According to einstiens e=mc^2 matter can be converted to energy. Does this include all matter?

Question

I know this sounds really stupid but I am confused. According to einstien, matter can be converted to energy. Why then cant plain oxygen or carbon atoms be converted into energy? Why must uranium be used in nuclear explosions?

Answer 1

No, absolutely not all matter. There is another natural law that absolutely cannot be violated, which is the conservation of baryons. Carbon and Oxygen nuclei are made of baryons, and so they cannot be converted to energy, unless they are annihilated by anti-baryons, and there aren't any of those occurring naturally in our universe.

Answer 2

Yep, any form of matter. Any.

See, E = MC^2 says more than the idea that matter can be converted into energy. It says that matter IS energy - just in another form. I've written a few responses to questions (one earlier today) about matter and energy - it was in a thread asking about elements in a vacuum. Anyway, if we could figure out a way to completely change matter to energy, like the annihilation of matter and antimatter, we would undoubtedly solve the world's energy problem.

You know, nuclear reactions (including explosions) liberate only between 2% and 5% of the total energy found within the matter used? The nuclear warhead the United States dropped on Hiroshima killed almost a quarter million people, and it used a softball-sized lump of atomic matter. If that many people were killed, and the chain reaction only liberated 5% of the total energy found in the matter contained therein... what would have happened if we could liberate 20%?

50%?

... what about total efficiency?

E = MC^2 has far-reaching implications... far beyond what we normally consider. If we ever figured out how to attain more efficient mass to energy reactions - imagine the crossroads at which the human race would stand. We could save ourselves with knowledge like that...

...or we could destroy ourselves.

Personally, I dread ever seeing the realization of such potential.

Answer 3

Oxygen and Carbon both absorb neutrons in a reactor. Both isotopes can be a constituent to reactivity. Boron is the only thing that I can think of that absolutely has a negative affect to reactivity due to it being a neutron poison, and as thus used as a modorator in PWR applications. Plutonium and Uranium are the easy to split atoms due to thier extremely LARGE and unstable structure. There is NOTHING to do with density on a molecular level. It is on an ATOMIC level. That is why they are used as fuel for reactors, and for triggers in other "applications". Fusion of light atoms such as deuterium and tritium are not reproducable on a small scale, such as for power generation. They can only be produced in "other" (larger more uncontrolled) applications. All atoms hold a certain amount of energy. The nucleus of any given atom is held together by coulumbic force. Larger atoms have more potential energy due to the greater coulumbic force, and therefore, generate more energy (enough to sustain fission is a minimum for a nuclear fuel). All matter can be split to release the energy stored in it, but most matter does not have the mass required to sustain the reaction. It is therefore an unusable fuel for fission reactions.

Answer 4

Very good question!

In a physical change, you manipulate intermolecular bonds (molecules move around). In chemical reactions you manipulate intramolecular bonds (electrons move around). In nuclear fission and fusion, you are splitting or joining nucleii (interbaryonic bonds?). The number of protons and neutrons (generally) don't change, just their configuration.

The idea is, the deeper you go into the atomic structure, the more powerful your reactions become. Einstein's equation is the maximum limit of energy that you can get out of some mass. There will be no leftover bits after the reaction.

We do not have a (commercially viable) way to conpletely change mass into energy, the only exception is matter-antimatter anihlation, where you have to have a supply of antimatter in the first place (very expensive to produce).

Answer 5

It's not so much that Einstein promised mass could be converted to energy. He just found how MUCH energy it could be converted to, if it could be converted.

But yes, probably anything COULD be converted to energy, just not by our present level of technology.

And let's hope we find a nice slow way to derive energy from random molecules and not need to have a huge explosion to go along with it.

In the case of Uranium, we are taking advantage of the fact that it is so dense (lots of molecules in a small space) that when we knock a couple hunks into each other fast enough, they achieve critical mass, forming a chain reaction where released neutrons from one atom run into the nucleus of nearby atoms and cause it to shed some more neutrons which then do the same thing.

A less dense object (or one which was not very 'radioactive' to begin with -- i.e. fewer excess neutrons) is less likely to get hit by loose neutrons in the first place, and less likely to have neutrons get knocked out of its nucleus if it DID get hit.

We *can* of course get energy out of regular carbon and oxygen atoms, just not via nuclear fission (at least not today.) We get LESS energy out of 'burning/oxydizing' carbon to oxygen (making carbon dioxide as the output) than we would from nuclear fission because we are not actually destroying the atoms in the process. We are just letting them get together in a more compact state, something they have a natural desire for, and they release a little energy in the process. We would have to give that energy back (plus a little more) to crack carbon dioxide back into carbon and oxygen. But we *could* do it. And plants do it (getting the necessary energy from the sun, which is where we need to be getting all our energy)

Answer 6

If you can figure out how to do it in a controlled manner, you'd be richer than Bill Gates.

It takes a certain amount of energy to hold an atom together. Medium-sized atoms are the most energy-efficient. You can release energy by splitting very large atoms (like uranium) into smaller ones, or fusing very small atoms (like hydrogen) into bigger ones.

The problem with fusing small atoms into bigger ones is that it takes place at very high temperature and pressure (normally found at the center of the Sun). Trying to duplicate these conditions on the surface of the Earth (without killing everyone nearby) is the tough part.

Answer 7

In both nuclear and chemical reaction a small portion of the mass is converted to energy associated with binding energy of nucleons and atomic bonds, respectively. Nuclear bonds are much stronger, so the difference in mass of the products is more easily measured.

Theoretically, all the mass can be converted to energy. There are practical limits though, like the absence of known natural deposits of antimatter or black holes.

