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Liquid water 'lake' revealed on Mars

bbc.co.uk

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Re: Liquid water 'lake' revealed on Mars

#111

Post by larkeith »

ryanmercer wrote: post #36
liberte82 wrote: post #11

Why don't we send a rover to some of these interesting places? It seems like we're constantly making fascinating finds on Mars, then send rovers to the middle of a random rocky desert.

For any exploratory drilling, or covering any real amount of ground, you need humans. For reference, Opportunity Rover has only traveled 45 km/28 mi in 14 years. A human can collect more specimens in a day than ALL of the rovers have to date. If we remove this year's launch window, you have 10 minimum-energy launch windows in the next 21 years. 2020, 2022, 2024, 2026, 2029, 2031, 2033, 2035, 2037, 2039. If we could g…

> For reference, Opportunity Rover has only traveled 45 km/28 mi in 14 years.

That's actually much further than I expected - Curiosity has traveled 11 miles in 6 years, it's surprising to me that Opportunity has a faster average pace (not that it's necessarily a hugely useful metric).

Re: Liquid water 'lake' revealed on Mars

#112

Post by ryanmercer »

wilsonnb2 wrote: post #64
ryanmercer wrote: post #36

Earlier quoted context omitted.

For any exploratory drilling, or covering any real amount of ground, you need humans. For reference, Opportunity Rover has only traveled 45 km/28 mi in 14 years. A human can collect more specimens in a day than ALL of the rovers have to date. If we remove this year's launch window, you have 10 minimum-energy launch windows in the next 21 years. 2020, 2022, 2024, 2026, 2029, 2031, 2033, 2035, 2037, 2039. If we could g…

The real question here is why bother spending 1% of our GDP on space exploration? What tangible benefits is it going to bring, and why are those benefits worth more than the benefit that will come from spending 1% of our GDP on something else?

Well, unless we outlaw reproduction without government approval we will hit the limit of what the planet can support as far as human life.

Unless we start recylcing 100% of our materials we will run out of various elements we use for production of effectively everything.

Commercially available sea salt has been found contaminated with microplastics, that means are oceans are already screwed so envetually it would be nice to have a new world to do things right on.

Opening up space opens up more physical space for humans and other life, it opens up more resources for construction (asteroids contain unfathomable amounts of rare and common elements that will be easy to exploit once the appropriate technologies are developed).

Space exploration will continue to add more and more technological and general scientific breakthroughs as it has been now for several decades. Look how GPS has changed the world, it's used in everything from tracking wildlife to your watch to moving goods around the world. Literally impossible if we'd not developed a space program.

Re: Liquid water 'lake' revealed on Mars

#113

Post by forapurpose »

Tushon wrote: post #68
hossbeast wrote: post #20

Earlier quoted context omitted.

It seems like, being under ground, it would also be subject a higher than normal pressure, which would also help

(not a scientist, but was skeptical of this statement given the general "incompressibility of water") From looking at the phase change chart[0], you don't really get into the "interesting" stuff as far as pressure goes until pretty deep (something like 9-10km, from looking at some sample number of pressure at various depths [1]). Given that they indicated in the article that this is under 1.5km of ice, I don't think…

A few considerations that may influence this question:

Pressure != compression, and water is otherwise sensitive to pressure. The boiling point of water varies by ambient air pressure, and in fact, the ambient air pressure on the surface of Mars is too low for liquid water, AFAIK; it boils away.

Also, see gmueckl's helpful comment: https://news.ycombinator.com/item?id=17610197

Re: Liquid water 'lake' revealed on Mars

#114

Post by mjburgess »

dekhn wrote: post #8
tzfld wrote: post #5

>an area of high reflectivity which is thought to be water This not seems to be entirely = to 'water revealed on Mars'

Scientists have excellent language to describe these sorts of things (ambiguity and confidence in guess). For example, from the actual paper's abstract: """Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.""" It's absolutely true that we…

> """

Python? Scala?

Re: Liquid water 'lake' revealed on Mars

#115

Post by ryanmercer »

zip1234 wrote: post #51
ryanmercer wrote: post #10

Earlier quoted context omitted.

Earth's atmosphere is 78% nitrogen, 21% oxygen, 0.9% argon, and 0.03% carbon dioxide, so no. If you want to create an atmospheric pressure that humans could survive without a suit, the dry ice in the polar regions is more than enough, the trick with Mars is raising the average temperature 5C at which point you'd create a runaway greenhouse. As for just water needs, the polar regions are lousy with water ice (the nort…

I thought part of the problem was the lack of a magnetic field? I'm not sure if that has anything to do with keeping an atmosphere or just the ability to survive on the surface with radiation protection though...

The magnetic field keeps the solar winds from stripping away atmosphere, that happens in appreciable amounts on a geological time scale.

It does offer some radiation protection too but it would take centuries with current technological means to raise the temperature enough on Mars to start a runaway greenhouse effect... as it stands now you'd basically have to go set up power plants on Mars then start producing greenhouse gasses from local materials, releasing them into the atmosphere, until you got that estimated 5C average temperature increase which would then start melting the polar caps' dry ice and water ice (as well as what is in the regolith all over the planet) and go runaway. At that point you'd be outpacing what the solar winds are peeling off the atmosphere (IIRC it's something like 100 grams a second which sounds like a lot but not on a planetary scale).

