Starship Asterisk*

https://www.nasa.gov/feature/jpl/nasas-juno-prepares-to-jump-jupiters-shadow wrote:
NASA's Juno Prepares to Jump Jupiter's Shadow : Oct. 1, 2019

Click to play embedded YouTube video.

Click to play embedded YouTube video.

<<Last night, NASA's Juno mission to Jupiter successfully executed a 10.5-hour propulsive maneuver — extraordinarily long by mission standards. The goal of the burn, as it's known, will keep the solar-powered spacecraft out of what would have been a mission-ending shadow cast by Jupiter on the spacecraft during its next close flyby of the planet on Nov. 3, 2019.

Juno began the maneuver yesterday, on Sept. 30, at 7:46 p.m. EDT (4:46 p.m. PDT) and completed it early on Oct. 1. Using the spacecraft's reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno's orbital velocity by 126 mph and consumed about 160 pounds of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter's shadow — more than enough time to drain the spacecraft's batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.

"With the success of this burn, we are on track to jump the shadow on Nov. 3," said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio.
"Jumping over the shadow was an amazingly creative solution to what seemed like a fatal geometry. Eclipses are generally not friends of solar-powered spacecraft. Now instead of worrying about freezing to death, I am looking forward to the next science discovery that Jupiter has in store for Juno."

Juno has been navigating in deep space since 2011. It entered an initial 53-day orbit around Jupiter on July 4, 2016. Originally, the mission planned to reduce the size of its orbit a few months later to decrease the period between science flybys of the gas giant to every 14 days. But the project team recommended to NASA to forgo the main engine burn due to concerns about the spacecraft's fuel delivery system. Juno's 53-day orbit provides all the science as originally planned; it just takes longer to do so. The spacecraft's longer life at Jupiter is what led to the need to avoid the gas giant's shadow. "Pre-launch mission planning did not anticipate a lengthy eclipse that would plunge our solar-powered spacecraft into darkness," said Ed Hirst, Juno project manager at NASA's Jet Propulsion Laboratory in Pasadena, California. "That we could plan and execute the necessary maneuver while operating in Jupiter's orbit is a testament to the ingenuity and skill of our team, along with the extraordinary capability and versatility of our spacecraft.">>

Guest wrote: ↑Tue Sep 10, 2019 7:45 am
Why can’t they just make an actual video in 2019 with this probe? It would be much more impressive and would give a better impression of being near this gas giant and also allow to experience the cloud movement in real time. Having to compose a crappy video out of some images seems like a joke considering they spend over a billion on that device, let alone all the effort and time they spent to get this thing all the way there.

https://en.wikipedia.org/wiki/JunoCam wrote:
<<JunoCam (or JCM) is the visible-light camera/telescope of the Juno Jupiter orbiter. The telescope/camera has a field of view of 58 degrees with four filters (3 for visible light). The camera takes a swath of imaging as the spacecraft rotates; the camera is fixed to the spacecraft so as it rotates, it gets one sweep of observation. Due to telecommunications constraints, Juno will only be able to return about 40 megabytes of camera data during each 11-day orbital period. This downlink average data rate of around 325 bits per second will limit the number of images that are captured and transmitted during each orbit to somewhere between 10 and 100 depending on the compression level used.

JunoCam is NOT of the probe's core scientific instruments; it was put on board primarily for public science and outreach, to increase public engagement, and to make all images available on NASA's website. It is capable of being used for science, and does have some coordinated activities in regards to this, as well as to engage amateur and as well as professional infrared astronomers. It was anticipated that it would operate through only eight orbits of Jupiter due to the planet's damaging radiation and magnetic field, but as of December 2018 (Perijove 17), JunoCam remains operational.>>
......................................................................
The Juno spacecraft's ACTUAL suite of science instruments will:

• Determine the ratio of oxygen to hydrogen, effectively measuring the abundance of water in Jupiter, which will help distinguish among prevailing theories linking Jupiter's formation to the Solar System.
  
  Obtain a better estimate of Jupiter's core mass, which will also help distinguish among prevailing theories linking Jupiter's formation to the Solar System.
  
  Precisely map Jupiter's gravitational field to assess the distribution of mass in Jupiter's interior, including properties of its structure and dynamics.
  
  Precisely map Jupiter's magnetic field to assess the origin and structure of the field and how deep in Jupiter the magnetic field is created. This experiment will also help scientists understand the fundamental physics of dynamo theory.
  
  Map the variation in atmospheric composition, temperature, structure, cloud opacity and dynamics to pressures far greater than 100 bars (10 MPa; 1,450 psi) at all latitudes.
  
