by Chris Peterson » Sat Aug 03, 2024 5:17 pm
johnnydeep wrote: ↑Sat Aug 03, 2024 5:15 pm
Chris Peterson wrote: ↑Sat Aug 03, 2024 5:09 pm
johnnydeep wrote: ↑Sat Aug 03, 2024 5:01 pm
That makes no sense to me. Why? But I assume if the "glory" is caused by the shadow of another object that you - and others - are inside (like an airplane), then everyone sees the same exact glory, no? And of course, if you and your buddy are side by side, and in actual contact, you would both see the same exact - or close enough - glory, right?
It's not a shadow being
cast on a plane, but a column of darker air extending directly away from the viewer towards the anti-solar point. You don't have to go very far off-axis until there's simply no longer enough contrast to see the glory. Of course, if someone has their head up against yours, you'll both see very close to the same thing (but not exactly). The shadow we see in today's APOD is substantially from the imager, not the guy with his hand up.
Alright. There's that "column of darker air" as opposed to a "shadow" distinction again. The text refers to cast shadows - the "shadow of the observer" - , so that's what I was regurgitating. And I assume you meant "cast
by a plane" not "cast
on a plane".
No, I meant cast
on a plane. Like a normal shadow. Anybody looking at that planar surface will see the same shadows, no matter where they're viewing it from. But in this case all that we're seeing is a column with reduced scatter. That's only going to be apparent when you're looking along that column, not across it.
[quote=johnnydeep post_id=340622 time=1722705311 user_id=132061]
[quote="Chris Peterson" post_id=340621 time=1722704991 user_id=117706]
[quote=johnnydeep post_id=340619 time=1722704518 user_id=132061]
That makes no sense to me. Why? But I assume if the "glory" is caused by the shadow of another object that you - and others - are inside (like an airplane), then everyone sees the same exact glory, no? And of course, if you and your buddy are side by side, and in actual contact, you would both see the same exact - or close enough - glory, right?
[/quote]
It's not a shadow being [b][color=#0040FF]cast on a plane[/color][/b], but a column of darker air extending directly away from the viewer towards the anti-solar point. You don't have to go very far off-axis until there's simply no longer enough contrast to see the glory. Of course, if someone has their head up against yours, you'll both see very close to the same thing (but not exactly). The shadow we see in today's APOD is substantially from the imager, not the guy with his hand up.
[/quote]
Alright. There's that "column of darker air" as opposed to a "shadow" distinction again. The text refers to cast shadows - the "shadow of the observer" - , so that's what I was regurgitating. And I assume you meant "cast [i][b][color=#0040FF]by[/color][/b][/i] a plane" not "cast [i][b][color=#0040FF]on[/color][/b][/i] a plane".
[/quote]
No, I meant cast [i]on [/i]a plane. Like a normal shadow. Anybody looking at that planar surface will see the same shadows, no matter where they're viewing it from. But in this case all that we're seeing is a column with reduced scatter. That's only going to be apparent when you're looking along that column, not across it.