They have a strong perverse incentive to glut the PhD market since their control of grads then becomes nearly absolute - the graduate students' futures depend on their profs letters of recommendation. Not just wage slavery but "Weinberg benefits" and "pump and dump" (steal the graduate students ideas and then kill their careers and publish those ideas) results. One helluvan incentive.
With such a power disparity, I wonder how long before the stories of professors sexually abusing their positions start coming out. The situation sounds like a breeding ground for that sort of exploitation.
I often wonder whether a much older professor sleeping with a much younger student (with consent; both adults obviously) is always a case of attraction based on intelligence and maturity as is often portrayed - esp. in books and films? e.g., One I watched recently - Pelican Brief. Just a random example really but my curiosity is broader in the sense that I want to know from people’s experiences - what they have seen around them.
My example seems to make my question sound like having fixed gender roles in this context - it kind of is so. I mean I rarely come across examples of such relationships with reversed gender roles. In fact when it’s an older female faculty member and a younger male pupil it’s often portrayed as, directly or subtly, something perverse or an abuse of some sort and isn’t shown to be as open and accepted as its counterpart (my example). Maybe the historical patriarchy or so?
Anyway, this has always intrigued me. Partially because where I am from this is rarely heard of and is a not at all socially accepted. In fact it was a taboo till very recently (maybe it still is), where as in the west it seems to be at least socially accepted (I am not sure how the reaction is at much smaller like concerned families level) and very common (unless I read it wrong from the films).
>I mean I rarely come across examples of such relationships with reversed gender roles. In fact when it’s an older female faculty member and a younger male pupil it’s often portrayed as, directly or subtly, something perverse or an abuse of some sort and isn’t shown to be as open and accepted as its counterpart (my example).
The current President of France met and fell in love with his wife when she was his teacher.
True. But in popular culture it's not depicted in the same proportion at all. Right? How is it in reality there, comparatively?
PS. Why the down-votes?
I am not asking directly to @logicchains (I can't edit that comment now so adding it here). I am really perplexed. I was not trolling or being offensive (hope I didn't turn out to be so) and it is one of the aspects of western culture I don't understand and tried to understand it from the people who live there or have been there since I noticed a comment on the same lines (or perceived so). Also I assumed there would be lots of (ex) grad students here. I was thinking is there intimidation, misleading, fear of losing career chances involved in such relationships (and a whole lot of things)?
I have noticed this quite a few times. Comment down-voted that were neither offensive, nor unconstructive (I would like to know if mine was either of these or something else and learn from my mistakes).
I have recently got the ability to down-vote (seeing the up and down arrows both) and I hardly down-vote (on other forums too I've the same habit). Am I doing it wrong? The saying that "don't down-vote just because you disagree or don't like something" is just for saying and in practice we should just down-vote based on whims and likes? Or is there a methodology to it?
wow, GS is the man! he still looks remarkably similar to the way he did almost 10 years ago when i took his class.
EDIT (to make this post not as content-free): Prof. Strang keeps the hope alive that some distinguished faculty in top research universities still place an emphasis on great undergraduate teaching
No idea actually, but it was something he mentioned the first day of class. He introduced it as "K, the second difference matrix, and my favorite". That was good enough for us.
So, yes, again, you can mount 'a brake' and be legal in some places but not everywhere, the whole thrill here seems to come from not having all that 'stuff' on the bike.
If you've ever done any serious bicycling then you realise that the fixed wheel bike has no other place than the track.
In traffic you'd have to be an artist to safely ride one and the problem with them being in traffic is not just that you'd have to be an artist but also that circumstances can determine what is safe and what is not.
Brakes are used for normal reduction in speed, in such cases a fixed gear will do, after all, all you're doing is removing energy from the 'system' (bike + rider) in the same way you put it in, through your leg muscles.
But brakes have a second function as well, which is to react to traffic conditions, things outside of your control. And you may find that you need to remove energy from the 'system' a lot quicker than you originally put it in.
For a bike with a fixed gear (one without a freewheel) this will mandate you to continue to make pedalling motions while you are using that other brake. If the reason why you need to brake stops you from doing that you are now in deep trouble because you will find two nice sized hammers roughly where your pedals used to be that are pounding the crap out of your legs, which can easily cause you to completely lose control of your bike. If you happen to be unbalanced a pedal can strike the road with incredible force and if your foot happens to be between the pedal and the road that's really bad.
So, where-ever the legislation hasn't caught up yet with fixed gear bikes being outlawed because of the 'trend' will sooner or later do so because they're simply not as safe as bikes that have freewheels.
It's a pity for the few people that started this trend and that know their stuff and are only endangering themselves, but now that the masses are flooding in and are copying the couriers legislation seems to be the answer taken by the authorities.
In the Netherlands, bicycle country #2 after China I believe they've been illegal since 1950 or so.
I've ridden a fixed gear bike exclusively for the past 15 years. (alright, that's not exactly true... I have a dutch bike for groceries and recently bought a Brompton for traveling) It was built for me by the patron saint of internet cyclists, Sheldon Brown (RIP).
