On Oct/12/2020 at 13:34, Greg (Strider) Moore wrote :
"Alain Fournier"Â* wrote in message ...

On Oct/12/2020 at 09:15, Greg (Strider) Moore wrote :
"Dean Markley"Â* wrote in message
...

On Saturday, October 10, 2020 at 11:46:52 AM UTC-4, Alain Fournier
wrote:
Imagine you are out one night and you see a plane flying over your
head.
Someone might note that it is 10 km high. Now imagine that exactly
behind the plane is the Andromeda galaxy. No one is going to say t hat
the galaxy is 2.5 million light years high, one would say it is 2.5
million light years away. Conversely, for the plane no one would
say it
is 10 km away if it is directly over head. So at what point does
something cease to be up and starts to be far.

Now this might seem like being only semantics, and it is. But I think
that discussing this particular point of semantics sheds light on how
people perceive space. I have my own opinion on the matter but I will
give it only after others have given their opinion, because I don't
want
this thread to be about discussing my opinion. I want it to be about
seeing what are the different opinions out there.


Alain Fournier
I suspect it is mostly human nature.Â* At least around here, we
consider anything north of us to be "up" there.Â* Conversely,
anything south is "down" there.Â* Being on the east coast, anything
west is "out" there.

Dean

I suspect anything that's within Earth's atmosphere is "high" and
even in most cases, if it's within the gravitational influence "high"
often applies.
Beyond that I think it's "out there" or "away".

So for you the moon is high not away?


Alain Fournier

Like I said, "even in most cases". I've heard both.

Personally I wouldn't say the Moon is high, at least not in the sense
that an air-plane is high, not in the sense of distance from the ground.
I might say that the Moon is high as we would say the sun is high at
noon, or even simply say high noon. But that isn't an indication of
distance but rather an indication of position in the sky. On the other
hand if we say that an air-plane is high, it can very well be low on the
horizon, what we are talking about when we say that an air-plane is
high, is the distance between the plane and the ground.

So why wouldn't I say that the Moon is 380,000 km high? For me it isn't
a question of gravitational influence, it is a question of geometry. If
someone on the Moon looks at Earth he doesn't see the "ground". He sees
a ball with stars around it. Someone in an air-plane can't see stars
around the Earth, they might see stars in one direction and Earth in
another, but if you see stars in one direction, you see Earth in the
opposite direction. From the Moon, you can easily see that Earth doesn't
fill half the directions.

For me, to be far enough from Earth to see it not as half (or nearly
half) of all directions is where I would sense being far from Earth, not
just high. I would put it at about 2000 km. Below that, even if
technically Earth doesn't fill half the sky, you don't easily see that
it fills less than half the sky.

Of course as I said from the onset, this is just semantics. And I am
very far from being an expert in semantics. So my opinion here is just
that, an opinion. Still if some of you have other opinions on where you
start being far, I would like to hear them. I think that gives an
interesting perspective on your perception of space.


Alain Fournier