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Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

theguardian.com

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Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#201

Post by webmaven »

Auracle wrote: post #146
walrus01 wrote: post #118

Earlier quoted context omitted.

Without a significant drop in the $ per kg cost of putting stuff in low earth orbit, I wouldn't take that bet. I don't think SpaceX starship will be revolutionary enough to put probes in LEO cheap enough. Once in orbit it's possible to reach things in the asteroid belt entirely through very high efficiency ion/hall effect thruster propulsion, which can have specific impulse as high as 8000. Any probe capable of drill…

Wouldn’t a nuke work?

> Wouldn’t a nuke work?

Do you mean NERVA?:

https://en.m.wikipedia.org/wiki/NERVA

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#202

Post by Chris2048 »

Symmetry wrote: post #186
PaulHoule wrote: post #65

Earlier quoted context omitted.

If your definition of habitable is "has liquid water" probably most of the habitable places in the universe are like Ceres, the moons of Saturn, even deep inside Pluto. Between the effects of pressure, geothermal energy, and gravitational tides you find liquid water in those places more than the inner solar system where water gets evaporated and blown away. (The trouble is that those places don't have sunlight and pr…

My pet theory is that life is pretty common in the universe, it happened on Earth almost as soon as the oceans formed. But photosynthesis, mitochondria, and multi-celularity each took a lot longer and probably represent the biggest barriers to intelligent life. Plus, as you say, most liquid water is in the deep dark under ice sheets far from the nearest star which makes photosynthesis difficult.

> it happened on Earth almost as soon as the oceans formed

But that might have been the final item in a long list of requirements. Maybe life form quickly (on a planetary-scale of quickness) once they are met, but who knows how long that list is.

TBH, I think people fixate on "life" because of some star-trekkian fantasy about aliens, and specifically, other space-faring aliens. There are lots of interesting life-forms on earth that are ignored. We have a lot yet to learn about chemistry, let alone the biochemistry of bacteria, algae, mould. Dolphins and octopi have yet to build boats, let alone spaceships (arguably the monkeys are ahead on this game).

TBH, I'm more interested in what kind of interesting materials and phenomena might exist on other planets. As for life, I think its more interesting to think about what kind of alien environments we can seed with life (and what would form) rather than the moon-shot of actually finding life we are exited about.

Also keep in mind: life or not, it might be more likely we find something else interesting or dangerous. e.g. some kind of adaptable self-replicating enzyme, but made of something more durable than protein (and reproducing in the environmental). Consider the rubber-eating contaminant in https://en.wikipedia.org/wiki/The_Andromeda_Strain

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#203

Post by gus_massa »

Symmetry wrote: post #186
PaulHoule wrote: post #65

Earlier quoted context omitted.

If your definition of habitable is "has liquid water" probably most of the habitable places in the universe are like Ceres, the moons of Saturn, even deep inside Pluto. Between the effects of pressure, geothermal energy, and gravitational tides you find liquid water in those places more than the inner solar system where water gets evaporated and blown away. (The trouble is that those places don't have sunlight and pr…

My pet theory is that life is pretty common in the universe, it happened on Earth almost as soon as the oceans formed. But photosynthesis, mitochondria, and multi-celularity each took a lot longer and probably represent the biggest barriers to intelligent life. Plus, as you say, most liquid water is in the deep dark under ice sheets far from the nearest star which makes photosynthesis difficult.

You are not so far from the current models. Take a look at https://en.wikipedia.org/wiki/Timeline_of_the_evolutionary_h...

(I think multicelularity of eucaryotes is easier in comparison with the other two steps, it has evolved like 20 times. But in the timeline, it took a long time...)

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#204

Post by Chris2048 »

elihu wrote: post #164
ncmncm wrote: post #87

Earlier quoted context omitted.

Earth-normal gravity, Earth-normal temperature, Earth-normal pressure, concentrated solar power, breathing air is buoyant, plastic and carbon fiber structural material--and breathing air and water--are convertable from atmosphere, cloud water is heavily enriched with deuterium. Way nicer than Mars. You can operate an unshielded nuke plant tethered some distance below your balloon habitat, no worries about leaks. We d…

Saturn, Neptune, and Uranus also have very close to Earth-normal gravity. I don't know what a human habitation at surface-level would be like on such a world, or how to escape the gravity well if you ever wanted to leave, but when it comes to surface gravity, it's pretty weird that our planetary system has five planets with almost the same gravity. It's either an amazing coincidence, or something about planet formati…

Gas-planets would be a challenge with no habitable surface, especially those with high winds. Would a floating sky habitat be any easier than just living in space?

