Did the apparent magnitude of the Sun change in the past 1000 years or so? If so, for what reasons?
$\begingroup$
$\endgroup$
1
-
$\begingroup$ @Jan Dvorak. Absolutely correct. I assumed questioner was looking for a variation due to the sun itself. A bad assumption on my part. I will update my answer after I determine difference. $\endgroup$– NatsfanJun 19, 2017 at 20:38
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
4
No. The apparent magnitude of the sun is constant to within 0.2% How long it has been that way is only speculation since measurements aren't available. 1000 years is a very short time period in the life cycle of a star. Its safe to say yes its been constant for 1,000 years. There is a small variation based on the 11 year sun spot cycle but this variation is reported at less than 0.1%. There is also a larger variation due to the difference in Earth-to-Sun distance caused by the earths elliptical orbit. This effect is about 7%. This is no due to the sun but rather due to the eccentricity of Earths orbit. There are also minor effects with a cycle time or much greater than 1,000 years. These also due to variations in Earths orbit.
-
1$\begingroup$ Don't discount the variation due to Earth's orbit eccentricity. $\endgroup$ Jun 19, 2017 at 20:33
-
$\begingroup$ @Jan Dvorak. Absolutely correct. I assumed questioner was looking for a variation due to the sun itself. A bad assumption on my part. I will update my answer after I determine difference. $\endgroup$– NatsfanJun 19, 2017 at 20:39
-
$\begingroup$ Could you add how the brightness of the Sun 1000 years ago is known? $\endgroup$– ProfRobJun 20, 2017 at 6:39
-