[Zechariah (OP)]

Theories on if you could destroy matter? (This is meant to be fun and creative, so don't be stuck up) I want to learn what science could be applied here, if even just loosely. I'm a fiction writer not a scientist, I'm curious as to what I can play with here. Thanks in advance if you decided to entertain my question. If you decide to be stuck up, I simply won't give you the time of day. Thank you.

[Eternal Student]

Hi.

   Annhiliation of matter does happen.   It involves a particle and it's corresponding anti-particle interacting.

There are other threads already discussing the geneal ideas.   Here's a recent one:
https://www.thenakedscientists.com/forum/index.php?topic=83267.msg657398#msg657398

There are tons of other references.   Here's one for Wikipedia:
https://en.wikipedia.org/wiki/Annihilation

More generally there are many ways in which some rest mass can be lost.   Nuclear reactions often have products with less rest mass than the intial atoms.   The difference in rest mass being liberated as an equivalent amount of energy,  for example gamma rays or high velocity Beta particles carrying energy away.

If there's something more specific you wanted to know about, write more on this thread.   Although.... in general it's a good idea to focus threads in the main sections of the forum around a question.  Also you should expect to have more responses based on science and not on speculation or science fiction.   If you're just seeking more general discussion including lots of science fiction ideas, it might be better to move the discussion to the "Just Chat" section  or something similar.    (I'm not a moderator, I'm just guiding you to what seems sensible and usually recommended in my limited experience).

Best Wishes.


LATE EDITING:  The other thread I linked to was "Questions that antimatter to me".    The better one to link to would have been the follow-up which was titled  "Even more questions that antimatter to me",  sorry.

[Kryptid]

I guess it depends on what you mean by matter being destroyed. Eternal Student has it right that matter can be annihilated. The total mass isn't lost, but is rather converted into a different form.

If you are talking about mass being destroyed, that's a different story. Under normal circumstances, that is impossible because of Noether's theorem. In cases where Noether's theorem does not hold, such as the metric expansion of the Universe, you can indeed destroy mass. Photons have a mass associated with their energy, and the energy of those photons weakens as they are stretched to lower frequencies by the expansion of space as they travel through it. Since energy is lost, mass is also lost.

[Eternal Student]

Hi.

   @Kryptid 's comments are extremely difficult to unpick.   It's perfectly fine for for a general answer but it's a quiet evening so we might just as well spend an hour thinking about it.
   
    Let's take the view of the man in the street that is fairly sure that mass is something a bit special and is not exactly the same as energy.

This is how they might reason things:
     "Mass" means "rest mass" and there's no other use to which the term should be put in these modern times.   Let's assume we're working in flat Minkowski space so nothing gets too complicated.   Now if a system has some total mass, then you know slightly more (actually a whole lot more) about the system then just that it has a certain total amount of energy:   You know that it is possible to construct a net 4-momentum vector for the system.  Furthermore, you know that is it possible change co-ordinates so that the system has 0 components in the i=1,2,3 (spatial) components of four-momentum  but retains a non-zero value in the i=0 (time) component of the four-momentum vector.   The rest mass of the system will then be given by  P₀/c where P₀ is the time component of the 4-momentum in that co-ordinate system.  So if you were actually told that a system has a specified amount of mass m,  then this is a lot of information:   You can now determine the Energy and spatial momentum components of the system in any frame you want by applying a suitable transformation on the four-momentum vector     ( mc , 0 , 0, 0 ).

    Conversely, if you are only told that a system has a certain amount of energy, E, then you know almost nothing about the system at all.   You must have some additional information about the spatial components of the four momentum if you want to determine the energy in some other frame of reference and you certainly can't determine if the system has some non-zero rest mass if you can't reduce the 3 momentum to 0.

     So, mass and energy aren't entirely equivalent.  Knowing the mass of a system you have a whole lot more information than just knowing the energy of a system.

   So our ordinary man might conclude with a statement like this:
   Yes, mass can be converted to energy and vice versa but that's still a long way short of saying that mass is entirely equivalent to energy.  Mass is an emergent property that a system can have.  There can only be mass when the system has a specific configuration of four-momentum so that various conditions are met:
1.  It is possible to apply a co-ordinate transformation that will reduce the spatial component of momentum to 0  and,
2.  The time component of the four-momentum is well defined under that transformation.
   
