Sun's surface seen in new detail | Hacker News Reader

Sun's surface seen in new detail

bbc.com

336 pointsPatient091 comments

I work as a graduate SW engineer at Andor, which produced the SCMOS camera they used to capture the images (https://andor.oxinst.com/balor-scmos).

Quite a nice surprise to see during my morning commute! Everyone here is extremely pleased to see how the images turned out. Very impressive work from DKIST

If you don’t mind the curiosity:

These images seem to have a sort of “enhanced blurring” and depth-flattening reminiscent of early 3d ultrasounds.

Am I interpreting that right? Or is the surface of the sun really like that?

You'd have to ask a solar physicist about those solar structures I'm afraid or an optical expert about the image properties, I just work with camera software. If you haven't already you can download their press release which goes into a bit more detail than the main article [1].

I've also found some interesting bonus footage of the camera in a test setup for those that are curious (the actuating gray box in the background) [2]

[1] https://www.nso.edu/wp-content/uploads/2020/01/MediaKit.zip (1.25GB)

[2] https://www.nso.edu/telescopes/dkist/image17/

You can view all the photos and videos directly on the National Solar Observatory's website: https://www.nso.edu/inouye-solar-telescope-first-light/ (and press release at https://www.nso.edu/press-release/inouye-solar-telescope-fir... )

Would way prefer people link the original sources in cases like this, where the news articles add almost nothing useful and instead bombard me with advertisements and user-tracking, etc.

utterly unusable on mobile. at least bbc has that part worked out.

The BBC only shows a very zoomed out video though, so you don't actually see the new bit, making it an article about new resolution illustrated at pretty low resolution -_-

I'm not seeing a video, could you give the URL of the actual media file instead?

https://www.nso.edu/wp-content/uploads/2016/04/DKIST-First-L...

4K – H.264 (45 MB)

There are some others here:

https://www.nso.edu/telescopes/dkist/first-light-cropped-fie...

Non cropped ones here:

https://www.nso.edu/telescopes/dkist/first-light-full-field-...

True - but why should desktop users get a worse source just because mobile users need a mobile site?

Maybe posts should have the ability to submit different URLs for mobile vs desktop? (I know that idea is problematic in multiple ways).

holy shit, they overdried the default scroll speed.

Brb, i am grabbing a spoon and i'll find the one who ordered this 'feature'..

But seriously - dropping a primary sources would be a neat habit to have in here :)

Indeed, fortunately the original pictures show a scale within the picture for clarity: https://www.nso.edu/telescopes/dkist/first-light-context-ful...

The granule flow in that animation would make a great RNG ;)

Congrats to all involved, and kudos for ushering in a new golden age of solar observations

At first glance of the static image, it appeared to me the granular structure of solar surface convection resembled a thousand other phenomena in Nature: poly-crystalline grain boundaries in metal alloys, lipid cells in fatty tissue, colloidal suspensions of cloud smoke

But watching the animation made me realize how unique and dissimilar this is to any other chaotic turbulent flow

Due to the sun's gargantuan scale, even throwing the world's fastest supercomputers at the problem, we cannot adequately simulate all the convection, plasma, rotation and magnetic interactions of solar surface and interior dynamics

These images make me feel very humbled, reminding us of our place in the cosmos!

Weak influence of near-surface layer on solar deep convection zone revealed by comprehensive simulation from base to surface

https://advances.sciencemag.org/content/5/1/eaau2307

The next wave of closely-guarded RNG secrets could very well be which solar coordinates your camera is pointed at!

For anyone curious, some years ago I talked with the NSO outreach folks, and they were aware then that the Sun is white, and that yellow/orange is a misconception widespread and problematic in both astronomy education and the general US population, and that their colorizations were not helping with that. Their justification was roughly that you need to hook people with what they expect, and only then can you make progress with educating them. I thought and think that that's very much the wrong call, as well as over the line ethically, but... oh well.

Though the misconception really is pervasively widespread, even among first-tier astronomy graduate students, so perhaps there might now be a degree of confusion present as well. And a (very) few instances of colorization are representationally valid, if unfortunate in their collateral damage, as when representing that some instrument's sampling band is in yellow.