But anything at or near Neptune receives very little light. There's a big gap between Mars and Jupiter (5.2au vs 1.5au), 10au to Saturn, and then a massive gap to Neptune (30au); anything habitable probably needs to be in the Mars-Venus band, fairly close to the sun.

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#205

Post by ragebol »

alex_duf wrote: post #177
bjo590 wrote: post #46

Earlier quoted context omitted.

No, it doesn't create a plot loop. The book explains that all of the H2O on Ceres was used to apply spin to Ceres to create artificial gravity. This is a symbol of Inner Planet's dominance over the Beleter's, because a _real_ Belter would never trade precious water for artificial gravity. This is mentioned fairly subtly in the first book, and is easy to miss while taking in the rest of the world. In addition the spin…

I had missed that Ceres' gravity is due to its spin. Does that mean humans are living upside down in their tunnels compared to Earth? And if that's the case, surely a spin that's greater than the local gravity should shatter the planet itself as the matter has no reason to stay concentrated around its core right? Am I missing something?

I vaguely remember something about Tycho Corporation wrapping cables around it and making it stronger, but maybe I'm confusing that with a Scott Manley video about Ceres in the Expanse.

But yes, walking feet towards the surface of Ceres, head to the core. The core is also where the poor people live in The Expanse, because the gravity is less/worse there together with weird Coriolis effects like this https://www.youtube.com/watch?v=ryrGPjyKhO4

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#207

Post by zaarn »

erik_seaberg wrote: post #121
thaumasiotes wrote: post #107

Earlier quoted context omitted.

And from an MSDS for that... > Hazardous combustion products: None that are more toxic than the product itself. ( https://www.boconline.ie/en/images/chlorine_trifluoride_tcm6... ) It's a fun read.

Material Safety: None. The End. > Contains no other components or impurities which will influence the classification of the product. In the unlikely event you survive adding something, you won’t make it any better. You certainly can’t make it worse. > Unsuitable extinguishing media: Water, Foam, Halons > Specific methods: Move away from the container and cool with water from a protected position. Um. > May react viol…

Similar fun would likely be the safety sheet for FOOF (Dioxygen diflouride), a compound that you can't really get to room temperature without said compound tearing itself and it's container apart. I do recall it reacts "vigourosly" (I believe the paper I read on this used those specific words) with Chlorine triflouride at 90K (-180C, -300F).

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#208

Post by Chris2048 »

acd wrote: post #157

Very interesting observations! I think many planets may have life below the surface. The hot core of planets behave like a heat reactor. Somewhere between the hot planet core and cold planet surface there should be a balanced temperature a mix. That mix may have a temperature of 0-37C. https://en.m.wikipedia.org/wiki/Planetary_core

We should be able to do the same on earth first. Where's our underground Polar habitats? I personally see Musks' Boring company" stuff as interesting as the rockets, I wish it where cheaper to build cities/tunnels underground.

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#209

Post by zaarn »

thaumasiotes wrote: post #107
erik_seaberg wrote: post #101

Earlier quoted context omitted.

I'm reminded of > [Chlorine trifluoride is] also a stronger oxidizing agent than oxygen itself, which also puts it into rare territory. That means that it can potentially go on to “burn” things that you would normally consider already burnt to hell and gone, and a practical consequence of that is that it’ll start roaring reactions with things like bricks and asbestos tile. It’s been used in the semiconductor industry…

And from an MSDS for that... > Hazardous combustion products: None that are more toxic than the product itself. ( https://www.boconline.ie/en/images/chlorine_trifluoride_tcm6... ) It's a fun read.

The statement that it produces no chemicals more toxic than itself is true but misleading because the combustion products will largely consist of chlorine gas, hydroflouric gas (not the acid, the gas) and a variety of other flourine compounds waiting to make your internal metabolism incompatible with life.

I would also argue that CO2 and dry powder isn't an suitable extinguishing media for this, as CF3 doesn't give much of a shit when it's got it's own hyperactive oxidizer on board.

Re: Planet Ceres is an 'ocean world' with sea water beneath surface, mission finds

#210

Post by eru »

bitreality wrote: post #161
eru wrote: post #117

Earlier quoted context omitted.

Though, of course, you might expect to see that, even if life can arise in extreme environments: It's uncontroversial that life is much denser in more hospitable environments. If the extreme environments are in regular contact with the hospitable environments, and if evolution is sufficiently random, you would expect over time that most organisms anywhere have an ancestor in the hospitable environment. Even if life c…

What is the most hospitable environment? A tide pool? Also the most hospitable environment for genesis is likely different from the most hospitable environment for a complex ecosystem.

That's an additional good question that would complicate the simplistic model I suggested in my comment.
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