The current widely-accepted view of science is that the Earth is only bombarded by about 300,000 tonnes of cosmic material per year. So when Dr Louis Frank and his colleagues made observations that they interpreted as a vast number of comet-like objects disintegrating as they hit the upper atmosphere they were startled. Conventional scientific wisdom told them these shouldn't exist.
After carefully examining all the evidence, they calculated that there were about ten million comet-like objects hitting the Earth's outer atmosphere each year, each one the size and weight of a small house. Since the mass of each of these comet-like objects was about 100 tonnes, the global mass accretion rate of comet-like material hitting the Earth amounted to 1,000,000,000 tonnes per year - vastly more than the current view of science.
Frank considered ignoring the evidence to avoid the controversy. Fortunately for us he didn't.
In his book, The Big Splash, Frank provides a very readable account of the astonishing investigations. At first they had thought the spots might be due to faulty instruments but after ruling out every possibility they could think of they had to face the fact that some sort of real event was causing the dark spots.
The likeliest candidate was vast amounts of water. Since the dark spots measured about thirty miles in diameter it amounted to about a hundred tons for each spot. The most likely explanation was relatively loose packed balls of water-snow comets breaking up as they hit the atmosphere, until they expanded into a thin ball of mist like gas some thirty miles across. The remnants of the small comet should continue down into the atmosphere until it slowed to subsonic speeds and finally mixed with the air in the upper atmosphere.
The big problem was the number of these objects. Every minute, twenty 100 tonne comets about the size of a house were slamming into the Earth's atmosphere.
If this rate was constant over the age of the Earth, the startling conclusion was enough water to fill the oceans.
Why had no one noticed this vast number of small comets? The answer given by Frank is that they are very difficult to observe and once they enter the atmosphere they mix with it and effectively disappear.
Man-made comet-like material was sent up by rocket into the upper atmosphere and produced the same dark spot on the ultraviolet images taken by the Dynamics Explorer satellite. This seemed to confirm the small comet explanation.
A dedicated search using a telescope found small dark objects in near-Earth space exactly where the ultra-violet images predicted. The rate of detection of these objects was the same rate as the atmospheric holes identified on the ultra-violet images from Dynamic Explorer satellite. It all fitted.
Frank describes how the number of small comets tended to strike a note of terror in other scientists.
Frank and his team believe future research will no doubt produce more surprises. This is only the beginning. I'm for one hoping he writes another readable account of those new investigations.
