On our approach to landing at Melbourne airport just after sunrise while aboard a commercial airplane I noted moving on the clouds at the same speed as the plane a circle of light with a rim of bright light and an outer rim of red light (see photo). On occasion I saw the shadow of the airplane within this circle of light.  It seems that this circle of light was from the rays of light from the rising sun and that they were being distorted by the airplane. What was happening?

This photo was taken by my neighbour in Tucson, Arizona, facing west at sunset. What is the peculiar light phenomenon?

Jeannette Hanby, Tucson, Arizona, US

I understand that on earth we feel the heat of the Sun because it radiates light to earth which then gets trapped within our atmosphere and gives out heat.  Space, being a vaccum, would contain no heat as there is no matter to conduct the heat of the Sun, so how close could you get to the sun before you would feel any heat from it?  Also would the sun not be able to radiate heat in the form of light to human skin in the same way as it radiates heat to the earth?

Many Thanks

James Stretton (Colchester)

Can light go faster, or slower, than light speed? If so, what do we call that speed?

A man looks at a small lit lightbulb, 5m away. He perceives it as being of a certain luminosity.

A woman looks at the same bulb from a different point 5m away. All things being equal, she will perceive it as having the same luminosity.

There are an infinite number of points from which the bulb could be observed. Does that mean the bulb actually has infinite luminosity?

I have five solar-powered lights in my garden. Something has spun silken masses inside their battery compartments, and in all five lights they are located at the negative terminal of the battery (see photo).

Is there a reason for this, or is it just coincidence?

Allen Lutins, Johnson City, New York, US