The h Bar

12:09 AM

Am I really wrong here?

-1 completely misleading answer. Metric spaces don't have anything to do with it. In fact, turning a manifold with metric tensor into a genuine metric space involves calculating the length of continuously differentiable curves, but calculating lengths only requires one to consider the norms of the tangent vectors, i.e. only inner products of the form $g(u,u)$. Thus, $d(A,B) = d(B,A)$ would be correct regardless of whether there's asymmetry in the metric. — Stan Liou 3 mins ago

David Hammen

@Sofia - I would have stuck through NASA, even with all their garbage (better: BS), had their goals with regard to humans in space been realistic. I was so excited ~five years ago when NASA finally wanted to return to the Moon. That was deemed a dumb idea for some reason. I was still excited when the goal changed to mining asteroids, with human help. Sending humans to Mars? That's such a dumb idea.

Danu

Hey, finally someone who agrees with me on that

ACuriousMind

@Danu I believe Stan has a point.

Danu

I don't get what he means :\

Please edit to improve my answer if you do

David Hammen

For one thing, it's going to take a long time. All it takes is one anti-science Congress or President, and poof, the project is canceled. (There are a lot of people, left and right, in the US that are anti-science.) For another, what if there is life on Mars? Humans have done a lot to hurt the Earth, but we've never committed planetocide before. There are a number of people high-up in NASA who say humans will never go to Mars if Mars still support life.

ACuriousMind

12:21 AM

@Danu When you impose the physical requirement that the distance between points should be symmetric, that distance is defined as the infimum of the length functional. The length functional only involves $g(u,u)$, and no metric product between two different vectors, so the path distance metric on M is symmetric even if the metric on the tangent spaces is not.

Danu

'u' being?

ACuriousMind

four-velocity/tangent vector to the curve whose length is calculated by integrating $\sqrt{g(u,u)}$ along it

Danu

oh, like $\int d s$

ACuriousMind

Exactly

user54412

@Danu I think ACuriousMind said it better than I would. I might also add that my intuition for the spacetime metric is that it is more concerned with angles than lengths. The metric means something even in just $T_p$, before considering the structure of a whole manifold.

Danu

12:26 AM

@ChrisWhite you are Stan Liou?!

ACuriousMind

^I was about to ask exactly that

Danu

Oh snap!

user54412

Wait, do I seem similar to him?

Danu

than me

user54412

Oh

Danu

12:27 AM

Hmmmmmmmm.... :P

suspicions have been raised

ACuriousMind

...annnnnnd the chat transcript is now inscrutable to anyone reading it.

user54412

That's what happens when I say something in my mind and refer back to it, forgetting that no one else hears my thoughts

Danu

Yeah, yeah, yeah, @ChrisLiou

user54412

Well a quick google search failed to prove that Stan Liou is at least a real person

user54412

This is like the opposite of identity theft: I can't get rid of someone else's identity.

Danu

12:32 AM

I can't delete my answer :(

T Abraham

what's the discussion about?

Danu

See the link to the comment above

T Abraham

@Danu what about it?

Danu

...our discussion.

Anyways, I'm off for tonight

cya all

Please edit and correct my answer!!!!

T Abraham

so I have a question that @alarge still hasn't answered...

So my question is I have this Hamiltonian:

$$ H = \sum_i \epsilon_i \sigma^+_i\sigma^-_i + \sum_{i\neq j} V_{ij} \sigma^+_i \sigma^-_j, $$

and I want to write it out for two site..

Is this correct?:

$$\sigma^+_1 \sigma^-_1 + \sigma^+_2 \sigma^+_2 + V_{12} \sigma^+_1 \sigma^+_2 +V_{21} \sigma^+_2 \sigma^+_2$$

Also:

Plants and Quantum Mechanics

To examine different aspects of a theory on plants and their r...

ACuriousMind

12:45 AM

@TAbraham You might want to think about the $\pm$ superscripts again.

