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Confronting the Credibility Gap for Crewed Exploration of Mars

caseyexaustralia.blogspot.com

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Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#11

Post by f0urtyfive »

omegaham wrote: post #10
mannykannot wrote: post #7

Earlier quoted context omitted.

As far as I can tell, the quote given by fapjacks is saying that the reactionless drive is impossible. Note that it is in a paragraph that begins "The other major kind of shonky coverage covers mythical propulsion..." (I had to look up 'shonky', but it is consistent with the above reading.)

I'm pretty sure that fapjacks believes that the reactionless drive is possible, and all of the "No, this is silly" folks are just contrarian deniers who are holding back progress. Gotta love starry-eyed futurology people.

Woah there horsey, you're basically sticking anyone that thinks reactionless drive might be possible into the crazy conspiracy theory category, and there are plenty of people that are interested in honest reproducible research on the topic.

Just blanket suggesting that it is in no way possible without any evidence is no better than blanket suggesting it is possible without any evidence (well, it's a little better, since the laws of physics are on your side, but...)

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#12

Post by fapjacks »

f0urtyfive wrote: post #11
omegaham wrote: post #10

Earlier quoted context omitted.

I'm pretty sure that fapjacks believes that the reactionless drive is possible, and all of the "No, this is silly" folks are just contrarian deniers who are holding back progress. Gotta love starry-eyed futurology people.

Woah there horsey, you're basically sticking anyone that thinks reactionless drive might be possible into the crazy conspiracy theory category, and there are plenty of people that are interested in honest reproducible research on the topic. Just blanket suggesting that it is in no way possible without any evidence is no better than blanket suggesting it is possible without any evidence (well, it's a little better, si…

Right. That's the spirit of my original comment. There are obviously people here with some serious investment in their own educations and egos that think this thing is impossible. Yet, here we are, peer-reviewed evidence[0] mounting.

[0] http://arc.aiaa.org/doi/10.2514/1.B36120

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#13

Post by fapjacks »

Daneel_ wrote: post #9
mannykannot wrote: post #7

Earlier quoted context omitted.

As far as I can tell, the quote given by fapjacks is saying that the reactionless drive is impossible. Note that it is in a paragraph that begins "The other major kind of shonky coverage covers mythical propulsion..." (I had to look up 'shonky', but it is consistent with the above reading.)

Correct - Casey believes that the drive is impossible, given our understanding of physics. Given his background and credentials, I'm happy to defer to his opinion on the matter, over my own optimism. Both he and I are firm believers of the scientific method though, so if researchers can show it experimentally then that's where the fun really begins. To my knowledge, the experiments until now have been fairly poor, wi…

But that's not what he's saying, now is it? He is dismissing it entirely as "impossible". Care to point me to the part of the scientific method which says "Feel free to dismiss outright things that don't make sense to you"?

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#14

Post by daveguy »

fapjacks wrote: post #13
Daneel_ wrote: post #9

Earlier quoted context omitted.

Correct - Casey believes that the drive is impossible, given our understanding of physics. Given his background and credentials, I'm happy to defer to his opinion on the matter, over my own optimism. Both he and I are firm believers of the scientific method though, so if researchers can show it experimentally then that's where the fun really begins. To my knowledge, the experiments until now have been fairly poor, wi…

But that's not what he's saying, now is it? He is dismissing it entirely as "impossible". Care to point me to the part of the scientific method which says "Feel free to dismiss outright things that don't make sense to you"?

Everything in science starts out impossible. It doesn't even get considered in science unless it has a chance of being impossible. Then it is up to the scientist to demonstrate that it is possible and explain how it is possible.

Edit:

The 1) demonstrate and 2) explain parts are critical and it's not science unless you have 1). Preferably 2) also. EM has neither to match the magnitude of the claims until they can push something across the solar system and back (such that loss of mass is ruled out and the propulsive effect is without a doubt not instrument error).

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#15

Post by avmich »

fapjacks wrote: post #13
Daneel_ wrote: post #9

Earlier quoted context omitted.

Correct - Casey believes that the drive is impossible, given our understanding of physics. Given his background and credentials, I'm happy to defer to his opinion on the matter, over my own optimism. Both he and I are firm believers of the scientific method though, so if researchers can show it experimentally then that's where the fun really begins. To my knowledge, the experiments until now have been fairly poor, wi…

But that's not what he's saying, now is it? He is dismissing it entirely as "impossible". Care to point me to the part of the scientific method which says "Feel free to dismiss outright things that don't make sense to you"?

