So, as this is very much a non-LTE problem (given the huge energy range of about a factor 1000 involved), the attempt to address this with methods of thermodynamics (as is usually done), are destined to yield wrong answers and/or result in just more questions. The hot coronal plasma is just likely due to the few plasma particles that make it through the photosphere without being slowed down by inelastic collisions. Scientists have finally decoded why the Suns million-degree corona or outermost atmosphere is so much hotter than its surface, which has baffled astronomers for decades. This defines the 'surface' of the Sun with its low temperature (which corresponds actually almost exactly to a cooling factor (electron mass/proton mass). The photosphere is the region where the density (which decreases outwards) has become low enough for atoms to exist, which then in turn cool the plasma due to inelastic collision. Below the photosphere the density is too high for atoms to exist (the interior of the sun is just a plasma of bare nuclei and electrons).
So the question should rather be: why is the temperature in the photosphere so low? There are no complicated theories needed to answer this, as cooling of a gas is always due to inelastic collisions, in this case the inelastic collisions of high energy ions and electrons with neutral atoms, which turn the high kinetic energy of the plasma into radiation. These speeds are so high that the particles can escape the Sun's gravity.Ĭonceptual animation (not to scale) showing the Sun's corona and solar wind.The problem is actually more likely the other way around: the temperature of the corona is pretty much the natural temperature of the Sun, reflecting its gravitational potential energy (corresponding to about $10^7 K$). The corona's temperature causes its particles to move at very high speeds. From it comes the solar wind that travels through our solar system. We can view these features in detail with special telescopes. These include streamers, loops, and plumes. The Sun's magnetic fields affect charged particles in the corona to form beautiful features. This is the force that makes magnets stick to metal, like the door of your refrigerator. The surface of the Sun is covered in magnetic fields. But astronomers think that this is only one of many ways in which the corona is heated. In the corona, the heat bombs explode and release their energy as heat.
The mission discovered packets of very hot material called "heat bombs" that travel from the Sun into the corona. Yet the corona is hundreds of times hotter than the Sun’s surface.Ī NASA mission called IRIS may have provided one possible answer. The corona is in the outer layer of the Sun’s atmosphere-far from its surface. This is the opposite of what seems to happen on the Sun.Īstronomers have been trying to solve this mystery for a long time. But when you walk away from the fire, you feel cooler. Imagine that you’re sitting next to a campfire. The corona’s high temperatures are a bit of a mystery. Image of corona from NASA's Solar Dynamics Observatory showing features created by magnetic fields. This low density makes the corona much less bright than the surface of the Sun. Why? The corona is about 10 million times less dense than the Sun’s surface. The corona reaches extremely high temperatures.
#Sun corona hotter how to#
Find tips on how to safely view an eclipse here. Remember to never look directly at the Sun, even during an eclipse.
0 kommentar(er)
