Some of the tech team at Sirona are here, if people have questions.
131 karma · joined January 20, 2012
I'm thinking about what would happen if instead of Assange we were dealing with a person from a country where religion and government are intertwined, and that person was asking for asylum to the UK for accusations that are not crimes in the UK.
That aside, real infinities is a vague concept. What's important is that any theory of gravity has to deal with the fact that the current understanding of classical gravity and quantum field theory make (when you combine them) a theory that has problems at the Planck scale. Those are problems that any theory of quantum gravity or every theory of everything have to deal with.
But it doesn't mean that those potential theories would have any infinities. Such a theory, though, has been very elusive.
With the exception of string theory, which is the leading theory in terms of its success, most theories tend to have fundamental problems. String theory research is certainly not complete, but it's in my opinion currently the best shot we have. Online, and in academia, you can find lots of very opinionated discussions about it, which include aspects of testability, predictivity, etc. which means that some people really dislike string theory and prefer other approaches.
The explanation of why gravity is only positive is a complex one, but physicists believe it's almost axiomatic.
This doesn't mean that you can't have repulsive type of effects, similar to one of the contributions that's believed to make the universe expand more quickly than with the simple 4 fources (often called fifth force, maybe related to dark energy, and to the rate of the universe expansion acceleration).
PS. There are a number of Sci-Fi stories that use this idea, including a famous one from Asimov, in which if I recall correctly the normal gravitational force was working negatively when traveling in FTL speed. Obviously that seemed fishy but the book was cool (Nemesis).
[1] http://www.uscis.gov/news/uscis-accept-h-1b-petitions-fiscal...
One think that I believe is important to point out is that this short essay is focusing on the experimental aspect of the measurement of the speed of gravity. It gives an explanation on why this is even an intelligent question to answer and why the answer we commonly accept is that gravity moves at the speed of light. I will never have better words than him so I won't add anything to what he said.
What I would like to point out, is that this essay is not talking about whether or not theoretically would be possible to have a speed of gravity faster than the speed of light. General relativity and special relativity have been tested on several aspects, and they pretty much are in agreement with all experimental constraint. There is no other theory that can explain everything we see (some theories tend to explain a few things, but not all of them, or they are too vague).
A theory in which the speed of gravity is faster than the speed of light isn't unconceivable per se, but no one has been able to write a completely consistent one yet, mostly because it would have large consequences on what special and general relativity imply for cosmology and particle physics (and causality). If gravity moved faster than the speed of light then we'd have to 'fix' a lot of problems coming down to paradoxes and stuff like that.
So take this essay as a way to appreciate how elegant and fine some experimental questions on gravity (and physics) are.
The reason why Google doesn't have a product, can be for multiple reasons, for example because they may (who knows) only want to create an Android OS-like self driving system, not necessarily building the cars. It's the same they did with smart phones.
If they want to dominate the car OS market, they might not need to present it as a product at this stage.
They just need, as Amazon, to push it enough to gain momentum and be one of the early players.
Amazon here is trying to play the same role that Google has been playing for a long time with their self driving cars. They are setting a standard and pushing for regulations and laws.
It is not that difficult to think that the future of unmanned vehicles won't be as naive as people may think. There will probably be a combination of different sets of vehicles that would go around for large distances and/or sizes, and different vehicles covering smaller distances and/or sizes. They can be used in series to optimize the traveling salesman problem in terms of what's powering these vehicles.
It's not that different from thinking of an ant-like distribution system.
And not that different from the Google approach of crawling the web, then crawling the actual world with google street view cars, eventually moving into self driving cars. Except you'll also get lots of metadata with it, that can be used and sold.
Amazon is now part of the game, moving the attention to drones and self flying objects.
In that case buyers just buy expensive objects and then open a dispute under the 'object not respondent to description' or 'broken' or something like that... (and they don't send the objects back)
Does anyone know a good list of approaches to take against this kind of scams?
In the future things like google glass or even active screens/windshields will be more and more able to show the same information and more, without necessarily implying any unsafe behavior on the road.
For example. I agree that within the circle of safety you can readjust your position however you want, given enough time for you to readjust.
What I don't necessarily see, is that one straight line is the best way to maximize the escape. For example, I could consider going at pi/2 for a bit, having the monster trying to catch up counter clock wise, and then slightly bend toward pi/2 + alpha.
This may be wrong, and maybe it's easy to see, but I failed at understanding whether or not that is possible from the explanation. After all, it's a similar strategy to the pi/2 one. I.e., the monster will have to get there covering more space. This would be very different from aiming at that point when you are at the edge of the safety circle, since now the monster is at a different relative position. So it depends on whether or not there is no solution that gives you some extra time.
