1972 and 1973, NASA sent two unmanned spacecraft on a one-way trip to the edge of the solar system and beyond, Pioneer I and Pioneer II. These two spacecraft were sent to take pictures of the gas giants and give us insight into their structure, they did their job, scientists oohed and aahed at the results, updated all the relevant textbooks, and moved onto the next big project in science. But because scientists are inquisitive, and care about the well-being of the Pioneer craft, they kept tabs on them, to make sure they stay fit and healthy. This was meant to be just a routine check-up every now and then, just to see how far they go, but physicists discovered something strange. The distance between where Einsteins physics predicted the spacecrafts should be and where they actually were was different. Somehow, the crafts where slowing down. Now, they amount of deceleration was very small, less than one nanometer per second per second, but this was enough for scientists to really consider revising physics books, because nobody could think of anything that would cause this extra deceleration.
For scientists, this was a prime time to witness a paradigm shift, something key to the process of science. Some may think that science is just a steady progress of learning about nature, but its not. It actually involves rapid changes of ideas most of the time, in so-called paradigm shifts. This is a stage in science which occurs when evidence comes up which is contradictory to current science. After new evidence shows up, there will be further investigation from scientists to try to figure out what is the correct model, if the first evidence is overturned, and science stays with the current theory, this is not a paradigm shift. When the evidence is confirmed and new evidence supports it, scientists will formulate a new model which accounts for this evidence, and this is known as a paradigm shift.
Paradigm shifts are very important to science, as they mean deeper knowledge of the universe. But a possible paradigm shift which turns out not to be one is good too, because it means that our current model is pretty good. Pioneer was worthy of study to find out if the physics textbooks needed a re-write.
For almost 30 years, there hasn’t been enough evidence to formulate a hypothesis either way, and it has been an unsolved mystery to science, often called the Pioneer Anomaly. But now, a team at the Jet Propulsion Laboratory in California have an answer. The team published a paper in Physical Review Letters in which they demonstrated that some electronic components on the craft where producing small amounts of heat, and the force imparted on the craft from this heat was enough to cause the deceleration. “I think it is solved for good” said lead author of the report Slava Turyshev.
Great! The mystery is solved. Just put this down as another proof of Einstein’s Gravity. As a good scientist, you should know that any result is a good result. Confirming evidence just means one more piece in the puzzle which proves our theories, contradicting evidence means new physics, which is also good.