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# Comments

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### 2014 Nobel Prize In Physics Awarded To the Inventors of the Blue LED

Saving Earth's resources? (243 comments)

As about one fourth of world electricity consumption is used for lighting purposes, the LEDs contribute to saving the Earth's resources.

Efficiency does not mean lower consumption. Efficiency remains a useful goal but not "to save the planet's resources". The latter can happen only if overall consumption is reduced. What will happen is that as electricity used for lighting purposes is consumed less, it will get cheaper to direct it elsewhere.

about 2 months ago
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### Physicist Claims Black Holes Mathematically Don't Exist

Re:Black holes are real, we observe them all the t (356 comments)

Maybe he should have meant the following version which seems very counter-intuitive:

Suppose you wrap a string around the Earth's equator so that it fits tightly. Now suppose you add an extra meter in the length of that string. Surely, the string won't be tight anymore. So pinch it at a point and pull it upwards as high as you can. (Now, the string goes tightly around most of the earth, and forms a triangle elsewhere with the apex being the point you pinched and pulled.)

How high this apex would be from the surface? The answer turns out to be well over a hundred meters. See Image 1

(Apart from the actual number, the surprising part is also that the bigger the initial object - earth here - the higher you can pull the string even though you add the same extra length of 1 m in each case.)

about 3 months ago
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### The Profoundly Weird, Gender-Specific Roots of the Turing Test

Re:Read the whole article (136 comments)

Also, either the author of the article has a listening comprehension problem or the assitant professor quoted in the article has a reading comprehension problem.

Look at Turing's original article. It says that the imitation game is played between a man (A), a woman (B), and a player C. C has to decide among A and B who is a man and who is a woman. Now, the _man_ is replaced is a computer and we ask if C will perform as well or poorly as before.

So in Turing's version we have a computer A pretending to be a woman to C, and a woman trying to convince C that she is the woman.

Turning's original test _does not_ have a man and a computer pretending to be a woman to a judge.

about 6 months ago
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### Aliens and the Fermi Paradox

Re:the joker in the formula (686 comments)

There are 7 billion people on earth but only one tallest person. Clearly the odds of finding a tallest being on any planet is 1:7_billion.

The point of parent is that if the intelligent "us" were not us, someone else would have evolved to be as intelligent. You can argue that point but don't argue probabilities based on 1 out of however many being intelligent. Two intelligent species would have competed and one would be killed off so far in earth's history.

about 6 months ago
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### The Disappearing Universe

Re:Fascinating, terrifying stuff is news (358 comments)

Do you realize that the whole point of the GP's "exercise" was that you can't ignore relativity? It is due to relativity that the time observed by the traveller would be so little. If you are travelling at a velocity very close to the speed of light, in your own frame time is essentially standing still. You would get to your destination before you could blink your eye.

Now redo the calculations taking time dilation into account.

about 7 months ago
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### Optical Levitation, Space Travel, Quantum Mechanics and Gravity

Usual /. (82 comments)

The summary (and the headline) unnecessarily highlights space travel as a usage for radiation pressure and delegates the most interesting part as a footnote-ish last line. The /. crowd as usual starts shouting pros and cons of space travel, as if every comment on this page is not saying what has already been said a million time around here, and nobody to talk about the interesting part.

I wish someone with the right background in physics posted something more interesting about the fact that a group of researchers have come up with prediction of how a non-quantized spacetime (gravity) would look in the presence of quantized matter/energy. Apparently this would look different than a quantized background with quantized foreground (IANAP, so I don't know what is this all about) in a measurable way. If they can levitate a tiny but macroscopic mirror using light and balance it then giving it a gentle push would create a pendulum with no friction slowing it down. By probing the frequency evolution one can potentially get closer to actually knowing whether a quantum theory of gravity is the right way to unify QM and GR.

It's fascinating that such things are possible even in principle with existing technology. I wish someone would explain something more related to this.

about 7 months ago
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### The Rule of Three Proved By Physicists

Re:Clueless (80 comments)

I don't think so.

Stability of ordinary matter is well explained by other more traditional theories (strong/weak forces for nucleus, electromagnetic for atoms and molecules, gravity for even larger structures). This theory described stable states that initially no one believed existed.

Morever, these configurations are stable but quite fragile.

about 7 months ago
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### The Rule of Three Proved By Physicists

Re:Clueless (80 comments)

I found the summary confusing but the article made more sense.

The theory was that there exist configurations of three particles that is stable in a strange sort of way. The strange part is that if a certain configuration was stable then putting the particles in the same configuration but the distances blown up by a certain factor (22.7 if the three particles were the same) gives another stable configuration. So you can keep blowing up the distances in multiples of 22.7 and would get an infinite sequence of stable configurations. These configurations are necessarily quantum and not classical since the distances involved would be much larger than the range of the forces between the particles. (Although even the initial distances are large too, if i understood correctly, you would agree that they _will_ get pretty large at some point).

Now some independent groups have shown the existence of such states with the required blowup. Since similar-particle setup required cooling things down to the limit of present day technology, only _one_ configuration was observed initially. Someone used a system of different particles resulting in a blowup factor less than 22.7 allowing them to observe _three_ of these configurations, essentially validating the theory.

