Sometimes I try to draw things from long ago memory and find that the file has been a bit corrupted, either thru age, ethanol or exhaust fumes. I should know these answers but I can't remember. Maybe I never knew in the first place. 1. Can matter be converted to energy? I don't mean getting energy from burning gasoline, resulting in conversion of liquid to gas+ liquid+ heat, I mean actual loss of matter in the liberation of energy. 2. Have all ( or virtually all) atoms (or maybe subatomic particles) now present ALWAYS been present since the beginning of time, or is there a source of new particles in the universe? 3. If there is a way to convert mass to energy, ultimately should we end up with all one or the other, and which one? 4. Is the only source of increased matter on earth from space dust funneling in at the poles (seen as the Aurora Borealis) ? Is there a mechanism by which the earth looses mass? If so, is the earth getting heavier or lighter? 5. What is the weight of a year's worth of polar funneled space dust? Addendum: I can't believe this thread is cheek and jawl with the "Stinky Running Shoe" thread.
Ummmm...the aurora's (there is the aurora borealis in the northern hemisphere and aurora australis in the southern) are not caused by dust. They are caused by plasma carried by the solar wind and its interaction with the Earth's magnetic field. See here --> http://en.wikipedia.org/wiki/Aurora_(astronomy) for more details...
For the record, it is now estimated that 40,000 tons of "space dust" get deposited on the Earth every year. There is a geological record of this going back an estimated 30,000 (from ice cores). Some elements such as Hydrogen and Helium do escape into space but the Earth has reached a more or less steady-state when it comes to these gases. That is, it produces the same amount that it loses (not exactly...but it's close enough). And, before you ask this one next, no...human population is not dramatically changing the weight of the Earth. We are what we eat...so people make up roughly the same mass that was already here...just in a different form.
No, that's a fundamental law of Junior High chemistry. Since Einstein, we've known that matter and energy are different manifestations of the same thing. The amount of energy in matter is equivalent to its mass times the speed of light squared - that's the famous equation E = mc^2. And you can definitely convert matter into energy. Don't dismiss the example of gasoline, because it's perfect. If you were to burn a kilogram of gasoline with 14 kilograms of oxygen, measure how much energy it released, and then measure the mass of the combustion byproducts, you would find: a) That there was less mass left over than you started with. b) That the amount of energy released is exactly equivalent to the missing mass, times c^2. Now, c^2 is such an enormous number that the actual amount of missing mass is quite small. But, it's not zero. The same applies to any chemical reaction that releases or consumes energy: if it releases energy, matter is destroyed, and if it consumes energy, matter is created. Of course, the classic example of this is an atomic bomb, which is a much more efficient way of turning matter into energy. But most people don't realize that the same principles apply to everyday reactions, like explosives, glow sticks, candles burning, and chemical hand warmers. Also, consider particle accelerators. The whole point of particle accelerators is to smash particles into each other and higher and higher speeds (with higher and higher energies). When this happens, the energy in both colliding particles is converted into matter, and a shower of other particles come flying out. The faster the colliding particles were travelling, the heavier the particles that are created. This is how many new subatomic particles are discovered, by watching what comes spewing out of high-energy collisions in particle accelerators. The image below is actual detector data from the particle accelerator at Brookhaven Labs, showing the shower of particles emitted when two gold atoms collided. As for your other questions: there is no significant source of new particles in the universe. However, there is a significant source of new energy. Matter is constantly being converted into energy. That's what happens inside every star. A star uses nuclear fusion: the high pressure inside them forces hydrogen atoms together, and you get helium. Once there are enough helium atoms, they start colliding too, forming beryllium and lithium. Then, the beryllium and lithium atoms collide, forming carbon, oxygen, nitrogen, and so forth, on and on. Every step in this process releases some small amount of matter as energy, and it keeps going on, with heavier and heavier elements. That's how all elements other than hydrogen came into being: inside stars. Everything you see in front of you was produced inside a star, billions of years ago. That doesn't mean that all the matter will eventually be turned into energy, because eventually the fusion reaction inside the star gets less and less efficient, as