Zooming into the Sun with Solar Orbiter | Hacker News Reader

Zooming into the Sun with Solar Orbiter

esa.int

96 pointsmhb42 comments

Original here: https://www.esa.int/ESA_Multimedia/Images/2022/03/The_Sun_in...

"a mosaic of 25 individual images is needed to cover the entire Sun. Taken one after the other, the full image was captured over a period of more than four hours because each tile takes about 10 minutes"

I would love to hear a bit about how movement captured across tile boundaries over the course of four hours was handled when stitching the pano. AI and/or human retouching could be involved which, IMO, are both acceptable to get such an amazing image. Just curious!

I think here I'd like to hope they correct it by using theoretical orbital models instead of AI (well, or a human really), I'd be very worried about that training set =)

Easy to miss: Earth to scale in the top right of the photo.

And to think there are stars in our galaxy that would dwarf our Sun to the same degree! Pale Blue Dot indeed...

I can recall seeing a research poster for something to do with brightness fluctuations of red giants. Just as an aside was an image of a red giant absolutely dwarfing Earth's orbit several times over. As in, if it were in the center of our solar system, Earth would be inside the star.

Even crazier is that these stars aren't actually much heavier than the sun, they're just that much less dense.

I can't believe that this is the highest-resolution photo of the sun that ESA has taken. Surely earth-based telescopes have done better?

A guy in his backyard takes pictures with similar resolution: https://twitter.com/AJamesMcCarthy/status/147297870519032217... (downscaled for Twitter, approx 9Kx9K / 81Mpix on his Patreon feed)

Make sure to look at the high resolution 50+ MB image and zoom in.

You can take an arbitrarily high pixel count photo of anything with enough cameras side by side. But this is exciting (to scientists) because it’s taking the photos in specific wavelength and outside of the Earth’s atmosphere.

The part that is confusing is highest resolution (1) full-disk and (2) outer atmosphere: (1) "Full-disk" is clear to understand: the higher the resolution, ^2 the work to make it also full-disk (especially when the Sun rotates differentially and evolves in high-cadence, so you gotta be fast. (2) "Outer atmosphere" is also tricky as only few wavelengths see the outer atmosphere. The vast majority of the light comes from the "surface" or photosphere (hence the name). In this case surface, the highest resolution is roughly 0.05 arcsec or 50km/pixel. But to see the outer parts, you have to do to emission of elements like Iron that only emit when highly ionized and super high temperatures (those are the special characteristics of the sun's outer atmosphere... yes, it's way hotter than the surface, just WAY less dense). Those emissions happen in the Ultraviolet, 17 nanometers, like the caption says. That's like 50 times smaller wavelength. Angular resolution is proportional to wavelength (1.22*wavelength/Diameter) which is on the order of 1000 km/pixel (but linear resolution makes less sense since the atmosphere is such a 3D shape... it's better to say 1 arcsec of resolution).

I might be too biased (I'm a solar physicist) but the explanation above makes the image way cooler and they should have added it): The most detailed image of the Sun's metal corona :D

The other comment goes into much cooler detail, but if it isn't clear, the reason they needed telescopes in space is because the UV they were detecting can't penetrate the atmosphere. At 17nm you're well into the "vacuum frequencies", just a little away from proper ionizing radiation.

We changed the URL from https://kottke.org/22/04/the-highest-resolution-photo-of-the..., which points to this.

I really love the compilations by Sean Doran of our Sun -- https://www.youtube.com/watch?v=FI0oVK4Pa44 for example. Perfect ambient background video.

If only there was a way to safely and economically send Earth's garbage into it!

You mean humans?

How edgy. You first, m'kay? Together with the telephone cleaners, middle managers etc. Don't wait for us, we need clean telephones when we arrive.

It would be easier to send the garbage to the moon, Mars, or even Jupiter. With enough Delta-V we could atomize garbage on impact to the moon.

