the take-off. (Two of his books, Rockets and Space Travel and Outer
Space, give fascinating and well-thought-out pictures of what we may
expect in years to come.)

Some authorities believe that our space travel will be confined to our
own solar system for a long time, perhaps forever. The trip to the
moon, though now a tremendous project, would be relatively simple
compared with a journey outside our system. Escape from the moon, for
the return trip, would be easier than leaving the earth; because of
its smaller mass, to escape the moon's gravitational pull would take a
speed of about 5,000 miles an hour, against 23,000 for the earth.
Navigation would be much simpler. Our globe would loom up in the
heavens, much larger and brighter than the moon appears to us. Radar
beams would also be a guide.

The greatest obstacle to reaching far-distant planet is the time
required. In the Project "Saucer" study of

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space travel, Wolf 359 was named as the nearest star likely to have
possibly inhabited areas. Wolf 359 is eight light-years from the
earth. The limiting speed in space, according to Einstein's law, would
be just under the speed of light--186,000 miles per second. At this
speed, Einstein states, matter is converted into energy. It is a
ridiculous assumption, but even if atomic power, or some force such as
cosmic rays, made an approach to that speed possible, it would still
take eight years to reach Wolf 359. The round trip would take sixteen.

There have been a few scientists who dispute Einstein's law, though no