Hacker News Reader

mchouzaon Fermi Space Telescope Fails to See Evidence Of Dark Matter

Additional evidence is provided by gravitational lensing observations, the most spectacular of which is the Bullet Cluster: http://apod.nasa.gov/apod/ap060824.html

mchouzaon The University Has No Clothes

It must be some protection against code injection. Here is the link in a different format, avoiding the explicit single quote: http://en.wikipedia.org/wiki/Baumol%27s_cost_disease

mchouzaon Out of Fuel: Why Hasn't Innovation Provided a Reliable Alternative to Oil?

I would not say that NIF is a scam, as they are quite open about their priorities: https://lasers.llnl.gov/about/missions/

mchouzaon A modest proposal for an interstellar communications network

Apparently, a significant background of 10^19 eV neutrinos is expected: http://web.phys.ntnu.no/~mika/taup.pdf

mchouzaon Plutonium is Forever

Are you sure the presence of plutonium indicates a containment breach at a reactor? Remember that the fuel at the reactor 4 SFP is probably damaged and was sprayed with water.

mchouzaon Plutonium is Forever

I'm no "atomic troll" and radioactive contamination at Fukushima is potentially a significant problem. But the detected plutonium levels are almost insignificant compared to the detected Cs-137 contamination (whose half-life is 30 years, not months):

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/im... (Pu) http://www.mext.go.jp/component/english/__icsFiles/afieldfil... (Cs-137)

The activity of Cs-137 is orders of magnitude greater.

mchouzaon Quantum computing device hints at powerful future

Quantum algorithms halve the "strength in bits" of symmetric encryption algorithms by using the Grover's search algorithm (AFAIK):

http://en.wikipedia.org/wiki/Quantum_computer#Potential

mchouzaon The 'why I am not worried' article, edited by MIT nuclear scientists

Please read carefully before making absurd accusations. I said: "even an infinite amount of unmoderated natural uranium cannot sustain a chain reaction". The nuclear excursion at Chernobyl occurred in a graphite-moderated reactor core.

I don't claim any special expertise in nuclear power but, as you don't seem to know the importance of moderation in criticality, I think you should refrain from accusing others of cluelessness in this topic.

mchouzaon The 'why I am not worried' article, edited by MIT nuclear scientists

Each reactor core holds over 100 tons of uranium, of which about 3-5 tons is U-235. Critical mass under perfect conditions is 50 kilograms.

Critical masses don't work that way: the additional U-238 absorbs neutrons making more difficult to achieve criticality. In fact, even an infinite amount of unmoderated natural uranium cannot sustain a chain reaction. See the figure 3.1 in [1] for more information about unmoderated critical masses for enriched uranium.

[1] http://www.ornl.gov/sci/radiation_transport_criticality/Hopp...

mchouzaon HTML + CSS3 is Turing complete

Link: http://www.ioccc.org/2001/ (herrmann1 files)

mchouzaon 2045: The Year Man Becomes Immortal

An interesting animation about this topic by John Weldon:

http://www.youtube.com/watch?v=pdxucpPq6Lc

mchouzaon The Size of the Human Radio-Broadcast Bubble in the Milky Way Galaxy

There is an analysis of the detectability of human radio signals at:

http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html

The main uncertainty is at estimating the level of radio technology that can be available to alien civilizations.

mchouzaon Russia poised to breach mysterious Antarctic lake

It's more complex than that:

http://lptms.u-psud.fr/membres/trizac/Ens/L3FIP/Ice.pdf

Even an extremely high pressure cannot melt ice at -25 °C, but skiing is still possible at that temperature.

mchouzaon Russia poised to breach mysterious Antarctic lake

It has some meaning. It's hotter than any positive temperature:

http://en.wikipedia.org/wiki/Negative_temperature :-D

mchouzaon Stephan Wolfram: 100 Years Since Principia Mathematica

An interesting project that is developing an updated version of this idea is Metamath: http://us.metamath.org/index.html

mchouzaon Photons cooled down to room temperature, made into a blob of matter

I believe that the preprint is at:

http://arxiv.org/abs/1007.4088

mchouzaon Cracking Passwords In The Cloud: Amazon’s New EC2 GPU Instances

If the original input is not very short, it's extremely unlikely that an input with the same SHA-1 hash could be found. These attacks work because the passwords are weak and SHA-1 is fast to compute, not due to any weakness of SHA-1 as a cryptographic hash function.

mchouzaon USPS sees $8.5 billion loss, warns Congress it'll be broke by 2011

Wrong, and many well respected economists will tell you you're wrong.

Yes and other well respected economists (at least at the time) told that we were in a "Great Moderation":

http://en.wikipedia.org/wiki/The_Great_Moderation

mchouzaon Video: 15 story Ark Hotel built in 6 days in Shanghai

A commenter says it's at Changsha:

http://maps.google.com/maps?f=q&source=s_q&hl=en&...

mchouzaon Implementing the auto-buying bot from xkcd #576

The bot has a Twitter account: http://twitter.com/trademe_xkcd576

mchouzaon John Carmack on government

As evidence that the costs are worth the benefits I submit the fact that you (perhaps not you in particular but any citizen of a country who makes this claim) haven't renounced your citizenship for that of another, better cost-benefit ratio, country.

A country and its government are not the same thing. The cost-benefit balance can be made positive by benefits that are independent of government, such as cultural attitudes or proximity to specific private institutions.

mchouzaon Using MySQL as NoSQL Store

It's similar to how FriendFeed uses (used?) MySQL:

http://bret.appspot.com/entry/how-friendfeed-uses-mysql

mchouzaon Write A Function To Determine If A Number Is A Power Of 2

Well... we can just check if it's nonzero. They didn't say real power of 2. :-)

mchouzaon Facebook Co-Founder Speaks Publicly: What I Learned

An histogram with the founding decades of the 2009 Fortune 500 is in this article: http://www.gathr.me/the-economic-future-just-happened.pdf (figure 2).

mchouzaon Gravity simulator [flash] - try "Generate proto disk"

The Earth is not attracted to where the Sun is "now", it is attracted to where the Sun was approx. 8 minutes ago

That's not entirely true as there are higher order effects in GR canceling this lag "to second order".

http://math.ucr.edu/home/baez/physics/Relativity/GR/grav_spe...

mchouzaon Emerald cockroach wasp - Reproductive behavior and life cycle

I believed that Alien was inspired by The Voyage of the Space Beagle, but Dan O'Bannon (the screenplay writer) denied it: "I didn't steal Alien from anybody. I stole it from everybody!"

http://en.wikipedia.org/wiki/Alien_(film)#Origins

mchouzaon Pity the Poor Couple Who Make $450,000 Per Year

Downvoting is downvoting, it's not censorship.

mchouzaon German Military Study Warns of Drastic Oil Crisis

One interesting study about this area, done by the JASON group for the DoD, is "Reducing DoD Fossil-Fuel Dependence, JSR-06-135":

http://www.fas.org/irp/agency/dod/jason/fossil.pdf