It was my turn to entertain the people with a lecture on the basics of satellite remote sensing. Since our students have very different backgrounds, I explained everything very carefully. We started with a short survey just to make people think about the topic. The funniest question was probably one about the animal that had been first launched into the space. We started the lecture with a discussion on why it is possible to investigate the Earth’s surface and the atmosphere remotely. The main reason is that all bodies have a temperature above absolute zero (which is the “absolute” coldest temperature possible), so the molecules in them move and emit electromagnetic waves. Additionally, bodies can also absorb and reflect those waves. Then we discussed “active sensors,” which can emit this radiation and receive it, and “passive sensors,” which only receive and measure the radiation emitted by other bodies. It is of importance also that some sensors get images instantly (just like a digital camera), while others get images pixel by pixel (just like scanners in offices).
A funny thing happened when we were discussing satellite orbits. Florence proposed to build a model of a satellite moving along a sun-synchronous orbit. Satellites on these orbits always see each piece of the Earth’s surface at the same time of day. She needed two assistants to make the model. Thus our Summer School Director Vladimir became the Earth, while Ioana became a satellite. Soon came the idea that sunlight was also needed, so Florence got a flashlight to simulate it. Then in a similar way we also approximated a satellite moving along a geostationary orbit. On these orbits, satellites always see the same part of the Earth’s surface. It was a great fun to observe these simulations and the audience was laughing and enjoying it. Due to this funny demonstration we realized how complicated the movement of satellites and other bodies in the Solar system are.
– Svetlana Karimova
