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Comment: Re: Alright smart guy (Score 1) 496

by drerwk (#47963789) Attached to: Ask Slashdot: Is iOS 8 a Pig?
I use safari too - which is what is failing to load all kinds of things - I'm going to give tenfourfox a try. I mostly like to have a 'puter that the two year old can tear the keys off of and I don't get stressed out. But it would also be nice if the browser worked well enough for the seven year old to run his blog.

Comment: Re:Just do it. (Score 2) 234

by drerwk (#47939077) Attached to: Ask Slashdot: How To Pick Up Astronomy and Physics As an Adult?
To add to the Galaxy Zoo suggestion:
Have a look at this book: "Statistics, data mining and machine learning in astronomy" http://www.britastro.org/journ...
I have my BS in Physics, but I write software. I think it would be pretty hard at 10 hours a week to pick up the math of most of the advanced topics - even mechanics. But, learning statistics and data mining and having public access to data like the Sloan Survey would put you in the position to make real discoveries as an amateur. And, a modicum of competence in statistics and data mining may give you some good options for paying gigs.

Comment: Re:Thermodynamic equilibrium is not required (Score 1) 211

by drerwk (#47874911) Attached to: Information Theory Places New Limits On Origin of Life

There's this "Sun" bombarding the planet with energy, constantly.

Then take the two-body system given by the Earth and the Sun as the closed system.

If it was a closed system the Earth would have cooked by now coming to equilibrium with the Sun - fortunately we have the cold bath of the rest of the universe to which most of the Sun's energy flows, as well as some heat from the night side of the Earth - so it is not a closed system.

Comment: Re:mini-explosion? (Score 1) 74

by drerwk (#47852039) Attached to: How Astrophysicists Hope To Turn the Entire Moon Into a Cosmic Ray Detector
You might enjoy reading http://www.ast.leeds.ac.uk/Aug... for an introduction. But to answer your question, the incoming cosmic rays usually (always?) begin interacting in the upper atmosphere, I don't know the cross sections particularly well, but it is possible that only very rarely do they make it to the ground. What we detect down here is the cascade of particles - like an avalanche - initiated in the upper atmosphere. The resultant cascade can affect detectors across hundreds of square kms.

Comment: Re:Nerd Blackface (Score 1) 442

by drerwk (#47641627) Attached to: Big Bang Actors To Earn $1M Per Episode

Do you really think that an IRL Sheldon without script immunity would be able to do the same? The TV Sheldon also seems to be a pretty crap physicist, given to conspiracy theories, junk science, and an inability to distinguish between fiction and reality.

I was an undergrad Physics major at Caltech. Other than the crap physicist qualifier, I knew professors in the department who were given to conspiracy theories, junk science, and an inability to distinguish between fiction and reality, though not all in a single individual.

Comment: Re:"and designed to fly near transonic speed" (Score 1) 44

by drerwk (#47593219) Attached to: Perlan II Project Aims To Fly a Glider To the Edge of Space
The lift produced by a wing is partly a function of the rate of air mass that passes over the wing. Keeping density constant an increase in velocity will increase lift. If the density of the air decreases, as it does with altitude, then one must increase velocity to get the same air mass to pass over the wing and generate the same lift. At the altitude they will be flying, they may well have to fly near the speed of sound to get enough air over the wing to provide sufficient lift. The higher they go, the higher their stall speed so they end up flying in a decreasing envelope between speed of sound and stall. The typical airspeed indicator is a static ram pressure transducer, which is also dependent on the mass of air impinging on it, so it will indicate 'normal' stall and flying speed even though the plane is going much faster.

Comment: Re:OR (Score 4, Interesting) 579

by drerwk (#47368065) Attached to: Unintended Consequences For Traffic Safety Feature

One could argue that in most cases, a pedestrian paying attention could have avoided getting ran over if they'd pulled their heads out of their phones long enough to look around them.

SFPD claims to be keeping better stats these days but I could not find them online.
However here is what I did find: http://www.ktvu.com/news/news/...

All three victims this year entered the crosswalk only after pushing a button to activate several flashing beacons to alert drivers to stop. There are six lanes of traffic across Sunset with an island in the middle. Thursday's crash occurred when several drivers stopped, but a Honda CRV kept going. The driver noticed the woman too late and skidded into her, clipping her with the front bumper and spinning her to the pavement. "She said she didn't see her, " San Franicsco Police Officer Gian Tozzini told KTVU. "I don't know how she didn't see the flashers. Maybe they're just looking forward and not paying attention."

That is three victims, one fatally injured, at a single crosswalk with flashing lights in the Sunset. The description matches what I see in my little New England town where I'll slow because I see a deer stepping into the road and the car behind me thinks they need to pass me on a two lane road so as not to slow down at all - not sure how bad I'd feel other than for the deer. A pedestrian was hit in our crosswalk same way - one car stopped, person started walking, car behind did not even slow down and passed in the next lane hitting the person in the crosswalk - actually tossing them into the front window of another car that had also stopped on the other side for the pedestrian - that car was full of kids coming home from little league.

Comment: Re:magical scenario where (Score 1) 737

by drerwk (#46737883) Attached to: Ask Slashdot: Are You Apocalypse-Useful?

So running a conductor through a changing magnetic field will no longer produce a charge?

No it won't. It will produce an electric field which can be used to push charges around, but will not produce a charge.

Putting two lead oxide plates in an acid batch will no longer cause a chemical reaction?

Nope - no electrochemical reaction. You need metals of differing electronegativity, like Pb and PbO2.

My goodness, I was unaware that a catastrophe large enough to cause an apocalyptic event would change the fundamental laws of physics.

You're right it won't, but you might want to brush up on what they are before the apocalypse.

You sound young.

...

Comment: Re:It's not trending. (Score 2) 371

by drerwk (#46696537) Attached to: Smart Car Tipping Trending In San Francisco
Seriously? Never wondered what it would feel like to hit a baseball across the street and through a window? Never wondered what the sound would be like and not thinking beyond the cool sound of breaking glass tossed the ball up and let swing. And then in unexpected joy realized you hit it perfectly, to hear the glorious sound of that window break only to have your stomach sink to the depths realizing that you broke a damn window?

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