Good to know this is "discover" in the sense of "confirm, understand better" rather than "suddenly find out about". Otherwise this would be quite the background-tv-in-a-disaater-movie headline!
Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
41–50 of 67 posts
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#42Earlier quoted context omitted.
Why would the sun’s energy be taken away?
It's the impending and inevitable heat death of the universe... several billions of years away...
Our nearest star, Sol, will grow cold well before then.
But even that is estimated to take trillions of years after it runs out of hydrogen for fusion.
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#43Not to undermine how cool this is but is there any reason why we are only getting a looped 3 second video?
Check out the last video on the page. It zooms in and you get a sense of just how much resolution there is.
> Check out the last video on the page. It zooms in
That's what I mean, it's a looped 3 second video of the same animation, zoomed in a few times.
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#44This kind of observation is a big deal for solar physics. It's been believed for decades that these small-scale (~100km and below) turbulent features are critical to understanding how energy dissipates in the Sun. And thus, how sunspots and flares form. The subject has been very qualitative but is yielding on both observational and simulation fronts. I worked adjacent to this area from the 1990s-2010s, and it had bee…
> The subject has been very qualitative What does this mean?
People were identifying gross features (like the convection cells in the first website I linked), and giving those features names. Like “sunspots”, “faculae”, “pores”, “granulation”, “bright points”, etc. That’s on the observational side.
I’m less informed about simulations in this era - perhaps some simplified MHD simulations had been more quantitative in linking equations of state to the emergence of these features - but I believe they were not realistic enough to provide definite constraints on the scale of the structures.
It was clear that these features had to do with energy transport and some of the mechanisms were hypothesized. But the spatial scale of the gross energy transfer in these convective cells was not known, either through simulations or observation.
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#45Earlier quoted context omitted.
Silly question but how does a 4m aperture focused onto a smaller area not concentrate the heat and melt the instruments?
It's highly filtered, you are only getting a small slice of all of the wavelengths. Only a tiny fraction of all that energy hits the photo collector. I believe the collector is also actively cooled, but I might be wrong there.
Yes, just 0.5nm of spectrum in the instrument used (https://dkist.virtualsolar.org/vanNoortfastcam/, see under “DataSetDescriptions.pdf”).
If the pixels really are 20x20km, located at 1AU, I get 500k photons (within that bandpass) per pixel per frame at 740 Hz, not counting optical losses.
Space solar instruments like HMI on SDO (https://science.nasa.gov/mission/sdo/) have one or more pre-filters in front of the instrument to block some light far from the passband and keep heating under control. I’m not sure if DKIST has such filters.
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#46The Sun impresses me. So much energy to dish out, so little of that is taken by planet Earth yet it helped yield and maintain life. Now what will happen when that energy is taken away ...
The sun will destroy the earth long before it stops providing energy.
Yeah, red giant sun will be 200 times the radius. So big it completely fills earth's orbit. Crazy to think that as hot and energetic as the sun already is, it has that much potential.
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#47This kind of observation is a big deal for solar physics. It's been believed for decades that these small-scale (~100km and below) turbulent features are critical to understanding how energy dissipates in the Sun. And thus, how sunspots and flares form. The subject has been very qualitative but is yielding on both observational and simulation fronts. I worked adjacent to this area from the 1990s-2010s, and it had bee…
Thanks a lot for sharing your experience with us. I worked adjacent to this area from the 1990s-2010s when the topic is solar physics is definitely why this forum is one of the last "places" of the internet.
It was a great comment, HN still offers nuggets now and then
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#48Earlier quoted context omitted.
Why would the sun’s energy be taken away?
It's the impending and inevitable heat death of the universe... several billions of years away...
Err, no. You're well out there! By literally 10^100 years or more https://www.youtube.com/watch?v=uD4izuDMUQA
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#49Earlier quoted context omitted.
Why would the sun’s energy be taken away?
It's the impending and inevitable heat death of the universe... several billions of years away...
Healthy adults don't think about this. It's rational but it's too rational and it makes you unable to function. If you find yourself fixed on the inevitability of the death of everything, maybe seek counseling.
Re: Scientists discover Kelvin-Helmholtz Instability on the surface of the Sun
#50Don't look directly at them.
Just get yourself a pair of these DuckDuckGo Paso Robles and enjoy the view. https://knockaround.com/products/duckduckgo-paso-robles
kinda a bummer that it somewhat looks like it does have a camera for the untrained eye. Defeats the whole purpose of "be X but also make it obvious it's X"