Observing the sun.

1. In case you can't see any sunspots on the surfice, I have an alternative observation for you to make: It is called Limb Darkening. Heard about it?
The edges of the solar disc -the limb- appear darker to the human eye than the center of the sun (the solar sphere actually), which appears more "illuminated". Can you guess why is that so?

Example: www.perseus.gr/Astro-Solar-Sunspots-2007-06-03.htm

2. This is a quiz!
Suppose a magical hand turns-off/shuts-down the thermonuclear fussion reactions in the solar core.
Assuming that the speed of light is 299,792.5 km/sec
and sun-earth distance is this week 147,608,219 km
When do you think an observer on earth, (ok, in the areas facing the shut-down Sun) will notice that the Sun has stopped shining?

Example: www.perseus.gr/Astro-Solar-Sunspots-2007-06-03.htm

HINT1: Don't answer 8 minutes, that's obviously wrong.
HINT2: Pick another unit of time, anything else EXCEPT minutes.

answer = 147,608,219 / 299,792.5 = 492.4 sec = 8.21 min

Good luck!

What does the winner get for a prize? A free trip to Novo?

The clock is running!

Lights out. Hey, who turned off the Sun? :mrgreen:

Is this a trick question?, as the light from the limb will take longer to reach us than the light from the centre of the disk.

Example: www.perseus.gr/Astro-Solar-Sunspots-2007-06-03.htm

Wrong answer, Anthony. :mrgreen:
I was expecting smth like en.wikipedia.org/wiki/Limb_darkening from you.

answer = 147,608,219 / 299,792.5 = 492.4 sec = 8.21 min

Way too wrong an answer, Anthony!!! :mrgreen:
Now you really disapointed me. It couldn't be any worse than that!
But I will let you make another try on this one .

What does the winner get for a prize? A free trip to Novo?

No, a Nikon body!!! :lol:

Lights out. Hey, who turned off the Sun?

Let's say the tunnel workers went on strike!


OK, it is the Tunnel Effect (quantum mechanics) that permits 2 protons to break the Coulomb Barrier and collide. This is the procedure that has been stopped by our magic hand, and the Sun seized to produce Helium (and light). The coulomb barrier became unpenetretable again.
Back to reality, the Coulomb Barrier is like a huge mountain which Hydrogen atoms (=protons+) is absolutely impossible to climb. The tremendous electromagnetic force repels protons(+) to come too close to each other. But, like a magic hand, the tunnel effect permits protons to magically appear on the other side of this collosal mountain, as if they have crossed a tunnel! From this point, since they have come close enough, the much stronger weak nuclear force takes the leadership and forces the protons to merge and the construction of Helium atoms proceeds. That is the reality! It is far more exotic than magic!

Is this a trick question?

Yes, it is a trick question, but wrong answer again, sorry. :mrgreen:

If you read my question carefully, and you are sober enough to walk in a straight line, + you study some solar interior physics, you can give the correct answer. :idea:
.

tik-tak, tik-tak, tik-tak, .....

Example: www.perseus.gr/Astro-Solar-Sunspots-2007-06-03.htm

Wrong answer, Anthony. :mrgreen:
I was expecting smth like en.wikipedia.org/wiki/Limb_darkening from you.

Komrad Vaggeli,

I provided an example of limb darkening. If you look closely at my example, komrad, you will see limb-darkening.

Anyway, my understanding is that we are looking at below the photosphere when looking at the limb (due to perspective) and where it is colder (ie. lower temperature). It is this lower temperature that mainfests itself as darker on white-light images.

answer = 147,608,219 / 299,792.5 = 492.4 sec = 8.21 min

Way too wrong an answer, Anthony!!! :mrgreen:
Now you really disapointed me. It couldn't be any worse than that!
But I will let you make another try on this one .

Would you also like us to consider how long it takes for the photosphere to "turn off" once the core has been "turned off" and then adding 8.21 min?

What does the winner get for a prize? A free trip to Novo?

No, a Nikon body!!! :lol:

You mean I just humiliated myself for a ... Nikon body?

Lights out. Hey, who turned off the Sun?

Let's say the tunnel workers went on strike!

OK, it is the Tunnel Effect (quantum mechanics) that permits 2 protons to break the Coulomb Barrier and collide. This is the procedure that has been stopped by our magic hand, and the Sun seized to produce Helium (and light). The coulomb barrier became unpenetretable again.
Back to reality, the Coulomb Barrier is like a huge mountain which Hydrogen atoms (=protons+) is absolutely impossible to climb. The tremendous electromagnetic force repels protons(+) to come too close to each other. But, like a magic hand, the tunnel effect permits protons to magically appear on the other side of this collosal mountain, as if they have crossed a tunnel! From this point, since they have come close enough, the much stronger weak nuclear force takes the leadership and forces the protons to merge and the construction of Helium atoms proceeds. That is the reality! It is far more exotic than magic!

Can someone translate for me? Anyone.

Is this a trick question?

Yes, it is a trick question, but wrong answer again, sorry. :mrgreen:

If you read my question carefully,

Bad assumption #1 ....

and you are sober enough to walk in a straight line,

Bad assumption #2 ....

+ you study some solar interior physics,

Bad assumption #3 ....

you can give the correct answer. :idea:.

Bad assumption (and conclusion) .... :mrgreen:

Komrad Vaggeli,

You write: "Suppose a magical hand turns-off/shuts-down the thermonuclear fussion reactions in the solar core." .... therefore, comments such as Coulomb barriers etc have little to no meaning.

Once we "shut-down the thermonuclear fussion reactions in the solar core", the photosphere WILL stop to glow and lights-out 8.21 minutes thereafter.

Will the Nikon body be sent by registered mail or courier?

Anyone else interested in a Nikon body at a good price? :mrgreen: