I must admit I wasn't sure whether he was still alive until I saw this. I've read a couple of his books, they were pretty good.
On the topic of geostationary satellites, which he invented, along with solar sails*, from the point of view of somebody standing on The Moon, Planet Earth is a geostationary satellite. Not many people know that!
* He had a bit part in inventing radar as well.
Nothing subtle about it
1 hour ago
5 comments:
He invented MMORGs too, in "The City and the Stars".
Are you sure about that? Surely an object has to orbit around something before it can be called a satellite. The earth may appear to be geostationary (lunarstationary?) from the moon, but it isn't really.
Yes. Think about it!
Wherever you are on earth, you only ever see one side of the moon. Ergo, if you are standing on the side of the moon that faces earth, let's say with earth straight overhead, earth is always straight overhead. It's like standing on earth and looking at a geo-stationary satellite straight above you. The satellite is not orbiting around the earth any more than a fixed point on earth is orbiting around the earth.
Alternatively, I could argue, the moon turns on its own axis (it has night and day, same as earth, only a lunar day is about 28 days, so it must be turning). So from the point of view of the moon, the earth is orbiting also once every 28 days, at exactly the same speed at the moon turns on its own axis.
The relative sizes of earth and moon are such that they are more like a double planet that revolves around a point somewhere between (a bit like a giant bola), than a planet with a satellite. Hence why we have tides.
So lets build the Severn barrage and put a stop to this state of affairs, Mark.
I doubt whether the Severn Barrage will affect the Moon's orbit, but it must be worth a try, I suppose.
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