You have mentioned a neat point that illustrates some of the complexity of an "image" like the ones shown.

After 20 or so minutes poking around, I'm not 100% sure what instrument took the images in the OP. There are five focal planes that can get the light from this much-anticipated solar telescope, which has been envisioned and prototyped going back at least 20 years.

Anyway, I think the instrument for the images was VBI, the Visible Broadband Imager (https://www.nso.edu/telescopes/dkist/instruments/vbi/). It takes images in 8 spectral bands, in the visible range. But these bands are very narrow, like 0.5nm or less. (Solar astronomy is cool that way, lots of photons of whatever energy you want.) The specific bands have been carefully selected.

One band that page calls call "continuum" (sometimes referred to as "pseudo-white-light", found in the "spectral resolution" submenu) is at 450nm, in the blue. All the 8 various bands illustrate activity at different altitudes in the solar atmosphere. The 450nm band will be from the solar photosphere, where sunspots and other familiar features live. Some others are much higher up, and sunspots will not be present as such in those bands.

If this conjecture is true, the displayed images are taken in a very narrow slice of spectrum around 450nm (or another one around 668nm, which is in red) and then mapped through a black/orange/yellow/white color map for display. This kind of "colorization" is pervasive throughout solar astronomy, and used universally by astronomers themselves for their own science images. (Visit https://umbra.nascom.nasa.gov/newsite/images.html and weep.)

As hinted in your last sentence, it's not at all clear what a "correct" colormap for light from 450nm +/- 0.5nm should be. Shades of blue?

For more on your point: http://solar-center.stanford.edu/SID/activities/GreenSun.htm... (old-fashioned site, but technically 100% solid).

The source article[0] linked in another thread says the images are of the 789nm band.

[0] https://www.nso.edu/inouye-solar-telescope-first-light/

Our vision is evolutionarily adapted to sunlight, so it makes all the sense that sunlight should be perceived as neutral white.

But we perceive it as yellow ... it's only white if you are outside the atmosphere, a condition to which we are not evolutionarily adapted.

The sun is not white, it actually is a lot of different colours that then happen to look white. White is anyway a rather difficult colour to use as base if you want to show any detail.

The importance of your "misconception" is unclear to me, most people have seen the sun for themselves (though I expect all have been told not to look) and can tell the difference between the real thing and a picture of it.

> a lot of different colours that then happen to look white.

Seeing as white is just "full spectrum", that is literally just the definition of white. So yes, the sun is white.

But it's not (evenly) full spectrum though, so why would it be white?

I can understand either green (the blackbody peak) or red/yellow (as seen with human eyes through our atmosphere). Who would considered it white, apart from an astronaut?

I think the sun is green, since its spectrum clearly peaks at those wavelengths. But if I tell that to anyone they often suggest I should go to sleep again.

G-class stars like the sun are called yellow dwarfs, which is also inaccurate.

I wonder how much of these disagreements are based on the individually different perception of colors [0]?

[0] https://en.wikipedia.org/wiki/The_dress

I don't think the dress is a good example of different people perceiving colors differently since individuals can see it both ways.

> ... the misconception really is pervasively widespread, even among first-tier astronomy graduate students ...

Even first-year undergraduate astronomy students dont't think a star "is a colour" considering the useful information when dealing withs come from spectra, not photos.

Stellar classification on an H-R diagram is a convenience, that is all. It's already acknowledging "colour shift" from the Doppler effect (aka "red shifting"), but every first-year astronomy undergrad knows no two stellar spectra are the same, none are a single wavelength, and "white light" is a perceptual phenomenon not a physical one.

Reminds me of the minor controversy around the color of the Mars sky. Turns out that replicating perceptual color as it would be experienced by a person standing on another body or looking directly at it is not really that simple. Cameras designed for use on Earth are calibrated for a certain environment and even then you can get differences in how colors show up or are perceived on photos.

Turns out a person on Mars would sometimes see a bluish sky depending on how much suspended dust is present, the altitude, and the time of day.

