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Mars likely to have enough oxygen to support life: study

phys.org

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Re: Mars likely to have enough oxygen to support life: study

#121

Post by raducu »

fuscy wrote: post #105
lmm wrote: post #101

Earlier quoted context omitted.

I can't see any path to colonising the galaxy that doesn't start with colonising the solar system. It's always going to be a long term project, there are always going to be things on earth that look like more immediate priorities, but I want humanity to spread among the stars, and if we don't start now then when?

Humans are terribly designed for space exploration: die quickly, require sustenance, can't handle high G forces, can't handle radiation. I always believed that if humanity is to colonize something, it would be through robots that do all the exploring and mining for us.

What's wrong with low G tolerance for interstellar travel? If speed of light is ~310^8, 1G ~ 10m/s^2, you would need (ignoring reletivistic effects) 310^7 seconds to reach the speed of light. There are 86400 seconds in a day, so you would need ~347 days to reach the speed of light if you were accelerating at 1G, were it not for relativistic effects.

Re: Mars likely to have enough oxygen to support life: study

#122

Post by adrianN »

coldtea wrote: post #74
ryanSrich wrote: post #15

Earlier quoted context omitted.

We have to start somewhere that isn’t earth. Interstellar travel over the next 100-1000 years will be a requirement for the next 5000-10000 years if humans expect to survive that long. Starting development now to understand terraforming and building out the primitives that allow for it in the future is something we owe to generations to come.

> Interstellar travel over the next 100-1000 years will be a requirement for the next 5000-10000 years if humans expect to survive that long. Given the mechanics, interstellar travel will most likely always be a pipe dream, because techies still have to believe to some fairy tales... http://www.antipope.org/charlie/blog-static/2007/06/the_high... http://www.antipope.org/charlie/blog-static/2009/11/the_myth...

Nuclear pulse propulsion[1] was deemed doable with 1960's technology and can accelerate several hundred tons of payload enough to reach the nearest stars in a couple of generations. This doesn't require any magic, just lots of money and nukes.

[1] https://en.wikipedia.org/wiki/Nuclear_pulse_propulsion

Re: Mars likely to have enough oxygen to support life: study

#123

Post by wongarsu »

fuscy wrote: post #105
lmm wrote: post #101

Earlier quoted context omitted.

I can't see any path to colonising the galaxy that doesn't start with colonising the solar system. It's always going to be a long term project, there are always going to be things on earth that look like more immediate priorities, but I want humanity to spread among the stars, and if we don't start now then when?

Humans are terribly designed for space exploration: die quickly, require sustenance, can't handle high G forces, can't handle radiation. I always believed that if humanity is to colonize something, it would be through robots that do all the exploring and mining for us.

Astronauts have traveled further on the moon on the three missions that included the Lunar Roving Vehicle than all our mars rovers managed combined.

If you give a mars rover a command, it takes an average of 12 minutes for that command to reach mars, and another 12 minutes for the confirmation to come back. That makes remote control very hard, and we aren't all that good with autonomous robots.

So until we figure that whole artificial intelligence thing out humans are a much better bet for getting significant amounts of science and mining done than robots.

Re: Mars likely to have enough oxygen to support life: study

#124

Post by wnkrshm »

verelo wrote: post #6
dymk wrote: post #5

Earlier quoted context omitted.

But surely terraforming a barren wasteland is going to be easier than terraforming a (relative) oasis of life! But in all seriousness, the point of colonizing Mars is not to be a replacement for Earth (although redundancy is quite motivating). It's because colonization and population growth has been our MO for the last 200,000 years.

But, why fixate on turning one planet into “habitable” while we do the opposite to the one we are already on? I’d like to see us address those issues of society first before we spread our influence across the literal galaxy.

I always wonder why people think that there's so much money you can take away from space exploration R&D when the whole sector is basically really tiny and funded on a comparable magnitude of public broadcasting in some countries (e.g. NASA's yearly budget of 16 billion EUR vs. Germany's public broadcasting budget of 8 billion EUR).