T Abraham

@ACuriousMind oh yeah..

T Abraham

1:22 AM

Is this a right answer?: physics.stackexchange.com/a/162689/65616

T Abraham

1:39 AM

0

Q: Two site Hamiltonian

So my question is I have this Hamiltonian: $$ H = \sum_i \epsilon_i \sigma^+_i\sigma^-_i + \sum_{i\neq j} V_{ij} \sigma^+_i \sigma^-_j, $$ and I want to write it out for two site. Is this correct?: $$\sigma^+_1 \sigma^-_1 + \sigma^+_2 \sigma^+_2 + V_{12} \sigma^+_1 \sigma^+_2 +V_{21} \sigma^+_2 \...

@alarge ? again, ignoring me..

Kyle Kanos

Chat is an asynchronous communications protocol. Just leave your questions for whomever, rather than pinging them 50 times.

They'll see the messages and read them and be able to respond to them

T Abraham

@KyleKanos I know @alarge is there and reading, but won't respond..

hey @MarkMitchison ? u there? Have u seen what I have been doing?

Kyle Kanos

The fact that his name appears indicates that alarge is logged in to chat room, it does not mean that he is there & reading

ACuriousMind

@TAbraham If you already believe they won't respond, why do you keep pinging them?

T Abraham

@ACuriousMind because, I am stuck..

Kyle Kanos

1:48 AM

At some point in our lives, we all got stuck on a problem

T Abraham

@MarkMitchison I see u have commented on my question.. let's talk about it...

@KyleKanos so what do we do? We ask for help!

Kyle Kanos

@TAbraham Or, you just tough it out and work it yourself.

One way is entirely rewarding

The other, not so much

T Abraham

@KyleKanos is that the point of stackexchange? I don't think so..

Kyle Kanos

@TAbraham Actually, SE fits in entirely with what I said. Read it again.

T Abraham

@KyleKanos ?

Kyle Kanos

2:00 AM

There's a two letter word that I lead off with, what is it?

T Abraham

@KyleKanos or..

Kyle Kanos

Which signifies that there are (at least) two options

What are those options?

T Abraham

@KyleKanos So I decide, correct? I decide the other method, asking for help...

Kyle Kanos

One method is asking for help, and the reward isn't that great. The other method is to keep going, and the reward is great.

T Abraham

@KyleKanos are u treating me like a kid?

Kyle Kanos

2:03 AM

SE panders to the first group.

I'm trying to show you the train of thought I was making

T Abraham

@KyleKanos some things are so simple that everybody gets it..

@KyleKanos which is why I am here!!!

Kyle Kanos

So, in a sense, I suppose yes, I am treating you like I do with my kids.

T Abraham

@KyleKanos anything else to say?

Kyle Kanos

An anecdote:

A class mate of mine gave a presentation on Thursday to the entire department about his research on quantum gravity

He showed some of his mathematical work in deriving his results

First slide contained 4 sheets of paper with about 10-20 lines per page

Then a big "WHAT!?"

(indicating it was wrong)

He then showed another set of 5 pages with an "EH?" at the end

Then he showed a series of 12 pages with a correct result

I imagine that he neglected a few more mistake sets of papers in that presentation as well

You seem to be trying once, maybe failing, and then asking for more help. My suggestion is to be more like my class mate and try it a few times before asking for help.

4

dmckee

2:56 AM

@DavidHammen Best of luck in your new endeavors. Every job comes with its share of BS, but every NASA employee I've talked with reports even more than goes on in the national labs I've worked at, and they're no slouches.

DanielSank

3:20 AM

@Danu Yeah, but once you pass your courses nobody in grad school cares what grades you got (at least, not in my experience).

Four votes to close? Really guys? I see questions that literally ask why such-and-such group has so-and-so property and y'all don't VTC (I know because I do VTC and then nobody else does). How can you honestly think a circuit topology question is off-topic but pure group theory is not?

