Starship Asterisk*

neufer wrote: ↑Thu Dec 23, 2021 9:10 pm

johnnydeep wrote: ↑Wed Dec 22, 2021 9:53 pm
I still don't understand the statement about the ripples: "The ripples were discrete, so there wasn't a lot of interaction to produce a blur that you might be used to seeing." What would the reflection look like if the water was a solid mirror instead? Wouldn't it be just as blurry as the rocket trail in the air?

The reflection off a solid mirror would be just as blurry as the rocket trail in the air.

• By spreading the brightest part of the rocket nozzle flame rapidly around
  as well a dimming it by ineffective water reflection the moving streak is less saturated
  and less obscured by the more lasting but dimmer parts of the flame.
  
  The ripple structure is probably mostly the result of two discrete surface waves
  propagating in perpendicular directions as in a "Blackburn double pendulum":

https://en.wikipedia.org/wiki/Harmonograph wrote:

Click to play embedded YouTube video.

<<A Blackburn pendulum is a device for illustrating simple harmonic motion, it was named after Hugh Blackburn, who described it in 1844. This was first discussed by James Dean in 1815 and analyzed mathematically by Nathaniel Bowditch in the same year. A bob is suspended from a string that in turn hangs from a V-shaped pair of strings, so that the pendulum oscillates simultaneously in two perpendicular directions with different periods. The bob consequently follows a path resembling a Lissajous curve; it belongs to the family of mechanical devices known as harmonographs. The drawings created typically are Lissajous curves or related drawings of greater complexity. Mid-20th century physics textbooks sometimes refer to this type of pendulum as a double pendulum.>>

Blackburn double pendulum in slow-mo.

johnnydeep wrote: ↑Wed Dec 22, 2021 9:53 pm
I still don't understand the statement about the ripples: "The ripples were discrete, so there wasn't a lot of interaction to produce a blur that you might be used to seeing." What would the reflection look like if the water was a solid mirror instead? Wouldn't it be just as blurry as the rocket trail in the air?

• By spreading the brightest part of the rocket nozzle flame rapidly around
  as well a dimming it by ineffective water reflection the moving streak is less saturated
  and less obscured by the more lasting but dimmer parts of the flame.
  
  The ripple structure is probably mostly the result of two discrete surface waves
  propagating in perpendicular directions as in a "Blackburn double pendulum":

https://en.wikipedia.org/wiki/Harmonograph wrote:

Click to play embedded YouTube video.

<<A Blackburn pendulum is a device for illustrating simple harmonic motion, it was named after Hugh Blackburn, who described it in 1844. This was first discussed by James Dean in 1815 and analyzed mathematically by Nathaniel Bowditch in the same year. A bob is suspended from a string that in turn hangs from a V-shaped pair of strings, so that the pendulum oscillates simultaneously in two perpendicular directions with different periods. The bob consequently follows a path resembling a Lissajous curve; it belongs to the family of mechanical devices known as harmonographs. The drawings created typically are Lissajous curves or related drawings of greater complexity. Mid-20th century physics textbooks sometimes refer to this type of pendulum as a double pendulum.>>

Blackburn double pendulum in slow-mo.

Ann wrote: ↑Wed Dec 22, 2021 6:18 pm

sir_oki wrote: ↑Wed Dec 22, 2021 12:48 pm

Ann wrote: ↑Wed Dec 22, 2021 5:33 am

APOD 22 December 2021 satellite launch annotated.png

Hello Ann, I'm the original photographer.

1. I'm not sure what star that is, I might be able to determine that based on my coordinates and time. I'll look into it.
2. Yes, the first stage of Falcon 9 is separated there. After Main Engine Cutoff (MECO), the first stage separates and the gridfins guide it towards the droneship. The fainter trail is Falcon's second stage, which is a single vacuum engine.
3. The ripples were caused by me moving out of the water and fish swimming around. The ripples were discrete, so there wasn't a lot of interaction to produce a blur that you might be used to seeing. The lack of wind helped with that as well.

Thank you for your explanation!

Ann

sir_oki wrote: ↑Wed Dec 22, 2021 12:48 pm

Ann wrote: ↑Wed Dec 22, 2021 5:33 am

APOD 22 December 2021 satellite launch annotated.png

Hello Ann, I'm the original photographer.

1. I'm not sure what star that is, I might be able to determine that based on my coordinates and time. I'll look into it.
2. Yes, the first stage of Falcon 9 is separated there. After Main Engine Cutoff (MECO), the first stage separates and the gridfins guide it towards the droneship. The fainter trail is Falcon's second stage, which is a single vacuum engine.
3. The ripples were caused by me moving out of the water and fish swimming around. The ripples were discrete, so there wasn't a lot of interaction to produce a blur that you might be used to seeing. The lack of wind helped with that as well.

sir_oki wrote: ↑Wed Dec 22, 2021 12:48 pm

Ann wrote: ↑Wed Dec 22, 2021 5:33 am
APOD 22 December 2021 satellite launch annotated.png

Hello Ann, I'm the original photographer.

1. I'm not sure what star that is, I might be able to determine that based on my coordinates and time. I'll look into it.

2. Yes, the first stage of Falcon 9 is separated there. After Main Engine Cutoff (MECO), the first stage separates and the gridfins guide it towards the droneship. The fainter trail is Falcon's second stage, which is a single vacuum engine.

3. The ripples were caused by me moving out of the water and fish swimming around. The ripples were discrete, so there wasn't a lot of interaction to produce a blur that you might be used to seeing. The lack of wind helped with that as well.

Explanation: Birds don't fly this high. Airplanes don't go this fast. The Statue of Liberty weighs less. No species other than human can even comprehend what is going on, nor could any human just a millennium ago. The launch of a rocket bound for space is an event that inspires awe and challenges description. Pictured here, a SpaceX Falcon 9 rocket lifted off from Kennedy Space Center, Florida earlier this month carrying the Imaging X-ray Polarimetry Explorer (IXPE). IXPE is scheduled to observe high-energy objects such as neutron stars, black holes, and the centers of distant galaxies to better determine the physics and geometries that create and control them. From a standing start, the 300,000+ kilogram rocket ship lifted IXPE up to circle the Earth, where the outside air is too thin to breathe. Rockets bound for space are now launched from somewhere on Earth every few days.

Ann wrote: ↑Wed Dec 22, 2021 5:33 am

APOD 22 December 2021 satellite launch annotated.png