APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4647
Joined: Fri Dec 04, 2009 3:27 am

APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by APOD Robot » Tue Jan 04, 2022 5:05 am

Image Moons Beyond Rings at Saturn

Explanation: What's happened to that moon of Saturn? Nothing -- Saturn's moon Rhea is just partly hidden behind Saturn's rings. In 2010, the robotic Cassini spacecraft then orbiting Saturn took this narrow-angle view looking across the Solar System's most famous rings. Rings visible in the foreground include the thin F ring on the outside and the much wider A and B rings just interior to it. Although it seems to be hovering over the rings, Saturn's moon Janus is actually far behind them. Janus is one of Saturn's smaller moons and measures only about 180 kilometers across. Farther out from the camera is the heavily cratered Rhea, a much larger moon measuring 1,500 kilometers across. The top of Rhea is visible only through gaps in the rings. After more than a decade of exploration and discovery, the Cassini spacecraft ran low on fuel in 2017 and was directed to enter Saturn's atmosphere, where it surely melted.

<< Previous APOD This Day in APOD Next APOD >>

heehaw

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by heehaw » Tue Jan 04, 2022 10:39 am

I can't imagine any human will EVER visit Saturn, or even Jupiter for that matter - radiation and particles are killers, and what would humans do there anyway?

User avatar
rstevenson
Quis custodiet ipsos custodes?
Posts: 2663
Joined: Fri Mar 28, 2008 1:24 pm
Location: Halifax, NS, Canada

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by rstevenson » Tue Jan 04, 2022 12:29 pm

heehaw wrote: Tue Jan 04, 2022 10:39 am I can't imagine any human will EVER visit Saturn, or even Jupiter for that matter - radiation and particles are killers, and what would humans do there anyway?
I can't imagine any human will EVER… cross the ocean, explore the Arctic, work in Antarctica, travel into space, visit the Moon, … . But we tend to do things anyway, despite those who can't imagine someone doing them. So yes, humans will certainly visit Saturn and Jupiter and all the other points of interest in our Solar system. Not soon, but they will go when it becomes possible. We will soon(ish) have a permanent science and later an industrial settlement on the Moon, and not too long after that at least an intermittently occupied science settlement on Mars. One step at a time we will get there.

Rob

User avatar
orin stepanek
Plutopian
Posts: 7435
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by orin stepanek » Tue Jan 04, 2022 1:01 pm

RheaJanus_Cassini_1020.jpg
I had post all done and lost it! :roll:
Two moons Rhea and Janus nice members of Saturn Family!
Saturn's rings always a turn on for beauty!
dog-tired.jpg
Doggy keeping food close during naptime! :lol2:
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

User avatar
Chris Peterson
Abominable Snowman
Posts: 16596
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by Chris Peterson » Tue Jan 04, 2022 2:05 pm

heehaw wrote: Tue Jan 04, 2022 10:39 am I can't imagine any human will EVER visit Saturn, or even Jupiter for that matter - radiation and particles are killers, and what would humans do there anyway?
Great place to go for a sightseeing tour... although the trip out and back is rough!
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
VictorBorun
Science Officer
Posts: 442
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by VictorBorun » Tue Jan 04, 2022 2:35 pm

In the posted pic, the disk of Sun is illuminating both surfaces of the rings, is not it?

User avatar
Chris Peterson
Abominable Snowman
Posts: 16596
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by Chris Peterson » Tue Jan 04, 2022 2:38 pm

VictorBorun wrote: Tue Jan 04, 2022 2:35 pm In the posted pic, the disk of Sun is illuminating both surfaces of the rings, is not it?
How do you conclude that? We can only see one side of the rings (as is always the case), and it appears to be the sunlit side (based also on the angle of the terminator on Rhea).
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
VictorBorun
Science Officer
Posts: 442
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by VictorBorun » Tue Jan 04, 2022 5:36 pm

The disk of Sun is 1.4 million km / 1400 million km = 0.001 radian = 0.06°
My bad, Sun from Saturn looks in fact 9 times smaller than from Earth.
That lamp is point-like and needs more precise alignment to illuminate both surfaces of the rings.