Kyle Kanos

I VTC because it's a "do this HW for me" type problem that we've declared as off-topic

Alfred Centauri

@DanielSank in fact, this question should be closed as an exact duplicate. I know I've seen it several times here. I'll find a duplicate and vote to close.

Kyle Kanos

Closest I could find as a duplicate was this one:

0

Q: Finding equivalent resistance in complex circuit

In my previous Phys.SE question, situated here, I asked about finding the equivalent resistance of the following circuit : I got some very good answers and some tips. Now what if the same circuit is modified by adding two more resistors on the free connecting wires like this : How should I fi...

homework-and-exercises electric-circuits resistance

Which also probably should be closed as a "do my work for me" problem

Alfred Centauri

3:57 AM

@KyleKanos I can't find it either. Maybe it was over at the EE site so no vote to close.

DanielSank

@KyleKanos Ok, how would you like that question phrased to pass your "do this for me"-o-meter?

Kyle Kanos

I currently do not see a way.

T Abraham

4:53 AM

0

Q: Two site Hamiltonian

So I am trying to write a matrix for a Hamiltonian and am having problems figuring it out. So the Hamiltonian is $$\epsilon_1\sigma^+_1 \sigma^-_1 + \epsilon_2\sigma^+_2 \sigma^-_2 + V_{12} \sigma^+_1 \sigma^-_2 +V_{21} \sigma^+_2 \sigma^-_1$$ I heard from my friend that the matrix would be so...

quantum-mechanics homework-and-exercises hamiltonian

user54412

@DanielSank My VTC was for being unclear (the original version of the question).

T Abraham

5:31 AM

@KyleKanos even when @alarge is responding.. he isn't talking to me! why? he's clearly ignoring me..

Sabre Tooth

@TAbraham he is not obliged to respond to you (or anyone)

DanielSank

@TAbraham: You can even choose to have certain users' messages not show up.

Gaurav

5:53 AM

@TAbraham Surely, you will not like anyone poking you again and again asking you to talk about something when you're busy with something else. Think about it, you'll understand. People will not take you seriously if you continue to do so. Please don't take it negatively.

tpg2114

11:48 AM

So maybe it's just me, but is it really coincidence that somebody who has gained just enough rep to complain on Meta about our policies in the past 23 hours of activity also has PO as the website in their profile?

seuser32111

61 6

homework-and-exercises electromagnetism faster-than-light induction semiconductor-physics temperature thermodynamics

innisfree

Zzzz

tpg2114

Sleep is so overrated.

innisfree

12:03 PM

Gosh, it looks like the honeymoon is over in the PO community, physicsoverflow.org/26624/…

physicsoverflow.org/26615/how-do-we-revive-physicsoverflow

tpg2114

@innisfree That's putting it mildly

If you go through the wall posts and comments, it totally blew up

innisfree

I can't say I'm sad, though it must be disappointing for those who have put their time, energy and money into the project.

tpg2114

I'm sure it was an eye opener for everybody there. Turns out running something is hard.

@ManishEarth Would I get in trouble if I posted a comment that said "Don't like it? Get the f*** out and leave those who do alone." ?

I'm thinking you guys might not let that one slide

ManishEarth

12:23 PM

@tpg2114 yes

where

innisfree

The project is still (officially) alive, though. I found the PO idea interesting, but only in a sociological sense. They broke away from an established community to found their own community with different rules, different power hierarchies.

