I off-handedly chose Mars as a subject for investigation, basically because there have been several missions to the Red Planet in the past 5 years. Those missions were expensive, they were designed to gather knowledge about Mars... so if human knowledge is doubling every 5 years in any given sector, we might imagine that one of the sectors is Mars. Well, I actually have an ulterior motive, but that's for the end of this post.
The Exploration of Mars is beautifully detailed on Wikipedia. The first probe to actually get close to Mars was in 1962, the Soviet mission Beta Nu 1. It was followed by the US Mariner 4 in 1964. So we have been collecting data from space missions for 45 years. The 1996 Mars Global Surveyor effectively returned more data than all previous missions combined, and the data is available to the public.
The Mars Pathfinder landed on Mars on July 4, 1997, and a remote controlled rover called Sojourner decamped from the lander and went walkabout. Pathfinder returned 16,500 images from the lander and 550 images from the rover, as well as 15 chemical analyses of rock and soil and extensive data on winds and weather. This was followed by a spate of unsuccessful attempts to return to Mars.
In 2001 the run of bad luck ended when NASA's Mars Odyssey orbiter arrived. Its mission is to use spectrometers and imagers to hunt for evidence of past or present water and volcanic activity on Mars. In 2002, it was announced that the probe's gamma ray spectrometer and neutron spectrometer had detected large amounts of hydrogen, indicating that there are vast deposits of water ice in the upper three meters of Mars' soil within 60° latitude of the south pole.
NASA sent a pair of twin rovers toward the planet as part of the Mars Exploration Rover Mission. On 10 June 2003, NASA's MER-A (Spirit) Mars Exploration Rover was launched. It successfully landed in Gusev Crater (believed once to have been a crater lake) on 3 January 2004. It examined rock and soil for evidence of the area's history of water. On July 7, 2003, a second rover, MER-B (Opportunity) was launched. It landed on 24 January 2004 in Meridiani Planum (where there are large deposits of hematite, indicating the presence of past water) to carry out similar geological work.
Mars Reconnaissance Orbiter is a multipurpose spacecraft designed to conduct reconnaissance and exploration of Mars from orbit. The $720 million USD spacecraft was built by Lockheed Martin under the supervision of the Jet Propulsion Laboratory, launched August 12, 2005, and attained Martian orbit on March 10, 2006.
The MRO contains a host of scientific instruments such as the HiRISE camera, CRISM, and SHARAD. The HiRISE camera is used to analyze Martian landforms, whereas CRISM and SHARAD can detect water, ice, and minerals on and below the surface. (In case you haven't guessed, I'm just copying from Wikipedia here.)
Now, the Wikipedia article on Mars itself is quite long. It contains very little material that could have been written before the past 45 years--the planet was mapped in 1840, some basic astronomical information has been long known, but almost all of what Wikipedia thinks is important is recent, and most of it really, really recent. Of the 79 citations at the bottom of the article, 30 were written after 2004.
So I'm ready to admit that human knowledge about Mars has doubled every 5 years since 1962. I'll be searching for more evidence to back this up. But here's my ulterior motive: I think that new sectors, or sectors that have big money thrown at it, or sectors where there is a clear public good to be obtained from applied research, might well indeed experience exponential increases in knowledge. But are they sustained? Does knowledge gained transfer readily to similar sectors? (Do we, for example, know as much about Venus or Mercury?) If new knowledge gained in the past 5 years about Mars (and I include getting to Mars, data collection design, etc.) leads to similar increases in knowledge about other planets in our solar system, then I think we're on to something here.
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