I imagine one of the biggest challenges is removal of perchlorate salts from the regolith.
Study: Potatoes can grow on Mars
81–90 of 146 posts
Re: Study: Potatoes can grow on Mars
#82Earlier quoted context omitted.
The actor is Matt Damon. Parent spelled it Matt Daemon, as in a hypothetical *nix process at /sbin/mattd
If this were Reddit we could keep this going until we had a meme about Matt Damon running in the background of movies, and a whole corpus of images where he's been photoshopped to be doing just that. Now I'm kind of regretting this conversation isn't on Reddit.
You can fix that, you know.
Re: Study: Potatoes can grow on Mars
#83Why exactly did this experiment require a satellite? For biological purposes Martian gravity is probably closer to Earth gravity than to microgravity, and all the other conditions could be reproduced for cheaper and at larger scale in a ground laboratory. This smells of a publicity stunt to me.
Martian gravity is lower than earth gravity, and if the test was run in earth like gravity there could be concerns that that variable would have an effect. By conducting the experiment in lower gravity than Mars's, it's hard to doubt that martian gravity would pose a problem.
Practically speaking, honest question, how do we simulate lower gravity for extended periods other than orbit? Seems hard.
Re: Study: Potatoes can grow on Mars
#84Earlier quoted context omitted.
Yeah, but a pound of water is not a cubic foot. A pint has nothing to do with inches.
That has nothing to do with temperature. You can keep metric and use Fahrenheit with very little change. And you got your units wrong anyway: "To heat one cubic centimetre of water up 1°C takes 1 Joule" - you mean 1 calorie, not 1 Joule. Change Celsius to Fahrenheit and only calorie changes, and since it's anyway not part of SI it makes little difference. Joule is the main energy unit, and it's not tied to Celsius at…
A difference in temperature has the same numerical value in both degrees C and K. Often differences in temperature are all we're interested in so C is often interchangeable with K.
If you use Fahrenheit, then you lose that easy relationship unless you also use Rankine for absolute temperature. But nobody, not even Americans, has even heard of Rankine so it would be a far bigger challenge to get anyone to use that than just Fahrenheit alone.
Perhaps an even more elegant unit for temperature would be thermal energy per degree of freedom per particle, which would be joules in SI. I'm not sure if that's really correct tho.
Re: Study: Potatoes can grow on Mars
#85Earlier quoted context omitted.
It takes one BTU to heat one pound of water, one pint, one degree Fahrenheit. The units may be arbitrary, but they still line up.
Yeah, but a pound of water is not a cubic foot. A pint has nothing to do with inches.
Yeah, but inches are a unit of length and pint is a unit of volume. Therefore a pint is more relevant here. Yeah technically a cubic inch/foot is volume, but it's not the purpose-built one.
To be honest, the volume system in US customary is the only one that makes sense. Everything's power-of-two friendly. If we could revise the others to mesh with that idea then we could have one power-of-10 system (metric) and then a power-of-two system.
Re: Study: Potatoes can grow on Mars
#86Earlier quoted context omitted.
Any central public library is fully stocked on Asimov.
It seems that this short story was originally published in an old science fiction magazine (that my local library doesn't stock). Was wondering if it also made its way into a compilation of some sort. Google hasn't turned up anything for me yet.
Contained in "Buy Jupiter and Other Stories"
Available on amazon (https://www.amazon.com/Jupiter-Other-Stories-Isaac-Asimov/dp...)
Re: Study: Potatoes can grow on Mars
#87Earlier quoted context omitted.
Yeah, but a pound of water is not a cubic foot. A pint has nothing to do with inches.
That has nothing to do with temperature. You can keep metric and use Fahrenheit with very little change. And you got your units wrong anyway: "To heat one cubic centimetre of water up 1°C takes 1 Joule" - you mean 1 calorie, not 1 Joule. Change Celsius to Fahrenheit and only calorie changes, and since it's anyway not part of SI it makes little difference. Joule is the main energy unit, and it's not tied to Celsius at…
Ah, you're right about calorie vs. Joule. That is a bit rough around the edges.