Going fast and having just a front brake can easily cause you to do a forward flip. 80% of your stopping power is in the front brake, but if you're going very fast engaging the front brake for an emergency stop can make a bad situation worse.
That's a pretty sad story there, I read a bit on his site and he seems to have been a very nice and knowledgeable guy. I'm pretty sure he would have smiled at the way you characterised him, there are worse things that people could say about you after you die.
For an analogue, you can drive in traffic with a car and never touch the brakes, if you're a really good driver and you plan ahead. So, in theory you could remove your brakes and still be safe.
So, now for the obligatory 'think of the children' argument, but it could just as easy be the think of other people in traffic that do unexpected stuff or the mistakes that you yourself might make (nobody is infallible):
Until the day that that toddler walks out in front of you. And then, whether you're in a car or on a bike doing a good clip you're going to be very happy that you have all the stopping power that you could possibly want.
Now a clever counter argument would be that a freewheel cycle with discs on front and rear wheels would offer less stopping power than a fixed gear cycle similarly equipped.
As for bike styles, I have a recumbent (a Zephyr) for fast touring on bike trails but I'd never ever take it in to traffic with vehicles around me (too low), also it has a very large bell on it (and I don't care if people think it's gay), because people are simply not used to bikes doing that sort of speed.
I've never bought the front brake argument. As a bicyclist, motorcyclist, and physicist, I know that 100% of your stopping power is on the front brake, exactly because (as you say) the front brake can make you do a forward flip. This means that all your weight is on the front wheel, and the only thing you can do with your rear brake is make the rear wheel lose traction, and that will indeed make a bad situation worse.
The answer is to become proficient in the use of your front brake and commit the proper brake pressure to muscle memory so that you do not grab at it and skip the front wheel before weight has shifted, or do a "stoppie". Practice maximum braking from speed, it could save your life!
There is one counter-argument to this: In situations with poor traction (on snow, ice, sand, etc.) you don't have enough traction to shift all your weight to the front. In those cases, the optimal case is judicious use of both brakes. But if you bike on such surfaces, you have much more to learn anyway...
Second lesson: People rely too much on brakes. In most high-speed situations, swerving is a better action. (Due to the way braking distance vs turning distance scales with speed.) Practice change direction quickly to avoid obstacles in your path!
Sorry for the long post, but it was fresh in my mind: My wife got side swiped by a car turning right yesterday. She's fine, but we had a long discussion about bicycle proficiency and the futility of being "dead right".
I went ass-over-teakettle once on a tenspeed in Amsterdam traffic, I was very much in a hurry (trying to catch the train to work) and rode faster than the car traffic, a guy turned right into my 'lane' and I hit the front brake in a reflex. Too hard, I flipped right over and bounced off the pavement after doing a salto. Bad scrapes everywhere, fortunately nothing more serious than that (I used to be made of elastic, if I tried that today I'd be dead). I never realised that you could do that until it happened.
I was 'right' too, but since swerving wasn't an option and my front brake worked a bit better than expected I wonder if there would have been a better way to handle this (sliding sideways for instance). Accidents lurk in remarkably small corners. My nightmare scenario for a fixed gear cycle would be downhill at a good speed with a sudden obstruction. That would be the 'perfect storm'.
Glad to hear your wife is fine, bicyclists are on the bad side of any close encounters of the third kind with other traffic.
It's easy to get tossed on any bike with an aggressive geometry if you are going fast and slam the front brake. Personally, I do not think the most popular bike styles in the USA have the right geometry for commuting in the city. The default accident for stopping abruptly should not be flying over the handlebars, which is what happens on road/track frames and MTB frames. My bikes are set up more like dutch bikes or beach cruisers, which have a very upright geometry with my bodyweight over the back wheel.
Employing high-altitude balloons to cut down on launch costs is potential feasible, as traditional launches can run into the tens of thousands of dollars (or more) per lb.
One potential problem with going small on the rover end is that the prize stipulates that the rover must travel a prescribed distance on the lunar surface, and going too small will make traversing distance a much greater obstacle that it already is. Additionally, how would one power the antenna necessary to communicate with earth (I am thinking specifically of battery power only, and I think it would in and of itself weigh more than a pound)?
Not by much. Most of the energy cost of a launch to Earth orbit involves getting to orbital velocity. Getting an object that high is pretty easy by comparison.
(Get out your physics textbook and compare the kinetic energy of something going Mach 24 to the potential energy of something dropping 100 km.)
I'd expect a mistake like this from a high school student or a freshman. If you're not clear about this, then you have a perhaps a bit of homework to do before posting questions about space to a social news site that prides itself on informed, intelligent discussion.
Perhaps start with Zubrin's _Entering Space_. Any number of books about the space program will do as well.
I don't think a person should "do his homework" before asking a mere thought-provoking toy question. However naive the question, it has potential for informed, intelligent discussion.
It's entirely logical: you just have to think outside the box (big enough baloon vs. small enough vehicle: plus it overcomes some of the niggly "near ground" effects [why do you think so many next-gen space vehicle designs launch from Airplanes??])
