Billy Frankcom, age 12, Brockville, Ont., for his question;

Which planet is the hottest?

We would expect the planet nearest to the fiery furnace of the sun to get the most heat. And so it does. This fellow is little Mercury who circles around its oval‑shaped orbit in 88 days, Part of its short year is spent only 28,550,000 miles from the sun. The furthest it gets is 43,350,000 miles from the sun.

The diameter of Mercury is about one and half times that of our small moon. And, like our moon, it travels around with the same face always towards the center. One side of the moon forever faces the earth. One side of Mercury forever faces the sun. This means that one side of the little planet swelters in the heat of day. The other side is turned away from the sun to face, the endless night and bitter cold of outer space, lend poor little Mercury has no blanket of filmy air to protect it from the heat of the sun. or the cold of space.

The temperature on the dayside of Mercury is about 350 degrees Centigrade, which is hot enough to melt lead. The other is estimated to be a few degrees above minus 273 degrees Centigrade. This is the temperature of Absolute Zero which is as cold as anything can get. Hence the hottest planet is also one of the coldest ‑ for nothing can got any colder than Absolute zero, not even little Pluto.