Satellites are similar to the horizontally launched projectiles we looked at last week.  A satellite moves horizontally at constant speed but also accelerates vertically towards the planet’s surface due to gravity.  Thankfully, the curvature of the Earth means the satellite doesn’t crash but keeps on orbiting the planet.

According to SQA, National 5 candidates need to know about the

Impact of space exploration on our understanding of planet Earth, including use of satellites.

So far this week, we have covered many applications in which satellites are used to study our planet.  Examples include;

monitoring volanoes

weather forecasting
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climate change




Satellites are also used for communication. Some of these communication satellites are part of the telephone network, others broadcast tv signals back to Earth.  Most of these communication satellites are placed in a geostationary orbit.  At an altitude of 36,000 km, a satellite positioned above the equator takes 24 hours to complete one orbit of the Earth.  In other words, a satellite at this height always sits above the same spot on the Earth’s surface.  You don’t need to change the position of your Sky dish because the Sky satellite always sits in the same location in above the Earth.  It is a geostationary satellite.

If you were able to see the Earth from the perspective of a geostationary satellite, your view would look like this.

I have included a BBC programme on satellites.  Please take time to watch both parts (it was split in to due to the file size) during the October break; you’ll need just under an hour to see the full programme.

Feel free to ask questions or discuss the program when we’re back to school.

Watch this one first…

Satellites-part1 from mr mackenzie on Vimeo.

and then this one.

Satellites-part2 from mr mackenzie on Vimeo.

If you’d rather watch the programme in one sitting, you can download the video file attached to the bottom of this post.

If the weather’s rubbish during the holidays, here is another video about satellite monitoring of the planet

Enjoy your holidays!

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