How can the empty space around the sun be millions of degrees hot and the surface only thousands ? it doesn’t make any sense.
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The empty space around the Sun isn’t completely empty, it has some particles in it, which happen to be extremely hot. However, since there are so few of them, they don’t effectively transfer temperature to anything. The same happens on Earth – exosphere, starting at an altitude of about 500 km, is extremely hot, at several thousand degrees.
The simple answer is we don’t know, this is something that has plagued scientists for nearly a hundred years.
Why is an are a few thousand kilometers above the surface of the sun hotter then the surface or even the core itself?
So, what can it be, to simplify, it can be one out of three reasons.
1. Heat has been stored there over a long period of time.
2. Heat is generated there.
3. Both 1. and 2. are true.
For 1. to be true, there must be some form of ‘atmosphere’ that keeps the heat in, maybe it’s just that most of the heat energy is stored there, since vacuum is terrible at transmitting energy, however it’s been hard to prove 100%, since it
For 2. to be true, it would be magnetic waves either colliding or just something akin to friction, and unlike earth with it’s north and south pole, the suns magnetic field are pretty gnarly.
3. Is probably more likely to be somewhat true, since both of these theoretically could produce the heat.
I remember the parker solar probe being launched in 2018, who has a goal to find evidence to answer this question. So look forward to it for answers.
ºC has the molecules move at an avarage speed of 475m/s, that’s pretty fast, increase the avarage speed and you get a hotter gas. if put your hand in that cloud of gas and your hand is colder than it, the molecules will bump ino the molecules that make up your arm transferring energy which will in term make your molecules average speed higher making it hotter, now solid’s molecules aren’t free to fly around, you could say that they vibrate in place but the principle is the same.
At very low gas densities near vacuum the molecules are free to fly round at very very high speeds very rarely bumping into each other If you were to measure their average speed you will find it’s very high, so you say “this gas is several thousands of degrees hot” but if you were to put your hand in it altho the collisions in your arm would transfer a lot of energy to heat up your arm, there is way to few collisions to actually heat up your arm before you radiate all that heat away and end up freezing.
soo yes the sun’s corona is technically extremely hot because the average speed of the gas molecules is extremely high but it’s so low density that it can’t actually heat anything up because objects would radiate heat away more quickly than they would gain it.
If you put something small in the microwave it heats up faster than something big.
If it is really small it gets really hot.
The few molecules around the sun get super hot because there is nothing else to get hot. Less stuff to share all the heat.
Why do they “say” it’s hotter than the surface?
Because all measurements of temperature show that it is far hotter than the ‘surface’ layer. This is a piece of data, and evidence that stands on it’s own. It needs no explanation to be true. It doesn’t need to ‘make sense’ for it is a measured, observable fact.
That phrasing aside, you have identified a currently unsettled question in Astronomy. We don’t really know, exactly, why it’s hotter.
It isn’t empty, it’s full of hydrogen and helium zipping around at high speeds. That’s why it has a temperature. But it doesn’t fit the simple model of things get cooler as you get further from the heat source (the core fusion). That’s how the rest of the sun seems to work, so it is a very big puzzle.
But the sparse plasma of the corona behaves a bit differently than the rest of the sun. Magnetic fields are more free to move through it for example, compared to the dense solar ‘surface’.
So waves in the magnetic field is one model they’re working with.
Another is interactions with solar flares, or even ‘nano-flares’ that serve as a way to introduce heat into the corona and crank the temperature up.
That said, the total energy in the hot corona is still far far lower than the energy in the surface of the sun, so we’re still obeying conservation laws.
The simple answer to your question is that we just don’t know. This has been a conundrum in solar physics for several decades at this point and although we have made some way forward to resolving it, we simply do not have enough evidence to support the current hypotheses.
You are correct that it doesn’t make any sense because at face value, this breaks the second law of thermodynamics. The current hypotheses basically revolve around some method of transporting heat from the suns interior through something akin to a soundwave but we have struggled to identify waves propagating through the corona. The competing hypothesis involves some weird interactions with magnetic fields breaking and reconnecting. This process generates electrical currents and waves supplying heat to the corona. This is how solar flares form (we think) and it’s thought that there are lots and lots of tiny solar flares occurring at all times which can provide heat to the corona.
The photoshpere is the light emiting layer of the sun that we actually see. It is measueured to be around 6125ºC at it’s base to 4125ºC on top
Above that is the Corona which is a much less dense region of gas above the photosphere, and usually only visible during an eclipse. It is measured to be up to 2,000,000 ºC.
WHY the corona is so much hotter is still a mystery and something we are working on figureing out.
We don’t know. That’s one of the things the Parker Solar Probe is investigating. I think maybe away from the sun’s surface the matter can move much faster in mostly one direction. The matter on the surface is mostly being held back and circulating in a turbulent flow. There’s some mechanism by which the temperature vastly increases when matter is propelled away from the sun.
There is strong evidence that the corona is really hot due to Alfvén waves. Alfvén waves is where magnetic waves are generated deeper into the sun and then transfer their energy into the corona (the gasses above the suns surface). Lots of energy from deeper into the sun gets dumped into comparitively few particles in the corona means that each individual particle will get a lot of energy.
20 years ago this was only theoretical, but since 2009 several probes (like SOHO, Parker probe and the Wind probe) have detected evidence that supports the Alfvén wave theory.
Note though that the corona being millions of degrees hot vs the surface of the sun being just a few thousand degrees hot is kind of like a 100 C sauna (feels hot, but you can sit in there for a while) vs 60 C water which will give you burns within 3 seconds.
I don’t know, but it makes sense. My body temp is 98.6, but according to my wife, when in bed at night, the area directly adjacent to my skin is 40000⁰
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