User avatar
Chris Peterson
Abominable Snowman
Posts: 16596
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by Chris Peterson » Tue Jan 04, 2022 5:38 pm

VictorBorun wrote: Tue Jan 04, 2022 5:36 pm The disk of Sun is 1.4 million km / 1400 million km = 0.001 radian = 0.06°
My bad, Sun from Saturn looks in fact 9 times smaller than from Earth.
That lamp is point-like and needs more precise alignment to illuminate both surfaces of the rings.
Ah, I see what you were getting at, that as an extended source there will be a ring tilt range where both sides could be obliquely illuminated at the same time.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18805
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by neufer » Wed Jan 05, 2022 2:15 am

Chris Peterson wrote: Tue Jan 04, 2022 2:05 pm
heehaw wrote: Tue Jan 04, 2022 10:39 am
I can't imagine any human will EVER visit Saturn, or even Jupiter for that matter - radiation and particles are killers, and what would humans do there anyway?
Great place to go for a sightseeing tour... although the trip out and back is rough!
  • National Lampoon's Europaean Vacation:
https://en.wikipedia.org/wiki/Europa_Report wrote:
<<Dr. Unger (Embeth Davidtz), CEO of Europa Ventures, narrates the story of the Europa One mission. Six astronauts embark on a privately funded mission to Jupiter's moon Europa to find potential sources of life. The crew members are commander William Xu (Daniel Wu), pilot Rosa Dasque (Anamaria Marinca), chief science officer Daniel Luxembourg (Christian Camargo), marine biology science officer Katya Petrovna (Karolina Wydra), junior engineer James Corrigan (Sharlto Copley) and chief engineer Andrei Blok (Michael Nyqvist).

After six months of mission time, a solar storm hits the ship, knocking out communication with mission control. Blok and Corrigan perform an extra-vehicular activity (EVA) to repair the system from outside but an accident rips Blok's suit. While he is being guided back into the airlock, Blok notices that Corrigan's suit has been coated with hydrazine and he cannot enter the airlock or else he would contaminate the rest of the ship. Blok attempts to save Corrigan by taking him out of his suit, but he blacks out from a lack of oxygen. Knowing there is no hope for himself, Corrigan pushes Blok into the airlock, thus propelling himself away from the ship as it continues its journey to Europa. Stranded, he dies in space; the crew continue with the mission, demoralized by Corrigan's death.

After twenty months, the ship goes into orbit around Europa and its lunar lander lands safely on Europa but misses its target zone. The crew drills through the ice and releases a probe into the underlying sea. Blok, who is sleep-deprived and eliciting concern in the rest of the crew, sees a light outside the ship but he is unable to record it or otherwise convince the crew of its occurrence. The probe is struck by an unknown lighted object and contact with it is lost.

Click to play embedded YouTube video.
Click to play embedded YouTube video.
Petrovna insists on collecting samples on Europa's surface; the crew votes and she is allowed to go. Analyzing the samples, Luxembourg discovers traces of a single-celled organism. Petrovna sees a blue light in the distance and decides to investigate it. As she approaches the light the ice below her breaks and she falls through. Her head-mounted camera continues to broadcast, displaying her terrified face as the blue bioluminescence is reflected in her eyes, before cutting out.

The crew agrees to leave to report their discovery to Earth but the engines malfunction. As the lander hurtles back to Europa's surface, Xu unbuckles from his seat to dump water shielding to reduce the impact speed. Remarkably, the ship crashes at the originally-targeted landing site. On impact, Xu is killed and the lander is damaged, leaking oxygen and losing heat. It begins to sink into the ice.

Blok and Luxembourg suit up to make repairs outside the ship. Luxembourg tries to descend but falls through the ice. Blok knows that there is no chance that he alone will be able to repair the lander before it sinks. Instead, he manages to fix the communication link to the orbiting mother ship, at the expense of turning off the life support systems, just before the same blue light Petrovna saw approaches and he appears to fall through the ice as well.

Dasque re-establishes communication with Earth; all the collected images and data that have been saved since the solar storm are relayed to Earth via the mother ship, just as the ice cracks and the lander begins to sink. Alone and anticipating her death, Dasque opens the airlock to flood the lander in hopes of revealing the source of the light. As the water rises to the cockpit, she sees a tentacled, bioluminescent creature rising toward her, before the camera cuts out.