May I recommend this weeks BBC "In Our Time" podcast on Solar Wind (I cannot link to it because my podcast app just throws up some html card thingy destroying 30 years of sanity / rant / moan)

As usual a deeply knowledgeable and enthusiastic set of guests and they were talking about this telescope and several other probes launched and due to be launched

well worth it

https://www.bbc.co.uk/programmes/m000dg9n

> Each night, a swimming pool’s worth of ice is emptied into eight tanks. During the day, coolant is routed through the ice tanks and distributed through the observatory by 7.5 miles (12km) of piping. More than 100 air jets are also positioned behind the main mirror.

Are they actually making a swimming pool's worth of ice cubes that are "emptied" into these tanks? I looked at the wikipedia page [0] for more information but there's no mention of the cooling system.

It sounds like a major part of the interesting engineering challenge, strange to not find photos or even a description of the cooling system's design.

[0] https://en.wikipedia.org/wiki/Daniel_K._Inouye_Solar_Telesco...

Yes - they actually make ice from the collected rainwater. Here's the paper with an overview of their cooling system: https://doi.org/10.1117/12.924592

Notably, the telescope enclosure is actively cooled to mitigate thermal seeing effects.

That was an interesting read, thanks!

The real question is, is the ice available for the scientist's cocktails? Can we express the total volume if ice in terms of Martini cocktail shakers?

Something I just realized while reading this article is that the Earth is only about 100 solar diameters from the Sun. This was completely out of proportion with my gut feel.

Edit: change "radii" to "diameters"

About 200 actually (you mistook the diameter for the radius).

https://www.wolframalpha.com/input/?i=1+au+%2F+radius+of+the...

Yes, you are correct. I meant diameters.

I presume you mean diameters, not radii.

Solar radius = 700000km Mean distance of Earth from sun = 1AU = 1.5e8 km = 214.3 solar radii.

From Earth, solar radius = 0.25 degrees. 233 solar radii in 1 radian.

Yep, I meant to write diameters.

> From Earth, solar radius = 0.25 degrees. 233 solar radii in 1 radian.

I don't understand this. I think I understand that the sun would take up 0.5 degrees of the "view" (I don't have a good word for this) when looked at from Earth, so radius is 0.25 degrees. But how does the second statement follow? I get that a radian is about 57.3 degrees, so 57.3 / 0.25 = 230, but why why does 1 radian make sense to use here?

An arc that spans one radian of a circle's circumference has the same length as the radius.

So if you imagine a connected line of 233 suns across the sky, spanning 57.3 degrees, the actual length of that line would be the same as the distance from your eyes to the sun.

If our sun was replaced by Betelgeuse, the earth would be inside the star:

    sun diameter = 1.3927 million km
    Betelgeuse diameter = 1.234 billion km
    Betelgeuse diameter / sun diameter = 886 > 100

The size of these stars is beyond mind boggling.

Similarly, the Moon is about 100 lunar diameters from the Earth. Hence the moon and sun look the same size in the sky, and both total and annular eclipses can happen.

It's weird I wrote some sun materials in the past, for a game, and I ended up roughly with that. What I based myself on was a sci-fi movie (can't remember), and they had it right. Can't really figure out why it looks that way though, anyone care to explain why it rises and drops like that? Is there anything like currents, or it's a straight up and down? Does the sun rotate at all or it's 'static' from our perspective? (I imagine it's rotating with the stars within our galaxy)

I know next to nothing about the sun but I think the article implies that it’s because of convection currents—closer to the center, plasma heats up and expands, rises, cools off, and falls back in. The picture looks vaguely like a Voronoi diagram too, which sort of fits as the plasma has to spread out of its own hot plume before sinking.

I had a similar comment about voronoi. Nature and science are beautiful.

Close. The Sun is not a fully convective star. Convection only occurs in the outer 30% or so. The inner part is called the radiation zone [1] and it is here that energy from fusion in the core makes its way out by radiative transfer as well as conduction. This is a very slow process compared to convection, taking more than 170,000 years for the photos produced by fusion to reach the convection zone.

[1] https://en.wikipedia.org/wiki/Radiation_zone

Wouldn’t we be observing the outer 30% (or 1%) though? From the diagram on the page you linked it seems that the granules in the photo exist in the photosphere, where convection is the dominant mode of energy transfer. That said, none of the conduction could happen without radiation further inside.

