[neilep (OP)]

Winter, Spring, Summer, Autumn (US Translation service "Autumn" = " Fall"....sheesh !!)...they're the main four seasons eh ?

I know the Sun has a twenty two (two x eleven years) year cycle of sunspot activity and I gather that.that may not constitute a ' season ' anyway......as we might know it.....so....does the Sun and the Gas Planets have Seasons ?....what about Mars too ?

Thanks


neil

[another_someone]

Planets do not have seasons - the hemispheres on a planet have seasons (i.e. that which is summer in the north, is winter in the south, but the whole planet never has a total season).  There is one slight caveat to that, insofar as the planets do not have an exact circular orbit around the Sun, for which reason the southern seasons are marginally more extreme than the northern seasons, since the Earth is slightly further away from the Sun during the northern summer (thus making it slightly cooler), which is also the souther winter (which makes that slightly cooler); and slightly closer to the Sun during the northern winter (making it slightly less cold), which the souther summer (making it slightly warmer).  This effect is only slight.

Any planet that is spinning on an axis that is not perpendicular to the plane of its orbit around the Sun will inevitably have seasons in its northern and southern temperate zones.  To a greater of lesser extent, this is true of all of the planets (the planets on Uranus must be pretty extreme, since it is tilted about 97.77° relative to its plane of orbit around the Sun).  Mars has a tilt of around 25.19°, compared to the tilt of the Earth of around 23.439281°, but the Earth's oceans and denser atmosphere will help reduce the impact of the seasons on the Earth.  Jupiter's tilt is only about 3.13°, so its seasons must be very mild; but Saturn has a more respectable 26.73° tilt, so it should have noticeable seasons.  The other issue with Saturn would be that it has, like the Earth, a hot interior, but is receiving much less sunlight, so I am not sure how much the surface temperature is dependent upon internal heating and how much upon solar heating.

Since the Sun does not orbit around the Sun, seasons in the sense they apply to planets would not be applicable to the Sun, although as you have noted, it does have internal cycles of activity.