Astronomy Photographer of the Year 2022

[HansV]

Astronomy Photographer of the Year 2022 – winning images

[ChrisGreaves]

Astronomy Photographer of the Year 2022 – winning images

"The sunspots create two bands on the solar disc, around 15–35 degrees north and south of the equator"
Who knew?!!???

Apart from that, the number of images of the sun submitted counters the advice I was given with my first Kodak flash (with 2 rolls of B&W film, 12 exposures) "Never point your camera towards the sun".
Cheers, Chris

[Graeme]

Some excellent images there. The Jupiter image is a lot harder to do than it looks as Jupiter is really bright and the moons are really dim!

I went to view the submissions at Greenwich a few years ago when I was a member of the Royal Greenwich Observatory. Lots of brilliant entries.

"The sunspots create two bands on the solar disc, around 15–35 degrees north and south of the equator"
Who knew?!!???

I did! They start near the equator in pairs and migrate away from each other towards the poles as the Sun rotates because it rotates faster at the equator.

[ChrisGreaves]

"... around 15–35 degrees north and south of the equator"...
I did! They start near the equator in pairs and migrate away from each other towards the poles...

OKs Smarty-Pants I note that you said "towards" rather than "to" the poles, so why do they aggregate in that twenty-degree band at 15-35?

if they gravitate (in the general sense of the word) to that twenty-degree band, there must be a reason for that gravitation/clustering, and since, as Mister Puzey told us, "all there is is energy", it ought to be explicable in terms of energy.
That is, the sunspots have levels of energy that find equilibrium in that twenty-degree band.
But equilibrium with what? OK other sources of energy, obviously, but then that band must form as a band of rotational speed, or mass.

"Please explain; give diagrams wherever possible"

Then, why in (spatial?) pairs? What characteristic causes the pairings? Opposite rotational velocities of each sub-spot? What characteristic encourages pairs and not triplets?

Cheers, Chris
P.S. "I just noticed that you say "away from each other", which all makes it sound as if they start in pairs of equal magnitude of rotational velocity and separate into clockwise and anti-clockwise sunspots, but then do all the clockwise head north? Or is it sufficient that each pair of sunspots separate to different hemispheres? C
P.P.S. The term "the Coriolis force" springs to mind. C
P.P.P.S If you have to rejoin and become a member of the Royal Greenwich Observatory to get the answer, I can chip in $cdn5 towards the membership fees. C

[ChrisGreaves]

P.P.S. The term "the Coriolis force" springs to mind. C

And now that I think of it, this would make a great high-school exam question.
A projectile is fired due south from a point north of the equator.
As the projectile travels towards the equator it appears to be deflected towards its right (the "Coriolis effect").
The projectile crosses the equator and continues its passage away from the North Pole.

Does the projectile now appear to be deflected to its left, or is the apparent deflection continued to the right.

I offer this question up to any Lounge Member with teenage children.
Cheers, Chris
P.S. If such children are also brilliant in Maths A and Maths B, have them calculate deflections for some real values. C

[ChrisGreaves]

I did! They start near the equator in pairs and migrate away from each other towards the poles...

But now that I think of it a bit more, why do they start near the equator? Do they climb from the sun's centre and then surface at the equator, or do they form at the equator.
And I think sunspots are allied with electromagnetic fields, but a pair of spots cannot form two magnetic monopoles, because by definition a magnet has two poles. So perhaps it is an electrical force that creates them and nurtures them in isolation.
I wish this cold sweeping rain would stop so I can go outside and play ...
Cheers, Chris

[Graeme]

Because, Joy's Law

Also, top of the "sunspot pairs" search list:

https://eos.org/research-spotlights/wha ... spot-pairs

Also, if it's still raining, from the Monthly notices of the RAS:

https://academic.oup.com/mnras/article/ ... chresult=1

The pairs of sunspots behave according to Joy's Law because the Sun is a big ball of plasma that rotates at a rate of once every 25 days at the equator and almost 35 days at the poles. As for why they appear on the Sun's surface in pairs opposite the equator, I don't know!

Regards

Graeme

[PJ_in_FL]

Looking at the Eye of God photograph, I'm reminded of the short story "The Star" by Arthur C. Clarke. With bittersweet thoughts, I'll leave the rest to be connected by the reader.

[Graeme]

"The Star" by Arthur C. Clarke.

An excellent short story!