I’ve heard a few times now in various scientific fields, mainly experiments, about things getting as hot as the sun.
How is this possible? Surely if you do something and you create heat that is that hot it would melt anything surrounding it?
Would love to know how this works 🙂
In: 175
The difference is in the anount of heat (and pressure), not the temperature.
Others are talking about creating solar temps in a lab and such. But my oxyacetylene welding torch creates a temperature hotter than the surface of the sun. That’s not exotic at all. The core of the sun is much, much hotter, but even if we were to create those temperatures in a lab on earth, or by exploding a thermonuclear weapon, the reason it wouldn’t somehow ignite everything is that it is a relatively small amount of matter being heated to that temperature.
Temperature measures how much energy is contained in each atom of whatever matter you are measuring. Heat is the energy of a whole system or volume of stuff. So, if you have a torch creating a temperature at its tip of 6000K, or some experiment creating a temperature of 10 million K, it will be in a tiny space. Each atom in there is that temperature, but they are surrounded by the rest of the world, at something like room temperature. As the very hot atoms collide with cooler ones (and also radiate heat) their surroundings are warmed, but they are losing heat in doing so. Their temperature is decreasing. So even an incredibly hot bunch of atoms can only warm so much of its surroundings before it loses all its heat energy and becomes the temperature of its surroundings.
Think of it in the extreme case. We somehow raise the temperature of one single atom to 20 million degrees and let it loose in the air. It will heat up the millions of atoms nearest to it by a bit, losing energy in the process. But those millions of atoms are within a millimeter if the first hot atom, and they are each a huge amount cooler. Out at a centimeter away you have a thousand times that number of atoms to heat, and they each rob the core of more energy. The amount of energy it took to raise an atom 20 million Kelvin will raise 20 million atoms a degree Kelvin, more or less (to an ELI5 approximation). So the heat energy dissipates quickly.
Even a hydrogen bomb faces the same situation. There is a lot more mass there, and it’s set up to create the conditions for fusion, so it releases incredible energy. Enough to be hugely destructive over a wide area. But the actual heat is dissipating the same way. Everything it heats up robs the hot parts of energy, and on a scale of the earth, or even the earth’s atmosphere, there is a lot of mass to heat up.
This leaves a lot out, of course, but covers the temperature question. The reason you don’t get a self-perpetuating fusion reaction has to do with mass as well, but it’s because you need incredible pressure and temperature to run the fusion core of a star, and that is only powered by the gravity of the gigantic mass of the star.
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