How much spreading can it do in an environment where the surrounding plasma is 150 times denser than water?

-the other Doug

Also good to hear that the decay of the plutonium in the RTG will have an insignificant impact, and that they may well wait a while before fueling the MMRTG.

-the other Doug

Spoke too soon, there, eh, Emily? Good to hear your voice!

-the other Doug

OK, Mike -- thanks. I just figured that since the cruise thermal vac was including the entire stack, with the assembled rover inside the aeroshell, that anything you'd be doing to calibrate the instruments on it would be involved with the T/V. Thanks for the correction.

-the other Doug

When asked why it's so important to have the actuators at this point for an '09 launch, McCuistion says "The actuators do everything we do on Mars. They turn the wheels, they stop the wheels, they move the robotic arm. If we get to Mars and we can't move, we can't move the arm, we can't take samples, we just have about a metric ton of junk on the Martian surface."

And someone just asked about the 2011 launch window -- McCuistion says the window extends from October through December, with highest likelihood of late October through early November. Sounds like it won't extend into 2012.

-the other Doug

And for those of you who are hoping that your pet instrument might now be added onto MSL, per Doug McCuistion, "Is this an opportunity to update the payload? No." There will be no re-scoping or changes to the payload that aren't driven by engineering concerns that arise out of continued testing. In other words, no changes to the science payload.

On the other hand, Ed Weiler says that this delay is the perfect opportunity (albeit for the wrong reasons) to begin to design the architecture for MSR, Mars Sample Return.

-the other Doug

You sure, Mike? Griffin says that the coast thermal vac tests are going ahead on their current schedule. I'm assuming the calibrations would be part of that series of tests.

-the other Doug

Charles Elachi -- "It doesn't matter if you're one day short, or one week short, or one month short, you have to wait 26 months."

-the other Doug

I understand the feeling.

In addition, there is a prospective cost of about $400 million generated simply by the delay. That cost will be absorbed first by the Mars program and after that, if necessary, by the rest of the planetary program.

-the other Doug

And it's official -- launch delay to 2011, primarily due to the delay in actuator delivery.

-the other Doug

Well, EC, the high resolution images of the "lumpier" terrain looks to me to be covered with linear ridges. There are a wide variety of orientations, and they're best seen near the terminator. But there are surely parallel linear ridges all over the place. And while some do seem to have been disrupted by small craters, some of them neatly align strings of craters, craters of almost identical sizes that are exactly as wide as the distance between the linear ridges and that are arrayed in strings between the ridges.

It happens so frequently I have a hard time believing it's all happenstance. Those crater strings are endogenously controlled, I'd bet the farm on it.

-the other Doug

EDIT: Here's a subframe illustrating what I'm seeing:



dvd

I think some kind of plasma form for the rocky core is most likely, by the time a star ignites. But the natural process of gravity is such that the heaviest elements in the molten rocky core (prior to its plasma-ization) would have settled in the very center, the core of the core, so to speak. The lighter elements, the silica and iron and aluminum, et. al., would have formed shells around the presumed nickel-iron-uranium-etc. core.

As such a highly differentiated core is pummeled by the energy of its immediate "atmosphere" fusing around it, it would dissociate into atomic forms, I imagine, but at those incredible temperatures and pressures, and with that many photons trying to force their way into the heavy element mass, you'd think that generally symmetrical pressures all around would keep the heavy elements in the center.

Now, if there is *turbulence* in the fusing atmosphere around the heavy elements, uneven or patterned flow of fusing plasma around the core, it could possibly be eroded, great hunks of heavy elements being picked up and tossed higher into the gas plasma. But being heavier, you'd think that even in the seething energy environment, they'd still evenutally sink back down to the center.

Also, as a star ages, more and more of its mass is made up of helium, the fused by-product of hydrogen fusion. The helium is heavier than the hydrogen, and sinks down toward the core, where the very high temperatures and pressures cause the helium to fuse, making lithium. The lithium continues to sink, and at some point it fuses, on through a process that creates elements as heavy as iron. So the star is slowly forming even more heavy elements, which I would imagine would sink and collect around the original heavy-element core.

So, even though you might think that a rocky stellar core might just be vaporized, and you'd be sort of correct, in the conditions at a stellar core the vapor would have nowhere else to go but to be compressed and sink back into the center of the core. And as the star gets older, it creates more and more heavy elements until the original heavy element abundance has increased greatly.

Of course, when the star is big enough, its rapid expansion as the last of the hydrogen is used up and the associated sudden light pressure release blows the star apart. The explosion occurs *between* the core and the surface of the star, though, causing an equally forceful implosion that blasts the heavy-element core so hard as to make iron fuse, and heavier elements fuse, creating the true heavy elements, and another supernova seeds clouds of gas with even more raw materials for new stars, planets and moons.

The really interesting information we might be able to extrapolate from Juno data is the dynamics of the core. The temperatures and pressures at the core of Jupiter may well be enough to have caused any rocky core it once had to have settled into a differentiated heavy element plasma ball. Understanding those dynamics would be very enlightening in extrapolating to the later phases of stellar core evolution about which I have been speculating above.

-the other Doug

I am both incredulous and relieved that no one has mentioned any diseases found on or near Uranus...



-the other Doug

I would say that it's the Buzz Aldrin Show, but I'm afraid that's a banned subject....

-the other Doug

Not failed planets -- spectacularly successful planets.

