Its size made it hard to find and thus still more of an achievement. But Tombaugh continued the search for seventeen weary years and many millions more films. If there is an Earth - size planet out there, it is at least three times as distant as Pluto, and a gas giant would have to be six times as far. Negative data win no prizes but they are the bedrock of science.
Until James W. Christy on 22 June 1978 discovered Pluto's satellite, Charon, it was possible for us romantics to entertain the happy thought that Pluto was loaded with valuable heavy metals; the best estimate of its density made this plausible. But the mass of a planet with a satellite can be calculated quite easily and accurately, and from that, its density.
The new figure was much too low, only half again as heavy as water. Methane snow? Perhaps.
So once again a lovely theory is demolished by an awkward fact.
Nevertheless Pluto remains a most mysterious and most intriguing heavenly body. A planet the size and mass of Mars might not be too much use to us out there ... but think of it as a fuel dump. Many stories and many nonfictional projections speak of using the gas giants and/or the rings of Saturn as sources of fuel. But if Pluto is methane ice or water ice or frozen hydrogen or all three, as a source of fuel - conventional, or fusion, or even reaction mass - Pluto has one supremely important advantage over the gas giants: Pluto is not at the bottom of a horridly deep gravity well.
Finished calculating? Good. Please turn to page 368 and see why I wanted our trip to Pluto to be a distance of 31.6 A.U. - plus other goodies, perhaps.
11. 1950 Your personal telephone will be small enough to carry in your handbag. Your house telephone will record messages, answer simple inquiries, and transmit vision.
1965 No new comment.
1980 This prediction is trivial and timid. Most of it has already come true and the telephone system will hand you the rest on a custom basis if you'll pay for it. In the year 2000, with modern telephones tied into home computers (as common then as flush toilets are today) you'll be able to have 3 - dimensional holovision along with stereo speech. Arthur C. Clarke says that this will do away with most personal contact in business. I agree with all of Mr. Clarke's arguments and disagree with his conclusion; with us monkey folk there is no substitute for personal contact; we enjoy it and it fills a spiritual need.
Besides that, the business conference is often an excuse to loaf on the boss's time and the business convention often supplies some of the benefits of the Roman Saturnalia.
Nevertheless I look forward to holovideostereophones without giving up personal contacts.
12. 1950 Intelligent life will be found on Mars.
1965 Predicting intelligent life on Mars looks pretty silly after those dismal photographs. But I shan't withdraw it until Mars has been thoroughly explored. As yet we really have no idea - and no data - as to just how ubiquitous and varied life may be in this galaxy; it is conceivable that life as we don't know it can evolve on any sort of a planet... and nothing in our present knowledge of chemistry rules this out. All the talk has been about life - as - we - know - it - which means terrestrial conditions.
But if you feel that this shows in me a childish reluctance to give up thoats and zitidars and beautiful Martian princesses until forced to, I won't argue with you - I'll just wait.
1980 The photographs made by the Martian Landers of 1976 and their orbiting companions make the prediction of intelligent Martian life look even sillier. But the new pictures and the new data make Mars even more mysterious. I'm a diehard because I suspect that life is ubiquitous - call that a religious opinion if you wish. But remember two things: Almost all discussion has been about Life - as - we - know - it.. . but what about Life - as - we - don't - know - it? If there were Martians around the time that those amazing gullies and canyons were formed, perhaps they went underground as their atmosphere thinned. At present, despite wonderful pictures, our data are very sparse; those two fixed Landers are analogous to two such landing here: one on Canadian tundra, the other in Antarctica - hardly sufficient to solve the question: Is there intelligent life on Sol III?
(Is there intelligent life in Washington, D.C.?)
Whistling in the dark - I think I goofed on this one. But if in fact Mars is uninhabited, shortly there will be a land rush that will make the Oklahoma land stampede look gentle. Since E = mc2 came into our lives, all real estate is potentially valuable; it can be terraformed to suit humans. There has been so much fiction and serious, able nonfiction published on how to terraform Mars that I shan't add to it, save to note one thing:
Power is no problem. Sunshine at that distance has dropped off to about 43% of the maximum here - but Mars gets all of it and gets it all day long save for infrequent dust storms ... whereas the most that Philadelphia (and like places) ever gets is 35% - and overcast days are common. Mars won't need solar power from orbit; it will be easier to do it on the ground.
But don't be surprised if the Japanese charge you a very high fee for stamping their visa into your passport plus requiring deposit of a prepaid return ticket or, if you ask for immigrant's visa, charge you a much, much higher fee plus proof of a needed colonial skill.
For there is intelligent life in Tokyo.
13. 1950 A thousand miles an hour at a cent a mile will be commonplace; short hauls will be made in evacuated subways at extreme speed.
1965 I must hedge number thirteen; the "cent" I meant was scaled by the 1950 dollar. But our currency has been going through a long steady inflation, and no nation in history has ever gone as far as we have along this route without reaching the explosive phase of inflation. Ten - dollar hamburgers? Brother, we are headed for the hundred - dollar hamburger - for the barter - only hamburger.
But this is only an inconvenience rather than a disaster as long as there is plenty of hamburger.
1980 I must scale that "cent" again. In 1950 gold was $35/troy ounce; this morning the London fix was $374/troy ounce. Just last week my wife and I flew San Francisco to Baltimore and return. We took neither the luxury class nor any of the special discounted fares; we simply flew what we could get.
Applying the inflation factor - 35/374 - our tickets cost a hair less than one cent a mile in 1950 dollars. From here on I had better give prices in troy ounces of gold, or in Swiss francs; not even the Man in the White House knows where this inflation is going. About those subways: possible, even probable, by 2000 A.D. But I see little chance that they will be financed until the dollar is stabilized - a most painful process our government hates to tackle.
14. 1950 A major objective of applied physics will be to control gravity.
1965 This prediction stands. But today physics is in a tremendous state of flux with new data piling up faster than it can be digested; it is anybody's guess as to where we are headed, but the wilder you guess, the more likely you are to hit it lucky. With "elementary particles" of nuclear physics now totaling about half the number we used to use to list the "immutable" chemical elements, a spectator needs a program just to keep track of the players. At the other end of the scale, "quasars" - quasi - stellar bodies - have come along; radio astronomy is now bigger than telescopic astronomy used to be; and we have redrawn our picture of the universe several times, each time enlarging it and making it more complex - I haven't seen this week's theory yet, which is well, as it would be out of date before this gets into print. Plasma physics was barely started in 1950; the same for solid - state physics. This is the Golden Age of physics - and it's an anarchy.
19801 stick by the basic prediction. There is so much work going on both by mathematical physicists and experimental physicists as to the nature of gravity that it seems inevitable that twenty years from now applied physicists will be trying to control it. But note that I said "trying" - succeeding may take a long time. If and when they do succeed, a spin-off is likely to be a spaceship that is in no way a rocket ship - and the Galaxy is ours! (Unless we meet that smarter, meaner, tougher race that kills us or enslaves us or eats us - or all three.)