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APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Tue Feb 21, 2023 5:06 am
by APOD Robot
Comet ZTF over Yosemite Falls
Explanation: They are both falling. The water in
Yosemite Falls,
California,
USA, is falling toward the Earth.
Comet ZTF is falling toward the
Sun. This double cosmic cascade was captured late last month as fading
Comet C/2022 E3 (ZTF) had just passed its closest to planet Earth. The orange star just over the falls is
Kochab. With the exception of a brief encounter with a
black bear, the
featured image was a
well-planned composite of a moonlit-foreground and long-duration background exposures - all designed to reconstruct a deep version of an actual single sight. Although
Comet ZTF is
now fading as it glides back to the outer
Solar System, its path is
determined by gravity and so it can be considered to still be falling toward the Sun -- but backwards.
Re: APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Tue Feb 21, 2023 5:21 am
by Guest
That's actually Bridalveil Falls
Re: APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Tue Feb 21, 2023 5:49 am
by Chris Peterson
I think it's a bit marginal to say that a body in an open (hyperbolic) orbit that is moving faster than the Solar System escape velocity and will never return is really falling toward the Sun... in either direction.
Re: APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Tue Feb 21, 2023 5:53 am
by Chris Peterson
Guest wrote: ↑Tue Feb 21, 2023 5:21 am
That's actually Bridalveil Falls
No, it's Upper Yosemite Fall.
Re: APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Tue Feb 21, 2023 1:41 pm
by Cousin Ricky
APOD Robot wrote: ↑Tue Feb 21, 2023 5:06 am
The orange star just over the falls is
Kochab. With the exception of a brief encounter with a
black bear, ...
So, two bears in this description!
Re: APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Tue Feb 21, 2023 2:44 pm
by johnnydeep
Chris Peterson wrote: ↑Tue Feb 21, 2023 5:49 am
I think it's a bit marginal to say that a body in an open (hyperbolic) orbit that is moving faster than the Solar System escape velocity and will never return is really falling toward the Sun... in either direction.
Yeah. Plus, though "intuitively", a body in a closed elliptical orbit around the Sun is only falling toward it prior to perihelion, such an object is in reality falling toward the sun at all times! And even a rock thrown upward from the Earth's surface is falling even when it is rising!
So, does "falling" just mean the direction that gravity is acting regardless of the direction of motion of the object?
Re: APOD: Comet ZTF over Yosemite Falls (2023 Feb 21)
Posted: Wed Feb 22, 2023 2:56 am
by orin stepanek