Notes from a meeting
Ken Tapping, 26th November, 2015
I have just returned from a meeting on research into the interaction between the Sun and Earth. What consequences occur here on Earth as a result of things happening on the Sun? Do current scientific results indicate a connection between the Sun, environmental instabilities and climate change? The latest results support a conclusion from earlier studies; what is happening to our climate is not the Sun’s fault. Many issues were discussed at the meeting, but two stand out: one is for us to be a bit proud of and the other has a certain irony, where some scientists have come up with an application for a space environment problem.
In 1946 Arthur Covington, a scientist at NRC in Ottawa, used parts of wartime radar equipment to make Canada’s first radio telescope. His radio telescope was relatively insensitive by modern standards, and the only cosmic radio source it could detect was the Sun, so he and his team started a programme of using the instrument to systematically measure the intensity of the solar radio emission and how it varied over time. Because the radar equipment operated at a wavelength of 10.7 cm, so did the radio telescope.
Entirely fortuitously, this turned out to be the best wavelength for monitoring the Sun’s magnetic activity, which lies at the very foundation of the solar processes that affect the Earth. This led to Covington’s programme being continued to the present day, providing data daily to a world-wide community of industries, government agencies, researchers and others involved in activities that are sensitive to the Sun’s behaviour. It is known internationally as the 10.7-cm solar radio flux, or simply F10.7. Some of the impacts solar activity has on us are short-term, such as power outages and communication blackouts. Others are long-term, such as enhanced corrosion of oil and gas pipelines. As our lives get more dependent on power, communications and transportation infrastructure, our vulnerability to the Sun’s bad behaviour increases too. It was really exciting to see this “Made in Canada” data turning up in many presentations made at last week’s meeting. Over and over again, in meeting presentations our data were described as “of critical importance”.
The other issue concerns space junk: the bits and pieces left in orbit as a result of our activities in space. Since these nuts, bolts, fragments of metal, launcher rockets and dead satellites are all moving at around 30,000 km/h, they pose a severe threat to space operations, one to which we have no solution. We just try to minimize the addition of new junk while hoping the existing stuff eventually comes down into our atmosphere, where it will burn up. The US Air Force is tracking all objects bigger than about 10 cm. Since a ¼-inch nut can destroy a spacecraft this is not entirely reassuring. However, someone has come up with a use for it.
Over recent decades we have come to appreciate the importance of the Earth’s upper atmosphere. Hundreds of kilometres above the ground the air is far too thin to breathe; it is almost a vacuum. However, it is still dense enough to affect satellite orbits, absorb harmful radiation from the Sun and be an important part of the Earth’s climate and weather machine. Unfortunately it is not easy to study. Our F10.7 data can tell us what the Sun is doing to the upper atmosphere, but not in fine detail. To do this we need lots of small satellites that we would track by radar, measuring how the upper atmosphere changes their orbits. At first it was assumed that such a project would be unaffordable due to all the launches required, until someone suggested the satellites were already there, ranging in size and mass – just what was wanted. In short, space junk. This is not a justification for making more of it, but it shows that with imagination we can make use of anything.
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