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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

#301

Post by messe »

messe wrote: post #246
thereddaikon wrote: post #222

Earlier quoted context omitted.

Oh man, I hadn't heard about that. Best of luck to him but he's right prostate cancer is a pretty bad one. What are the other few sites you do know of? And you are absolutely right about the rocket equation. You can't really get around it.

I'm sure there's more but the first few that come to mind are Greg Egan's homepage[1], Xenology[2], and on a completely different topic "Gramadach na Gaeilge"[3] (Irish Grammar). [1]: https://gregegan.net [2]: https://xenology.info [3]: http://nualeargais.ie/gnag/gram.htm

It's too late to edit, but the link to xenology should be http and not https:

[2]: http://xenology.info

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

#302

Post by ncmncm »

mannerheim wrote: post #298
ncmncm wrote: post #297

Earlier quoted context omitted.

I see you are finding this very hard. Try to think it through: If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra . If you will need extra fuel to get home with, sending it to Mars is completely useless, because where you need it to be is not at Mars, but at the place where you will be at the time when you need it. That place is not…

> If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra. This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.

If you will need more delta-V than you have on-board tankage for, sending another ship at the same time and acceleration, and refueling from it on the way, is overwhelmingly better than launching literally dozens of ships to get even more fuel parked at Mars, and then spending extra fuel stopping there to pick it up, and more again to get moving again.

If your true goal is to have crap on and in orbit around Mars, do that without pretending it has any other value. You don't fool anybody, but you make people wonder about you.

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

#303

Post by mannerheim »

ncmncm wrote: post #302
mannerheim wrote: post #298

Earlier quoted context omitted.

> If you can't get there without a stop at Mars, then you really, really can't get there with a stop at Mars. Stopping at Mars costs extra. This simply isn't true. From Mars to Jupiter is a little over 6 km/s of delta-v. From Earth to Jupiter is almost 9. The latter is just barely possible with SpaceX's Starship. The former allows for not only some breathing room, but more payload.

If you will need more delta-V than you have on-board tankage for, sending another ship at the same time and acceleration, and refueling from it on the way, is overwhelmingly better than launching literally dozens of ships to get even more fuel parked at Mars, and then spending extra fuel stopping there to pick it up, and more again to get moving again. If your true goal is to have crap on and in orbit around Mars, do…

Or, hear me out, you get the available infrastructure set up on the surface of Mars to manufacture fuel and propellant, and then you can send a single ship from Mars to Jupiter. And, if you can bring payload, you can set up the infrastructure to do ISRU from one of the moons of Jupiter, and eventually bring your ships back with samples.

Versus, cannibalising several extremely expensive ships in order to get one ship to a destination it's never coming back from.

And this is just one example. The lower delta-v from Mars would allow extra payload to the belt, so if anyone ever intend to exploit those resources, starting from Mars will allow them to get heavy equipment there in less time and fewer trips (provided, of course, that they can manufacture that equipment on Mars).

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

#304

Post by ncmncm »

mannerheim wrote: post #303
ncmncm wrote: post #302

Earlier quoted context omitted.

If you will need more delta-V than you have on-board tankage for, sending another ship at the same time and acceleration, and refueling from it on the way, is overwhelmingly better than launching literally dozens of ships to get even more fuel parked at Mars, and then spending extra fuel stopping there to pick it up, and more again to get moving again. If your true goal is to have crap on and in orbit around Mars, do…

Or, hear me out, you get the available infrastructure set up on the surface of Mars to manufacture fuel and propellant, and then you can send a single ship from Mars to Jupiter. And, if you can bring payload, you can set up the infrastructure to do ISRU from one of the moons of Jupiter, and eventually bring your ships back with samples. Versus, cannibalising several extremely expensive ships in order to get one ship…

You start by shipping a million tons of freight to Mars, while I do meaningful stuff at places that are not a waste of time and effort. By the time you are ready to supply fuel FOB at Mars, I have sent a million tons to places worth sending it to, instead.

Maybe my million tons of freight includes a liquid methane sump on Titan, where I don't even need to synthesize, never mind liquify the stuff; it is sloshing around in puddles everywhere. There is an interior liquid water ocean, and ice lava flows.

Seriously, if you need more delta-V for a Jupiter or Saturn trip than spaceship design A gives you, you are much better off making a spaceship design B with enough tankage to make the trip. (Maybe B is just A with an extra tank strapped on; or, a tug boosts A to escape velocity and then loops around Luna and back, aerobraking to LEO.) Park fuel depots at both low and high Earth orbits; you waste nothing by using those, unlike anything parked foolishly at Luna or Mars.

Luna, anyway, has stuff that is worth visiting, like craters in permanent shade at the south pole, and lava tubes where vapors have maybe drifted in and froze for hundreds of millions of years. Mars is the armpit of the Solar System.

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

#305

Post by mannerheim »

ncmncm wrote: post #304
mannerheim wrote: post #303

Earlier quoted context omitted.