ManishEarth

You mean the thank you meta post?

tpg2114

Yeah. I'm super tired of every post becoming the exact same thing

Doesn't matter what it starts out as

@innisfree And ironically, fell to problems more significant than the community they left. They left what they considered to be heavy-handed moderation (which, in many of the discussions now, they admit at least was mostly open) to go to a place that was more heavy-handed and much more secretive about it

ManishEarth

@tpg2114 Yeah, jsut step away from the computer and remember it's just an internet community when you feel that urge :p

innisfree

@manis amen to that. that's good advice.

alarge

12:27 PM

@tpg2114 Not too surprised considering the real world examples (take Egypt as a recent one).

tpg2114

@ManishEarth All work and no sleep... significantly reduces my tolerance

ManishEarth

hah

glance

1:09 PM

@dmckee should this post be closed as a duplicate of this other question? Or more generally, are these kind of things (i.e. about matters clearly spelled out by network-wide policies) debatable?

tpg2114

1:22 PM

I'm totally calling puppet account on that user.

tpg2114

1:43 PM

@DavidZ Ah, just when it was getting good... :)

Physics Meta

2:13 PM

0

Q: Re-establishing the “thank-you-policy-in-only-questions” of www.physics.stackexchange.com and meta.physics.stackexchange.com

What is the community consensus over the current "thank you" policy of www.physics.stackexchange.com and meta.physics.stackexchange.com. According to the current policy a user is not allowed to say "Thank You" in their question. Should it be changed? I've provided an answer whose net score will d...

feature-request scope policy faq-proposed

ACuriousMind

@PhysicsMeta Is that guy trolling us?

glance

@ACuriousMind evidence seems to suggest that :D

@ACuriousMind a question: does flagging as duplicate a question which has clearly already been flagged (and/or voted for closure) by others has some value? Or is it just redundant?

ACuriousMind

@glance Gives you a "helpful flag" ;)

Nothing else, I think

glance

@ACuriousMind yea well, one could ask if that is useful in some ways. But I wonder how does that mechanism work on your (i.e. >10k rep users) side. Where does the "flag" go? Is it an annoying notice or does it just put the question on the close queue, eventually specifying who flagged it?

ACuriousMind

@glance A flag just puts it in the close review queue

(and you can VTC there as soon as you have >3k rep, not 10k)

It is wholly invisible who flagged it to us, though

glance

2:21 PM

oh ok, so no noise added, good

@ACuriousMind hahahaha I guess this answers you question: "@ACuriousMind This question is not duplicate, because it asks for re-establishing a policy, whereas the one you linked asks for the current policy."

ACuriousMind

Yep. I'm not responding that that guy, I think.

glance

me neither, his nature has been determined now

Gaurav

2:55 PM

@ManishEarth I don't understand the distinction made between homework questions which "concern a particular physics concept" and those "which ask of methods to get to the answer" as mentioned in the homework policy. My reasoning is that the latter is no less in educational value than the former since it does demand an understanding or involvement of a particular physics concept. Can you please clarify this to me?

ACuriousMind

3:21 PM

@Gaurav "Methods to get to the answer" is primarily intended to mean mathematical manipulations of formulae. There are quite a few homework questions that have the correct equations to start from and just ask how to get to the correct answer - which involves no physics at all.

Gaurav

@ACuriousMind Okay, that seems clear. Thanks. :)

Physics Meta

4:19 PM

0

Q: How is this question duplicate of my previous question?

My latest question Re-establishing the “thank-you-policy-in-only-questions” of www.physics.stackexchange.com and meta.physics.stackexchange.com has been marked as the duplicate of my previous question. The two questions are different. So my question to user ACuriousMind, user Alfred Centauri, use...

support

ACuriousMind

^seriously?

dmckee

@tpg2114 We've often said to people that it is very easy to get enough rep to access basic privileges. Case in point for that.

Gowtham

4:45 PM

@ACuriousMind is she back ? :D

ACuriousMind

@Gowtham Heh. Not a self-identified she this time, but definitely almost as annoying

Emilio Pisanty

5:19 PM

So it looks like we're back to square 1 on those microwave background B modes...

skyandtelescope.com/astronomy-news/…

2

dmckee

5:35 PM

@EmilioPisanty One of the things I do when I teach our "Physics for Poets" type class is give the class a number of "case studies": stories about episodes in the history of the physical sciences where the science process went off the rails for a while (and one where the laymen might have concluded that , but they really hadn't).