the elements it produces get heavier and heavier, until the reaction stops producing energy. At this point the star dies, or goes supernova - I don't really know my astrophysics. Also, note that, while these reactions do turn matter into energy, they don't completely destroy matter. When you fuse two hydrogen atoms to form helium, 99.7% of the mass is still left, and that's true for the other fusion reactions too. So, even if the universe were one gigantic star, you'd never end up with only energy and no matter. I don't know anything about the earth's gain or loss of mass, though. EDIT: Also, if you're really curious - lead is the heaviest element that is produced inside stars. Beyond that, nuclear fusion stops producing energy. The heavier elements than lead (uranium and plutonium among them) actually require energy to fuse, and they're produced in supernovas. Lead is the last stop on the energy production train: you can't anything more out of it (there's still lots of energy trapped in it, according to E=mc^2, but you can't get at it). But, you can release the energy produced in these heavier-than-lead elements using nuclear fission, which is what powered the original atomic bomb, and is what's used in nuclear power plants. Conventional nuclear power is simply releasing the energy stored as matter inside supernovas, billions of years ago. Nuclear fusion and nuclear fission both lead to the same place: lead. Fusion starts with hydrogen and builds heavier elements, releasing energy along the way, and fission starts with heavier elements and gets lighter, also releasing energy. But, they both end at lead. If you look on the periodic table, elements get heavier as you go to the right, and as you go down, in that order.
One other thing: there is a way to completely extract all the energy out of matter (even lead) - bring it into contact with antimatter. Antimatter and normal matter, when they touch each other, completely obliterate each other, releasing all of their mass as energy. Immediately after the Big Bang, everything was energy. Matter and antimatter sort of coalesced out of it (after, literally, a few minutes), a process that is not well understood. Now, there is essentially zero antimatter in the universe. It can be produced artifically (the world's most expensive substance, at a cost of 63 trillion dollars per gram), and is produced naturally only in incredibly small amounts (individual particles), which quickly come into contact with normal matter, and disappear. On the other hand, matter is (obviously) everyhwere. One of the deepest questions in physics today is, why did we end up with significantly more matter than antimatter after the Big Bang? At the moment, no one knows.
Thats why his location says MIT. Excellent explaination Avalys. Even a dull pencil like me could follow you. It's all very interesting but leaves me with a headache. I think that I will take a Tylenol and go read Maxim for a while.
I'm not exactly up on astrophysics but I was under the impression that buildup of heavier elements was limited to the iron group and below...... anything above Ni 62 required the addition of energy. Now for a really tough question..... why is Uro still Ferrariless? One additional note.... It's really amazing to go out someplace dark and watch for meteors with night vision goggles, there is a lot of rocks and space junk falling out of the sky that can't be seen with the unaided eye.
Oh hell, you're right - I don't know where I got lead from. Iron is the eventual end product of fusion and fission, not lead. Replace every time I said lead in the above posts with iron. Oh well, that explains why I'm studying EECS, and not physics.
Thanks Avalys ... I feel completely retarded now. Feel free to post more stuff like this, it's fascinating. To me, at least!
I've been emailing my friend this and here's some of his response *Nuclear fusion and nuclear fission both lead to the same place: lead.* What type of fission? What type of fusion? (and tell them yes there are different kinds.) >* Fusion starts with hydrogen and builds heavier elements,* Check the validity of the statement. There's more than hydrogen at the beginning. What are the heavier elements? No blanket statements. Break it down. What do you mean "builds heavier elements"? What are they? >* releasing energy along the way* What type of enegy and what are it's measurements? What/where is "the way"? Where does this statement come from? Where is it's origin? Who's idea is it? Is their view still valid today? How do you know it releases energy? > , and fission starts with heavier elements and > gets lighter, For example? What are the "heavier" elements? Heavier than what? Other elements? What are the specific elements? What is meant by "starts"? > also releasing energy. What type of energy and what are it's measurements? What form is it in? > But, they both end at lead. What do you mean "end at lead". Which one? In what form is "end" used here? What form is "lead" in? A nuclear explosion doesn't "end in lead" does it? Get them to break these down and I'll look into it.