Yeah, we’re seeing the convection from the outer 30%, bubbling up on the surface of the photosphere. All of the fusion takes place down in the core though. It’s very difficult to fuse hydrogen and so it can only occur at the extreme pressures in the middle of the sun.

>a sci-fi movie (can't remember)

Sunshine, perhaps? https://en.wikipedia.org/wiki/Sunshine_(2007_film)

Brilliant, brilliant film. The premise is shonky as they come but it's obvious that the film itself has little to do with the premise. Awesome acting, literally-awesome SFX (their ability to give the sun so much weight is amazing, you really get a sense of an immortal unstoppable force), and a message that's neither shallow nor deep but prompts some self-reflection in ways you don't expect.

But at one point, they jump between two airlocks, and while in space for 10 seconds they become completely covered in ice and freeze to death.

I vaguely recall something about the making of the movie where they acknowledge that this wouldn't happen, but it was done because that's what the audience expects.

I always thought that would be a good opportunity to teach people, but I guess if you're in it to make money it makes sense to just pander to what audiences expect.

It's not about pandering or making money (did people go to the movie because they heard there was a scene where a guy freezes in space?????), it is entertainment.

It's absolutely about making money. Most movies are made primarily to make money. And the way to make money is to make it entertaining. Is it less entertaining if it's more realistic? In this particular example the answer seems to be, "yes."

My comment was from the view point of the creators (director, writer, and rest of the crew). There were better ways to make money in movies in 2007 then with a sci-fi space thriller inspired by Solaris and Alien.

To be more clear, I don't think the creators were thinking "will this scene make us more money", nor do I think it's their job. And on the topic of realism in a movie, unless it's a historical film or the goal is to educate, then realism should be near the bottom of the checklist when creating a scene.

Frustratingly, when the main character did exactly this in 2001: A Space Odyssey, the audience were frustrated because it was so unrealistic that someone would survive it (-_-)

I remember seeing the promo material for this film and thinking "nah I'll skip that one" and then I think a few years later I had a dull evening, found this film and really enjoyed it. After seeing it I recall thinking they really sold it short with the marketing, it was much better than I had expected.

Maybe I'll give it a shot. For me the premise occupies a sort of uncanny valley of realism: there's no space wizards or wormholes or FTL or aliens, but it's also not realistic enough to be something that could happen. It's kind of like that movie The Day After Tomorrow. It felt like there should have been some kind of mystical or supernatural force behind it all because it could never happen as presented, but they want it to come across as plausible.

No, it's nothing The Day After Tomorrow; the characters in sunshine aren't paper-thin stereotypes. I'd say it's a lot more like Interstellar - though all three involve "do or die" threats to the character to propel the plot, it's much more a drama working within the constraints of a proposed system, rather than a dumb big-budget thriller.

Great soundtrack too.

"[...] The gasses and plasma near the sun’s equator rotate around the sun’s axis every 25 days. As you move towards the sun’s poles, the rotation speed slows. Near the north and south poles, the sun rotates once every 36 days. That means the sun’s poles take 11 more days to rotate around the sun’s axis than its equator. The differing speeds of rotation is called differential rotation, meaning different parts rotate at different speeds. In fact, scientists divide the sun into four general sections and each section spins at a different speed.[...]"

https://nineplanets.org/questions/does-the-sun-rotate/

> Does the sun rotate at all or it's 'static' from our perspective?

It does, though not being a rigid body, the rate of rotation is a function of latitude. Near the equator, the period of rotation is ~24 days. As you near the poles, the period is closer to 30-35 days. A means of measuring these rates available to backyard astronomers is through measuring the positions of sunspots over time. [1]

[1] Please don't look at the sun through a telescope or really at all without knowing what you're doing and taking appropriate precautions: https://www.youtube.com/watch?v=R9cMXCemoJI

Not very weird, since the BBC video only illustrates resolution that's been available for the last decades.

Here's a really old picture that is at essentially the same scale as what the BBC decided to show, but made in 1997: https://en.wikipedia.org/wiki/Swedish_Vacuum_Solar_Telescope...

