Guest essay by Eric Worrall
Consider the following descriptions of three scientific theories. Which is the odd one out?
1. The buildup of anthropogenic carbon dioxide may lead to dangerous climate change, not because CO2 is a particularly powerful greenhouse gas, but because the slight warming caused by excess CO2 will cause sea water to evaporate, filling the atmosphere with water vapour. Water vapour is a far more powerful greenhouse gas than CO2. The evaporation of water vapour will trigger a chain reaction, a runaway greenhouse effect, in which global warming caused by the evaporation of ever increasing amounts of sea water forces yet more sea water to evaporate. In Dr. James Hansen’s words, “The oceans will begin to boil”.
2. We have already been visited by aliens, who most likely continue to monitor us. The alternative is to believe the preposterous proposition that we are the only intelligent life inhabiting any of the planets circling our galaxy’s 100 billion stars. The reason this must be true – all we have to do is look in the mirror. In a few decades, or at most a few centuries, humans will have the technology to build nanotech space probes the size of a grain of sand or smaller. Probes which can visit other stars, and transmit information back to us. Such probes are already on the drawing board.
Since the probes we shall build will be incredibly small, it will be possible to launch them at near light speed, for trivial economic cost. Scientists have even discovered ways such probes could be steered and decelerated as they approach their destination, using the Galactic magnetic field. If just one group of intelligent aliens in our galaxy of 100 billion stars reached our level of technology, at least half a million years ago, and made the decision to send out such space probes, then there has already been enough time for their high speed probes to reach our star system, and report back what they found.
3. Human lives are in danger right now, from asteroids and comets flying through space. As the shock advent of the Chelyabinsk meteor demonstrated, Earth can be struck unexpectedly at any time by meteors and other space bodies, many of which have the potential to cause widespread devastation. The Chelyabinsk meteor detonated with a force of 500 kilotons of TNT – it is only due to good fortune that the explosion, which caused some buildings to collapse and widespread damage and injuries from breaking glass, did not cause serious loss of life.
So which theory is the odd one out?
The answer is theory three of course. Unlike the other two theories, theory three is supported by observational evidence. The other two theories, however compelling they seem, are just speculation.
|Story Title||Separating fact from fantasy|
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