In the epilogue, narrator Samantha Unger confirms that the crew of Europa had discovered life and exceeded every expectation, as the footage plays from an earlier scene of the crew posing in front of the camera.>>
Art Neuendorffer

User avatar
johnnydeep
Captain
Posts: 1214
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Moons Beyond Rings at Saturn (2022 Jan 04)

Post by johnnydeep » Wed Jan 05, 2022 1:23 pm

neufer wrote: Wed Jan 05, 2022 2:15 am
Chris Peterson wrote: Tue Jan 04, 2022 2:05 pm
heehaw wrote: Tue Jan 04, 2022 10:39 am
I can't imagine any human will EVER visit Saturn, or even Jupiter for that matter - radiation and particles are killers, and what would humans do there anyway?
Great place to go for a sightseeing tour... although the trip out and back is rough!
  • National Lampoon's Europaean Vacation:
https://en.wikipedia.org/wiki/Europa_Report wrote:
<<Dr. Unger (Embeth Davidtz), CEO of Europa Ventures, narrates the story of the Europa One mission. Six astronauts embark on a privately funded mission to Jupiter's moon Europa to find potential sources of life. The crew members are commander William Xu (Daniel Wu), pilot Rosa Dasque (Anamaria Marinca), chief science officer Daniel Luxembourg (Christian Camargo), marine biology science officer Katya Petrovna (Karolina Wydra), junior engineer James Corrigan (Sharlto Copley) and chief engineer Andrei Blok (Michael Nyqvist).

After six months of mission time, a solar storm hits the ship, knocking out communication with mission control. Blok and Corrigan perform an extra-vehicular activity (EVA) to repair the system from outside but an accident rips Blok's suit. While he is being guided back into the airlock, Blok notices that Corrigan's suit has been coated with hydrazine and he cannot enter the airlock or else he would contaminate the rest of the ship. Blok attempts to save Corrigan by taking him out of his suit, but he blacks out from a lack of oxygen. Knowing there is no hope for himself, Corrigan pushes Blok into the airlock, thus propelling himself away from the ship as it continues its journey to Europa. Stranded, he dies in space; the crew continue with the mission, demoralized by Corrigan's death.

After twenty months, the ship goes into orbit around Europa and its lunar lander lands safely on Europa but misses its target zone. The crew drills through the ice and releases a probe into the underlying sea. Blok, who is sleep-deprived and eliciting concern in the rest of the crew, sees a light outside the ship but he is unable to record it or otherwise convince the crew of its occurrence. The probe is struck by an unknown lighted object and contact with it is lost.

Click to play embedded YouTube video.
Click to play embedded YouTube video.
Petrovna insists on collecting samples on Europa's surface; the crew votes and she is allowed to go. Analyzing the samples, Luxembourg discovers traces of a single-celled organism. Petrovna sees a blue light in the distance and decides to investigate it. As she approaches the light the ice below her breaks and she falls through. Her head-mounted camera continues to broadcast, displaying her terrified face as the blue bioluminescence is reflected in her eyes, before cutting out.

The crew agrees to leave to report their discovery to Earth but the engines malfunction. As the lander hurtles back to Europa's surface, Xu unbuckles from his seat to dump water shielding to reduce the impact speed. Remarkably, the ship crashes at the originally-targeted landing site. On impact, Xu is killed and the lander is damaged, leaking oxygen and losing heat. It begins to sink into the ice.

Blok and Luxembourg suit up to make repairs outside the ship. Luxembourg tries to descend but falls through the ice. Blok knows that there is no chance that he alone will be able to repair the lander before it sinks. Instead, he manages to fix the communication link to the orbiting mother ship, at the expense of turning off the life support systems, just before the same blue light Petrovna saw approaches and he appears to fall through the ice as well.

Dasque re-establishes communication with Earth; all the collected images and data that have been saved since the solar storm are relayed to Earth via the mother ship, just as the ice cracks and the lander begins to sink. Alone and anticipating her death, Dasque opens the airlock to flood the lander in hopes of revealing the source of the light. As the water rises to the cockpit, she sees a tentacled, bioluminescent creature rising toward her, before the camera cuts out.

In the epilogue, narrator Samantha Unger confirms that the crew of Europa had discovered life and exceeded every expectation, as the footage plays from an earlier scene of the crew posing in front of the camera.>>
I saw that movie. Pretty well done, but I was underwhelmed by the ending. I wasn't looking for any science goofs, but I don't remember anything glaringly dumb. I'll have to watch it again!
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."