Paula Gauthier, Age 11, Of Oramocto, N.B., for her question:
How does science know there are other solar systems?
Galileo proved that the sun is the center of our solar system and his generation did not like the idea. It was hard to give up the notion that our world was the center of the universe. In time, people settled for the idea that ours was the only system of planets. Now science has found that a star only six light years away has a planet.
There are about 100 billion stars in our galaxy, and there are millions of other starry galaxies in outer space. It would be big headed to suppose that our sun was the only star with a family of planets. For several years, astronarners have had enough eviderice to suggest that three other stars may have solar systems like our own.
The nearest suspect was Barnard's star, the second closest star to our sun. In April., 1962, astrononers announced that this small star is orbited by an invisible body which could be a planet or a dark star. It might, they said, take five years to solve the problem but it took only one year. In April, 1963, it was announced that Barnard's Star is orbited by a planet: our solar system has a neighbor.
The planetary detective work was done with the help of telescopic photographs. Yet the planet appears on none of these plates. Barnard's star is only six light years, or 36 million million miles away. Since 1916, its motions have been checked against the fixed background of more distant stars. The small star has a wobbling motion caused by the gravitational pull from some orbiting body. Detailed measurernents proved that the wobbling motion is caused by a whopping planet.
The planet of Barnard's star weighs 427 times more than our earth and orbits its sun once in 24 earth years. Its surface is colder than 300 degrees below zero. Scientists took exact measurements of the star's wobbling motion. Then they estimated the size and orbit of the planet causing this motion, yet it has never been seen or photographed.
The brightness of heavenly bodies is measured on a scale of magnitude. Our eyes can see thin stars of the 6th magnitude, and our best telescopes can photograph stars of the 23rd magnitude. Barnard's star is 10th magnitude much too dim to be seen. The planet of Barnard's Star is estimated to be magnitude 30, which is too small to be photographed.
The constellation Scorpio sprawls over the summer skies, and the big red star antares at the heart of the scorpion is magnitude 1.2 North of Scorpio is the tent shaped constellation ophiuchus. Here, though your eyes cannot see it, are Barnard's star and its planet. Traveling at the speed of light, a space ship could reach our neighboring solar system in just six years.
Recent observations and calculation indicated there are numerous stars with planetary systems.