Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Vast new stores of water reported on the moon

spectrum.ieee.org

Post reply on HN
Print view View original

131–140 of 189 posts

Re: Vast new stores of water reported on the moon

#131

Post by hutzlibu »

rikthevik wrote: post #128
areoform wrote: post #50

Every such discovery reaffirms that the moon is a time machine. Next to (or inside) the ice from the Permanently Shadowed Regions, there may be clues to how life got started on Earth. https://link.springer.com/chapter/10.1007/978-94-007-6546-7_... It's estimated that this trapped ice may be from the Earth and the Moon from 3.6B to 4.2B+ years ago. Along with other volatiles, this may give humanity an unprecedented lo…

> I'm so excited about what the future has in store for us. Me too. But sometimes I read too many snarky HN comments and I forget. We are very fortunate.

Reading ordinary news, does not help either.

Re: Vast new stores of water reported on the moon

#132

Post by credit_guy »

flavius29663 wrote: post #130
credit_guy wrote: post #113

Just to be clear, the "vast stores" of water are only theoretical. There are no implications for Moon colonies. You are not going to try to extract water from glass beads. You would need to go through thousands of tons of regolith before extracting a single liter of water, and that's only if you have 100% efficiency, which you will not have. If we ever decide to have Moon colonies we'll have 3 big problems: we won't…

> since your weight in carbon, hydrogen and nitrogen will exceed many times your weight in gold Your weight is the same in any element, maybe you meant your worth?

Yes, good point.

Re: Vast new stores of water reported on the moon

#133

Post by johnwalkr »

chiefalchemist wrote: post #97
TaylorAlexander wrote: post #54

Earlier quoted context omitted.

Reminder that the moon does not have a "dark side". This is a misnomer. The back of the moon gets the same amount of sunlight as the front. Unless you mean the side which is not presently illuminated. Water could freeze there but it would boil off again when the sun lights it up again. However there are craters at the poles that never experience sunlight, and water does accumulate in them. You don't need any atmosphe…

Why does the water vapor gravitate to the poles? Also, if there is X amount of water, and ever thaw / freeze cycle loses some amount Y, can't we estimate what X was Z years ago?

It doesn't really gravitate to the poles, it's just that once water reaches a permanently shadowed bit of a crater, it stays there forever.

Re: Vast new stores of water reported on the moon

#134

Post by slashdev »

Firadeoclus wrote: post #125
credit_guy wrote: post #113

Just to be clear, the "vast stores" of water are only theoretical. There are no implications for Moon colonies. You are not going to try to extract water from glass beads. You would need to go through thousands of tons of regolith before extracting a single liter of water, and that's only if you have 100% efficiency, which you will not have. If we ever decide to have Moon colonies we'll have 3 big problems: we won't…

Certainly, getting those elements in larger quantities will be important, but by the time we have the cargo capacity to build colonies on the moon it seems likely that someone would be very happy to trade, say, 100t of Earth-sourced C/N/H for 100t of Moon-mined Au, shipping included.

I don’t expect there to be much in the way of heavy elements on the moon. It’s mostly made of lighter stuff that got blasted off in the collision with earth when the moon was formed.

Re: Vast new stores of water reported on the moon

#135

Post by mucle6 »

areoform wrote: post #50

Every such discovery reaffirms that the moon is a time machine. Next to (or inside) the ice from the Permanently Shadowed Regions, there may be clues to how life got started on Earth. https://link.springer.com/chapter/10.1007/978-94-007-6546-7_... It's estimated that this trapped ice may be from the Earth and the Moon from 3.6B to 4.2B+ years ago. Along with other volatiles, this may give humanity an unprecedented lo…

time capsule*

Re: Vast new stores of water reported on the moon

#136

Post by stametseater »

drtgh wrote: post #102
Simon_O_Rourke wrote: post #53

It's only a matter of time now before we get the first craft brewery and tap room on the Moon.

