Quote:
Originally Posted by The Bad Astronomer
...Without a reference point, the statement is meaningless. And in this case, by stating it as a fact, the statement is wrong.
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If a person said that the hands of a clock move clockwise, would you consider that statement to be meaningless and wrong as well?
I'm inclined to agree with Cevlakohn. Granted, specifying clockwise is meanless without some sort of reference viewing direction. But in almost every instance, when we use the term clockwise, the viewing direction is implied. And the English language has many examples where implication is permitted when stating the obvious. (Go to the store = You go to the store, etc.)
When stating that a person is jogging around a track, need we state "as viewed from above" as to not upset the underground gophers who think he is jogging counter-clockwise? Without actually saying so, our statement is technically meaningless. When we say that the hands of a clock move clockwise do we need to state "as viewed facing the front of the clock" to avoid confusing people who might be standing behind the clock? Or perhaps to make certain that we aren't talking about the gag clock they sell in novelty shops, where the hands actually do move backwards? Again, without stating the obvious, our statement is technically meaningless. But we can ignore that because in both these cases, the reference viewing direction is implied.
In the case of the solar system, the reference viewing direction is implied as well. I've seen many, many orbital diagrams of our solar system, and the moon systems within our solar system, and I don't ever think I've seen one looking towards the Sun's south pole. The implication here is "as viewed from above" because that's just how we draw orbits.
As long as we're on the topic of things that are technically wrong, here's 3 more examples that make me wonder:
#1. "I'm going to drive from San Francisco down to LA". Do I use the term "down" simply because LA is below San Francisco on any map or globe where north is up? What if the place in LA has a higher elevation than San Francisco? People would look at me strange if I said that I'm driving up to LA. But what if I live on the north side of a hill. Do I drive down to the top of the hill? This too seems weird. How far does one need to drive before the implication for up and down switches from elevation to latitude?
#2. Are the Philippines north or south of San Francisco? Intuition would tell me to say south. After all, its a tropical country, and San Francisco is far north of the tropics. But if you stretch a piece of string across a globe, you will see that to get to the Philippines from San Francisco, a boat or plane needs to travel northwest. The Philippines are northwest of San Francisco.
#3. Venus at is brighest is brilliant enough to cast shadows on the snow. But if you're standing in the snow and you see your shadow in the Venus light, YOU are casting the shadow, not Venus.
Here's a link to a Nasa page using similar language
Quote:
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Originally Posted by http://science.nasa.gov/headlines/y2005/28nov_venusshadows.htm
November 28, 2005: It's often said (by astronomers) that Venus is bright enough to cast shadows.
So where are they?
Few people have ever seen a Venus shadow. But they're there, elusive and delicate—and, if you appreciate rare things, a thrill to witness.
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The NASA site gets it right for the wrong reason when it says that few people have ever seen a Venus shadow. Venus casts two types of shadows: an umbra, and a penumbra, complete with an anti-umbra. Anyone whose ever witnessed Venus transiting the face of the Sun has been in a shadow cast by Venus.