Don't get too excited about the prospect of a rapid trip to Victoria just yet. As Squyres says, if they find something different and interesting at the Mogollon Rim they're not going to leave it behind unexamined.

My bet is it will be into March before they're done with Erebus completely.

Sorry I've been away for a while - that was not my intent!

Anyway, thanks for all the suggestions and pointers. It seems that superheated plasma is the way to go as far as a propulsion system is concerned, and since getting such a large mass moving at speeds that will get it from star to star in at least a few hundred years would need a huge amount of fuel (mass) to accerelate it.

Yes, I think a fission reactor is more plausible since they do occur (abeit in a limited way) in nature, and water could be used as a regulator as well as mass for the accelerant. In fact, since heavy water reactors can be used (along with natural uranium) to power the fission, perhaps there's another need for water (heavy water is present in sea water - 1 in 3200).

Of course a fission reactor would, as you point out, need nuclear fuel. My assumption was that perhaps the creature would not need to refuel its uranium at every stop, but would have to restock its reaction mass, so bypassing (conveniently) the need to worry about that .

The story is told from the creature's (fairly limited) POV, with the point being that if and when alien life encounters us (or vice versa) they might be so alien that they might not even recognize what we are, much to our detriment!

Since this is a short story I don't want to get too bogged down with the details (as long as they don't beggar belief). If I was writing a novel then I would certainly have to nail down the details since there would be more time in which to do so.

If I ever get it published (a long shot, for sure) I'll let you guys know!

Mike

No, I haven't... looks interesting. I'm sure that Benford, being a scientist, has thought out the technical nature of his beast in great detail.

In my case, since it's a short story, I don't really have the time to delve too deep into the nature of my beast, I just want it to be possible, if not plausible. I wanted to come up with something that is so alien, so different that it would not even comprehend that other life, particularly on our scale, could exist. So something that simply sees the solar system as a feeding ground is going to cause major problems - especially if the planet we happen to be living on is seen as a "Tasty Morsel" (the name of the story).

Good point - but the way the story stands the creature has an internal fission reactor, not fusion. Does that make any difference? (Probably not, I guess). Thanks for the tip.

Hi, I've just written the first draft of a science fiction short story and I need little help with the plausibility factor . Since many highly educated people hang out in this forum (flattery will get me everywhere... I hope!) I thought this might be a good place to ask a few questions.

The story is about a colossal creature (think Titan-sized, as in the moon Titan) that lives amongst the stars, travelling from solar system to solar system, hibernating while in between. (Hey, I didn't claim it was original .) I'm not so concerned about the plausibility of such a species evolving as I am about how the creature is powered.

The creature's internal systems are powered (for want of a better word) by a fission reactor, which I think is okay. But its propulsion is powered by the burning of hydrogen and oxygen (i.e. as in rocket fuel) extracted from water - and this is the bit I'm unsure about.

I know hydrogen and oxygen can be extracted from water, and with a colossal nuclear reactor at its core there is enough energy for the creature to do so, but I just don't know how plausible this whole propulsion set up it. (I guess I can live with "unlikely", I just don't want to base the story on something that's "impossible".

An important aspect of the story as it is written is that the creature needs to stock up on its water supply and has to munch on moon-sized objects to do so (think Europa-sized or smaller in this instance). So its critical for the story that water, and the need to replenish its supply of water, plays a very large factor in the creature's life. I know we are talking colossal sizes and amounts of water here, but that's part of the nature of the story.

So, what do you think? Am I on the right track or careening off the rails?

Any help at all would be greatly appreciated.

Thanks,

Mike

Aside from the coolness factor, is there any remaining science to be gained from photographing these eclipses? I would have thought they had nailed down all the specifics about Phobos and Deimos by now.

That crater to the west of Victoria looks particularly inviting....

But I'm not holding my breath!

Oops - just realized this is "Spaced Based Observing" forum. Sorry about that - feel free to move or delete this topic if deemed inappropriate for this section. (Good story though!)

I found this article a few days ago on the BBC News website:


Click this link for the rest of the article and some video.

There is a lot more information at the Lucky Imaging website. Check it out.

Now, to my purely amateur mind, this strikes me as revolutionary. They are claiming that Lucky Imaging can equal or even better Adaptive Optics in many cases, and at a tiny fraction of the cost of installing and operating the equipment.

Now of course, if you have to "throw away" 90% or more of your images, then your going to need longer exposures to see the faintest objects, but for many situations, lucky imaging would appear to be a no-brainer considering the cost.

Is this merely hype or are we soon going to be able to get cut-price Hubble-like clarity from telescopes that install their own LI instruments?

I wouldn't worry about being "Ultreya-ish" unless you start imagining the outcrop conceals caverns, sinkholes, geysers, or whatever else it was he was claiming.

I think you're safe for now.

I asked that same question way back, and I believe the answer I got was no, you need the batteries.

I guess they're not going to fail all at once, so there will be a period of time where there batteries will continue to function but not be able to retain a full charge. But when the time comes, and the writing is on the wall, they will reach a point where the diminishing returns will no longer justify the funding, and the project will be shut down and the rover switched off.

Here's hoping that it happens when she's perched on the edge of Victoria crater after one last panoramic vista.

Except that Opportunity's batteries only have a finite number of charges in them, so even if nothing catastrophic happens, she will eventually reach the point where her batteries will no longer hold enough charge to operate.

I seem to recall the batteries have about a 1000 cycle lifespan. Is that correct?

Wind....

Yeah, I know, the obvious, unhelpful answer, but true anyway.

They probably took the photos with the sun at an angle to accentuate the surface variations. It looks impressive but I expect they are all aeolian features.

Whoever is studying the dunes on Mars is probably drooling over the photos as we "speak"

Obviously not a geologist then...

Now that Opportunity is in the right "groove" between dunes, I doubt it would be wise to attempt any more east/west travel unless it comes across an impassable obstruction (like a shelf). Worst case, they can always backtrack to the current point and attempt a detour later.

Besides, the geologist are probably tired of dune travel by now!

Nice animation. Looks like they risked going over a very small dune (pretty safe really) rather than continue into some deeper looking sand. Wise move, I'd say.

That's pretty consistent at 0.5cm per metre so far.

It was a blind drive, and I assume that any checks that the rover can make did not involve "digging in". It's a safe bet they'll be adding that to the repetoire if they can.

Yes - Latest Squyres Update.

"We're still testing, and it's going to be a few more days, at least, before we're ready to try anything on Mars."

Looks like it'll be next week before they have a got at getting out.

Software doesn't get old, but programmers make mistakes. They've been tweaking the driving software for some time now, and one of the recent changes (to compensate for the drive actuator failure, I belive) did indeed cause the type of software glitch being discussed, causing the rover to veer off to the left for a few metres before the drive stopped prematurely.

Now I'm not saying that I know for sure that a software bug was to blame, but it certainly can't be ruled out yet.