Seriously, stars are formed, almost by definition, around the largest mass concentrations in a given stellar nursery nebula. What starts that process? For Population I stars, where there is almost nothing except gas in the birth nebula, obviously heavier elements play a very limited role, if any role at all. But for Population II stars, I've always wondered if the star begins with the largest collection of heavy elements (i.e., rocks) in the neighborhood, working from there to gather up enough gas to create such a super-gas-giant that the gas pressure in the interior becomes intense enough to support hydrogen fusion.

Looked at from the opposite side -- if a brown dwarf is a super-super Jupiter and is a failed star, and Jupiter-class planets require rocky cores to begin accretion, then doesn't it track that successful Pop II stars would start their accretion processes in the same manner as gas giants?

Something that has occurred to me more than once is that, if Pop II stars indeed accrete around rocky cores, what state do those cores achieve after several billion years of the temperatures and pressures at the core of their stars?

-the other Doug

Perhaps something exposed the rock below the former sand line and the wind got in and eroded the rock out from below? Remember, the rock probably eroded down flat to ground level a few hundred million years ago, and then something (perhaps ground shock from the Victoria impact) pushed it up a little bit, and over several hundred million years, the less armored underside of the rock has been eroding away?

We're talking long time frames here, you know?

-the other Doug

And if rock is required to initiate accretion of gas giants... what about stars?

-the other Doug

(This discussion was originally in the Juno thread but was moved to a separate topic - moderator)

As with many things, I recall reading something but not exactly where and when. My memory is that when the regional dust storm hit at Gusev, there was some update somewhere (surely either posted here or linked to from here) stating that MERA (i.e., Spirit) had just completed a mini-TES shaking and that initial results looked promising. The news was in juxtaposition to the new dust storm, irony in the possibility that just after getting her mini-TES dusted off, a bunch more dust got dumped on the poor girl.

As with anything, I admit the possibility of remembering this incorrectly.

-the other Doug

Well, yes, but... it's my understanding that this "shaking" plan actually improved the dust situation on Spirit's mini-TES. So while in Oppy's case the main dust problem may be in the internal optics, it was certainly worth a shot.

-the other Doug

Oh, I understand. I'm thankful that I've been able to use this skin as long as I have (Verdana being my font of choice for more than 10 years, now, far predating this forum).

But, and I think I speak for most everyone here, in the final analysis, it's not the font and colors that keep me coming back to UMSF. It's the content, and that content is, pardon the expression, color-blind...

-the other Doug

Even more astonishing is the possibility (small, I know) that Phoenix may not be permanently dead. There is always the Lazarus mode -- we may hear from her again in the Martian spring.

Mind you, I don't expect Phoenix to survive the winter. But there is a chance. If we do hear from her again, it's going to be an amazing day here at UMSF.

-the other Doug

All I can say is that I'm glad when someone notes here when the logo is changed on the IP.Board Pro skin, since I find that skin rather ugly and never use it, and would never see the new logos unless someone pointed them out (at which time I switch skins for a minute to see them).

The logo on the IPB 2.2.0 Default skin that I vastly prefer still reads "1500 Sols," and while I know I'm likely the only guy who prefers this skin and am not asking for that logo to be updated on this skin when it's changed on the Pro skin, it's nice that I can get some notice when the main skin is updated so I can at least switch over and take a look, before going back to my preferred skin.

-the other Doug

Fascinating concept, the broken window theory, and one that fits very nicely into what I've always called the "Will to be stupid" theory.

People in general (with the exceptions that prove the rule, of course) tend to do what they feel they can get away with... and driving that function is what I call the will to be stupid. It's the powerful desire to act on impulses that you can easily determine to be negative, disruptive or just plain not in anyone's best interests. The disruptive/self-indulgent/just-plain-stupid act almost always brings with it some very transient gratification, but is characterized by immediate remorse and realization that, even if you can get away with it, it's still a wrong (or at least completely non-useful) thing to do.

However, even when you realize you did something stupid, the immediate response when challenged on the action is usually either "You'd have done it, too" or "Everyone was doing it." It's the anonymity of the mob that drives the self-justification; after all, most people would never do, as individuals, what mobs are known to do.

So yes, policing is always necessary. The great pitfall in the policing function is when a megalomaniac gets into a position of power over the policing function, and attempts to limit all discourse to that which supoprts his/her own opinions. That becomes an oppressive environment which may maintain order, but at the expense of the free flow of ideas.

I do feel that Doug has come across the primary means of avoiding that pitfall, though -- appointing a team of moderators that can self-check itself against any one person imposing such an oppressive limit on discourse. And Doug has selected as his mods people who weren't necessarily desirous of being the "board cops," but instead those people he thought would be good at it. That's important, since megalomania is one of the more powerful motivators for seeking authority over others. (In other words, you don't want the police to be composed entirely of people who *want* to do the job, because the desire to impose your will onto others is precisely the trait that ought to disqualify you from achieving such power.)

It's good to remember, though, that the will to be stupid is omnipresent, and just because you wear a badge (or have "Moderator" pinned next to your name) doesn't mean you're immune. I'm pleased to say that, for the most part, the mods here have done a good job of avoiding mob-think amongst themselves and allowing discordant opinions (when presented respectfully, and when in keeping with the mutually-agreed subject matter limitations of the forum) to be expressed.

-the other Doug

Along the beer keg line, we could use the following ditty as a mission theme:

"Ninety-nine samples of rock on the ground,
Ninety-nine samples of rock!
Shoot one down,
Sniff all around,
Ninety-eight samples of rock on the ground..."



-the other Doug

I'm sorry, I can't hold this in any longer...

Every time I see the title of this thread, all I can think of is a bunch of little people popping up from behind the ripples, dressed like miners, singing "We represent the Hematite Guild!"

Sorry... we now take you back to your dry, serious thread...

-the other Doug