Hope that made sense (IANAP).

about 7 months ago
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### Asteroid Impacts Bigger Risk Than Thought

What increases the risk (172 comments)

I don't think anyone is implying that we are doomed because of _these_ impacts.

However, in general the frequency of an impact event is inversely proportional to the size of the impacting body. Smaller impacts happen more often than the larger ones. Counting the smaller ones precisely gives you an idea of what the risk of a big event is.

So far people underestimated these smaller ones that is being reported. The wikipedia article I linked to earlier, suggests one impact every five years at the level of 5 kT of TNT. These guys being right would imply a risk of at least a magnitude higher than previously estimated. That increases the risk for the really big ones too.

about 8 months ago
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### NASA Uncovers Millions of New Black Holes

Re:I know what you're thinking.. (77 comments)

A black hole would dissipate via Hawking radiation only if it doesn't absorb more energy than it emits. Large blackholes absorb more energy (cosmic background radiation) than they would emit and hence will not necessarily dissipate. From wikipedia:

"A black hole of one solar mass has a temperature of only 60 nanokelvins; in fact, such a black hole would absorb far more cosmic microwave background radiation than it emits. A black hole of 4.5 × 1022 kg (about the mass of the Moon) would be in equilibrium at 2.7 kelvin, absorbing as much radiation as it emits. Yet smaller primordial black holes would emit more than they absorb, and thereby lose mass."

more than 2 years ago
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### Bitcoin-Based Drug Market Silk Road Thriving With \$2 Million In Monthly Sales

Re:And in countries where it's legal? (498 comments)

Not cocaine or ecstacy, but Switzerland allows you to buy heroine. Apparently the same referendum that legalized medicinal heroin use for addicts made marijuana illegal for medicinal purposes.

more than 2 years ago
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### 50 New Exoplanets Found, Billions More Await

Re:Great Super Earths. (208 comments)

Our planet has a very energetic core. Any civilization having that kind of technology could be interested in harvesting it (They also get a huge core made of solid iron as a bonus!)

more than 3 years ago
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### Samsung and VMWare Bringing Virtualization to Android

Re:VMs on a mobile device? (135 comments)

Except that in the context of this discussion the OS running in the virtual environment is the same kind as the host OS.

more than 3 years ago
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### Google Reaches \$500 Million Settlement With Feds

Re:Completely wrong post at +5 Insightful (172 comments)

Slashdot moderation sucks.

It used to work better when there were fewer stories on slashdot. These days the front pages gets updated at such a rapid rate that I suspect a big chunk of readers with mod points going past just a few comments in any one story. If they keep jumping from story to story then faulty moderations are bound to go uncorrected for relatively long times.

Give it a while though; residents of the internet wake up at different times :)

more than 3 years ago
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### Ask Slashdot: Am I Too Old To Learn New Programming Languages?

Re:Stay Put (772 comments)

I think he was saying that the choice was between being a developer or switch to management. I don't think he is worried about being unemployed.

more than 3 years ago
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### China Catches Up With Google's Driverless Car

Re:Catches up? Yeah right... (258 comments)

You are an idiot. Any research available to a chinese scholar (any non-citizen for that matter) would be publicly - or for a small fee - available to anyone. It is not called stealing; that's how research is done.

more than 3 years ago
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### Orange Goo Invades Alaskan Village

Re:Well... (153 comments)

Then you might want to go see a doctor.

more than 3 years ago
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### Macs More Vulnerable Than Windows For Enterprise

Re:All computers are less secure (281 comments)

Do you have a link to the presentation? The linked article doesn't really get into any technical details and the language made me think that what you said was the case.

more than 3 years ago
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### Macs More Vulnerable Than Windows For Enterprise

Re:All computers are less secure (281 comments)

The whole point of TFA is that if even one computer gets infected on the network then it can be used to infect other machines without requiring the admin password on the remote machine. All it would take is one malicious person with physical access to one mac, or one careless click from someone who does has admin access to their own mac in the building.

more than 3 years ago
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### Analyzing Culture With Google Books

Re:handwringing over multiculturalism (20 comments)

Academic libraries frequently already have a big portion of their catalogue in digital form: mostly theses and journals. So my guess would be that someone starting out with a goal of digitizing all books would naturally start with the academic libraries.

more than 3 years ago

# Submissions

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### Google Assists In Arrest Of Indian Man

hansraj (458504) writes "The latest in Google's compliance to local law-enforcement authorities involves helping arrest an Indian man "for posting derogatory content about Congress chief Sonia Gandhi and Mahatma Gandhi on an [O]rkut community named — I hate Sonia Gandhi". Sonia Gandhi is an Italian born Indian politician. Before you make up your mind whether Google was right in complying with local laws or not, the same story has the following to say:

Interestingly, the person who formed this community is not guilty as per the law. The police said that hating Sonia Gandhi is a personal opinion of the person who formed the community and having a personal opinion about someone is not an offence as per the law.
"

Link to Original Source

# Slashdot: News for Nerds

What is wanted is not the will to believe, but the will to find out, which is the exact opposite. -- Bertrand Russell, "Skeptical Essays", 1928

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