4

Physics, Astronomy & Cosmology / Re: Why water does not fall into space ?

« on: 12/04/2019 13:26:26 »

Why water does not fall into space ?

Because space is "up" from where the water is.

5

Plant Sciences, Zoology & Evolution / Re: What does a chin do for us?

« on: 10/04/2019 22:47:26 »

I would guess that it might be related to the fact that we walk on two legs. The chin offers pretty good protection for our faces and heads as we learn to walk and run and jump (I say this having gotten 7 stitches in my chin as a 3-year-old).

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Physics, Astronomy & Cosmology / Re: How (in)effficient is electrolysis for storing energy?

« on: 10/04/2019 16:27:30 »

Splitting water into hydrogen and oxygen using electrolysis is quite easy to do (and scalable), with reasonably efficiency. It doesn't necessarily have the same round trip efficiency as pumped hydro, but electrolysis also takes up several orders of magnitude less space than pumped hydro to store similar amounts of energy.

To alancalverd's point--hydrogen is annoying to handle, but can be reacted with CO₂ to make hydrocarbon fuels. Alan mentioned methane, but it is also possible to use Fisher-Tropsch type chemistry to make essentially any alkanes with between 1 and 16 carbons.

These liquid or gaseous hydrocarbons are useful as portable forms of stored energy, but if we are just thinking of stationary power storage, then another way to avoid the hydrogen problem is to split something other than water. Zinc oxide is a leading contender: 2 ZnO → 2 Zn + O₂
• No membranes required to keep the O₂ and Zn separated, because one is a gas, and the other is a solid (a significant amount of the expense of water splitting devices is the membrane that keeps the O₂ and H₂ apart while allowing the ions to flow efficiently)
• Zinc metal has an energy density of about 38 MJ/L (40 kWh/gal), which is comparable to gasoline, while even liquified hydrogen only has an energy density of about 8.5 MJ/L (8.9 kWh/gal).
• Zinc is abundant, cheap, nontoxic, and easily recycled.

But zinc is also very heavy, so it would not work so well for powering vehicles...

7

Physics, Astronomy & Cosmology / Re: Does the Neutrino flux thru a radioactive substance affect the decay rate

« on: 07/04/2019 17:58:18 »

There are other isotopes whose decay pathways are influenced by neutrino flux. Notably 39Cl

I think you mean 37Cl
But anyway, I'm not sure that counts as a "decay"- the rate of that reaction without the neutrino flux is zero.
It's a reaction. 37Cl is as stable as anything.

Indeed--that was a typo! Thank you for catching it. (I have corrected it in the original post). And yes, I suppose that would count as a nuclear reaction.

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Plant Sciences, Zoology & Evolution / Re: Do all birds hop?

« on: 07/04/2019 01:35:14 »

(Off the top of my head) I think that birds that primarily live in the trees/bushes (parrots, sparrows, blackbirds etc.) hop, and those that live on the ground (ostriches, emus, turkeys, etc.) or in the water (ducks, geese, seagulls, etc.) do not.

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Physics, Astronomy & Cosmology / Re: Does the Neutrino flux thru a radioactive substance affect the decay rate

« on: 07/04/2019 01:30:53 »

Funny--I was just talking about this with somebody earlier this week!

No, ¹⁴C half life is independent of neutrino flux, so it wouldn't matter how close we are to the sun, or what the solar weather is like, or if there are nearby supernovae.

There are other isotopes whose decay pathways are influenced by neutrino flux. Notably ³⁷Cl (thanks for catching my typo) (https://iopscience.iop.org/article/10.1086/305343/pdf).

Apparently, there is some controversy over whether ⁵⁴Mn does or not:
https://physicsworld.com/a/radioactive-decay-of-manganese-54-is-not-affected-by-the-seasons-says-physicist/
https://www.economist.com/babbage/2012/08/23/and-now-the-space-weather-forecast
http://blogs.discovermagazine.com/80beats/2010/08/26/scientist-smackdown-are-solar-neutrinos-messing-with-matter/#.XKlEletKh0s

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Physics, Astronomy & Cosmology / Re: Why do neutrons weigh more than protons?

« on: 05/04/2019 17:32:11 »

1) A neutron can decompose into a proton and an electron (also releasing a neutrino). It's actual mass is determined by the masses of the quarks and binding energy (a proton is made of two up quarks and a down quark, while a neutron is made of two down quarks and an up quark).

2) This is a very tricky question. We can use different models to account for the different speeds of light in different materials--one model essentially views the photon as being absorbed and re-emitted repeatedly, and one model just looks at the effective permittivities (both electric and magnetic), and uses that to calculate the speed of light. Both models predict the same speeds (as far as I know), but sometimes it is better to use one model than the other.

3) The free electrons stay in the plasma in a gaseous state. (overall the plasma is neutral, with an equal number of protons and electrons in it)

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Physics, Astronomy & Cosmology / Re: Do electrostatic charges interact with magnets or electromagnetic fields?

