Stella Luna, age 11, of La Habra., Calif., for her question:
Does the sun weigh more than all the planets?
It is hard for our minds to grasp the weight of the world, let alone the weight of the entire Solar System. So this calls for some stretching exercise. And what we must stretch is the old imagination. Let s begin by thinking about the total weight of our wonderful world.
Of course we cannot put the big old ball on the scales For any set of scales we know of must be considered as part of the weight of the world. Experts weigh the world by estimating the pull of gravity in relation to other heavenly bodies. They tell us the answer is in tons 6,570 followed by 18 zeros. This is six sextillion, 570 quintillion tons. Maybe you contribute about 100 pounds to this enormous weight. For it includes everyone on the earth, the inside of the earth and even the air above the earth.
Earth is but one of nine planets. Lots total up the weight of the rest of them. We shall need every ounce if the planets are to compete with the weight of the sun. Little Mercury weighs but a fraction of the earth. Our sister planet Venus weighs quite a bit less than we do. In fact, Mercury and Venus together weigh 0.87 as much as the earth. The weight of Mars, our other neighbor, equals 0,11 that of the earth. Giant Jupiter, however, weighs 312 times more than the earth. This big planet weighs more than all the other eight planets together.
Saturn weighs as much as 95 earth sized planets, Uranus weighs over 14.5, Neptune over 17 and distant Pluto weighs somewhat less than one earth sized planet. Added together, the weight of the nine planets equals the weight of about 450 earth type planets. This weight is tremendous. It is 450 times 6 sextillion 570 quintillion tons ‑ or thereabouts.
Lets imagine a pair of celestial scales. The enormous weight of the planets will go in one side. In the other side will go the weight of trio sun. And the sun, we are told, is a mass of burning gases. True, it is big, big enough to hold over a million earth sized planets. But gas is light, or so it seems to be on earth. Which side of the scales will bow under the greater weight? The sun or the planets?
The answer is the sun. In fact, the contest is hardly fair at all. For the entire weight of the planets is but a fraction of the weight of the sun. In fact there would be no contest if we included all the moons, the meteorites, the comets and every speck of floating dust between the planets.
On our imaginary celestial scales, the weight of the blazing sun is equal to the weight of 333,400 earths. Over 99 percent of the total weight of the Solar System belongs to the sun. In fact the sun contains 99 and 6/7 percent of the total mass of the Solar System.
The weighty world, the other planets, the moons, the meteorites, asteroids, comets and dust are made from what is lefty Of the total weight of the Solar System, these children of the sun have only one 700th part between them. Can you stretch your imagination to grasp those enormous figures? The total weight of the planets equals about 450 earths. The weight of the sun equals about 333,400 earths.