> For temperature Fahrenheit is the better scale.
Yeah, no. It's a stupid system. It's not even calibrated properly. 100° was supposed to be body temperature. They got it wrong. 0° was the lowest temperature they could measure at the time because that's when mercury froze. That's so useful! I really want to know if the mercury I carry around all the time is going to freeze outside.
Meanwhile °C is simple: 0°C is "watch for ice" and 100°C is "water boils" (minus altitude factor).
I don't know how you can praise Kelvin and slam Celsius since they're the same "size", it's just that the zero point of Kelvin was set to absolute zero instead of the freezing point of water. °C = °K + 273.15. That's it.
Re: Study: Potatoes can grow on Mars
#88Earlier quoted context omitted.
Yeah, but a pound of water is not a cubic foot. A pint has nothing to do with inches.
Yeah, but inches are a unit of length and pint is a unit of volume. Therefore a pint is more relevant here. Yeah technically a cubic inch/foot is volume, but it's not the purpose-built one. To be honest, the volume system in US customary is the only one that makes sense. Everything's power-of-two friendly. If we could revise the others to mesh with that idea then we could have one power-of-10 system (metric) and then…
That's why there's acre-feet! Because gallons aren't good enough.
Re: Study: Potatoes can grow on Mars
#89Earlier quoted context omitted.
Any central public library is fully stocked on Asimov.
It seems that this short story was originally published in an old science fiction magazine (that my local library doesn't stock). Was wondering if it also made its way into a compilation of some sort. Google hasn't turned up anything for me yet.
Is this the story? http://www.young-adult-books.com/read/buy-jupiter-and-other-... (link says "buy", but looks like the entire story is on that page)
Re: Study: Potatoes can grow on Mars
#90Earlier quoted context omitted.
That has nothing to do with temperature. You can keep metric and use Fahrenheit with very little change. And you got your units wrong anyway: "To heat one cubic centimetre of water up 1°C takes 1 Joule" - you mean 1 calorie, not 1 Joule. Change Celsius to Fahrenheit and only calorie changes, and since it's anyway not part of SI it makes little difference. Joule is the main energy unit, and it's not tied to Celsius at…
Ah, you're right about calorie vs. Joule. That is a bit rough around the edges. > For temperature Fahrenheit is the better scale. Yeah, no. It's a stupid system. It's not even calibrated properly. 100° was supposed to be body temperature. They got it wrong. 0° was the lowest temperature they could measure at the time because that's when mercury froze. That's so useful! I really want to know if the mercury I carry aro…
> That is a bit rough around the edges.
Correct. It would be one thing if Celsius is somehow tied into the rest of the SI units, but it is not, which means we can replace it.
> It's not even calibrated properly.
Who cares if they got the calibration of Fahrenheit wrong, at the end of the day it's more usable than Celsius for humans.
0 Fahrenheit is the temperature when it's really cold outside, 100 is when it's hot. It doesn't get simpler than that. If you are outside those ranges you need to take special precautions. No, I don't care about mercury either, but I do care to know when it's cold.
It's not that hard to remember 32 for ice. With Celsius you need to deal with negative temperatures all the time, and worse, the size of the degrees is too coarse.
> 100°C is "water boils"
And exactly how often do you need to measure the temperature when water boils? Probably about as often as I freeze mercury. So 100 is a very useless range on Celsius - you are using your "best" numerical range on useless temperatures.
On the other hand it's quite common to want to know when it's hot enough that you will sweat. Above 100 (body temperature) you will sweat.
Labs and Ovens don't really care about which exact unit, so let them deal with the higher (or lower) numbers - the only time it matters is for ordinary humans checking the weather.
> I don't know how you can praise Kelvin and slam Celsius
You misread, I did not praise Kelvin, I said we could replace it.