It's convection cells, not unlike water boiling in a kettle, the atmospheric circulation that gives us weather, or the ever-so-slow churning of solid rock in Earth's mantle that gives rise to volcanism and plate tectonics. The timescales are very different, though.

https://www.nso.edu/press-release/inouye-solar-telescope-fir...

Going to be a good decade for Sun observations because the Parker Solar Probe will make closer and closer passes around the Sun for the next 5 years. https://en.wikipedia.org/wiki/Parker_Solar_Probe

And the ESA Solar Orbiter: https://en.wikipedia.org/wiki/Solar_Orbiter

This is great. But I really hope to see close pictures of the Sun during my lifetime. And by close, I mean ultra high resolution pictures and footage taken from one million kilometers or closer. I want to see the grainy detail of these cell like structures.

Man, it says each of those cells is 30k km, imagine how quickly the plasma most be moving in there for the effects you see to happen.

Certain that is the case, but is it necessarily in real time?

It says each cell is the size of France. The resolution of the scope is 30km.

Yeah but how many Libraries of Congress is France across?

I want to know how many american football fields long it is, and how many olympic-sized swimming pools all that plasma would fill up.

Lots and... Lots.

https://www.wolframalpha.com/input/?i=size+of+france+%2F++ar...

Also, how many Hiroshimas of energy is emitted, and what is the CO2 equivalent in terms of global warming?

https://www.wolframalpha.com/input/?i=volume+of+sun+%2F+volu...

The article I read said each cell was the size of Texas. Which is it?

The same video is uncropped on nso.edu and shows a timestamp. Looks like it's sped up about 100x.

It's crazy how big it is.

https://www.nso.edu/wp-content/uploads/2020/01/full_image_wi...

That image covers an area 2.5x the size of Earth, but it's showing less than 0.1% of the Sun.

Does that mean that the material within those structures is moving at supersonic speeds? The video makes it look almost serene.

I wonder what the speed of sound is in the solar medium, at the ambient temperature and pressure.

About 7000 m/s on the surface.

> The observations could help resolve longstanding mysteries of the sun, including the counterintuitive feature that the corona – the sun’s atmosphere – is heated to millions of degrees when its surface is only 6,000C.

Is that really a "mystery"?

I mean, you can easily create plasma in a microwave oven, and the magnetron doesn't get very hot.

The magnetron does not produce the energy though. That's what makes the sun case counterintuitive.

I guess.

But consider that the total thermal energy of the Sun is negligible compared to the total energy flux. And that thermal conduction is way too slow, anyway.

Really, do the math. Take the sun's mass, and multiply by average absolute temperature and the specific heat of hydrogen. That'll be a huge number, but far less than the sun's energy output.

You could also compare energy output with what's possible through thermal conduction, based on the sun's radius, its density at various depths, and the heat transfer coefficient of hydrogen.

This news is stunningly correlated to my lecture this morning from Dr Bailey at Virginia Tech. The man was in Alaska finishing the launch of his sounding rocket for NASA.

The ideal gas law dictates these amazing structures of the solar atmosphere. But.... incredible cosmic magnetic powers influence these structures in the solar atmosphere... That we still can't explain.

Later I hope to discover alien life in the distributions of charged particles and their induced magnet fields... I may need to aquire another degree in the mean time.

#fields #studyhard

In Surface Detail, Iain Banks mentioned life forms based on stellar magnetic fields.

It also has an amusing ship mind, which presents as a young male sociopath: "Falling Outside The Normal Moral Constraints".

Does anyone know where I can find DC-blocked audiorate measurements of solar intensty / noise? Or alternatively forward me to an observatory that measures this?

It would be a source of background noise in the LIGO readings which were converted to audio, but I'm not sure how loud the sun is relative to other cosmic (and terrestrial) phenomena, and of course those clips are also going to feature a loud chirp from merging neutron stars and black holes.

https://www.ligo.caltech.edu/video/ligo20160211v2

Discussion 9 hours ago, The Guardian: https://news.ycombinator.com/item?id=22185565

We've merged that discussion hither.

Can't wait to see sunspots this close. What if they all have an angry face in them?

Reply on news.ycombinator.com