The discussions ensuing about the usefulness of space exploration are always passionate and of course argue the humanitarian point of using that money to better our planet before doing anything somewhere else.

How much combat ship, Nth generation fighter, railgun and hypersonic weapon R&D do you get for the same price?

Re: Mars likely to have enough oxygen to support life: study

#125

Post by raducu »

adrianN wrote: post #116
richardknop wrote: post #97

Earlier quoted context omitted.

What are the current thoughts on what caused oceans on Mars to disappear (with some remainder concentrating in ice caps)? Was it some impact of a really big meteor/comet? It is accepted that Mars used to have liquid water oceans and rivers in the past, correct? You can see geological remains of rivers and oceans, for example, quite clearly on Mars.

Mars gravitiy is not strong enough causing it to very slowly lose gases to the solar wind. Water vapor included.

I wonder if it's the solar wind or just the escape velocity vs. the termal escape.

I'm sure in a couple of centuries humans would be able to build superconducting magnets powerful enough to shield Mars from the solar wind (those would double as energy storage as well), but we can't do anything about the fundamental properties of gases and escape velocity.

Re: Mars likely to have enough oxygen to support life: study

#126

Post by cbkeller »

adrianN wrote: post #116
richardknop wrote: post #97

Earlier quoted context omitted.

What are the current thoughts on what caused oceans on Mars to disappear (with some remainder concentrating in ice caps)? Was it some impact of a really big meteor/comet? It is accepted that Mars used to have liquid water oceans and rivers in the past, correct? You can see geological remains of rivers and oceans, for example, quite clearly on Mars.

Mars gravitiy is not strong enough causing it to very slowly lose gases to the solar wind. Water vapor included.

Yep! Plus the lack of a magnetic field, which is largely also due to Mars being too small, and losing heat too fast to have any liquid metal convecting in the core anymore

Re: Mars likely to have enough oxygen to support life: study

#127

Post by TheSpiceIsLife »

sebazzz wrote: post #81
thaumasiotes wrote: post #71

Earlier quoted context omitted.

To be fair, most of your Earth facts don't apply to the more inhospitable areas of Earth, where people live anyway. The Sahara and the Arctic both feature a breathable atmosphere. The Arctic is missing the other four items. The Sahara will let you feel sunlight on your face if you want, but it isn't really recommended. "Breathable atmosphere" is a much bigger deal than everything else.

True, and heat. We can tolerate heat better than cold, also from a technical perspective. Heat can be used for energy production as well.

To produce energy you need a temperature gradient.

Re: Mars likely to have enough oxygen to support life: study

#128

Post by adrianN »

bobm_kite9 wrote: post #110
sigstoat wrote: post #27

Earlier quoted context omitted.

there are other, significantly more effective, greenhouse gases.

I thought the absence of a magnetosphere would mean that any atmosphere would be stripped away by solar radiation anyway?

Over millions of years.

Re: Mars likely to have enough oxygen to support life: study

#129

Post by wongarsu »

sebazzz wrote: post #81
thaumasiotes wrote: post #71

Earlier quoted context omitted.

To be fair, most of your Earth facts don't apply to the more inhospitable areas of Earth, where people live anyway. The Sahara and the Arctic both feature a breathable atmosphere. The Arctic is missing the other four items. The Sahara will let you feel sunlight on your face if you want, but it isn't really recommended. "Breathable atmosphere" is a much bigger deal than everything else.

True, and heat. We can tolerate heat better than cold, also from a technical perspective. Heat can be used for energy production as well.

Our comfortable temperature is around 25°C. Let's set that as our baseline. In dry conditions we can bear about 90°C above that for a few minutes and only about 20°C above baseline sustained. In comparison we have many permanent settlements where days 75°C below baseline are a yearly occurrence.

If we talk about the more humid climates found in much of Europe and the US, the weaker members of our society start dying on days just 15°C above baseline.

I think we handle cold much better than heat.

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