Subject: How critical is the distance of the earth to the sun for life to exist?

As a child in the sixties, I remember being taught that if the earth was
just a little closer to the sun, no life could exist because the planet
would be too hot.  A little further away, and the planet would be too cold.
This has never quite made sense to me.  The earth's orbit is eliptical, and
varies as much as 4-5 million miles in distance each year.  The earth/moon
wobble varies in the thousands of miles.  Isn't the angle of the sun's rays
to the earth more crucial than the absolute distance in determining how hot
or how cold the planet is going to be?

Re: How critical is the distance of the earth to the sun for life to exist?