This might be a candidate in a year or two, when the fall out starts to become apparent.

Hmmm ...

8

Popular Science

Proposed Q&A site for people interesting in scientific questions on a non-professional level, non-fictional literature, and sociological phenomenona around science.

Currently in definition.

I can't say I see where an adequate base of experts would come from for that.

Sofia

6:59 PM

@DavidHammen : it's very worrying what you say that Nasa's research program is not realistic. You say ". . . had their goals with regard to humans in space been realistic. I was so excited ~five years ago when NASA finally wanted to return to the Moon. . . . Sending humans to Mars? That's such a dumb idea." But, we were on the Moon. We can't do "terra-forming" there. No air, gravitation by far insufficient. But there may be chance of terra-forming on Mars.

Kyle Kanos

@Sofia I'm going to disagree on that one

Neither object has an atmosphere, so you'd have to build a dome of some sort

We were lucky to land Curiosity on Mars (I recall that England had a failed attempt several years ago), landing a shuttle full of people is going to be pretty hard, if not entirely impossible

Actually that should say "useful atmosphere." Mars' atmosphere is almost entirely CO2 and is about 2 orders of magnitude less dense than Earth's atmosphere

dmckee

I suspect that David's comments were not all about the manned mission (or lack of one), but about the overall situation. NASA has not been able to maintain the congressional support to stay at the front of the pack for decades.

They recently retired the only program that made them at all unique and the proposed replacement is some year away even if all goes well.

There has been a long-standing lack of vision in the agency. Or at least a lack of vision brought to fruition; I suspect that lots of people there have had clear visions of what could be done it...

Kyle Kanos

Well, they have royally screwed themselves up by overspending JWST by about an order of magnitude

dmckee

Political pressures have made it hard for NASA to be serious about inexpensive access to space, so they are losing to private enterprise.

@KyleKanos Could be, but it is such a cool project.

It's a shame, of course, because they have such a pool of talent and institutional memory.

We don't want to lose that, but it's going to be hard to hold onto in the current climate.

Kyle Kanos

@dmckee It has great implications to science

But if it fails.....

dmckee

7:12 PM

Yeah. All their eggs in one basket. And during the alleged "Smaller, faster, better" era, too.

Kyle Kanos

I am actually curious as to what would happen to NASA if JWST does not open up in 3-4 years

Danu

this is like the cutest thing ever

0

Q: Boy Scouts Pinewood Derby

I I'm new here and hoping I'm doing this right? I'm asking to get help with building a proper pinewood derby car for my son as we have a year to build and looking and checking out all our options. The reason is simple the answers may not be? My son just started cub scouts a tiger cub at 5yrs old....

experimental-physics

...but off-topic

Kyle Kanos

I would expect that a "few" higher-ups would be forced to resign, but I'm not sure that it would actually happen

dmckee

@KyleKanos And typically the resignation would be in the form of someone senior accepting a early-retirement package that they'd been considering any way. A head to display, but not much actual carnage. (To use a metaphor that strikes too close to home these days. Must find a better one.)

Kyle Kanos

If I were POTUS, I'd ask for the whole department be replaced.

The ones in charge of JWST at least. The other teams in the building seem to be doing alright.

Danu

7:21 PM

@dmckee The last part of this message confuses me

dmckee

About the heads?

There is a saying "heads will roll" (i.e. be cut off) when something goes really bad. It used to mean that people would get fired in a way that really hurts their career.

Danu

I get that

but the strikes too lcose to home these days

did that happen to you?

dmckee

No. I was thinking of those @ssh@les in the middle east.

Danu

oh...

Do you really think that's something new?

It's more that nobody ever cared

dmckee

@Danu No, it's not new, but its been in the news.

Danu

7:24 PM

That is certainly true

I guess my cynicism makes me very insensitive to this kind of stuff...