Re: Liquid water 'lake' revealed on Mars

#116

Post by larkeith »

CPLX wrote: post #87
joshstrange wrote: post #66

Earlier quoted context omitted.

Love a good Monty Python reference even if most humor-only posts are discouraged on HN.

My experience has been that Monty Python and Douglas Adams references are the clear exceptions to the no humor rules on HN, though I don't suppose you'll find that written down anywhere.

From what I've seen, a bit of reasonably mature humor seems acceptable, it's just multiple posts devoted to jokes derailing the conversation where it's frowned upon. I quite like this system, as it prevents Reddit-esque threads with the same tired memes being repeated back and forth ad nauseum, but still allows for a bit of levity to lighten the conversation and provide some mental refreshment.

And yes, I realize I just called a Monty Python and the Holy Grail reference mature.

Re: Liquid water 'lake' revealed on Mars

#117

Post by AstralStorm »

Gravityloss wrote: post #101
ryanmercer wrote: post #36

Earlier quoted context omitted.

For any exploratory drilling, or covering any real amount of ground, you need humans. For reference, Opportunity Rover has only traveled 45 km/28 mi in 14 years. A human can collect more specimens in a day than ALL of the rovers have to date. If we remove this year's launch window, you have 10 minimum-energy launch windows in the next 21 years. 2020, 2022, 2024, 2026, 2029, 2031, 2033, 2035, 2037, 2039. If we could g…

Or better robots. Not more expensive ones but more launches and faster progress. One would need to iterate and tolerate some failure.

The problem is that any launch to Mars is going to be really expensive, even if you adopt the cheapest known means (currently owned by SpaceX).

It might be actually cheaper to solve ancillary problems and actually send humans one than say try 20 unmanned missions... With more benefits too.

Re: Liquid water 'lake' revealed on Mars

#118

Post by enraged_camel »

wilsonnb2 wrote: post #61
ChuckMcM wrote: post #56

Earlier quoted context omitted.

This is a false dichotomy that always annoys me. It is entirely possible that by spending $400B to safely send people to Mars and live there, especially in a moderately high radiation environment, that we will discover EXACTLY the mechanisms that send cells into cancer states and how to reverse that so they stop. Otherwise we're going to have colonists getting cancer and dying too quickly. Then not only do we get to…

It's also entirely possible that the cure for all forms of cancer is a diet consisting entirely of frosted flakes, and that spending $400B researching the effects of all-cereal diets would also discover the cure for cancer. However, it's far more likely that $400B in cancer research will do more for curing cancer than hoping for side effects from $400B in other research.

There are about a thousand things you use and benefit from everyday that were side effects of other research and spending (primarily military). But you take them for granted and so it is easy for you to make value judgments regarding how money is spent.

Re: Liquid water 'lake' revealed on Mars

#119

Post by forapurpose »

ChuckMcM wrote: post #94
wilsonnb2 wrote: post #61

Earlier quoted context omitted.

It's also entirely possible that the cure for all forms of cancer is a diet consisting entirely of frosted flakes, and that spending $400B researching the effects of all-cereal diets would also discover the cure for cancer. However, it's far more likely that $400B in cancer research will do more for curing cancer than hoping for side effects from $400B in other research.

We have already spent $500B on cancer research[1] and it hasn't cured. This also isn't an "either/or" proposition. As I mentioned, people travelling in space are subject to a lot of radiation which is known to cause cancer, so part of the research is going to be figuring out how to fix cells that are cancerous. Cancer is a systemic problem, it isn't measles or polio or TB. You have to understand the system in order t…

> We have already spent $500B on cancer research[1] and it hasn't cured

That's a pretty absolutist statement. We've spent more preventing murder, but murder still happens. We have developed many treatments for cancer that have added many quality life years for millions of people.

Re: Liquid water 'lake' revealed on Mars

#120

Post by AstralStorm »

Nadya wrote: post #96
remote_phone wrote: post #43

Earlier quoted context omitted.

I was talking to an oncologist yesterday. Her biggest frustration is that Silicon Valley billionaires are spending billions upon billions to send things to space, when there are serious problems on Earth that could be fought, most importantly cancer. It’s hard to argue with her. $400B/yr would fund a lot of research that would benefit humanity a lot better than a coordinated mission to Mars, even though it would be v…

A sufficiently sized meteor could wipe out all life on Earth as we know it - or play "Pick your end of days scenario" between WW3, superviruses, or whatever. Having a few backup humans on the Moon or Mars is more beneficial to the survival of the human race than curing cancer is. Curing cancer saves individuals - establishing an off-Earth colony of humans could save all of humanity. Are the chances of a mass extincti…

Unfortunately, super plagues still have a chance to propagate and Mars (even more so Moon) still can be bombed in the course of WW3.

That is assuming the colony actually is reasonably self sustainable, which is quite a high bar.

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