For example, why is a spiral (that keeps being a spiral after leaving the safety circle) worse than a J shape? (same point as above but with a curve instead of two straight lines at an angle).
Another point is the optimal strategy for the monster. If the monster waits for a second waiting for you to move, would pi/2 still be the best strategy?
To be honest I think that the solution sounds perfectly reasonable. I just thought I wasn't mathematically 100% convinced.
And I liked the website and the other puzzles (I'm still thinking about the Ace of Spade, on which I have a question).
The monster will always have to run towards the direction where the angle between itself and the boat is smaller, otherwise it'd be choosing a longer path.
In facts, if at some point the monster decides to go clockwise, the boat could simply choose the symmetrical direction compared to the relative position of the monster.
This being sad, I'm not sure I am convinced that no other trajectory can be faster, since many of the arguments seem to be a little too wavy.
One think that I believe is important to point out is that this short essay is focusing on the experimental aspect of the measurement of the speed of gravity. It gives an explanation on why this is even an intelligent question to answer and why the answer we commonly accept is that gravity moves at the speed of light. I will never have better words than him so I won't add anything to what he said.
What I would like to point out, based on some comments I read here, is that this essay is not talking about whether or not theoretically would be possible to have a speed of gravity faster than the speed of light.
General relativity and special relativity have been tested on several aspects, and they pretty much are in agreement with all experimental constraint. There is no other theory that can explain everything we see (some theories tend to explain a few things, but not all of them, or they are too vague).
A theory in which the speed of gravity is faster than the speed of light isn't unconceivable per se, but no one has been able to write a completely consistent one yet, mostly because it would have large consequences on what special and general relativity imply for cosmology and particle physics (and causality). If gravity moved faster than the speed of light then we'd have to 'fix' a lot of problems coming down to paradoxes and stuff like that.
So take this essay as a way to appreciate how elegant and fine some experimental questions on gravity (and physics) are.
Either you say that something is dangerous (as in your example, drugs, weapons... etc), or it has to be considered a scam.
I may be wrong and I would like to understand this better, but I don't see how they can declare it illegal to buy unless they find a loophole (money laundry, etc).
But just saying you're not allow to buy it, without associating with it a motivation (which could eventually be challenged via various Courts), doesn't see easy to me in the US.
They can't even manage to ban weapons really.
It seems to me hard to enforce in some western countries.
How can you enforce people not to buy or sell something, unless you decide it's a scam.
Regulations could be enforced, I suppose, the same way short-selling can be 'paused' in situation in which the market is going crazy or volatility is too high. But unless you use these loopholes I am not sure it would be possible.
Does anyone know of ways to enforce such a thing in the states? Or in any of the western european countries?
In Europe free sodas are more rare.
In Italy, at least until I left, I had never heard of free sodas at work. But I heard of a lot of free work 'for experience'.
But honestly, you are talking about a different thing.
If you can't afford to pay much of anything it's fine, as long as, for example, you give me a bunch of shares which would be worth nothing now, but something in case you become a billionaire.
But if you don't want to give anything back for my work, then I tend to think that you are trying to use my time.
Of course there may be a million exceptions to this, and there are. But in my experience those where the exceptions, and the usual case was just a way to get free labor.
The high unemployment rate pushes people to accept them to have at least more experience to use in their following job applications, but basically this created an ecosystem in which there is companies that count of a few employees working for free.
I can also tell you that in most cases the owners of these companies are not exactly starving, so there isn't a real reason why they shouldn't pay for good work.
Fortunately it seems that the startup culture is picking up a little, and hopefully this will improve the situation.
But I agree with you, and here in the Bay we are fairly lucky.
There is no reason why those companies can't pay a basic internship salary which at least allows you not to work somewhere else to be able to eat and sleep somewhere else than a friends couch (or floor).
And if the company really can't afford that basic salary, I would double question if it's really worth for you to work for them.
Isn't this a solved game that, given optimal strategy, is either won or lost based on the where the first tile is placed?
San Francisco: http://farm8.staticflickr.com/7315/8798020541_80aa618bab_o.p...
Manhattan: http://farm9.staticflickr.com/8136/8808603540_e298c96fd3_o.p...
I may be wrong but I disagree with who says that the difference from a data analyst and a data scientist is that the data scientist is a software engineer.
I would say instead that the difference between a software engineer and a data scientist is that the data scientist is a scientist that has a strong CV in data structures and algorithms, as well as in (maybe pure) science, with experience in statistics, math, or physics, and that knows very well how to work with models, test hypotheses, spot patterns, anomalies etc...
The clause that was impossible to make disappear suddenly disappeared overnight.
P.S. Congrats for Matasano, I am a fan of your company.