If We Push Super-Saturn to the Distance of Neptune

A large, visible set of rings is the most conspicuous element that sets Saturn apart from the other planets. The whole system is 175,000 miles (280,000 km) wide but only two-thirds of a mile thick.

Now multiply that number by 200.

Such is the case when J1407b was first discovered in 2012.

No one knows how or why such a large system exists. Some say that this planet is far younger than Saturn and therefore is a reflection of Saturn's childhood. Whatever the case, if Saturn's rings were just as extensive, then the sky on Earth would have looked like this:

This bugs me personally because, at 888.2 million miles (1.43 billion km) from the sun, the rings would still be visible enough to interfere with cultural customs. Zeus would no longer be King of the Greeks. The Jewish, Christian and Muslim faiths would have taken a more radical direction. Ra would have had a neighborhood bully in his birth, death and rebirth journey from dawn to dusk. The Norse would have viewed this as an always-open gateway to another of the nine realms. In short, to have Saturn's rings as large as J1407b's would complicate the cultural aspect of worldbuilding, perhaps to the extent of justifying the "Ancient Aliens" Space Bats.

So let's push this Super Saturn a little farther out--say, the distance of Neptune, 2.795 billion miles (4.5 billion km). Would this still make Super Saturn's rings visible, or would they be as small in Earth's night sky as any other star?

• Can you provide the math / calculations for J1407b and how it would appear from Earth? Or a source for those images? It may help us answer. – Zxyrra Feb 7 '17 at 4:22
• Why should it bug you? Why think of it as complicating cultural worldbuilding? This is an utterly superb concept. An object like that would make the wonderful basis of a whole slew of alternative histories. Someone use the concept for a themed anthology. Anyone? You should be congratulated on devising a brilliant novum! – a4android Feb 7 '17 at 11:43
• It would not look like this. That drawing just illustrates the scale, but the brightness is not realistic. It would be a lot fainter than the moon and only visible at night. – gerrit Feb 7 '17 at 12:13
• I believe the extent of the rings would only appear about twice the size of the moon (Saturn is $\approx$ 19" and looking at it through $\approx$ 100x magnification makes it look about the size of the moon, the rings are about 40'' across so they would look about twice the size of the moon). However, as gerrit already said - they would be a lot dimmer. – Lio Elbammalf Feb 7 '17 at 13:36
• I'm curious: You're worldbuilding a scenario in which this super-saturn exists in the system but pushing it out so that it isn't visible. What part is it going to play in your worldbuilding if you're ruling out all the obvious implications? – Simba Feb 7 '17 at 14:15

It depends

The planet's ring system extends 0.6 AU.
Neptune is about 30 AU away from Earth, give or take a couple AU, meaning we see the edge of the ring about 29.4 AU away.

The unaided human eye - especially while culture develops, before the invention of glasses - has a hard time seeing Uranus, at about 19 AU, so the planet itself is not visible.

However, the ring system has a diameter of 1.2 AU, which is greater than the distance between the Earth and the Sun!
I won't do the math to figure out exactly how large the rings appear, but 1.2 AU is about 3644 times the diameter of Neptune. That's visible...

... depending on the rings' inclination! If they are perfectly horizontal relative to Earth, we will just see a cross-section, which is not visible. Depending on how you choose to tilt them, you can put the planet pretty much anywhere beyond Uranus and hide it from view.

• The axial tilt is the same--26.7 degrees. – JohnWDailey Feb 7 '17 at 5:38
• Needs to cover brightness (apparent magnitude) as well as size. – gerrit Feb 7 '17 at 12:13
• @gerrit Brightness is relevant but all we need to see Neptune are binoculars - a fair amount of light hits. Surely if we expand the diameter 3644 times it will be more visible. – Zxyrra Feb 7 '17 at 12:55
• @Zxyrra No. Unless you can see Saturn with binoculars during the day, that is not at all sure. – gerrit Feb 7 '17 at 12:57
• @gerrit I was referring to night visibility, I should have clarified. Yeah, it shouldn't be visible during the day. – Zxyrra Feb 7 '17 at 16:30

Saturn where it is now:

We didn't see the rings of Saturn until Galileo (1610) and they weren't observed to be rings until Huygens (1655). The fact is the size and albedo (how bright something appears) of the gassy planet vs the thin layer of rocky dust means the planet will always appear much brighter.

Increasing the ring size by 200 would only make the rings appear to extend to about twice the size of the moon in the night sky. Not quite the extent of what you see in your picture but still sizeable....however we still wouldn't be able to discern them with the naked eye. (With the possible exception of seeing their shadow cast onto Saturn's surface).

The important thing to note is how thin the rings are and the density of the material in the rings. To make a comparison, the asteroid belt is much closer but we cannot see that for similar reasons - there just isn't enough of it to get in the way.

Moving it out to Neptune's orbit:

The brightness of even the planet would pale to the point where observing it with the naked eye was impossible.

If you give us an idea of what it is you want to see in your story perhaps we can suggest changes to the system (denser rings if you do want them visible, for example).

• I'm exploring all possibilities of removing the post-LHB asteroid field greatly if not entirely. – JohnWDailey Feb 7 '17 at 14:46