Couldn't we just aim something in the right direction, give it a little thrust, and then forget about it? There's no rush after it has left earth.

Don't know, but I don't think we'd want mountains of trash (whatever its composition) to wind up orbiting Earth. AFAIK a lot of energy/thrust/velocity is necessary to escape Earth gravity altogether. I'd guess launching stuff into deep space is expensive. Considering how much trash humans generate, well, space disposal isn't practical.

Besides "trash" could be a useful resource. To some extent it's already done. Some is convertible to energy. Other fractions (plastics, metals) recycled to make new stuff, etc. Could these uses be extended? I can't say, but more R&D is likely a better investment vs. rocketing trash away.

> AFAIK a lot of energy/thrust/velocity is necessary to escape Earth gravity altogether.

I was responding to the claim that it would be easier to send trash to Jupiter, etc. than the sun. Yes, escaping Earth's gravity in the first place would be a major expense.

> I don't think we'd want mountains of trash (whatever its composition) to wind up orbiting Earth.

While I probably agree, there is a lot more room up there than down here!

It takes more energy to hit the sun than it does to escape the solar system entirely. Earth's orbital velocity is closer to solar escape velocity than it is to 0 (or any velocity for an orbit with a periapsis that intersects Sol and an apoapsis at Earth's orbit).

yes, for example it would take about 55 times more energy to get something to the sun than it would to get it to mars

Thanks, but why?

For both Mars and the Sun, we need to escape Earth's gravity, so the energy seems roughly the same there.

If we direct an object at the Sun or Mars, with the same momentum, it will eventually get to either. What is the difference?

If you mean it takes 55 times more energy to get to the Sun or Mars in the same fixed time interval, that I could see. (For our theoretical space trash, the start of this subthread, it doesn't matter how long it takes.)

You're forgetting that we're all orbiting around the sun.

Just escaping earths gravity puts you an orbit around the sun at the same distance as earth. With a bit more speed you get into an orbit a bit closer or further depending on the direction you took. More explanation with more exact numbers: https://space.stackexchange.com/a/45619

So the issue is that an object would have to be slowed considerably (relative to the Sun) in order to hit it?

Exactly.

> While I probably agree, there is a lot more room up there than down here!

Even I can pick up the joking intent here, but just for others reading, the issue with stuff in space isn't physical volume. The problem is intersecting orbits. Even if we had the lift capacity for it, there aren't enough orbits to put all our garbage in without causing collisions and probably Kessler Syndrome. There's orders of magnitude more garbage than satellites we could ever want.

Right, agreed!

If you can atomize garbage it'd be useful as reaction mass for some space transport - one step closer to Mr. Fusion from Back to the Future.

> It would be easier to send the garbage to the moon, Mars, or even Jupiter.

Indeed it would be easier to send it flying out of the solar system completely.

all those resources... being destroyed.

what a waste that would be.

Why does the sun have such a clear boundary, in this photo? Is there an actual surface of stuff where matter changes phase or density, and over what kind of distance does that change happen?

More or less, yes - the googlable term for it is 'photosphere'

https://en.wikipedia.org/wiki/Photosphere

there's also a bit of an illusion of scale, you're looking at bumps and protrusions that are multiple-earth-diameters-sized.

Thank you! I suppose the spherical shape around a gravity well, from where the majority of an object’a photons originate, is correctly called a photosphere.

I am currently standing on Earth’s photosphere!

It is a mosaic with 25 images captured over the course of 4 hours.

You can see the Human Torch on the top left.

I found he too myself)

That blog has one of my favorite posts:

https://kottke.org/17/05/the-struggle-with-the-self

I didn't expect it to be this lackluster and ugly.

Are you my mother?

Interesting. I'm looking at the same image and find it stunningly beautiful. De gustibus non est disputandum, I guess.

You find the sun to be lacking in luster? Rather ironic...

You know what, we need more of your energy. Screw nature, we can aspire to something better

Reply on news.ycombinator.com