I'm always debating whether that's a terrible thing or actually very good

Kyle Kanos

0

Q: Separating this Proposal from the other Sciences

Proposal: Popular Science From the Example Questions, it appears that most of these questions would actually be on-topic at Physics.SE. In some cases, they actually have been asked and answered: http://physics.stackexchange.com/questions/40985/what-does-it-mean-how-is-it-visualized-for-a-parti...

science duplicate site-definition

So it actually turns out that all of Peter's questions on his proposal are from Physics

Some are closed, some are not

dmckee

@Danu You need a little cynism to get through the day if you have a clear view the brutality that goes on. And some folks need to have that clear view. So it's mostly a good thing.

Kyle Kanos

That latter bit has me a bit confused, as I figured he would have taken only closed questions

Danu

That's what I like to think

@KyleKanos lol

I don't think a popular science site is a good idea

Kyle Kanos

BTW: Thanks for the clean up on bobie's post @dmckee

Danu

7:27 PM

it's just asking for bad content, basically

Kyle Kanos

Not only that, it's been tried and failed before

Danu

Also, who's going to offer up their precious time on providing good content on there?

dmckee

Like I said above, I don't think that a popular science site can attract an adequate base of experts.

Danu

certainly not me

Kyle Kanos

Oddly, Dilaton & Dimension10 tried that previous version

Danu

7:28 PM

hahaha neat

dmckee

So it'll become like Yahoo answers: the ignorant leading the even more ignorant to the wrong conclusions that go unchallenged.

Yuck.

Kyle Kanos

Well, maybe not oddly. They may have done it to take the popular stuff from here (shoving it over there) and making Physics.SE be the higher level

JohnRennie made a Meta post about it sometime last year. I recall Qmechanic had a fantastic answer to it

dmckee

@KyleKanos I'm trying not to be so much of a kitten these days. I'll only put up with some much passive-aggressive repetition.

Kyle Kanos

Here it is:

17

Q: Should we have a Popular Physics SE?

I've been looking through the new Physics Overflow beta¹ and looking back at some of the discussion about the closure of the Theoretical Physics SE. From a purely personal perspective I would prefer research level questions to be asked here because though it's very unlikely I could answer any it'...

discussion

Also, I've never heard/seen the phrase "whingefest" before this morning

dmckee

@KyleKanos I used to hang out on alt.peeves on the USENET. They used exclusively the British spelling of whine and I picked it up from there. Sticking "fest" on the end was a flourish born of frustration.

Kyle Kanos

7:35 PM

I had to Google it. It was defined on Urban Dictionary back in 2007

innisfree

What do people think of this entry on wiki DM page? en.wikipedia.org/wiki/…

AFAIK, the claim of axion DM in the sun wasn't widely accepted (and was derided in some quarters as an elementary blunder). i don't think it ought to be in an encyclopedia entry about DM.

ACuriousMind

@innisfree I think you are right - it shouldn't be there

Yet, as written, it is not wrong to speak of "possible detection", and it is sourced, so I don't think deleting it would achieve anything - it would probably be restored.

innisfree

Really? i don't have much experience in editing wikipedia. my impression is that it's working incredibly well, but it's still somewhat suboptimal.

i mean, there are millions of articles, but many of them could be improved, or have a few strange edits. there isn't the same level of interest in eg maintaining the DM wiki page as there is in answering questions on DM here.

dmckee

7:54 PM

I think I've edited WP articles exactly twice, so I'm a long way from an expert. But I think that NPOV rules would allow you to hang a "but the result has been challenged as flawed [new citation(s)]" off of that even if you can't get rid of it.

innisfree

i only have this resonaances.blogspot.fr/2015/01/2014-mad-hat-award.html

Kyle Kanos

@innisfree there was this: adsabs.harvard.edu/abs/2014arXiv1411.3297R

dmckee

@innisfree Research strategy: most journals and preprint sites make it possible to identify what papers cite a known paper. Scanning the titles of citing articles would let you find any that are obviously critical and review articles. If none are obviously critical then scan the review articles ...

innisfree

Unfortunately, we have identified three distinct flaws in the analysis by Fraser et al. which ultimately make it totally irrelevant both for axions and for cold dark matter.

