It is way beyond luck that we live where we do. This planet of ours is in the right place to sustain life as we know it. And life it has in every shape and size and located in every nook and cranny on the land and in the sea. The location of planet Earth is just inside the habitable zone of our nearest star, the Sun.
What is a “habitable zone”? Scientists describe it as a zone that allows liquid water to exist on a planet. Or words to that affect. I would just say that it is the area around a star that life can survive.
Now that doesn’t mean that we will always be safe. Notice that I said “just” inside the habitable zone? We are very close to the hottest edge of the “zone” and we better hope that nothing makes us move to a tighter orbit or that the sun doesn’t speed up its slow expansion. Yes, the sun is now slowly expanding and getting brighter. The key word here is “slowly”.
Here is a picture that was taken from “Astronomy” magazine showing the sun, the habitable zone, and the orbits of the four planets that are closest to the sun:
As you can see, Earth is the only planet that stays within the zone for its complete orbit. But notice that the orbit is close to the hot side and at part of its orbit, it gets very close to leaving the zone. That would put us in a very precarious position, especially since the sun is growing larger.
All sorts of things can happen to change orbits. Although space is almost empty, it does contain matter and other things like the solar wind, cosmic radiation, and other forces that act ever so slightly on the earth. This orbital friction can slow a planet and decrease its orbit which will, in turn, allow it to keep its momentum. The moon is moving away from us, and we are constantly being bombarded with stuff from space, hopefully all small stuff and hopefully not enough to change our velocity or mass.
Of course, we are also lucky that we are on the hot side of the zone. Just think how cold this winter would have been if we were way out there on the cold side?!?!