I think, given the structure of phrase, we can assume some irony there - not only baseless dismissal.

EM drive remains pretty controversial, and does present significant problems with explanation, and as an extraordinary device requires extraordinary evidence. So it could be conceivable not to focus too deeply on a remark which isn't the main point of the article.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#16

Post by Daneel_ »

fapjacks wrote: post #13
Daneel_ wrote: post #9

Earlier quoted context omitted.

Correct - Casey believes that the drive is impossible, given our understanding of physics. Given his background and credentials, I'm happy to defer to his opinion on the matter, over my own optimism. Both he and I are firm believers of the scientific method though, so if researchers can show it experimentally then that's where the fun really begins. To my knowledge, the experiments until now have been fairly poor, wi…

But that's not what he's saying, now is it? He is dismissing it entirely as "impossible". Care to point me to the part of the scientific method which says "Feel free to dismiss outright things that don't make sense to you"?

I think he's just expressing a healthy degree of skepticism, with a touch of hyperbole for flavour. He's likely just a bit sick of being asked his opinion on the drive until there's further experiments and research conducted on the matter.

I'm not dismissing your interest and excitement in the topic either. I'd love for it to be functional, and for us to learn new information on the way our universe works. The bar for entry is set particularly high on this, that's all :)

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#17

Post by nickparker »

There's a very enjoyable discussion in the comment section with my (brilliant) former colleague Max Fagin. He points out that Casey's first draft of this post neglects the curvature of Mars, and when you account for it Casey's model predicts the craft punching out the other side of the atmosphere.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#18

Post by avmich »

The document linked at the end of the talk currently contains summary regarding the radiation problem on the way to Mars.

I've heard of the following approach. The spacecraft generates a magnetic field which spreads around it in flight, having some substantial size (order of kilometers). Relatively small amounts of matter (some gas) are constantly emitted from spacecraft, get ionized and trapped in the magnetic field. Such a low density thick "cushion" of ions makes the radiation shielding.

I'd like to learn more about effectiveness of such an approach.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#19

Post by robbiep »

I had the pleasure of attending high school with Casey. He (and his brother as well, who i worked under as a doctor) are both capital G geniuses. Anyone wanting to be highly informed on interesting topics like the hyperloop (with his potential biases due to involvement with Hyperloop one), terraforming, space travel or other similar things would do well to follow him on quora.

Re: Confronting the Credibility Gap for Crewed Exploration of Mars

#20

Post by XorNot »

techdragon wrote: post #8
XorNot wrote: post #6

Earlier quoted context omitted.

It violates conservation of momentum (i.e. why solar sails work). This is a pretty big problem with any evidence purporting that it does work because it requires a massive reinterpretation of our understanding of existing physical laws: i.e. it's mechanism of operation has to simplify to existing theory in such a way as to also explain why the effect is undetectable at the staggeringly high resolutions of measurement…

There is a big difference between "does violate" and "appears to violate". The orbital motion of Mercury "violates" Newtonian gravity. There are other examples but I'm not trying to make a history lesson. I just want to point out, that science moves forward by impartial investigation of EVERYTHING. It's misguided to assume we know all and that there cannot be some thing we don't understand. I'm as sceptical as anyone…

The Relativity of Wrong [http://chem.tufts.edu/answersinscience/relativityofwrong.htm]

Mercury's motion does violate Newtonian gravity. General Relativity however simplifies to Newtonian gravity for various low-dimension applications though (i.e. an Apple falling from a tree, the orbit of the moon for most astronomical guidance purposes over that distance etc.)

In much the same way we don't account for the curvature of the Earth when building a house's foundations.

That's my point though: when you violate a fundamental physical law, it can't just be wrong. You have to somehow also account for why it doesn't happen all the time elsewhere (i.e. the effect is small to within experimental error over common measurement cases) and by necessity the new theory to explain it has to encompass the predictions of the old i.e. the benefit of Newtonian gravity was that it easily recovers the behaviour of nested epicycles of orbital motion (and made new predictions successfully where epicycles could not).

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