The physics is there and probably workable.
(EDIT: my initial thoughts would tend towards a high altitude launch of several smaller sized vehicles that re-assemble on the lunar surface... or interact there. S o for example someone above mentions the comms issue: a static relay planted on the surface interfacing with a seperate rover device would probably work well. In fact I would launch 2 or 3 of each type (assuming cost could be kept low) to ensure that you got at least one functioning pair :D)
Jet airplanes also give you something like 600 mph of initial velocity. In the case of Pegasus and Space Ship One, they are like the first stage rocket.
The Rocket Equation is pretty nasty. When your required delta-v goes up, your reaction mass requirement goes up faster than a polynomial function. Saving the initial 600 mph is very significant. Balloons -- only sounding rockets use those, but they don't do anything but gain altitude anyhow. If you need escape velocity or orbit, then they are pretty much useless. (You might as well build a slightly bigger rocket.)
Please actually do the physics before you post vacuous statements like:
The physics is there and probably workable.
People are having "intelligent discussions" about balloon assisted launch? Eternal September has gotten to HN!
I have done the physics: or spoken to people that have.
In fact I have seen a successful small rocket launched from a 100 ft high ballon platform (the physics is painful but it is possible).
Other ideas like centrifuge acceleration I know have been discussed: and I personally see potential in them (Ammers & Myers, Oxford University Press, 2006 I think: I'll try and dig out a reference #).
With equal respect I suggest you actually try to think outside the box before posting vacuous statements stating it is impossible.... ;)
EDIT: BTW you do know NASA have recently been exploring the possiblity too.... admittedly for low earth orbit sattelites (and i know that a major problem is breaking that barrier - but it is proof of an initial concept....)
The crucial data is that ballons can carry rockets to a MUCH higher altitude than planes. The reduced drag at that altitude means a lot less propellant is needed (and even a solid fuel propellant could suffice).
NASA has plans for a ballon that can carry up to a ton of equipment to a height of 33Km which is pretty good!
You've also missed the point of the airplane: 600MPH is frankyl nothing (4% of the speed required for LEO). The important thing is the lowered drag and kinetic requirements to get the payload to LEO.
You've also missed the point of the airplane: 600MPH is frankyl nothing (4% of the speed required for LEO).
Small increases in speed would indeed be relatively unimportant in regard to only a final stage. When, instead, an increase in speed affects an entire rocket stack, it becomes important, since lower stages are exponentially more massive than upper stages. For the same reason, it can be important to launch from the equator, since equatorial launch provides 465 m/s of speed, not only for the final payload, but for the entire rocket stack.
Why are you presenting that? Did you read that page? It discusses the launching of sounding rockets (rockets that go up, not into orbit). Is there anything about orbital launch, or orbital speed, there?
They also have a design for a ballon to reach 110,000 feet which could carry up to a ton of equipment. I'm thinking centrifuge or "gun" launch at the altitude might go well :D
I am a bit disappointed in this "cant be done" give up attitude.
What are you referring to?
I assure you it can and will be done.
What can be done? Orbital launch from a balloon? If the subject is orbital launch from a balloon, why did you post a link to the Wikipedia article on CU spaceflight?
I assumed you'd have the initiative to follow the links and read up on CU Spaceflight
Which links? The Martlet Project link http://www.srcf.ucam.org/~cuspaceflight/martlet.php says, "The aim of the Martlet Project is to develop a small sounding rocket system that will be launched from a helium balloon." There is nothing there about orbital launch from a balloon. Do you know what a sounding rocket is?
Please post the specific links that you think have to do with orbital launch from balloons.
I posted one, the NASA link: which is research into exaclty what we were talking about.
CU Spaceflight is launching a new test flight later this year: I was told (by an ex-team member actually) that it was intended to pave the way for orbital launches.
As to what I was referring to: I meant the off hand dismissal of every piece of work towards launching from Balloons... I agree sounding rockets (yes I know what they are thanks ;)) are not orbital devices - but it proves the groundwork and paves the way to more exciting stuff.. surely.. dismissing such data offhand seems a little unhackerish and uninspired :(
To clarify my point... (as it seems to have got lost in the noise)
- There have been no orbital launches from balloons to date
- There HAVE been sub orbital launches to date
- NASA (and possible CU) are looking into launching orbital devices from balloons
- NASA have plans for a Balloon which will be able to carry a ton of equipment up to a "launchable" height.
- My conclusion from this is that far from being impossible it is perfectly within possibility, probably with our current technology.
@all Sorry to feed the trolling.. now that my point is clear I shall move on ;) :D
assuming we take SpaceX on their word, that the "Falcon 1 is the world’s lowest cost per flight to orbit of a production rocket", and take the cost and payload weight right of the website, then for a 1010 kg payload at $9.1M, that works out to be roughly, $4095 / lb.
I dont think the question was intended to be phrased in regards to 'physical' needs, but I understand and agree with your intent. I would also have to second the vote for soy protein.
[1] https://en.wikipedia.org/wiki/Ethereum#Ether_supply_increase...