Perihelion and Aphelion (2009 July 3)

[smita]

Today's - July 3, 2009 - APOD
http://apod.nasa.gov/apod/ap090703.html

Does the proximity to sun affect the weather? By how much?

I think in the northeastern US, we are seeing the effect of it

Thanks.

[Chris Peterson]

Does the proximity to sun affect the weather? By how much?

Yes, global weather patterns are affected by the Sun's distance. Models used for weather and climate analysis consider as a primary input solar irradiance, which is determined in part by the distance to the Sun. Given the current orbit of Earth, northern summers and southern winters are slightly cooler then they would otherwise be. Our orbit changes, however, so over time the position of aphelion changes as well.

[smita]

Thanks for the info.

[Phil G]

Question:
When the distance sun to earth is listed, is that surface-surface or center-center?
Thanks

[The Code]

I think its an approximation.. because the actual distance changes...

Mark

[bystander]

When the distance sun to earth is listed, is that surface-surface or center-center?

The distance is large enough that the radius of the respective orbs is insignificant.

[BMAONE23]

Considering that the difference between perihelion and aphelion is roughly 5m k. The difference between surface distance and center distance (radii differential) is 701,373 k. So as bystander points out, the difference is likely negligible.

[Phil G]

Thank you all.
You have successfully made me feel much more significant
Peace,
Phil

[DavidLeodis]

It is a fascinating comparison. One thing though is causing me confusion.

The perihelion image is dated January 4th and the explanation states it was in 2008. The "on the date of" in the explanation is a link to perihelion and aphelion dates/times (under Universal Time). The periheion for 2008 is stated there to have been on January 3rd at 00 hours (the times will likely be rounded to a nearest hour). I'm probably wrong but doesn't that mean that perihelion was at the start of January 3rd 2008, as 1 hour earlier it would have been January 2nd whereas 1 hour later it would still have been January 3rd.