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Earth-like planet spotted orbiting Sun’s closest star

nature.com

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Re: Earth-like planet spotted orbiting Sun’s closest star

#271

Post by ncmncm »

mannerheim wrote: post #259
spaetzleesser wrote: post #199

Earlier quoted context omitted.

Then create one in the Sahara or the Atacana desert at 5000m elevation. Still way easier than Mars.

They are certainly easier, but how useful are they? A base on Mars will bring down the fuel requirements to exploring and exploiting the belt and outer planets tremendously. Missions that are impossible or uneconomical to do from Earth could be made possible and cheap if launched from Mars.

Anything that seems easier from Mars is overwhelmingly easier without stopping at Mars first. Even Phobos would be a better choice.

The only thing Mars has going for it is hype.

Re: Earth-like planet spotted orbiting Sun’s closest star

#272

Post by qwytw »

ethbr0 wrote: post #242
qwytw wrote: post #224

Earlier quoted context omitted.

How would the increase in the number of nuclear power plants lead to more nuclear weapons? There is no direct connection besides edge cases like Iran using it as a cover to develop nuclear weapons.

Someone please correct me if I'm speaking inaccurately, but early reactor design (1950s/60s/70s) focused on light water reactors, which meant enriched U-235 fuel (@ ~3%?). By design, these reactors also convert a portion of their U-238 to P-239, only some of which is then consumed in the reactor. Consequently, for widespread nuclear reactors (read: in many countries), you also had widespread proliferation of lightly…

The number of new nuclear reactors only stopped growing in the 80's. In any case I don't think access to material is the limiting factor in nuclear proliferation. If we're talking about the US and USSR, it's completely irrelevant, even if they had 100x more reactors since they already have more than enough bombs to more or less to blow up the entire world. Other western countries either have enough nukes already or don't need or want them and I don't see why would they export technology or material to countries which are hostile to them.

It's not obvious to me that having more nuclear reactors in the US, Britain or Germany would had made it significantly easier for rogue states like Iraq, Iran or North Korea to developed nuclear weapons.

Re: Earth-like planet spotted orbiting Sun’s closest star

#273

Post by mannerheim »

ncmncm wrote: post #271
mannerheim wrote: post #259

Earlier quoted context omitted.

They are certainly easier, but how useful are they? A base on Mars will bring down the fuel requirements to exploring and exploiting the belt and outer planets tremendously. Missions that are impossible or uneconomical to do from Earth could be made possible and cheap if launched from Mars.

Anything that seems easier from Mars is overwhelmingly easier without stopping at Mars first. Even Phobos would be a better choice. The only thing Mars has going for it is hype.

You need some way to make fuel and propellant, though. Phobos would be a great choice for a launchpad, but in such a scenario you would do ISRU on Mars and lift fuel and propellant there - which will be much more efficient than on Earth, since there's less gravity and less atmosphere.

Re: Earth-like planet spotted orbiting Sun’s closest star

#274

Post by mannerheim »

ncmncm wrote: post #270
mannerheim wrote: post #213

Earlier quoted context omitted.

Mars can already be useful as a springboard for space exploration. It's a literal stepping stone, both closer to the belt and outer planets in terms of distance, but also in terms of delta-v, since both the gravity well on Mars is smaller, and it's higher up in the Sun's gravity well, too. Any future space exploration and exploitation will be made tremendously easier if you can launch from Mars instead of Earth.

Mars is, even at absolute best, a dump: dry, cold, airless, at the bottom of a gravity well, and subject to dust storms besides. We can build much better outside of gravity wells. Whatever you would land on Mars is more useful in solar orbit, parked next to any convenient asteroid.

Admittedly my knowledge on this matter derives from KSP, but I've found that rendezvous is much trickier outside of gravity wells.

And there's still the problem of ISRU.

Re: Earth-like planet spotted orbiting Sun’s closest star

#275

Post by ncmncm »

BurningFrog wrote: post #210
spaetzleesser wrote: post #64

Earlier quoted context omitted.

Going to Mars seems pretty useless to me at this time. It’s a super hostile environment and we don’t have the technology yet to have a self sustaining base there. Give it a few decades and progress in robotics will make a Mars base much easier. There is plenty of work to be done on Earth. We have to solve clean energy production and in general reduce pollution. These are massive technological challenges that deserve…

If you think going to Mars is useless, don't go. Just don't stand in the way of those who chose to go.

By all means, go. But pay for it yourself. If you can't personally afford Mars, the middle of the Sahara Desert is unoccupied and overwhelmingly easier and cheaper to get established in. Or, under the ice in Greenland. Or, revitalize an abandoned whaling station on an island off Antarctica. If those seem uninviting, I promise Mars will be a thousand times moreso.