The radiation level exposure on the Moon is estimated to be around 60 microsieverts every hour [1], while the limit of amount of radiation received by the general public in a year is set to 1'000 microsieverts (1 millisievert) [2]. It would then be necessary to be achieved the regenerative medicine in the first place, with a major revolution in radiation shielding technology. Unfortunately does not appear to be on th…

60 microseverts an hour works out to about 525 millisieverts (mSv) per year. The general public limit is set very low, so for additional reference, the annual limit for emergency worker was raised to 250 mSv per year after Fukushima, half of what you'd get on the Moon. An effective dose (whole body, sum of all equivalent doses for the organs) of 200 mSv is enough to increase your risk of fatal cancer from 25% to 26%, so 525 mSv obviously represents a substantial stochastic risk.

The ICRP occupational equivalent dose limit for hands, feet and skin are 500 mSv per year, so for these you're under the limit (the 525 mSv effective dose above is spread across you, not on one organ). However the equivalent dose limit for eyes is 20 mSv average with no more than 50 mSv per year. I haven't done the math but I think 525 mSv effective dose over a year would put you at substantial risk of deterministic damage to the lenses of your eyes.

In other words, Moon men probably get cataracts and are more likely to die of cancer.

Re: Vast new stores of water reported on the moon

#137

Post by Retric »

slashdev wrote: post #134
Firadeoclus wrote: post #125

Earlier quoted context omitted.

Certainly, getting those elements in larger quantities will be important, but by the time we have the cargo capacity to build colonies on the moon it seems likely that someone would be very happy to trade, say, 100t of Earth-sourced C/N/H for 100t of Moon-mined Au, shipping included.

I don’t expect there to be much in the way of heavy elements on the moon. It’s mostly made of lighter stuff that got blasted off in the collision with earth when the moon was formed.

The surface has been slowly bombarded long after the moons creation. So surface mining could have a very different elemental mix than subsurface mining.

~48.5 tons of material hits the earth’s atmosphere per day. The moons smaller, but suck impacts where likely more common in the past * 4 billion years and you’re talking a few feet of such material across the entire surface. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/me...

Re: Vast new stores of water reported on the moon

#138

Post by csomar »

slashdev wrote: post #134
Firadeoclus wrote: post #125

Earlier quoted context omitted.

Certainly, getting those elements in larger quantities will be important, but by the time we have the cargo capacity to build colonies on the moon it seems likely that someone would be very happy to trade, say, 100t of Earth-sourced C/N/H for 100t of Moon-mined Au, shipping included.

I don’t expect there to be much in the way of heavy elements on the moon. It’s mostly made of lighter stuff that got blasted off in the collision with earth when the moon was formed.

But shipping from the moon to the earth should be much cheaper? I don't have the math (so someone please do?) but based on the size of the Apollo 11, it seems to be trivial to send stuff to earth.

Re: Vast new stores of water reported on the moon

#139

Post by stametseater »

drtgh wrote: post #111
Brendinooo wrote: post #106

Earlier quoted context omitted.

If water is plentiful and accessible, that could be used as shielding, no?

It is not my field, but if plentiful and accessible, we are talking about several thousand tonnes of water around a small habitat that could theoretically be used. Nevertheless, if I understood right, that immense amount of water would have a limited shelf life until acidification corrodes the containment structures, so it would need to be continuously treated and refrigerated, " Ionizing cosmic radiation is mostly g…

Chemically neutralizing the shielding water should be trivial. But why would the water need to be refrigerated? Energy absorbed from radiation would be emitted as thermal radiation, and lose a ton of thermal energy during the long lunar nights. If well insulated, the water tanks could serve as thermal batteries to keep the rest of the base warm.

Re: Vast new stores of water reported on the moon

#140

Post by stametseater »

thaumasiotes wrote: post #68
TaylorAlexander wrote: post #54

Earlier quoted context omitted.

Reminder that the moon does not have a "dark side". This is a misnomer. The back of the moon gets the same amount of sunlight as the front. Unless you mean the side which is not presently illuminated. Water could freeze there but it would boil off again when the sun lights it up again. However there are craters at the poles that never experience sunlight, and water does accumulate in them. You don't need any atmosphe…

> Reminder that the moon does not have a "dark side". This is a misnomer. It isn't. The side of the moon that cannot be seen from Earth is called the dark side of the moon. It's called that for the same reason that the Dark Ages are called dark: because we can't see them. It is true that the dark side of the moon gets just as much sunlight as the light side does.

The context was thermal energy received from the sun, not attention received from man.

Your clap-back might make sense when somebody is criticizing Pink Floyd, but it doesn't make sense here.

Post reply on HN