SandySandfort on July 08, 2009, 09:26:58 pm
When I saw the name the first thing that I thought of was the "Kobiyashi Maru".  That's a name that every "Star Trek TOS" fan knows well.  ;D

I built the name based on the meaning of forest and racing clouds, or something like that. I don't have my notes in front of me. That is why he has the Rolls Royce Silver Cloud and other things with cloud or trees/forest in their names.

KBCraig on July 09, 2009, 03:57:02 am
I thought "Guy Kawasaki", but that's because he's the only computer genius of Japanese descent who springs to mind.

Yes, I was an Evangelista back in the day.  ;)


Rocketman on July 09, 2009, 02:13:11 pm
I have a screenplay that I'm working on occasionally that one of the characters name is Dr. Iwamoto.  The name comes from Tetsuzo Iwamoto was the second highest scoring fighter pilot of WW2 with about 87 known kills and was nicknamed "Tiger Tetsu".

Rocketman on July 09, 2009, 02:19:02 pm
Sandy:  You may remember this.  Back in I think 1968 there was a television show called Burke's law starring Gene Barry (Bat Masterson).  He was a multimillionaire detective that instead of a squad car drove around in a 1967 Rolls Royce Silver Shadow.   I always loved that car and wanted one.  8)

SandySandfort on July 09, 2009, 04:05:08 pm
Sandy:  You may remember this.  Back in I think 1968 there was a television show called Burke's law starring Gene Barry (Bat Masterson).  He was a multimillionaire detective that instead of a squad car drove around in a 1967 Rolls Royce Silver Shadow.   I always loved that car and wanted one.  8)

I remember the show, but I don't think I watched it much.

The Rolls Royce has always had a certain cachet, that's for sure.

Colonel Healy on July 10, 2009, 06:05:23 pm
So  Kobayashi's ship  just stumbled accross TLP, with its .61 gravity. That would imply that there should be other such planetoids out there as well.

SandySandfort on July 10, 2009, 07:24:17 pm
So  Kobayashi's ship  just stumbled accross TLP, with its .61 gravity. That would imply that there should be other such planetoids out there as well.

I'm not sure how that follows. Asteroids are really few and far between, given the volume of the Belt. They are even rarer in the Kirkwood 3:2 Gap. This is a real gap in the Belt where harmonic perturbations, caused by Jupiter's gravity, sweep the area mostly clear.

A survey ship that happened upon TLP would first notice that it was as round as a cue ball. As they did a fly-by, their trajectory would be noticeably affect by its gravity.

One note of clarification. TLP has a surface gravity of .61 g. If you stand on a tall enough tower on earth, at some point you would also experience .62 g. Gravity varies inversely as to the square of the distance. Twice as far from the center of mass results in 1/4 the effect of gravity.

NeitherRuleNorBeRuled on July 10, 2009, 08:07:39 pm
I'm not sure how that follows. Asteroids are really few and far between, given the volume of the Belt. They are even rarer in the Kirkwood 3:2 Gap. This is a real gap in the Belt where harmonic perturbations, caused by Jupiter's gravity, sweep the area mostly clear.

A survey ship that happened upon TLP would first notice that it was as round as a cue ball. As they did a fly-by, their trajectory would be noticeably affect by its gravity.

The paper at http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?letter=.&classic=YES&bibcode=1990MNRAS.244..513M&page=&type=SCREEN_VIEW&data_type=PDF_LOW&send=GET&filetype=.pdf does not share the opinion that the area is "swept mostly clear" (see the first paragraph of the introduction). 

Also, if the area is, in fact, not that clear, I would expect the shape to be far from "round as a cue ball", since it has sufficient gravity to pull in smaller asteroids/debris in, but insuffucient surface gravity to flatten it out.

SandySandfort on July 10, 2009, 11:06:02 pm
I'm not sure how that follows. Asteroids are really few and far between, given the volume of the Belt. They are even rarer in the Kirkwood 3:2 Gap. This is a real gap in the Belt where harmonic perturbations, caused by Jupiter's gravity, sweep the area mostly clear.

A survey ship that happened upon TLP would first notice that it was as round as a cue ball. As they did a fly-by, their trajectory would be noticeably affect by its gravity.

The paper at http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?letter=.&classic=YES&bibcode=1990MNRAS.244..513M&page=&type=SCREEN_VIEW&data_type=PDF_LOW&send=GET&filetype=.pdf does not share the opinion that the area is "swept mostly clear" (see the first paragraph of the introduction).

No, the paper refers to the idea that the Kirkwood gap is a region where asteroids do not exist. I never posited that. Then it says the statistical analysis ensures that the gap is "well populated." It does not say, however, compared to what. In general, you can rarely even see one asteroid from another even in the main belt. And they are even less dense in the K Gap. At any rate, we are talking about an isolated case. The paper's argument is only statistical. Climate is what you expect; weather is what you get.  

Also, if the area is, in fact, not that clear, I would expect the shape to be far from "round as a cue ball", since it has sufficient gravity to pull in smaller asteroids/debris in, but insuffucient surface gravity to flatten it out.

What is your basis for that claim? Encounters between asteroids is relatively rare. Remember, when the asteroid captured the black hole (or more correctly, when the black hole captured the asteroid) a lot of orbiting about the black hole would have heated and reshaped the asteroid until things settled down. The Kirkwood Gap is less populated than the main belt.  2.3 x 1018 kilograms is nothing to sneeze at, nor is a surface gravity of .62 g. I contend that TLP would not have pulled in a lot of other objects because (a) they are not that many to be swept up and (b) while TLP's gravity well is relatively deep (high gradient), it wouldn't be all that wide. After that, I think that hydrostatic equilibrium would make for a pretty round world. Of course there will be mountains and other raised and lowered terrain, but as seen from a distance, "round as a cue ball" isn't too much of an exaggeration.

