So much for the size of the solar system. It consists of a Sun and eight planets, and the outer planet's orbit is one of 5,584 millions of miles in diameter, which it would take an express train, at 60 miles an hour, 10,560 years to cross.
But this distance is as nothing when we come to deal with the distances of the other stars from our Sun.
The distance from our Sun to the nearest fixed (?) star is more than 20 millions of millions of miles. Our express train, which crosses the diameter of the solar system in 10,560 years, would take, if it went 60 miles an hour day and night, about 40 million years to reach the nearest fixed star from the Sun.
And if we had to mark the nearest fixed star on our chart made on a scale of 1 inch to the million miles, we should find that whereas a sheet of 465 feet would take in the outermost planet of the solar system, a sheet to take in the nearest fixed star would have to be about 620 miles wide. On this sheet, as wide as from London to Inverness, the Sun would be represented by a dot three-quarters of an inch in diameter, and the Earth by a pin-prick.
But these immense distances only relate to the nearest stars. Now, the nearest stars are about four "light years" distant from us. That is to say, that light, travelling at a rate of about 182,000 miles in one second, takes four years to come from the nearest fixed star to the Earth.
But I have seen the distance from the Earth to the Great Nebula in Orion given as a thousand light years, or 250 times the distance of the fixed star above alluded to.
To reach that nebula at 60 miles an hour, an express train would have to travel for 35 millions of years multiplied by 250—that is to say, for 8,750 million years.
And yet there are millions of stars whose distances are even greater than the distance of the Great Nebula in Orion.
How many stars are there? No one can even guess. But L. Struve estimates the number of those visible to the great telescopes at 20 millions.
Twenty millions of suns. And as for the size of these suns, Sir Robert Ball says Sirius is ten times as large as our Sun; and a well-known astronomer, writing in the English Mechanic about a week ago, remarks that Alpha Orionis (Betelgeuze) has probably 700 times the light of our Sun.