Your "golly I'm on Mars!" euphoria would thin out very, very fast. "This place f'n sucks!" malaise would grow steadily and without bound.

Re: Earth-like planet spotted orbiting Sun’s closest star

#276

Post by s1artibartfast »

jrumbut wrote: post #265
ncmncm wrote: post #250

Earlier quoted context omitted.

Mercury orbits in 88 days. This other place orbits in 5 days. And Mercury is almost tidally locked. Venus will be, before long.

For us kids at the back of the class, how are those two facts related? Why couldn't something orbit the star fast without being tidally locked?

Rotational drag depends on distance between the star and planet.

Planets with fast orbits are closer to the star and get more drag- hence more likely to be locked.

Re: Earth-like planet spotted orbiting Sun’s closest star

#277

Post by ethbr0 »

qwytw wrote: post #272
ethbr0 wrote: post #242

Earlier quoted context omitted.

Someone please correct me if I'm speaking inaccurately, but early reactor design (1950s/60s/70s) focused on light water reactors, which meant enriched U-235 fuel (@ ~3%?). By design, these reactors also convert a portion of their U-238 to P-239, only some of which is then consumed in the reactor. Consequently, for widespread nuclear reactors (read: in many countries), you also had widespread proliferation of lightly…

The number of new nuclear reactors only stopped growing in the 80's. In any case I don't think access to material is the limiting factor in nuclear proliferation. If we're talking about the US and USSR, it's completely irrelevant, even if they had 100x more reactors since they already have more than enough bombs to more or less to blow up the entire world. Other western countries either have enough nukes already or d…

So you're talking about having more nuclear power, but only in First World economies?

That seems... ethically dubious.

Re: Earth-like planet spotted orbiting Sun’s closest star

#278

Post by ncmncm »

s1artibartfast wrote: post #177
semi-extrinsic wrote: post #60

Earlier quoted context omitted.

Maybe an unpopular opinion, but Musk is just plain wrong when he thinks there is any urgency to Mars exploration (or it's just vicarious arguments because rockets are cool). Basically, the tech you need to make a Mars colony truly self sufficient is something like a compact fusion powerplant. Before we have that, no point in worrying about using Mars as a "backup plan", because if Earth was screwed, Mars would have a…

>And obviously it would be vastly better for humanity if Musk spent money on zero-emission large scale energy production, than on rockets. Classic zero sum thinking. Spacex doesn't cost money, it makes it. How much money do you think Musk put into it? The answer is ~100 million seed. It is now worth 35,000 million. How far do you think that 100m would go to develop fusion. The ITER project alone costs 65,000 million.

While US gov't put in $billions. But who kept ownership? Mars hype turns out to be good for drawing money out of governments.

ITER is a dead end, no matter what, so not a useful data point.

Re: Earth-like planet spotted orbiting Sun’s closest star

#279

Post by s1artibartfast »

ncmncm wrote: post #275
BurningFrog wrote: post #210

Earlier quoted context omitted.

If you think going to Mars is useless, don't go. Just don't stand in the way of those who chose to go.

By all means, go . But pay for it yourself. If you can't personally afford Mars, the middle of the Sahara Desert is unoccupied and overwhelmingly easier and cheaper to get established in. Or, under the ice in Greenland. Or, revitalize an abandoned whaling station on an island off Antarctica. If those seem uninviting, I promise Mars will be a thousand times moreso. Your "golly I'm on Mars!" euphoria would thin out ver…

So we have this thing called a government that we give money too. Different people want it to do different things. You can recognize that while you may pay for things you dont want, other people are paying for the things that you want but they dont.

Re: Earth-like planet spotted orbiting Sun’s closest star

#280

Post by ncmncm »

moffkalast wrote: post #115
semi-extrinsic wrote: post #60

Earlier quoted context omitted.

Maybe an unpopular opinion, but Musk is just plain wrong when he thinks there is any urgency to Mars exploration (or it's just vicarious arguments because rockets are cool). Basically, the tech you need to make a Mars colony truly self sufficient is something like a compact fusion powerplant. Before we have that, no point in worrying about using Mars as a "backup plan", because if Earth was screwed, Mars would have a…

There is an inherent urgency in all of his plans, mainly because he wants to see it done within his lifetime. He's got 40 years left tops, but more like 20 during which he could still theoretically do anything significant in. Rockets take decades to develop.

The urgency is because you can fool enough people only so long before they catch on and recognize what they are being sold.
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