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Chip
2001-Dec-02, 08:35 AM
On a recent episode of Farscape they were orbiting a Saturn-like ringed planet, just "above" the outer ring. It was a lovely special effect, which leads to an idle question:

If we were in a nice spaceship near Saturn (in our solar system,) and we decided to orbit from above the outer ring, so that we were gliding above the ice and dust of the ring, how clean would the space be above the ring plane? How close could we get? Is there a sharp demarcation between the ring debris and the space near it? Just a thought, (in case I want to open a floating hotel with spectacular dining hall views of the rings from above.) /phpBB/images/smiles/icon_smile.gif

Chip

"Why haven't I've seen this all along?!" - Dr. Morbius from Forbidden Planet

GrapesOfWrath
2001-Dec-02, 02:58 PM
Didn't see the show, so I'm not sure what you mean by above? Do you mean radially outward, or do you mean above in the sense of normal to the plane of the rings?

The first one might not be much of a view--you'd see the rings more on end. The second one would be a hard orbit to maintain, unless you were adjusting your orbit constantly, and that might be expensive. I guess you could dip up and then back.

Kaptain K
2001-Dec-02, 07:37 PM
You can't orbit "above" the rings. The plane of any orbit must contain the center of mass of the body being orbited. Any orbit that is not co-planar with the rings will intersect the plane of the rings twice per orbit. If the orbital distance is between the minimum and maximum of the rings, your orbiting hotel will go crashing through the rings twice per orbit (ouch!).

David Hall
2001-Dec-02, 08:21 PM
On 2001-12-02 14:37, Kaptain K wrote:
You can't orbit "above" the rings. The plane of any orbit must contain the center of mass of the body being orbited.


Not 100% true. I remember seeing a photo once of a "halo ring" around the north pole of Saturn (or maybe Jupiter, I forget which). I can't seem to find it on the web now, so maybe it was just a simulated photo, because this page talks about the theoretical side of it, and it doesn't say anything about having detected them yet.

http://www.nature.com/nsu/000420/000420-9.html

Admittedly though, these are only very light particles, and are only orbiting in such a strange way because the gravitational forces are balanced by magnetic fields. But it is an off-center orbit. /phpBB/images/smiles/icon_smile.gif

Also, I suppose it would be possible to artificially maintain a trajectory just above a ring plane. I don't doubt it would be a nightmare to hold, however.

Kaptain K
2001-Dec-03, 12:53 AM
Also, I suppose it would be possible to artificially maintain a trajectory just above a ring plane. I don't doubt it would be a nightmare to hold, however.
The key word here is "trajectory". Maintaining such a path would require constant thrust and would be extremely expensive in terms of fuel.

Peter B
2001-Dec-03, 05:34 AM
Wouldn't it be more logical to have an orbit inclined at an angle to the rings, and a greater distance from the planet than the rings. That way you'd get to see the rings at varying angles.

David Hall
2001-Dec-03, 11:26 AM
On 2001-12-02 03:35, Chip wrote:

... how clean would the space be above the ring plane? How close could we get? Is there a sharp demarcation between the ring debris and the space near it?

Chip


With all this talk on orbital dynamics, I decided someone should take a stab at answering the actual question of the OP. /phpBB/images/smiles/icon_smile.gif

This site I found seems to have a lot of info on Saturn and it's rings. There don't seem to be any direct answers, but I think it's possible to make some guesses.

http://www.jpl.nasa.gov/saturn/saturn.html

First, the Fact Sheet has some good ring data (There's a really cool ring graphic there too.): http://www.jpl.nasa.gov/saturn/fact.html . The rings show a lot of variabliity, but seem to be mostly very thin.

The FAQ page has a couple of good answers also: http://www.jpl.nasa.gov/saturn/faq.html#compose. First, it says the rings are no more than 200m wide, and particles are generally from a few centimeters to a few meters across, with probably a few very large ones as well. It goes on to say the "spokes" seen in the rings may be microscopic particles pushed out from the ring plane by some means or other. Shepherding moons tend to hold the rings in pretty tight formation, too. The BA's astronomy bite on the rings was also helpful here: http://www.badastronomy.com/bitesize/saturnrings.html

In my layman's opinion then, it looks like the main rings at least have pretty clear boundries. Maybe some fuzziness in the range of a dozen meters or so. But there also seem to be some clouds of microscopic particles and the maybe the occasional large chunk popping out of the ring plain from time to time.

So my guess is, your floating hotel would be safe as long as it didn't get too close. (But you'd get a better view from further out anyway, and could save money by not having to force an unnatural orbit on it. /phpBB/images/smiles/icon_biggrin.gif

_________________
David Hall
"Dave... my mind is going... I can feel it... I can feel it." (http://www.occn.zaq.ne.jp/cuaea503/whatnots/2001_feel_it.wav)

<font size=-1>(Fixed a non-working link)</font>

<font size=-1>[ This Message was edited by: David Hall on 2001-12-03 06:34 ]</font>

Mnemonia
2001-Dec-03, 03:43 PM
On 2001-12-02 14:37, Kaptain K wrote:
You can't orbit "above" the rings. The plane of any orbit must contain the center of mass of the body being orbited. Any orbit that is not co-planar with the rings will intersect the plane of the rings twice per orbit. If the orbital distance is between the minimum and maximum of the rings, your orbiting hotel will go crashing through the rings twice per orbit (ouch!).


While that's very true you could orbit at a distance that would send you through one of the divisions. In fact, that would give the hotel patrons both edge-on (twice per orbit) and top-down views of the rings, with relatively little danger of impact.

Chip
2001-Dec-03, 04:32 PM
David Hall, and the rest of you guys -
Wow. A lot of good information! Thanks.
Chip /phpBB/images/smiles/icon_eek.gif

Also Mnemonia,
Your idea allows my hotel bar to collect some extra ice for the drinks! (Not to mention partial fuel sources of hydrogen for the engines -- for needed orbital corrections.)

Chip /phpBB/images/smiles/icon_smile.gif

"Why haven't I've seen this all along?!" - Dr. Morbius from Forbidden Planet




<font size=-1>[ This Message was edited by: Chip on 2001-12-03 11:38 ]</font>

<font size=-1>[ This Message was edited by: Chip on 2001-12-03 11:39 ]</font>