The section should definitely go, thanks for the paper

Kyle Kanos

8:11 PM

I'm not so sure that "it should go" is the right thing

The paper I linked has not been cited by anyone

innisfree

urm, too late :S

Kyle Kanos

So maybe something along the lines of, "<Paper> disputes the claim, saying the x-rays are results of bad analysis (or whatever)."

T Abraham

@MarkMitchison i'm sorry for wasting your time but since this community isn't supportive, I can't work on this problem u gave me....

innisfree

@kyle i don't think every small claim about DM should be addressed, especially not on an equal footing as established, undisputed experimental evidence. something should be widely accepted by the community before it appears in an encyclopedia.

Maybe it could be added again and put in the direct detection section, along with eg DAMA.

I definitely think the article is better without it.

but you're free to start a revert war with me on wiki ;)

just kidding...

Kyle Kanos

@TAbraham: Note that "check my work problems" are considered off-topic by the community; this is how you were asking your questions. The community is supportive of you learning something about QM & such (hence all the help you've received thus far!), but you can't ask your questions in that particular manner

@innisfree I have no interest in doing that! But leaving the comment you did in the edit history certainly addresses your reasons for deletion!

I just am hesitant to approve of rash decisions! (though content can always be reverted on Wiki!)

David Hammen

8:27 PM

@dmckee - You hit the nail. NASA has had plenty of ideas. Congress and multiple administrations have nixed them. Congress thinks they are better rocket scientists than the very few real rocket scientists at NASA, so NASA has to build this atrocity called the Senate Launch System (the official name is the Space Launch System; nobody calls it that). NASA has very few rocket scientists. What NASA does have is a lot of (mis)managers.

David Hammen

8:43 PM

@Sofia The most optimistic plans for sending humans to Mars call for a trip in 2035 or so. That's three or four administrations and ten congresses in the future. Twenty years is too long a span of time to be realistic. All it takes is one money-tightening, anti-science administration or congress and poof! it's canceled. A realistic plan is something that can be done in a decade or less. NASA sent people to the Moon for a two day visit. Nobody has sent people to the Moon to live there.

Kyle Kanos

@DavidHammen A reasonable assumption would be that if something happened to a Moon-based habitat, we'd be able to send help in a more reasonable timeframe than if something happened to a Mars-based. Am I wrong in that assumption?

vzn

DH interesting stuff re NASA but keep in mind with congress its nothing personal, look what happened to the supercollider. US not so interested in "big science" anymore after kennedy. & the politics makes it difficult. US focused on just trying to have a halfway decent economy since 2008. lots of internal problems (eg inequality) make any big ambitions difficult. US (govt) spends most of its $$$ on so-called "defense"....

there is some significant innovation going on in private industry re spaceflight...

in recent times NASA has done quite well with all the robotics probes to mars, thats not so gigantic but defn something to be proud of. (some run Java, yay!) :)

afaik US hasnt put all that much $$$ into the european LHC...

US congress can barely agree on the validity of global warming! its a sort of major breakthru the senate resolved recently its real... but that small gesture maybe all that can be achieved politically on the issue in the near future!

Kyle Kanos

@vzn I'd consider the >$500 million we put in to be a fair chunk of change

vzn

9:00 PM

over $500M on LHC? really? surprised...

Kyle Kanos

I think that's what we spent on it

Yeah, NYT confirms: nytimes.com/2013/03/05/science/…

$531 million

vzn

good stuff but alas, compared to EU etc that is probably low...

also measured over its multiyear lifetime...

Sofia

@DavidHammen : I see. But, I apologize for naivety, what's our business to visit the moon more? It is useless. I would understand if the gravitation on it were better, but, what can one do there? (Military use? No chance.)