« on: 03/04/2019 14:24:59 »

Yes. Magnetic fields exert a force on moving charges that is proportional to the velocity of the charge (relative to the magnetic field), the strength of the magnetic field, and the amount of charge that is moving. The force is perpendicular to both the magnetic field lines and the instantaneous velocity of the charge.

see: https://phys.libretexts.org/Bookshelves/University_Physics/Book%3A_University_Physics_(OpenStax)/Map%3A_University_Physics_II_-_Thermodynamics%2C_Electricity%2C_and_Magnetism_(OpenStax)/11%3A_Magnetic_Forces_and_Fields/11.3%3A_Motion_of_a_Charged_Particle_in_a_Magnetic_Field

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Physics, Astronomy & Cosmology / MOVED: How do we measure the energy of a photon?

« on: 30/03/2019 19:03:06 »

What initially appeared to be an interesting question regarding quantum epistemology has turned out to be (or transformed along the way into) the original poster trying to proselytize a new theory that is outside generally accepted science--thus I have moved the entire thread to the "New Theories" section, where this discussion may continue.

You may find it here: https://www.thenakedscientists.com/forum/index.php?topic=75960.0

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Physics, Astronomy & Cosmology / Re: Why don't atmospheric gases separate according to specific gravities?

« on: 29/03/2019 18:58:12 »

There is a very small amount of separation, but this is largely due to the fact that most of the gases that make up the atmosphere have very similar molecular masses (N₂ 28, O₂ 32, Ar 40).

The difference in gravitational potential energy that would occur by stratifying would be less than the energy equivalent of the decrease in entropy (due to unmixing) at the temperature that the atmosphere is. Same reason that vodka doesn't spontaneously separate into water and ethanol (which is about 20% less dense than water).

14

Physics, Astronomy & Cosmology / Re: How fundamental is time?

« on: 29/03/2019 15:16:27 »

Hi All, there is some great discussion here--and I will contribute to it more when I have gotten some answers from a friend who knows more about cosmology than I do! In the mean time, I noticed that this thread kinda went off on a tangent, so I have taken the liberty of splitting it here. Apologies, if there are relevant posts in the bit that I removed....

15

Physics, Astronomy & Cosmology / Re: How to patent and submit a theory

« on: 29/03/2019 15:05:53 »

If you are in the US, then the USPTO is the place to submit patents: https://www.uspto.gov/

I would warn you that there are limitations on what can be patented though (ie you cannot patent an equation or a business model, or a perpetual motion machine).

It is possible to patent something that you have not yet made, but it is much easier if you have a prototype or proof of concept that allows you to establish the parameters of what you try to protect.

If your theory is purely theoretical, and you yourself (or people in general) can't actually make something that directly makes use of it, perhaps trying to publish in a scientific paper would be a better avenue.

16

Physics, Astronomy & Cosmology / Re: Would removing material from the moon change its orbit?

« on: 28/03/2019 17:32:48 »

Launching the mass from the moon might have some influence on the orbit of the moon, but this will depend on the trajectory of the launch...


oops, I see I crossed posts with Halc

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Physics, Astronomy & Cosmology / Re: Would removing material from the moon change its orbit?

« on: 28/03/2019 13:52:23 »

Hi Frankwopsy. As a mod, I have taken the liberty of splitting this post into its own topic (it has nothing to do with measuring photon energy, so doesn't belong in that thread).

In the future, if you would like to start a new thread, navigate to the subforum that makes the most sense for the topic (physics/astronomy, chemistry, new theories etc.) and click the button (it's dark blue in my browser) that says "New Topic":
Screen Shot 2019-03-28 at 9.51.14 AM.png (163.05 kB . 2180x526 - viewed 219 times)

And welcome to the forum!

18

New Theories / Re: How do we measure the energy of a photon?

« on: 26/03/2019 13:09:20 »

https://en.wikipedia.org/wiki/Sealioning

19

New Theories / Re: Atomic battery idea

« on: 26/03/2019 03:35:41 »

Oh I'm sorry... I thought you were seeking truth.

The point is:

20

New Theories / Re: Atomic battery idea

« on: 26/03/2019 03:06:16 »

Unfortunately for this invention (but very good for life in general), the neutral atoms are already in their low-energy state. Neutrons spontaneously decompose, releasing electrons and protons (and energy and other particles), as do nuclei that have too many neutrons compared to protons (see: https://en.wikipedia.org/wiki/Free_neutron_decay and https://en.wikipedia.org/wiki/Beta_decay)

THERE IS NOTHING KEEPING THE ELECTRON FROM TOUCHING THE PROTON IN A HYDROGEN ATOM BECAUSE THEY ARE ALREADY "TOUCHING". (sorry for the caps--but this is a very important point).

Quantum mechanics is very non-intuitive in some ways: one of them is that the lighter a particle is, the greater its effective volume is. A proton is 1836 times heavier than an electron, and only occupies a radius just smaller than one femtometer (10^–15 meters). The electron in a hydrogen atom, is as close to "touching" the proton as one can get in the quantum world (the electron and proton have the same center of mass), but because the electron is so much lighter, it takes up more space (you can think of it as being fluffy or smeared out, whichever you prefer)--most of the electron is within 1 Å (10^–10 meters) of the center (within 1 Å of the proton).

https://www.chemistry.mcmaster.ca/esam/Chapter_3/section_2.html