Comments on: Super hi-res sunspot

By: Ed

Ed — Tue, 07 Aug 2012 19:33:34 +0000

The penumbra looks like it could have been made from the brushstrokes of a Van Gogh painting. A “starry night” indeed. Or perhaps a sunflower analogy is more appropriate? Nice coincidence…or is it a painter’s presience? Bom bom BOM!

By: cosmogeist

cosmogeist — Mon, 06 Aug 2012 09:17:29 +0000

Hard to fathom each one of those ‘cells’ is roughly the size of a continent

By: Regner Trampedach

Regner Trampedach — Sun, 05 Aug 2012 04:50:48 +0000

Bart Declercq @ 3: Thanks for a beautiful picture of both sunspots and granulation. The quality can measure up to the best professional scopes! Well done!
MadScientist @ 9: I am afraid you are not quite right there. What you see there on the surface of the Sun is not waves. There are waves too, and looking up ‘helioseismology’ is always a good idea. But the waves are pretty hard to see, since they have small amplitude – easiest to see in Doppler (velocity) movies, but still very hard as there are thousands of (standing) modes superimposed on each other. You might be thinking of the noisy looking MDI images of the Sun. It can look like barely resolved granulation, but is in fact highly unresolved, with 5-8 granules per pixel. With MDI the granulations is lost, so you can see the waves – some are on very small scales. There is nothing wavy about granulation.
Granulation is what convection turns into at a sharp cooling surface, like the solar photosphere. Each cell has smooth warm upflowing plasma at the center, that cools at the surface, turns over and forms the cooler, turbulent downdrafts in the intergranular lanes. We see the granules at about 6400 K and the integranular lanes at 6000K. But you actually see deeper into the integranular lanes because of atomic physics: The plasma gets much more opaque at higher temperatures, so we can’t see nearly as deep in the granules as in the intergranular lanes (about 57km = 36mi difference).
Sorry for the long explanation – I actually run 3D simulations of these guys
Cheers, Regner

By: Charles Gaunce

Charles Gaunce — Sun, 05 Aug 2012 02:08:18 +0000

Isn’t the diameter of the earth roughly equal to 8000 miles?

By: MadScientist

MadScientist — Sat, 04 Aug 2012 23:16:57 +0000

@Greg#6: more like waves rather than grains (and with the right post-processing you can even have amber waves of grain), but ‘granular’ is commonly used to describe the appearance. Look up ‘helioseismology’.

Is there anyone out there who’s tracked a persistent sunspot group from limb to limb (and preferably a group near the sun’s equator)? Daily shots showing the rotation of the sun (and the tiny contribution of the revolution of the earth) are pretty neat.

By: Phil Seymour

Phil Seymour — Sat, 04 Aug 2012 21:26:34 +0000

@Bart – Thank you for your time, talent, and dedication to achieving such spectacular results. I look forward to seeing your ‘boiling sun’ video.

By: Tara Li

Tara Li — Sat, 04 Aug 2012 20:15:13 +0000

Awesome!

By: Greg M. Johnson (@pteranodo)

Greg M. Johnson (@pteranodo) — Sat, 04 Aug 2012 18:58:20 +0000

Grains!! in the surface of the sun. Wonder if there are any applications for metallographic principles in astronomy.

By: Klay

Klay — Sat, 04 Aug 2012 17:26:02 +0000

Its kind of surprising how similar this shot looks like a magnification of regular skin cells. All the slightly darker lines almost look like cell membranes, though I’m just assuming those are slight temperature variations.

By: Becky in Atlanta

Becky in Atlanta — Sat, 04 Aug 2012 17:18:39 +0000

The sun better have that looked at. It has asymmetry, an uneven border, variations in color AND it’s larger than a pencil eraser.

(Sorry…I couldn’t stop myself.)