Can Matter be Created or Destroyed?

[Rhondazvous]

I’m reading about a process of matter creation called pair production in which a boson, such as a photon, interacts with a heavy nucleus, such as lead or uranium, and splits to form a fermion, such as an electro, and its antiparticle, such as a positron.

Now all my life I’ve been told that scientist say that matter cannot be destroyed or created. I wonder did scientist really used to say that based on limited knowledge, and now with new technology they have discovered that it can be destroyed (annihilated when a particle collides with its antiparticle and produces gamma rays). Or did theists say scientists said that so they could have straw man to knock down?

[Chad32]

The wonderful thing about science is that if they find new information that discredits old information, they will change what they believe. I've heard matter can't be created or destroyed too, but I've also heard that particles pop in and out of existence from time to time. The universe is still a mysterious place to explore.

[Tiberius]

According to Wikipedia:

"In order for pair production to occur, the incoming energy of the interaction must be above a threshold in order to create the pair – at least the total rest mass energy of the two particles – and that the situation allows both energy and momentum to be conserved."

As far as I understand it, you can neither create / destroy matter or energy, but you can change matter into energy and vice versa, though in most cases you lose energy overall when doing so. It's not strictly "creating" anything. Neither is annihilating a particle strictly "destroying" it, as you said yourself, it creates gamma rays, which is a form of energy.

[Aoi Magi]

Wait, I thought it was "energy" that couldn't be created or destroyed but only change form

[Rhondazvous]

The wonderful thing about science is that if they find new information that discredits old information, they will change what they believe. I've heard matter can't be created or destroyed too, but I've also heard that particles pop in and out of existence from time to time. The universe is still a mysterious place to explore.

Gee, and all this time, I thought I was just mislaying my cell phone. How is it I always end up in apartments that have a portal to a parallel universe?

[Rhondazvous]

According to Wikipedia:

"In order for pair production to occur, the incoming energy of the interaction must be above a threshold in order to create the pair – at least the total rest mass energy of the two particles – and that the situation allows both energy and momentum to be conserved."

As far as I understand it, you can neither create / destroy matter or energy, but you can change matter into energy and vice versa, though in most cases you lose energy overall when doing so. It's not strictly "creating" anything. Neither is annihilating a particle strictly "destroying" it, as you said yourself, it creates gamma rays, which is a form of energy.

Precisely!

[Rhondazvous]

Wait, I thought it was "energy" that couldn't be created or destroyed but only change form

Apparently, it's a cycle. Neither can be created or destroyed.

[zebo-the-fat]

Energy can be converted into matter and matter into energy that's what E=MC^2 means, but the total mass/energy will stay the same

[brewer]

Apparently, it's a cycle. Neither can be created or destroyed.

Menstrual or motor? (hilk, hilk)

How about the word transformed?

Tibs, how do you "loose energy"? My understanding is that it may take a higher amount of energy to make the transformation to the end product. It's just that the end product does not contain all the initial energy. In a closed system the total amount of energy would still exist, just not necessarily in the transformed product. If course I could be wrong, ain't no ricket scientwist.

[Alex K]

Mass is simply the measure of how much energy of any form is contained in an object (*). Energy is conserved at short time spans, but can be converted and in particular, energy which appears as mass, can be freed from its confines and converted into other types. However, cosmic expansion removes energy from the universe via the redshift.

(*) This holds always. For example, a spring under tension has more mass than a relaxed one, precisely differing by the stored energy divided by c^2