  Meanwhile a system having Energy is much less restrictive.  A system has energy when the time component of the net four-momentum vector isn't 0 and that's all you need.

   Item 1, the ability to apply a co-ordinate transformation is more limiting than we might have realised  - but this post is already too long, so I'll just end as fast as possible.   A photon or system of photons all travelling in the same direction has a net 4-momentum with non-zero spatial component in any non-degenerate reference frame, so there's no rest mass (arguably rest mass can't even be defined for the system) but it clearly has a non-zero energy.   If you can have a system with energy but no mass then mass and energy are not entirely equivalent.

Best Wishes.

[Bored chemist]

    Let's take the view of the man in the street that is fairly sure that mass is something a bit special and is not exactly the same as energy.

Other people who are wrong are also available.

[evan_au]

Another way you can "destroy" matter is by shooting it into a black hole - and then colliding black holes with each other.

As an object spirals into a black hole, it radiates gravity waves, which carry away a significant fraction of the original mass/energy. Once it enters the black hole, that mass becomes indistinguishable from anything else that fell in - including radiation.

When two black holes collide, the mass of the resulting black hole is less than the mass of the two original black holes - the remainder has been radiated across the universe as gravitational waves.
For example, Gravitational Wave event GW150914 (the name tells you that it was observed in September 2015) is estimated to be the collision of two black holes, with mass 35.6 + 30.6 which combined to produce a larger black hole of 63.1 (the units are the mass of our Sun). The missing mass equivalent to 3.1 times the mass of the Sun was radiated away as gravitational waves, most of it in the last 0.1 seconds.

If you wait long enough (far greater than the current age of the universe), that mass of the black hole will "leak out" slowly as Hawking radiation, spreading throughout the universe as radiation.

[Eternal Student]

Hi.

Other people who are wrong are also available.

   Maybe.   I don't think it's silly to suggest that mass isn't exactly the same as energy.
Photons have energy and momentum but no mass.  That's not under much dispute by any scientists to the best of my knowledge.
    However, it's not a trivial matter to explain what mass really is.   For example, most of the mass of a baryon is not due to the Higgs field, it's due to what might be called binding energy of the quarks in close proximity.   Mass is an extremely difficult thing to explain.
    It just seemed that the original Poster has gone quiet so whatever appears here probably won't bother them anyway.  On those grounds I was prepared to risk some confusion and challenge (in a purely friendly and I have some spare time this evening, kind of way) @Kryptid  on what they had written and broaden the thread to discuss what "mass" might actually be.  I'm optimistic that @Kryptid won't be too troubled, they are a moderator and we already know they are experts in at least some field of science, that's not in doubt.

Kryptid made comments like this:

Photons have a mass associated with their energy...

   Which is contestable.  Photons certainly have energy associated with them, whether they have a mass associated with them is less certain. If the entire system is just a collection of photons all travelling in the same direction than I don't think the system has a well defined mass (rest mass) you can give it.

   Then there was this comment about expanding space:

...and the energy of those photons weakens as they are stretched to lower frequencies by the expansion of space as they travel through it. Since energy is lost, mass is also lost.

    Which seems extremely complicated and controversial.   Let's just simplify the situation down to two photons initially of the same energy and setting off in opposite directions from a fixed co-moving location in space.   We'll have that as our entire system and consider what mass is associated with that system.   The good news is that there is a mass associated with that system, at least initially, and it  is   2hf/c²   at the initial time t=0 when the photons were at the same place.    However, as the photons move apart we have  two momentums  p₁   and  p₂   which are now vectors in completely different tangent spaces (because expanding space isn't flat Minkowski space) and so there's no obvious way to add them and check that the net momentum of the system is 0 .    Arguably, you could parallel transport one of those vectors to the location of the other one but I'm not sure that Kryptid has actually tried to do that.   I'm not even sure that this is reasonable, it may be best to stick with the idea that mass is only a locally defined property (so that the curvature of the space does not need to be considered).   If (rest) mass is only a locally defined property then as the photons move apart you lose your ability to define a total mass for the system.   I don't know, maybe that's what @Kryptid meant when they said   "...mass is also lost".

Best Wishes.