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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

#161

Post by bitreality »

eru wrote: post #117
crowbahr wrote: post #108

Earlier quoted context omitted.

The question is can life arise in such an environment, or only migrate to one. That's yet to be determined as far as I know: extremophiles have all evolved from less tolerant life forms as far as I'm aware.

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.

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

#162

Post by raghava »

clarkmoody wrote: post #109
loosetypes wrote: post #91

Earlier quoted context omitted.

Would evolutionary timelines or cycles be slower in an overall colder planet? (Thinking of those interactive diagrams for temperature on the kinetic energy of molecules zooming around in closed space)

Did you ever read Dragon's Egg ? It's a speculative hard sci-fi that posits ultra-fast evolution for life on the surface crust of a neutron star !

> Dragon's Egg

TIL!

Oh, looks like this movie "Evolution" ( https://en.wikipedia.org/wiki/Evolution_(2001_film) ) was also on those lines then!

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

#163

Post by sfvisser »

crowbahr wrote: post #108
walrus01 wrote: post #97

Earlier quoted context omitted.

Considering that there's organisms that live at ridiculous pressures, with absolutely no sunlight and at the extreme temperatures of deep sea volcanic vents, I would not be surprised at all. https://en.wikipedia.org/wiki/Hydrothermal_vent https://en.wikipedia.org/wiki/Hydrothermal_vent_microbial_co...

The question is can life arise in such an environment, or only migrate to one. That's yet to be determined as far as I know: extremophiles have all evolved from less tolerant life forms as far as I'm aware.

Live on earth might actually originate from geothermal vents at extreme (for us) conditions.

See the excellent book The Vital Question by Nick Lane.

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

#164

Post by elihu »

ncmncm wrote: post #87
randomdude402 wrote: post #79

Earlier quoted context omitted.

I thought the atmosphere was mostly carbon dioxide and sulfuric acid. What makes it potentially high value?

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 formation in our solar system that makes ~1G planets very likely.

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

#165

Post by renewiltord »

edgyquant wrote: post #113
renewiltord wrote: post #73

Earlier quoted context omitted.

What other kind of substance is called 'water'? As far as I know only H2O is described as water.

Water usually means liquid H2O. Europa, for instance, isn't liquid water but ice that is squeezed and loosened to the point it acts like a liquid while still being well below freezing and basically just ice sand

Very cool!

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

#166

Post by progval »

bjo590 wrote: post #46
outworlder wrote: post #17

There goes the water rationing narrative in The Expanse...

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…

> For scientific context to my statement H2O can be turned into really good propellant

Note that in The Expanse universe, water isn't usually used as propellant, but simply as reaction mass. All we know about the actual propellant is that it's used in fusion reactors and is surprisingly efficient.

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

#167

Post by simonh »

valuearb wrote: post #126
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…

The Space Shuttle payloads to LEO cost $40,000 per pound. Before SpaceX commercial launch payloads cost $5,000 to $10,000 per pound. Falcon 9 payloads cost around $1,500 per pound. Falcon Heavy payloads cost around $1,100 per pound. Starship payloads will cost between $100 and $500 per pound. It will be able to lift at least 100 tons to orbit. And using in orbit refueling, it will be able to accelerate that 100 ton p…

True, but in orbit refuelling means 3 or 4 additional refuelling launches, so now your cost per kg is back up to a few thousand $ per kg again. Still cheap for Ceres though.

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

#168

Post by imtringued »

simonh wrote: post #167
valuearb wrote: post #126

Earlier quoted context omitted.

The Space Shuttle payloads to LEO cost $40,000 per pound. Before SpaceX commercial launch payloads cost $5,000 to $10,000 per pound. Falcon 9 payloads cost around $1,500 per pound. Falcon Heavy payloads cost around $1,100 per pound. Starship payloads will cost between $100 and $500 per pound. It will be able to lift at least 100 tons to orbit. And using in orbit refueling, it will be able to accelerate that 100 ton p…

True, but in orbit refuelling means 3 or 4 additional refuelling launches, so now your cost per kg is back up to a few thousand $ per kg again. Still cheap for Ceres though.

Yeah, orbital refueling doesn't change the rocket equation unless you can manufacture fuel in space. The only benefit is that you don't need a bigger rocket.

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

#169

Post by guerrilla »

crowbahr wrote: post #108
walrus01 wrote: post #97

Earlier quoted context omitted.

Considering that there's organisms that live at ridiculous pressures, with absolutely no sunlight and at the extreme temperatures of deep sea volcanic vents, I would not be surprised at all. https://en.wikipedia.org/wiki/Hydrothermal_vent https://en.wikipedia.org/wiki/Hydrothermal_vent_microbial_co...

The question is can life arise in such an environment, or only migrate to one. That's yet to be determined as far as I know: extremophiles have all evolved from less tolerant life forms as far as I'm aware.

One of the theories I heard recently was that life could arise anywhere there are energy gradients, conditions for forming bubbles and the right substrates. I'm not sure how accepted that is (heard it in a popsci lecture) but it seems plausible.

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

#170

Post by walrus01 »

valuearb wrote: post #126
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…

The Space Shuttle payloads to LEO cost $40,000 per pound. Before SpaceX commercial launch payloads cost $5,000 to $10,000 per pound. Falcon 9 payloads cost around $1,500 per pound. Falcon Heavy payloads cost around $1,100 per pound. Starship payloads will cost between $100 and $500 per pound. It will be able to lift at least 100 tons to orbit. And using in orbit refueling, it will be able to accelerate that 100 ton p…

I am hopeful that Starship will really achieve those figures, but I am also skeptical... I'll believe it when I see it being done.

That's still not cheap enough to do lander/surface manipulation science in the asteroid belt without significant philanthropic or government funding.

At $500/pound, if a Ceres unmanned probe lander with drill/melting apparatus weighs 15000 kg when placed in low earth orbit (before whatever staging/fuel it expends to get to ceres and land), that's still a $16.5 million launch cost before you add the cost of the R&D to build the spacecraft, operate its command and control network, etc.

I will be very pleased and enthusiastic but also shocked if something like that is accomplished for a project budget under $30-40m in the next 20 years.

Not saying it's impossible but we're well within the realm of "big budget" science. Like the operating budgets of one of the smaller (not McMurdo or Amundsen-Scott) permanent research bases in Antarctica, or something like the this:

https://en.wikipedia.org/wiki/Chiky%C5%AB

Big enough that even top tier universities form consortia to collaborate in science projects such as the ALMA array.

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