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Comment: Re:Wildly premature question (Score 1) 66

by Bruce Perens (#48620117) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

If we look at jet aircraft, wear depends on the airframe and the engines, and the airframe seems to be the number of pressurize/depressurize cycles as well as the running hours. Engines get swapped out routinely but when the airframe has enough stress it's time to retire the aircraft lest it suffer catastrophic failure. Rockets are different in scale (much greater stresses) but we can expect the failure points due to age to be those two, with the addition of one main rocket-specific failure point: cryogenic tanks.

How long each will be reliable can be established using ground-based environmental testing. Nobody has the numbers for Falcon 9R yet.

Weight vs. reusable life will become a design decision in rocket design.

Comment: Re:Backups are not secure (Score 1) 109

by jandrese (#48619981) Attached to: Backblaze's 6 TB Hard Drive Face-Off
This is really not a good approach to using public key crypto. The private key shouldn't be on the servers, it should be on the client. I know it's a pain to handle per-file backups and especially deltas when everything is encrypted, but that's the tradeoff for proper security. In fact there's really no need for expensive public key crypto here at all. Just have the client use a cheapish symmetric key (AES256 perhaps) and send only encrypted data to the servers. There's no need at all for the servers to ever have the data in the clear.

Comment: Re:Someone doesn't understand basic relativity (Score 1) 66

The mass is less, and presumably easier to control, but yes, that is a difference.

The relative speeds are the same. Launch starts at 0 and increases to 1300. Landing starts at 1300 and ends at 0.

Actually, that is a small difference. Launch starts at 0, but landing ends at 2 m/s, leaving shock absorbers to reduce it to the final 0.

Comment: Someone doesn't understand basic relativity (Score -1) 66

And I don't mean the speed of light kind.

At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm.

EXACTLY the same as takeoff. NO difference.

+ - Is the Higgs Boson a Piece of the Matter-Antimatter Puzzle?->

Submitted by TaleSlinger
TaleSlinger (3080869) writes "Why there's more matter than antimatter is one of the biggest questions confounding particle physicists and cosmologists, and it cuts to the heart of our own existence. In the time following the Big Bang, when the budding universe cooled enough for matter to form, most matter-antimatter particle pairs that popped into existence annihilated each other. Yet something tipped the balance in favor of matter, or we – and stars, planets, galaxies, life – would not be here.

The paper is based on a phenomenon called CP – or charge-parity – violation, the same phenomenon investigated by BaBar. CP violation means that nature treats a particle and its oppositely charged mirror-image version differently.

"Searching for CP violation at the LHC is tricky," Dolan said. "We've just started to look into the properties of the Higgs, and the experiments must be very carefully designed if we are to improve our understanding of how the Higgs behaves under different conditions.”

The theorists proposed that experimenters look for a process in which a Higgs decays into two tau particles, which are like supersized cousins of electrons, while the remainder of the energy from the original proton-proton collision sprays outward in two jets. Any mix of CP-even and CP-odd in the Higgs is revealed by the angle between the two jets.

"I wanted to add a CP violation measurement to our analysis, and what Matt, Martin and Michael proposed is the most viable avenue,” Philip Harris, a staff physicist at CERN and co-author of the paper said, adding that he's looking forward to all the data the LHC will generate when it starts up again early next year at its full design strength.

"Even with just a few months of data we can start to make real statements about the Higgs and CP violation," he said."

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If entropy is increasing, where is it coming from?

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