Study: Potatoes can grow on Mars • Hacker News Board

Re: Study: Potatoes can grow on Mars

#141

Post by posterboy » Sat, Mar 11, 2017, 8:37 AM UTC

astrodust wrote: post #50

ars wrote: post #37

Earlier quoted context omitted.

Celsius is equally arbitrary to Fahrenheit. No, Martians measure in Nano Yocto Planck Degrees above Absolute Zero, I hereby dub that unit the Plancktigrade.

Celsius at least has a family of units that mesh with it precisely. To heat one cubic centimetre of water up 1°C takes 1 Joule. It also essentially weighs 1 gram at normal temperatures. How many BTUs does it take to heat up one cubic foot of water by one degree Fahrenheit?

I thought Kelvin would be the appropriate unit for temperature differences, deg. Celsius be only used for absolute values.

Re: Study: Potatoes can grow on Mars

#142

Post by posterboy » Sat, Mar 11, 2017, 8:50 AM UTC

douche wrote: post #122

astrodust wrote: post #99

Earlier quoted context omitted.

I can't think of a weather station that uses decimals, the forecasts and current temperature reports are almost always whole numbers. My Nest thermostat goes to the closest 0.5°C because I guess why not, but even that seems overkill. Most systems go to the nearest whole degree. Decimals are only for those who are making a fuss over nothing unless they're doing something that requires precision, like chemistry or in r…

Good luck getting the US to ever change. I'm personally on the side that Fahrenheit is more useful for day-to-day usage, because it has a range calibrated to the temperatures experienced in the part of the world I happen to live in. But it would take a whole generation to get people to change their frame of reference into Celsius, which isn't likely to happen, because the biggest interaction people have with temperat…

So, 40 or 50 Degree for when it's dangerously hot is too hard to remember, just like 32 for freezing is somewhat easier than 37 for body temperature?

Why let's just change the numeral base to 5, or use roman numerals for that matter. Then scientists can finally stop to convert some arcane unit to get to the Standard International Base Unit, ie. Kelvin. At least everyone gets to convert their numbers then and it's only a division by two, too.

Re: Study: Potatoes can grow on Mars

#143

Post by nikosdabizas » Sun, Mar 12, 2017, 7:23 AM UTC

rmeertens wrote: post #121

nikosdabizas wrote: post #117

Hi guys, I helped build the Cubesat. Any questions: Fire away!

Hey! Great that you answer questions. A question I had was if you took the temperature into account in your experiments. A second question I has was: how similar is the sand you are using to real martian sand? Do you have any images of the resulting potatoes? Would they be edible?

So, we are regulating temperature in the cubesat. We're assuming the best conditions possible on Mars, which is summer near the equator. This means up to 20°C during the day and around zero at night (if you watch the timelapse you can occasionally see the humidity freeze and defrost, dripping on the soil)

Re: Study: Potatoes can grow on Mars

#144

Post by nikosdabizas » Sun, Mar 12, 2017, 7:25 AM UTC

TeeWEE wrote: post #120

nikosdabizas wrote: post #116

Hey guys, I helped build the Cubesat, any questions - Fire away!

What was the atmospheric pressure during the tests? Martian like?

It is about 40% of Earth's pressure. So low, but not as low as the actual pressure on Mars, which is too low to even consider. This assumes a greenhouse environment but without the necessity to create exact earth pressure, making it easier to maintain, using less energy.

Re: Study: Potatoes can grow on Mars

#145

Post by nikosdabizas » Sun, Mar 12, 2017, 7:27 AM UTC

rmeertens wrote: post #121

nikosdabizas wrote: post #117

Hi guys, I helped build the Cubesat. Any questions: Fire away!

Hey! Great that you answer questions. A question I had was if you took the temperature into account in your experiments. A second question I has was: how similar is the sand you are using to real martian sand? Do you have any images of the resulting potatoes? Would they be edible?

The sand is very similar to Martian soil samples observed by various NASA landers over the years. It comes from a very special region in the Atacama desert called Pampas De La Joya. Our lead biologist, Julio, has been doing experiments there for years. You can read more about it on potatoes.space/mars

Re: Study: Potatoes can grow on Mars

#146

Post by nikosdabizas » Sun, Mar 12, 2017, 7:29 AM UTC

rmeertens wrote: post #121

nikosdabizas wrote: post #117

Hi guys, I helped build the Cubesat. Any questions: Fire away!

Hey! Great that you answer questions. A question I had was if you took the temperature into account in your experiments. A second question I has was: how similar is the sand you are using to real martian sand? Do you have any images of the resulting potatoes? Would they be edible?

Lastly, the potatoes are still growing, but we expect them to be edible. Tests done outside the cubesat prior to this, growing potatoes in the soil from La Joya, were safe to eat.