Jupiter's horizon

[ffutures]

In The Struggle For Empire, the source book for FF XII, Jupiter, Saturn, Uranus and Neptune are earth-like and habitable, just very big (but don't have crushingly high gravity). So I've started to think about what things would be like there, ignoring the sheer implausibility of this idea and assuming Earth-normal temperature, pressure, atmosphere etc.

One of the questions to cross my mind is if it would be possible to see things coming over the horizon. Which leads to the question "how far away is the horizon?" Fortunately someone has already worked that one out:
http://vastfrontier.blogspot.com/2010/07/horizon-distance.html

So the next question is how far it is theoretically possible to see through the atmosphere at sea level pressure? The answer seems to be more than far enough - the definitive source for this is probably Ringworld, which has visibility in the thousands of kilometers, and it seems plausible given that we can see stars from the bottom of our atmosphere. Anyone able to confirm this? And what would refraction effects do? Extend the distance?

While looking up Ringworld I found this rather nice animation

and there appear to be dozens of others on Youtube, Nifty!

Comments

[keristor.livejournal.com]

My only complaint about the Ringworld animation is that the ship wasn't a GP hull, and anyone piloting it in hyperspace would have been incapacitated by the transparent hull disappearing into the "blind spot". Even B. found he could only stand it for a few minutes at a time. (Sorry, I've been a Niven geek for far too long...)

[gonzo21.livejournal.com]

Truly, youtube has everything.

[vicarage.livejournal.com]

Atmospheric extinction and refraction is complicated, and I could say moer, but you are not allowing real physics to act here. Taking Jupiter mass but insisting on Earth normal conditions takes you out of real physics into fantasy, and you could have any answer that fits your plot.

[nelc.livejournal.com]

Isn't that a General Products No 3 hull? It's been a while since I read Ringworld, how did Speaker-to-Animals handle the Blind Spot?

My problem with the ship is that the wings are just too weedy for it to be The Lying Bastard. I always imagined it to be more of a flying wing design, like an Avro Vulcan. Not to mention that the animator chose to leave the engines on while flying past the Ringworld wall, without accelerating the craft. Bad physics model!

[ffutures.livejournal.com]

I know - it's hard to make the worlds feel different given the way things are described, which is one of the reasons why I'm going a bit slowly on this one.

[ffutures.livejournal.com]

I think it's about right for the ship as described in Ringworld. They basically took a GP hull and bolted on wings that weren't protected by the hull.

Agree about the transparency - but I recall the Lying Bastard as mostly being transparent apart from personal quarters. Can't remember how that was rationalised in the book.

[ffutures.livejournal.com]

Actually it's more or less how I'd imagined it - too much Thunderbirds influence. Since the Ringworld rotates faster than orbital speed you would need engines, I think.

[ffutures.livejournal.com]

Yup.

[johnreiher.livejournal.com]

I'd say that atmospheric haze will be the main limiter. Remember even though we're looking up, the majority of the atmosphere is in the first 7 or so miles, then it gets thin fast. The best view is from a plane about a mile or more up in the air. There you can see about hundred miles.

http://dheiser.myncblogs.com/files/2009/09/mt-rainier-from-plane-far.JPG

What will ruin the view is the atmospheric haze, the white band that you see in this picture.

[dsample.livejournal.com]

A big part of the reason you can see stars through a 100 miles of atmosphere, when things get fuzzy when looking through a couple of dozen miles horizontally, is that the air thins out pretty quickly as you go up, and most of the dust, and water vapour and other stuff that obstructs the view is mostly present in the lower atmosphere.

I would expect that on a Jupiter sized object, unless you're having a particularly clear day, anything out at the horizon will be pretty much obscured by the haze.

Refraction effects already extend the distance that you can see the Earth's horizon. Given Jupiter's lower curvature, they might even make the world look like you're standing in the bottom of a bowl.

[pbristow.livejournal.com]

You'd need engines firing *outward*, to curve your trajectory to follow the rim rather than shooting off at a stright tangent. Then again, the curvature of the rim should be so slight at that radius, you could coast along it sans engines for quite a while before making a correction, I would think.

[pbristow.livejournal.com]

Nifty indeed! And far too long since I read those books...

[ffutures.livejournal.com]

Given that even on Jupiter the horizon is only 15km away I'm inclined to go with it being visible but hazy at "sea level," and with visibility about the same as on Earth at greater altitudes.

[ffutures.livejournal.com]

It's actually only 15km or so even on Jupiter, so I'm inclined to go with things being visible but hazy. I'm not sure about the refraction effects - you get the bowl effect on Venus in our universe, but that's a horrendously hot high pressure atmosphere.

[ffutures.livejournal.com]

The first couple were good, not so sure about the later ones.