SandySandfort on July 11, 2009, 08:00:51 am
I just noticed that I made one mistake with regard to TLP. I referred to the Kirkwood 3:2 Gap. There ain't no such thing. It should have been the Kirkwood 3:1 Gap. For a very revealing look at the profoundness of the Kirkwood Gaps, see the histogram at http://en.wikipedia.org/wiki/Kirkwood_gap

The paper cited was written in 1990. The Wikipedia article on Kirkwood Gaps was last updated in April. My guess is that 19 years of further study has yielded more accurate results.

Rocketman on July 11, 2009, 03:04:44 pm
Sandy:
     Just out of cursiousity did you choose .62g because that is roughly the minimum amount of gravity neccessarity to prevent the oxygen in the atmosphere from escaping into space?  I don't know what the calculation is, but I imagine that it's somewhere in that neighborhood.  :D

SandySandfort on July 11, 2009, 03:49:08 pm
Sandy:
     Just out of cursiousity did you choose .62g because that is roughly the minimum amount of gravity necessary to prevent the oxygen in the atmosphere from escaping into space?  I don't know what the calculation is, but I imagine that it's somewhere in that neighborhood.  :D

Well, now things gets confusing. I had wanted a reasonably large planetoid, so I could have some interesting islands and an ocean... of sorts. I also wanted to have a moon that was in synchronous orbit. Plus a surface gravity less than one g. So I had to monkey with the mass of the black hole and other factors. Unfortunately, my original back-of-the-envelope figures turned out to be flawed. So we got Anton Sherwood to come up with a spread sheet to let us play with the values. (Thank you, Anton.) Ultimately, we came up with a couple of good sets of values. Due to a communications snafu, Scott and I thought we were talking about the same preferred set. Actually, I liked one set (which I will use in the collection of short stories I am working on) and Scott liked the other. By the time we became aware of the discrepancy, the scripting and drawing were too far along to change things without a lot of sturm und drang, so we went with Scott's preference. It's good enough for anti-government work, so that's where the .62 g came from.

Now as to your specific question, I don't think there is such a number that applies to all objects. The reason is that even though a surface gravity may be a particular value, that is irrelevant to loss of any particular gas. What is relevant is escape velocity which is determined by the mass of the object and from how far away from its center of gravity you are when you try to escape. Mars and Mercury have almost exactly the same surface gravity (.38 g), but significantly different escape velocities, 5.027 km/s and 4.25 km/s, respectively. Mars has an atmosphere, Mercury doesn't. There are other factors at play, of course, but escape velocity is the primary one. For some very large differences, Venus, Earth, Saturn, Uranus and Neptune all have about the same surface gravity, but wildly difference escape velocities. (E.g., Earth is 11.186 km/s; Saturn is 35.5 km/s.)

TLP, with an escape velocity of only .247 km/s (1/45 that of earth) is way too small to keep an atmosphere. So the whole planetoid is covered with an "airskin." You will learn more about this as the strip progresses.

Rocketman on July 11, 2009, 08:55:50 pm
Sandy:  Okay, thanks for the quick reply.  I HAD forgotten about the airskin.  You addressed very nicely my error in assuming there was no difference between escape velocity and gravity as it pertains to the atmosphere.   Thanks. 

pchkoreff on July 12, 2009, 10:23:58 pm
I knew it had to be a black hole!

I'm just trying to figure out the physics of how the planetoid can avoid
being sucked into the black hole eventually.  I know the black hole is
only 50 nm across.  Nevertheless, the gravity near that thing must be
something enormous, like 100g or something, who knows.

So maybe the core material is in orbit around the black hole, spinning
very rapidly.  The farther out you went from the center, the more slowly
the material would have to travel to maintain orbit.  I don't think you
could have a smoothly graduated speed difference from center all the way
out to surface, because it wouldn't have an structural integrity.  So
maybe as the illustration suggests there's an inner liquid core that
orbits around the black hole rapidly, and at the "interface" between
liquid magma and solid crust the velocity is low enough to avoid any
serious turbulence that would eat away the crust from the inside out.
Or maybe that interface is plasma gas and thus very low friction, like
water drops skating around on a hot grill.

It's a neat puzzle, and I look forward to hearing the explanation.

Sean Roach on July 12, 2009, 11:16:25 pm
Hmm.

How does an arch avoid falling to earth?

Why can't the planetoid be hollow?

Since all objects, regardless of mass or size, accelerate toward a gravity well at the same rate, a planetoid and an isolated black hole within, would fall together.

Any impact on the planetoid would cause it to jostle, allowing the black hole to hit one of the sides, and absorbing some more mass, but it'd eventually fall back to equilibrium at the center of mass.

The real puzzle, to me, is how a black hole came to rest inside a planetoid in the first place.  If it was flying through, it should have punched a clean hole and kept going.  To do otherwise would be akin to making a break, and causing the cueball to knock the 13 ball free, and sit motionless against the 9.  (I had to look up the layout of a pool table to make this analogy.)

In short, I can see this being STABLE, more or less, but not forming.  It'd be easier to find a black hole and decide to drop a small planet around it.  I also don't think such a small planet would reform itself round any more than our own 1G planet has sucked all the mountains into the plains.  Now, a constructed planet around a captured black hole, (perhaps a new jovian moon,) leveled with dynamite and bulldozers, that I can see.

 

anything