Or, hear me out, you get the available infrastructure set up on the surface of Mars to manufacture fuel and propellant, and then you can send a single ship from Mars to Jupiter. And, if you can bring payload, you can set up the infrastructure to do ISRU from one of the moons of Jupiter, and eventually bring your ships back with samples. Versus, cannibalising several extremely expensive ships in order to get one ship…

You start by shipping a million tons of freight to Mars, while I do meaningful stuff at places that are not a waste of time and effort. By the time you are ready to supply fuel FOB at Mars, I have sent a million tons to places worth sending it to, instead. Maybe my million tons of freight includes a liquid methane sump on Titan, where I don't even need to synthesize, never mind liquify the stuff; it is sloshing aroun…

You seem pretty contentious here; I'm just making a case that Mars makes sense as a destination, not trying to convince you that this is something you need to pay for. IMO, the numbers work out for it being a hub for traffic to the belt and outer planets. Maybe you don't agree. That's fine. Again, I'm not asking you, personally, to start backing this. Just stop spouting off nonsense like 'if you can't get somewhere from Earth, you can't get there from Mars'. It's a matter of fact that delta v requirements from Mars are lower than they are from Earth, and this would have been obvious if you had thought just for a second about any of this.

> You start by shipping a million tons of freight to Mars

The equipment for generating the electricity to perform ISRU on Mars is supposedly within the payload capabilities of a single Starship, 100-150 tons, not a million, and this should be enough for a ton per day, enough to resupply in the 26 month launch window. The equipment for collecting water and CO2 is another matter, and I don't see estimates on that, but with the above and some engineering margin, it seems plausible that this operation can get off the ground in under ten ship-trips to Mars.

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

#306

Post by datavirtue »

spaetzleesser wrote: post #64
uwuemu wrote: post #33

Earlier quoted context omitted.

A probe based on nuclear pulse propulsion could do it in around 50 years, with today's technology. It's not that we can't do it fast (within one average human lifespan), it's that the project would be very expensive and something like Nasa has a relatively tight budget. I mean we, as humanity, have to have an eccentric billionaire start a Martian fire (SpaceX Starship) under our lazy asses to even start to think abou…

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…

Not to mention that you would need to figure out how to keep the humans from having a mental breakdown. Myself, I would probably be clawing at the windows for a look at a non-existent tree in about two days.

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

#307

Post by datavirtue »

ethbr0 wrote: post #204
TheOtherHobbes wrote: post #180

Earlier quoted context omitted.

This is absolutely, objectively, incorrect. You might as well argue that you can build a self-sustaining base on Antarctica. Of course you can't, because Antarctica can't support life. No amount of shouting into a bullhorn about adventure will change that. It might be possible with an absolutely epic effort to airlift soil, nuclear reactors, nuclear and other fuels, machinery for every eventually (including chip fabs…

At the end of the day, profit determines reality. And that's where futurists have always screwed up, because profit funds solutions. Nobody has colonized Antarctica not because it's impossible, but because it's difficult enough and useless enough that we all agreed on a treaty prohibiting it. In contrast, we constructed the 63 radars (some with bases) of the DEW line in the late 1950s in under 3 years, with part of t…

Fantasies. None of us will be known or remembered. We will never colonize the universe in these bodies.

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

#308

Post by jsjohnst »

rbanffy wrote: post #99
jsjohnst wrote: post #95

Earlier quoted context omitted.

> a trip to the next star can be a week-long affair from your point of view You’d need to travel at around 233x the speed of light to make getting to the nearest star be a week trip, no?

From the passenger's point of view, yes. For everyone else you'd be veeeery close to c, but not quite there.

My point was it’s hyperbolic. You’d have to be going so close[0] to C that it’d be impossible.

[0] about 0.99999c if what someone else in this thread said is correct

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

#309

Post by ethbr0 »

qwytw wrote: post #287
ethbr0 wrote: post #277

Earlier quoted context omitted.

So you're talking about having more nuclear power, but only in First World economies? That seems... ethically dubious.

Why is it anymore ethically dubious than having more solar or wind power in first world countries? But no, I'm not necessarily saying that. I just disagree with the claim that if nuclear power continued growing at the same rate as it did prior to 1979 that would somehow have lead to higher proliferation of nuclear weapons.

It's ethically dubious because solar or wind power wasn't an option in the 50s-70s. So you're effectively gating the majority of the world off from nuclear power, enjoyed by developed economies. Which would have developed economies of scale (see: France) with the end result of developed countries having access to cheaper power than developing ones.

And I'm confused. Your reasoning around why more reactors wouldn't have increased nuclear weapon proliferation was contingent on only the US, USSR, Britain, and Germany (and presumably countries like them, to an approximation) having more reactors.

Either you get to say that (a) all countries, or (b) only "responsible" (for lack of a better word) countries should have used more nuclear power.

If (a), then you have increased proliferation risk. If (b), then you're establishing (and presumably militarily enforcing) a two-tier ability to access cheap energy, that favors developed nations.

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

#310

Post by datavirtue »

ethbr0 wrote: post #194
spywaregorilla wrote: post #179

Earlier quoted context omitted.

And so you think you can just mush those two claims together and come to the conclusion that sustaining life on mars must be achievable?

Not must be. Is probably achievable, and is worth attempting, even at the cost of lives. You can argue from either the perspective of futility of attempt (no chance of success) or futility of outcome (success wouldn't be worth it), but I'm pretty convinced both would be weak arguments, both logically and historically.

There is no survival advantage to us on Mars. What are we all arguing about? This site is staring to feel a bit unhinged when it comes colonizing the solar system. Like SGC Ori unhinged.
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