  Characterize and explore the three-dimensional structure of Jupiter's polar magnetosphere and auroras.
  
  Measure the orbital frame-dragging, known also as Lense–Thirring precession caused by the angular momentum of Jupiter, and possibly a new test of general relativity effects connected with the Jovian rotation.
  
  Among early results, Juno gathered information about Jovian lightning that revised earlier theories.

stowaway wrote: ↑Mon Sep 09, 2019 6:44 pm
Why Beethoven?

Ann wrote: ↑Mon Sep 09, 2019 2:53 am

neufer wrote: ↑Sun Sep 08, 2019 10:18 pm

Muggins2 wrote: ↑Sun Sep 08, 2019 9:03 pm
The colors are so varied and distinct in Saturn's atmosphere.
Why don't these colors mix or homogenize into some greyish color?

Assuming you mean JUPITER's atmosphere:

• The zones/bands of color don't mix because conservation of angular momentum
  resists mixing adjacent bands of strongly varying angular momentum
  within the rapidly rotating Jupiter.
  
  Why the red and white vortices last so very long is still a mystery, however.

Is that math-speak for saying that the winds blow in opposite directions and at different speeds in the different belts and zones in Jupiter?

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

IR Jupiter shows lack of pole to equator temperature gradient

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---

The origin of Jupiter's banded structure is not completely clear, though it may be similar to that driving the Earth's Hadley cells. The simplest interpretation is that [white] zones are sites of atmospheric upwelling, whereas belts are manifestations of downwelling. When air enriched in ammonia rises in zones, it expands and cools, forming high and dense clouds. In belts, however, the air descends, warming adiabatically as in a convergence zone on Earth, and white ammonia clouds evaporate, revealing lower, darker clouds. The location and width of bands, speed and location of jets on Jupiter are remarkably stable, having changed only slightly between 1980 and 2000.

neufer wrote: ↑Sun Sep 08, 2019 10:18 pm

Muggins2 wrote: ↑Sun Sep 08, 2019 9:03 pm
The colors are so varied and distinct in Saturn's atmosphere.
Why don't these colors mix or homogenize into some greyish color?

Assuming you mean JUPITER's atmosphere:

• The zones/bands of color don't mix because conservation of angular momentum
  resists mixing adjacent bands of strongly varying angular momentum
  within the rapidly rotating Jupiter.
  
  Why the red and white vortices last so very long is still a mystery, however.

neufer wrote: ↑Sun Sep 08, 2019 1:25 pm

Click to play embedded YouTube video.

orin stepanek wrote: ↑Sun Sep 08, 2019 11:39 am

starsurfer wrote: ↑Sun Sep 08, 2019 9:01 am
This is a really relaxing start to a sunny Sunday morning.

Yes starsurfer it was very relaxing!

• Well...Hermione Granger can fix that:
  • Presto agitato !
  Moonlight sonata - 3rd Movement: Presto agitato

Muggins2 wrote: ↑Sun Sep 08, 2019 9:03 pm
The colors are so varied and distinct in Saturn's atmosphere.
Why don't these colors mix or homogenize into some greyish color?

• The zones/bands of color don't mix because conservation of angular momentum
  resists mixing adjacent bands of strongly varying angular momentum
  within the rapidly rotating Jupiter.
  
  Why the red and white vortices last so very long is still a mystery, however.

heehaw wrote: ↑Sun Sep 08, 2019 2:10 pm
Does anyone know if there is a level in the atmosphere of Jupiter that has temperature in the liquid-water range, AND reasonable pressures? Where floating living creatures could have evolved? There is a scientific paper by Carl Sagan speculating on life in Jupiter!

• They would have to survive in tents (radiation):

https://en.wikipedia.org/wiki/Extraterrestrial_life#Jupiter wrote:
<<Carl Sagan and others in the 1960s and 1970s computed conditions for hypothetical microorganisms living in the atmosphere of Jupiter.

The intense radiation and other conditions, however, do not appear to permit
encapsulation and molecular biochemistry, so life there is thought unlikely.>>

https://ui.adsabs.harvard.edu/abs/2001A ... I/abstract

orin stepanek wrote: ↑Sun Sep 08, 2019 11:39 am

starsurfer wrote: ↑Sun Sep 08, 2019 9:01 am
This is a really relaxing start to a sunny Sunday morning.

Yes starsurfer it was very relaxing!

• Well...Hermione Granger can fix that:
  • Presto agitato !
  Moonlight sonata - 3rd Movement: Presto agitato