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Comment Re:Uh, D-Wave produces Quantum Computers already? (Score 1) 92

D-Wave's claimed quantum computers depend very much on what you call a quantum computer. D-Waves machines use a form of quantum annealing but they are not a universal quantum computer in the traditional sense, and even for quantum annealing they are very limited in what they can do and it isn't even clear that the problems that the D-Wave machine can do are any problems where we should expect any actual speedup from a quantum computer, and certainly the D-Wave machines have no capability for doing many of the problems we do want to use quantum computers for like factoring large integers.

Comment SETH is a pretty big assumption (Score 2) 82

SETH is a very big assumption, much stronger than even assuming P != NP. Essentially, the exponential time hypothesis (ETH) says that any algorithm which solves instances of 3-SAT will have worst case running time that is exponential. However, it is conceivable that one could have a whole series of algorithms which each solves 3-SAT better and better. The idea is that there's an algorithm a_i which solves 3-SAT in time O(x_i^n) and as i goes to infinity, x_i goes to 1. SETH is the hypothesis that says essentially that that doesn't happen. Many people are not convinced that ETH is true although it certainly looks plausible. I think most people who have thought about this consider the possibility that ETH holds and SETH doesn't hold to be a deeply weird and generally unlikely option.

Comment Re:Any possibility that sunscreen causes cancer? (Score 1) 210

This is incredibly confused. 103 was the *maximum recorded lifespan.* What matters is the *average lifespan.* It is true that if one takes into account improvements in infant mortality the jump in life expectancy hasn't been as large But even given that, life expectancy on average has gone up by about a decade in the US in the last 200 years even if one only works at people surviving past infancy.

Comment Re:Germany wants a lot... (Score 1) 728

*Raises hand* I don't know what hate speech is, but I'm not in favor of laws censoring speech, and that includes Holocaust denial. My grandmother had a number on her arm. Many people on my mother's side of the family were killed in the Holocaust. Holocaust denial is disgusting and these people spouting this denial are in the very best case reprehensible fucktards. That doesn't mean they don't have a right to spout their reprehensible fucktardery.

Comment Re:Graph explains everything (Score 5, Informative) 399

Unfortunately, while some do, many loud and prominent ones do not. Greenpeace is the most obvious example. See especially their opposition to ITER:,,

The Sierra Club which is in many ways more moderate than Greenpeace weakly opposes such fusion also, and while their main argument is that it is too expensive compared to more conventional renewables, they also cite "The dangers posed by the probable releases of tritium used by fusion plants, the problems with decommissioning these plants" which only makes sense if you both don't fully understand how little tritium is being used and how think that the plants will be highly radioactive like conventional fission plants.

Sortir du nucléaire, one of the major French anti-nuclear groups are basically treating ITER and fusion in general very close to how they treat fission power. See e.g.

The environmental movement has done a lot of good and continues to do a lot of good. But there is a definite anti-technology bent in some parts and general anti-nuclear bent which is very unfortunate. There are some environmentalists who understand the potential benefits of fusion and how it is different than fission power, but it is definitely not all of them and certainly doesn't include some of the most prominent organizations.

Comment 39% without secondary false-positives. (Score 3, Informative) 257

If you have 100 studies you are replicating, by sheer chance you are likely still going to have a few who you successfully replicate but aren't real. So the problem may be worse than that (slightly). Psychology isn't the only field with these issues. There have been a lot of problems in medicine also. See Part of the problem is one of incentives: the incentives to do a study which simply replicates a pre-existing study is low, and many journals won't even publish them. This also combines in bad ways with post-hoc analysis where you look at your data and find a pattern in it that is worth publishing; the worst offender here is medicine where people use different statistical tests and different subgroup analysis until they get a positive result.

Comment Re:Confirming the obvious (Score 1) 27

Well yes, but keep in mind that we detect a much larger fraction of the neutrinos from the sun. So if the sun was producing a lot more high energy neutrinos than we expect, some of it could show up here. (Although really that would be ruled out by other considerations- IceCube has directional data for where it detects the neutrinos and that would show up very soon, and in fact, for various reasons related to the shape of the detector, it can only detect a small set of solar neutrinos anyways.)

Comment Re:Confirming the obvious (Score 2) 27

Well, it wasn't obvious that they weren't coming from a combination of the sun and the galactic center. The sun might be producing a few much higher energy neutrinos than we expect which would indicate a deep misunderstanding in our models of the core but it was definitely a possibility. The galactic center is very poorly understood, and there's a lot of dust in the way, so some neutrino production method there would have been very plausible.

Comment The current status (Score 5, Informative) 27

As of right now, the only confirmed neutrino sources we have that aren't artificial are the sun and SN 1987A SN 1987A was a supernova in 1987 (the first one discovered that year, hence the A). The supernova was in the Large Magellanic Cloud, a very nearby galaxy (which is close enough and small enough that there's been some question whether we should really call it a separate galaxy). The supernova was one of the every few that was close enough that it was visible to earth by the naked eye. While every supernova is believed to create many neutrinos (and in fact this flood is an important part of the process) most supernovas are too far away for us to detect the neutrinos from the supernova because neutrinos are so hard to detect.

As of right now, we don't have any way of making any neutrino detector that is more sophisticated than putting a big bunch of mass in the way and hoping to notice when neutrinos happen to hit it by sheer chance (which is extremely rarely). IceCube is one of a next-generation detector where we have used pre-existing mass, in this case, ice as the South Pole for the bulk of the detector. It turns out that the ice very deep down under high pressure (from the ice above it) is nearly perfectly transparent at the light frequencies need, while the bulk of ice on top blocks out stray light and a lot of stray particles that would swamp the signal.

Detectors like IceCube can be used to actually detect the neutrinos from a supernova before the supernova's light reaches Earth. This isn't due to the erroneous claim from a few years ago that neutrinos travel faster than light, but rather because when a supernova occurs, the light from the core of the star takes multiple hours to get out of the core because of all the mass in the way, while the neutrinos aren't slowed down by this almost at all. This means that the neutrinos effectively get a few hours head start on the light- since they are traveling so close to the speed of light, they get to keep almost all this head start by the time they reach Earth. In the case of SN 1987A the neutrinos did as predicted arrive a few hours before the light. This means we can if we detect a neutrino burst and can get its directional data (which IceCube can approximately do) then we can point our telescopes at a supernova *before the light arrives at Earth* which means we'll get to see the very beginning of the supernova and hopefully get a much better understanding.

Right now, to assist in this there is a Supernova Early Warning System which is tied in to the various big detectors so it can let astronomers know that a neutrino surge has been detected- this could of course be a supernova, but there's also the even more exciting possibility of an as yet unrecognized event that produces a lot of neutrinos. It will be very important in either case that a lot astronomers get a good early look at it, both professional and amateur, so the system is designed so that anyone can sign up for alerts from it. So if you are an amateur astronomer you should probably sign up- they send out about once test alert a year.

Comment Based in parts on "Mars Direct" (Score 4, Informative) 60

The basic plan in the book is a variant of Mars Direct, which was a proposal for a much cheaper way of getting to Mars than previous proposals. The primary cost savings are in making some resources on site (especially fuel for the return). If you haven't read The Martian you should. The book was excellent. Also, relevant XKCD

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