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Liquid water 'lake' revealed on Mars

bbc.co.uk

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Re: Liquid water 'lake' revealed on Mars

#81

Post by beamatronic »

hoorayimhelping wrote: post #25
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.

A couple of reasons. The first is that to make a mission to Mars cost effective, we have to wait about 18 months for Earth and Mars to line up in the right positions, otherwise it costs too much in rocket fuel to be worthwhile. The second is that the missions lag behind the discoveries - it's much easier to analyze pictures and spectographs than it is to design a mission, secure funding for it, and then do it. Sendin…

We have a proven design in Spirit/Opportunity. There should be an assembly line cranking them out.

Re: Liquid water 'lake' revealed on Mars

#82

Post by wilsonnb2 »

endtime wrote: post #74
wilsonnb2 wrote: post #65

Earlier quoted context omitted.

> Getting off this rock is the first step towards getting all of our eggs out of one basket. Yes it is, but why should I care whether all of our eggs are in one basket, or two baskets, or a million baskets? The survival of the human race as a whole is not a concern of mine.

Then why do you expect anyone to value your opinion on what to do with human-race-as-a-whole-scale resources?

Because I care to what happens about all living humans today. I simply don't care about the long term survival of our species.

Spreading across the galaxy or the universe so that there can be more humans alive or to ensure that if one planet gets wiped out, some humans live on are placing value on the existence of humans as a species in the universe. That's what I don't care about. I don't think we have intrinsic value that needs to be preserved.

Re: Liquid water 'lake' revealed on Mars

#83

Post by gmueckl »

AnimalMuppet wrote: post #59
simias wrote: post #27

Earlier quoted context omitted.

I was wondering about that, how deep is it exactly? If TFA mentions it I missed it. Given the planet's low gravity and very thin atmosphere I presume it must be pretty deep in order to remain liquid. They mention Lake Vostok at the end of the article which is 4km deep but it's probably not directly comparable.

It says 1.5 km down. I'd expect there to be significant pressure down there. Enough to make it liquid at -10C? I suspect so, but I'm not an expert on the pressure gradient on Mars...

Mars only has a surface gravity of about 3.71m/s^2 compared to Earth's 9.81m/s^2. This means that 1.5km of ice will just create something like 0.38 times the pressure the same column of ice of the same density would create here on Earth. If this ice were densely packed, the mass of a 1m^2 column of ice that high would be a bit less than 1400 tons. This creates a pressure of 5.1MPa or around 51 bar.

Now if I could get my hand on a phase diagram for water on which I could find that point (263K, 5.1MPa) I could tell you how close pure ice is to melting under these conditions.

Re: Liquid water 'lake' revealed on Mars

#84

Post by wastedhours »

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?

The real question here is why bother spending 1% of our GDP on anything?

It's the same argument as to why we shouldn't invest in infrastructure "don't build those high speed train routes, we'll only see the benefit in 30 years" - space exploration is an investment in the future, and like a lot of investments, the potential payoff is variable but we can never know without trying.

If we take a VC analogy (being here on HN and all), then you might as well utilise some of your fund on a literal moonshot - if it fails, you scrub it off, take the learnings (and employ, I suspect, a tonne of people in jobs trying to make it happen). If it wins, you get your outsized outcome to 10x.

Sometimes we need state actors to make big bets - like investing in CERN (which has given us the WWW, the LHC, etc...).

Re: Liquid water 'lake' revealed on Mars

#85

Post by softawre »

zilian wrote: post #73
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…

That's a mainstream argument against space exploration. We could then apply it to, "we could try to feed everybody before developing new medication for the rich"... We can tackle many problems at once and we have to ask ourselves : what's the goal of humanity ? Also : are we safe forever on Earth ?

> are we safe forever on Earth ?

and that's why Mars exploration is more important than curing cancer. Cancer is unlikely to kill everyone of us all at once.

Re: Liquid water 'lake' revealed on Mars

#86

Post by waiquoo »

remote_phone wrote: post #43
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…

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…

To be fair, dealing with radiation induced carcinogenesis is already on NASA's radar (https://humanresearchroadmap.nasa.gov/risks/risk.aspx?i=96). Any long-term space mission will require mitigating cancer risk, which is probably about as close to a cure that we can reasonably hope for. So the two (space travel and cancer) are actually very closely linked.

Re: Liquid water 'lake' revealed on Mars

#87

Post by CPLX »

joshstrange wrote: post #66
keketi wrote: post #37

Earlier quoted context omitted.

NASA scientist: I built this space mission up from nothing. When I started, all I had was a martian lake! Other scientists said I was daft to send a rover into a lake, but I sent it all the same, just to show 'em! It sank into the lake, so I built a second one. That sank into the lake. I built a third one. It got stuck, fell over, and then it sank into the lake. But the fourth one floated! And that's what you're goin…

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.

Re: Liquid water 'lake' revealed on Mars

#88

Post by softawre »

wilsonnb2 wrote: post #82
endtime wrote: post #74

Earlier quoted context omitted.

Then why do you expect anyone to value your opinion on what to do with human-race-as-a-whole-scale resources?

Because I care to what happens about all living humans today. I simply don't care about the long term survival of our species. Spreading across the galaxy or the universe so that there can be more humans alive or to ensure that if one planet gets wiped out, some humans live on are placing value on the existence of humans as a species in the universe. That's what I don't care about. I don't think we have intrinsic val…

How many generations down do you care about? Do you think fixing global warming is a waste of time, if it might affect 3 generations down?

Re: Liquid water 'lake' revealed on Mars

#89

Post by Thaxll »

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…

Or just decrease the insane US defense budget.
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