Spectroscopy in general. Then understanding nucleosynthesis when a star goes supernova.

Spectroscopy enables the observation of emission and absorption wavelengths of objects. The spectroscopy pattern can be determined in a lab with the respective elements.

Oxygen is in close contention with carbon it appears.

Like for every person. Does it smell the same?

As has been described in a few reply’s already, to make a black hole you have to “squeeze” an amount of mass to a size so small the density will be enough to create a black hole. This size is given by a radius called the Schwarzchild radius. The equation is R = 2GM / c^2 where G is the gravitational constant and c is the speed of light. M is the mass in question. c^2 is a huge number compared the the numbers it is dividing meaning you need a LOT!!!! Of mass (M) for R to be a meaningful to a human scale measurement. As a slight aside, Saying something like shrinking the sun to a sphere 5km across is a little meaningless to most of us.. we understand 5km but we absolutely cannot comprehend the sheer size of our own sun. Back to tiny black holes.. the other part you need to understand is that physics has shown that there is an fundamental smallest distance that still makes sense… that distance is called the Planck length and is about 10^-35m or a decimal with 35 0s and a 1 on the end. So you can see that if the mass is relatively small it will not be able To make a black hole because it would need To be squeezed in to a size smaller than the Planck length.

Question is too vague. It's obvious that there are appreciable differences in the smell of poop. If you've lived for any length of time you must be aware of the fact that, while always generally unpleasant, the specific smell can change quite a bit. Which makes me wonder if you've fully explained your question.

I feel like you need to provide more context about why you're asking this. Or maybe you're asking whether it's nornal if yours smells different occasionally, in which case the answer is: yes, totally normal.

[removed]

[removed]

[removed]

Is there a particular "science for the lay-person" type of book you'd recommend, that discusses things like this without requiring the reader to know the math?

I loved books like A Brief History of Time, Cosmos, and Black Holes and Time Warps by Kip Thorne, for example, but I'd love to read more about black holes (time and space switch inside the event horizon??), quasi-stars, quark stars, proton structure (what does it mean to have force-carriers inside the proton that would have individual masses greater than that of the proton?), etc..

There seem to be so many books out there on these topics that I have no idea how to tell which ones might be what I'm really looking for.

[removed]

We can only take out large chunks at the surface. The small stuff goes into the animals and into river and seabed floors. We have a lot of water on this planet. There are bacteria that can break it down but this highlights the issue of plastic recycling. Ideonella sakaiensis can degrade PET and use it as energy but it converts it into carbon dioxide. Then there are a huge array of other plastics.

Taking even a reliably large clean part of plastic and making it back into plastic, when you know the exact material it is (called regrade in plastic moulding terms) degrades the properties. You would normally mix a small percentage of it in with virgin material. But over use means the moulding won’t work. That’s why you see a lot of it used in simple extrusions like decking.

We have too much plastic. We need to reduce its use to important components. Most sea plastic from land sources come from 5 main rivers. Mainly in Asia. So we need to stop throwing it in the sea while we’re at it. That largest contributor to sea plastics is from boats. One easy way to help reduce sea plastic is strangely to not eat fish.

[removed]

[removed]

[removed]

[removed]

[removed]

[removed]

[removed]

Thank you! So if I understand correctly, once it is at this glass state, it can become rubber if heat is continuously applied or is this glass state permanent? Hopefully I’m understanding this process correctly

[removed]

[removed]

[removed]

Usually polymers go through a glass transition at a certain temperature (called, surprise, surprise, the glass transition temperature). Below that they are hard and rigid (like glass), above that they become rubbery. Smaller molecules, called plasticisers, can be added which will artificially decrease the glass transition temperature (e.g. PVC tubing compared to uPVC used in windows and doors). Since these are small molecules they are more volatile and once gone, the polymer will become glassy (those PVC tubes stiffening with age). So my guess would be that the plasticisers in the bag have evaporated, causing the polymer to transition from rubber to glass despite the increase in temperature.

[removed]

Elementary particles don't have a size in the way classical objects do, but their wave function is never perfectly localized - they have a non-zero volume in that sense (for electrons in atoms it would be the volume of their orbitals, for example). The larger the center-of-mass energy the smaller the radius of that volume can be. As you increase the energy of e.g. a collision process you can make the system "smaller" and the Schwarzschild radius grows. The two get to a similar length at the Planck energy (2GJ) which corresponds to the Planck mass (~20 microgram) and the corresponding Schwarzschild radius is the Planck length. It's expected that the smallest black hole is somewhere around that. These are order of magnitude estimates, the precise numbers will depend on a quantum theory of gravity which we don't have yet (at least not in a way that we would be able to calculate this).

If there are microscopic extra dimensions and if gravity extends into them then gravity could be much stronger at very small distances. This would effectively mean the Schwarzschild radius is larger and you need less energy to produce a black hole. The energy might be so low that we can reach it with accelerators, so we look for possible black hole signatures at the LHC. Nothing found so far. It's pretty much an all-or-nothing search: If you have enough energy then you expect to produce tons of them and it's obvious within weeks, so we are pretty sure the LHC energy is not enough to make black holes.

Well I don't know what plastic you are working with, but my guesses are that it is a thermosetting polymer. Basically, picture polymers as chains of molecules that are weakly bonded. In some cases, heating the plastic will push the molecules to create hard covalent bonds between themselves called crosslinks, which causes these plastics to irreversibly harden. You will not be able to melt it, or even reshape it.