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Ask Slashdot: How To Pick Up Astronomy and Physics As an Adult?

drerwk Re:Just do it. (220 comments)

To add to the Galaxy Zoo suggestion:
Have a look at this book: "Statistics, data mining and machine learning in astronomy"
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.


Universal Big Bang Lithium Deficit Confirmed

drerwk Re:3 times less? (170 comments)

Yes, exactly.

about a week ago

Information Theory Places New Limits On Origin of Life

drerwk Re:Thermodynamic equilibrium is not required (211 comments)

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.

about two weeks ago

How Astrophysicists Hope To Turn the Entire Moon Into a Cosmic Ray Detector

drerwk Re:mini-explosion? (74 comments)

You might enjoy reading 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.

about two weeks ago

Big Bang Actors To Earn $1M Per Episode

drerwk Re:Nerd Blackface (442 comments)

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.

about a month ago

Perlan II Project Aims To Fly a Glider To the Edge of Space

drerwk Re:"and designed to fly near transonic speed" (44 comments)

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.

about a month and a half ago

NASA Tests Microwave Space Drive

drerwk Mod up - and thanks. (201 comments)

Mod up - and thanks for dropping the $25 to inform the rest of us.

about a month and a half ago

Unintended Consequences For Traffic Safety Feature

drerwk Re:OR (579 comments)

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:

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.

about 3 months ago

Ask Slashdot: Are You Apocalypse-Useful?

drerwk Re:magical scenario where (737 comments)

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.


about 5 months ago

Smart Car Tipping Trending In San Francisco

drerwk Re:Smart Cars = HiTech ??? (371 comments)

That has always bother me too. I'd much rather get an old 2CV - 48 mpg, 4 people seated in comfort, front wheel drive. Not a single thing better than a 60 year old French marvel of engineering.

about 5 months ago

Smart Car Tipping Trending In San Francisco

drerwk Re:It's not trending. (371 comments)

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?

about 5 months ago

Killing Cancer By Retraining the Patient's Immune System

drerwk Re:Avoid cancer (175 comments)

I am sure you can lower the risk with dietary choices. But in fact genetic mutations that lead to cancer do just happen - that is more physics than choice.

about 9 months ago

How Many Android OEMs Cheat Benchmark Scores? Pretty Much All of Them

drerwk Re:Wrong, they are boosting clock speed above norm (189 comments)

There is no way to build a game on Android that can run at the speed the benchmarks are getting run at on each of the devices "cheating".

What happens if you name your game to match the benchmark that the phone is looking for?

about a year ago

Time For a Hobbyist Smartphone?

drerwk Prograph (207 comments)

I loved using this in the mid 90s. I was 5x to 10x productive. But there was no diff available, no way to do SCM, it was hard to come back to code I'd written 6 months before and refresh my memory of what it did. And it was next to impossible to collaborate will a team. I was forced to use using some horrible tools (Kennedy Carter iUML) in the 2005s - same exact problems.
Now iBuilder or what ever the I tool is in XCode is pretty nice. But building software that works, is maintainable, is extendible, and so on is a hard task - I don't think it is the lack of drag and drop tools.

1 year,6 days

A New Spate of Deaths In the Wireless Industry

drerwk Re:Acrophobia? Don't watch. (247 comments)

No, that is not my video. I can watch it till 1:40. When the guy goes outside the mast that's when my stomach feels like it is in free fall.

1 year,27 days

A New Spate of Deaths In the Wireless Industry

drerwk Mod up please (247 comments)

wish I had known - thought that was weird.

1 year,28 days



Powering the Planet

drerwk drerwk writes  |  more than 6 years ago

drerwk writes "An article in the Caltech magazine Engineering and Science by Prof. Nathan Lewis gives a clear and cogent argument that solar is the only likely solution in the next fifty years to the clean energy problem. Discussions on /. regarding clean energy run the gamut and include arguments regarding nuclear, fusion, solar, coal and so on. In contrast, Prof. Lewis's article covers the pros and cons of these same arguments with actual journal references. Let's hope those paint on solar cells are coming soon!

This talk was the opening keynote speech at the first annual California Clean Innovation Conference, held at Caltech on May 11, 2007. The event, a partnership with UCLA and UC San Diego, included discussions on the futures of assorted energy technologies and how to finance them. In other sessions, clean-energy startup companies were given the opportunity to "fast pitch" their business plans, in three to five minutes each, to a panel of venture capitalists. Nathan S. Lewis (BS '77, MS '77) is Caltech's Argyros Professor and professor of chemistry. Much more on global energy issues and on his own research in solar power can be found at

Link to Original Source


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