Don Gates, age 10, of Des Moines, Iowa, for his question:
Is there any time in outer apace?
Our wonderful satellites have made us all wonder about what is going on in the vastness of apace. Andy thinks that this is a very good thing, for it stretches and exercises the old mind. He alas thinks that Don ha,,: asked a very thoughtful question. He must have thought of it after he realized how we tell time on earth. We do this, of course, from the movements of the earth itself. Out in apace, our way of telling time would not count.
A day on earth is equal to the time it takes our world to awing around once on its axis about 4 hours. An earth year is the time it takes the earth to circle its orbit around the sun. Our earth, of course, is but one of nine planets orbiting the sun.
A day on Mercury is equal to 88 earth days and its day is the came length as its year. We do not know the length of a day on Venus for no one has even seen the face of this planet through its dense veil of atmosphere. The year on Venus is equal to only 225 earth days. The Martian day is a half hour r than ours, but its year is equal to almost two of our years. Giant Jupiter turns on its axis in ten hours, which means that a whole day and night would pass by while we were passing from noon to ten o'clock at night. Jupiter's year, however, is equal to, 12 earth years.
A day on Saturn is equal to only ten and a half hours, but its year is equal to 29 earth years. A day on Uranus is a little, but not much= longer than a day on Saturn but its year is equal to 85 earth years. Neptune's day is about 15 hours long but our earth makes 165 yearly orbits while this big cold planet is making only one.
These facts give you some idea of how confusing days and years can be on other planets. Perhaps we shall hate to cope with this when human colonists set out to make their homes on new worlds. The time we go by is a man made device based on the movements of our little earth. The people on other planets will have to work out their own time systems. When they want to check with us, we shall have to figure out the time differences much as we have to figure out the differences in time between Des Moines and San Francisco
Our Solar System, of course, is but a small item in the vast heavens. The nearest star to our sun is some 27 million, million miles away – and for all we know it too has a family of planets. Here we have distance on a grand scale and when it comes to time in outer space we have to think of it as distance. The nearest star to the sun is about 1 light years away. And a light year is the time it takes far light to travel one year Light travels at about 186,000 miles per second and a light year is a unit of both time and distance somewhat like miles per hour.