Combining mass m of antimatter with mass m of matter (of complemenary composition) produces 2mc^2 of energy in the form of gamma rays. Anitmatter can be manufactured, but it requires more energy to produce than mc^2, so would be considered an energy "carrier", or fuel (like hydrogen). Spaceships which hope to achieve anywhere near light speed would require such a fuel.

A significant percentage of conventional matter can be converted to energy with the help of a stellar black hole. The accretion disk of a black hole kicks back 10's of percent of the mass in the form of radiation. There are more controllable schemes involving close passes of solid matter, though. Baryon number (mentioned as limiting factor) is not a property of a black hole, so is not a limiting factor this case. See "no hair theorem" reference. In about 10^60 years, the black hole will theoretically evaporate, having emitted no net baryons, leaving no quibble about whether it is a "hidden" conserved property of the black hole.

A entirely theoretical low mass quantum black hole is even better. If they exist at all, they would be left over from the big bang. They convert all the matter contained there-in into Hawking radiation of significant power. Although of primorial origin, they explode when out of mass. They can be refueled, though, by dropping stuff in before this happens.

The reason black holes work for this purpose is because gravity wells in general contain mass with negative gravitational potential energy. That means dropping stuff in inelastically in such a way as to create radiation causes a positive energy release to the outside (far from the well), while conserving energy overall. Being a black hole means it can be done with high efficiency, resulting in significant or total mass conversion.

Answer 8

So, matter is equal to energy, but the energy worth looking at is nuclear binding energy (kind of analagous to electron binding energy). Except nuclear binding energy is much higher.

Now, just like how electrons have shells that make them more stable, so does the nucleus. However, the nucleus also has a magic NUMBER of protons and neutrons that makes it most stable. That number is 26 protons, 30 neutrons, (56 atomic mass units total): Iron.

Iron is the most stable element in the universe. Anything below iron, given enough energy, will try to fuse into iron (that's what our sun does). Anything above iron (uranium) will try to decay into iron.

Now, the cool part is that anything heavier than iron is actually created by a very, very strong fusing force, the kind found in supernovas (So yes, every element on earth that is heavier than iron was created either in a supernova, or a particle collider that simulates similiar conditions).

Okay, so that explains fission, now for converting matter to energy:

All energy initially in the universe (right after the big bang) was a like a giant soup. A very unstable, energetic (well it WAS pure energy after all) soup. As you probably know, nature tries to assume configurations having the least amount of energy. Turning into Matter was the next step for this soup.

By coalescing into a solid chunk (proton, electron, neutron), it could release a LOT of energy and become more "stable".

Basically, nuclear fusion of two hydrogen particles Deuterium and Tritium (found in hydrogen bomb) releases 200MeV of energy. The energy released by soup to turn into just ONE of those particles? Roughly 2000 GeV

That's 20,000 times more energy.


So you'd have to pump a LOT of energy back into that one particle, just to get it to turn back into energetic soup.
And we Have done this, at particle accelerators and colliders, we take heavy elements and smash them into each other, and for a small fraction of time, those particles turn into the same highly energetic soup that was present after the big bang. We can actually study this soup's behavior too.

Oh and a minor note for anyone who caught it, yes it takes a lot of energy and science to make matter turn PURELY into energy. That's why hydrogen bombs and uranium fussion never actually destroys whole neutrons or protons, just makes them weigh slightly less (since they're approaching iron), and turns that little fraction of a proton's mass into energy (which is still alot!).

Answer 9

The theory says that matter and energy are equivalent, so yes, all matter can be converted. The reason for using uranium is that it is unstable and prone to decay. When it decays it forms new elements which have less mass than the original. The extra mass in converted to energy. Other elements can be used, for instance hydrogen in nuclear fussion in a hydrogen bomb or the sun.

Answer 10

SRT.
SRT are based on two laws.
1) The First law of SRT - the speed of a quantum of light in vacuum has
a maximal magnitude (constant, absolute) of c=1.
2) The second law - no other particle can travel with the speed c = 1.
Hence, a quantum of light is a privileged particle and SRT
examines the behaviour of a quantum of light in the Vacuum. SRT solve the problem:
that will take place, if quantum of light will change the rectilinear movement c=1.
He can change the rectilinear movement c=1 only on rotary movement.
And then these changes are described by the Lorentz transformations.
The circle turns to a sphere. And he works as electron .
And in this item electron is connected to electrodynamics of Maxwell.
In Maxwell's theory, the electron is considered local,
as though the particle is "at rest".
This means that it particle does not move rectilinearly,
but rotates around the diameter (has the form of a sphere).
The rotation of the electron creates electrical waves.
And then at the beginning of the last century many scientists
(Einstein, Lorents, Fitzgerald, Poincare, Abraham) were interested in the question:
What will take place, if the electron (Maxwell's) begins to move - rectilinearly?
All of them came to the conclusion that there would be radical changes with the electron.
These changes are described by the Lorentz transformations.
* * *
What borders of change the electron,s parameters ?
The Quantum theory approves, that at interaction electron with Vacuum
its parameters get infinite magnitudes.
It is possible only then the geometrical form of electron - sphere will be
transformed in flat phantom - circle.
Electron and quantum of light is one particle, which can be in different physical condition.
* * *
Such simple explanation seems surprising.
But business that the Quantum theory and SRT describe the beginning conditions
of Existence .
And beginning conditions can not be complex (difficult).
The development and evolution of Existence goes from simple to complex .

Answer 11

Mass and energy are different states of the same thing. This means that all the energy and mass that ever existed already exist. You cannot create new mass or energy, just convert between them.

Get the book E=mc^2. It's an incredible read that will cover off all of your questions and really expand your interest in physics.