David Hammen

@KyleKanos Exactly. Suppose someone on the Moon or Mars breaks their back and needs to come home. (I broke my back 25 years ago. I feel their pain.) A return to Earth from the Moon means launching NOW and then drifting for three to five days. A return to Earth from Mars means waiting a long, long time and then drifting for six to nine months.

Sofia

@DavidHammen : A return from the Moon? How can you stay on the Moon? The poor gravity is the problem.

Kyle Kanos

9:15 PM

@Sofia ? While it is a third of Earth's gravitational acceleration, it's still capable of keeping someone there

I mean, they drove on the moon:

►

David Hammen

@Sofia - We do know that zero-g is not good for humans. What level doesn't cause harm? We don't know that.

Kyle Kanos

And jumped

dmckee

@vzn Don't overlook that the supercollider had deep management problems aside from the funding issues.

They "designed" the fool thing simply assuming that they would get a break-though in superconducting magnet technology: the design called for magnets stronger than those on the LHC.

They didn't have in place management structures adequate to manage a billion dollar project--something that we do have now, but it has taken twenty years to seep into the culture and added a whole extra layer of complexity to experiments.

Money was mis-allocated all over the place, which was one of the causes of the overruns.

@Sofia We went to the moon as part of a national greatness stunt. To show up the soviets, mostly. To be first at something in a really big, visible way.

There never was a long term plan, and the science goals were tacked on.

David Hammen

@dmckee - Controlled fusion is another one of those pipe dreams. (Aside: I mistyped "pipe dreams" and my autocorrect wanted me to write pipe dramas.) When I was a kid, fusion supposedly was but a decade in the future. A decade passed, and that decade had become two decades. Now its five.

Sofia

@dmckee this is what I thought. But, bottom line, is there any chance to build there some military base?

dmckee

9:28 PM

@Sofia To what purpose? Who are you going to threaten with what? Or what are you protecting from whom?

I suppose I should note that over the long run the lunar mission science outcomes have been really, really good. People keep finding new things to look for in those rocks. BUt that was beyond anticipation in the 60s.

David Hammen

@Sofia The Moon Is a Harsh Mistress by Robert Heinlein.

Sofia

Oh, @dmckee , in which part of the world do you live (don't feel offended !)? With which weapons militaristic regimes threat? With nuclear.

dmckee

@Sofia I'm in the US. We can (do?) threaten everyone with nuclear attack now.

vzn

agreed moon has little military value. and @#$& lets not militarize space more than its already been (eg @#%& chinese satellite destruction experiment few yrs ago, lobbing space junk all over the place, no intl warning/ agreement whatsoever)

Sofia

@dmckee ...... Ohhhh ! It's not enough to have the means. The difference is big.

@dmckee Is there someone who fears the USA?

vzn

9:35 PM

re controlled fusion, was just going to mention that, (aka "feasible in roughly 20years" ad infiinitum) there was a really neat article on that recently ... re european challenge ... gotta dig that up ... yeah feel that billions are being blown on too-big experiments, think smaller scale fusion ideas should be pursued...! current large funding balance is near madness

Sofia

We don't worry of government which are humanitarian and logical.

@vzn , can't you write full English?

David Hammen

@dmckee Yup. One of my many jobs involved things that went way high up, came back down, and ended with the grandest possible finale. That was thirty+ years ago; I had to cleanse my soul after that. Anything more, deponent say nought.

Getting back to the mundane, yesterday I looked at the map I hung over my bed decades ago, and I told my wife "We need to go back there!" She is my financial manager, and she said yes! Where? The Boundary Waters Canoe Area (US) / Quetico Provincial Park (Canada). Permits are extremely limited, and this is the time to reserve a permit. I'll check with my new employer whether its okay to completely escape the modern world for two weeks in July or August.

vzn

9:53 PM

lol sofia this is a chat room did you notice :p

wont criticize your english if you dont criticize mine :p

ACuriousMind

@vzn I think that was less a critique of your grammar than of the stream-of-consciousness quality your utterances have