Why doesn't hardware designed for schoolchildren not have a shutdown button?

Would a button or even a pair of jumpers really add that much to the cost of materials?

Anyone who has an ebook reader with Wi-Fi is asking for trouble.

It will be a sad day for me when my Sony PRS-300 reader fails to start. This reader has no Wi-Fi.

What is that I hear you say? Turn off the Wi-Fi on the reader? Please, how naive do you think I am?

"The only controls available to those on board were two push-buttons on the center post of the cabin -- one labeled on and one labeled off. The on button simply started a flight from Mars. The off button connected to nothing. It was installed at the insistence of the Martian mental-health experts, who said that human beings were always happier with machinery they thought they could turn off."

- Kurt Vonnegut, The Sirens of Titan

The idea of using Lunar Seismic activilty to measure gravitational radiation dates back to the 1970s.

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

In particular, consider the purpose of the Lunar Surface Gravimeter (LSG).

I do not believe that what you wrote is correct.

Empty space is globally flat, but because gravity is a force with unlimited range no universe with any mass in it is globally flat.

At small enough scale every spacetime is locally flat, although that scale may be very small near a black hole. Only at the location of the singularity is it impossible to find a locally flat reference frame.

During the 1987 Whittier Narrows earthquake every car alarm in the area was set off.

Although I now live in quake-free Texas the first thing I think of when a car alarm goes off is Earthquake! It must be the reptile part of the brain or something. Once my heart starts beating and the rest of my brain starts working I realize there is no earthquake.

Note taking on paper has a number of advantages, but one disadvantage is that the information is indexed only one way: by date. I prefer bound, numbered laboratory notebooks, but unless you have a pretty good idea when you wrote it down it is difficult to find the information you want.

Retrieving information is the reason you write it down, isn't it?

Of course, I learned in a lecture by Jack Kilby that the only reason he was granted the patent on the integrated circuit (and, later, his Nobel Prize) was because he had the bound notebooks he used periodically signed and dated by his manager and then notarized.

I, too, have an e-book reader that does not have the hardware to go on the internet.

Isn't the Unix philosophy to have a single command that does only one job well? "cat", "head", "tail", "ls" are examples of the commands I have in mind. Extend this idea to the real world. I have an e-book reader, a music player, a (dumb) phone, and a wristwatch.

A smart phone is a bit like the Microsoft operating system: it does everything, but does not do any of them well.

Not much of a bargain. Mediocre performance AND the loss of privacy.

I am old enough to remember seeing restrooms marked "white" and "colored". During the bad old days everyone understood that a sign that said "We reserve the right to refuse service to any person" was a code phrase for "whites only". It is sad to read that GitHub is so tone-deaf to the lessons of American history.

from http://www.legalmatch.com/law-library/article/restaurants-right-to-refuse-service.html

"Does a Restaurant Have the Unrestricted Right to Refuse Service to Specific Patrons?

No. The Civil Rights Act of 1964 explicitly prohibits restaurants from refusing service to patrons on the basis of race, color, religion, or natural origin. In addition, most courts don't allow restaurants to refuse service to patrons based on extremely arbitrary conditions. For example, a person likely can't be refused service due to having a lazy eye."

As a happy owner of the Adafruit Blue&White 16x2 LCD+Keypad Kit for Raspberry Pi I have used and modified the software that originally came with this kit.

There are some obvious uses for this kit. Two examples would be displaying its IP address and using the keypad to shutdown the Pi.

However, when I was modifying the software I could not find specific instructions on how to contribute software back to your site. I just checked again this morning (even the FAQ), and, if these instructions exist, I could not find them.

How does one contribute back?

I watched on TV the Mercury capsules launch on TV as a boy, and as a young man I worked on the Galileo mission. Of all the books I have read about the space program none is better than Chris Karft's "Flight - My Life in Mission Control".

It is not an engineering book, but a book written by an engineer. For example, the description of the problems during Apollo 13 are described better here than anywhere. He never tries to make hemself or anyone else look better than they actually were. He often is quite critical of NASA's spin control.

The velocity of the craft does matter, and I will explain why.

If the velocity of the craft is much greater than the particles (think of dust floating in the air), then the craft will indeed sweep out all the particles in its line of motion.

However, the the velocity of the craft is much less that the particles (think cosmic rays in interplanetary space), then there will be the same number of collisions per unit time during the trip. A five hundred day trip will have ten times the number of collisions as a fifty day trip. Consequently, the faster your craft travels, the fewer particles you encounter during your journey.

Professor Dyson

I had the pleasure of listening to you speak at Caltech in the 1980s about the Nuclear Freeze Movement. You were a supporter even though you indicated that since the number of nuclear weapons was decreasing (at that time), keeping the current number of nuclear weapons was not desirable.

Thirty years have passed. Do you think this movement accomplished any of their goals?

Thank you.

Speaking as someone who was classified 1-A in 1973 I would claim you left off one of his important actions:

"On January 27, 1973, Secretary of Defense Melvin R. Laird announced the creation of an all-volunteer armed forces, negating the need for the military draft."

It is a violation of federal law in the USA to fire a worker for discussing their salary with a co-worker. This law dates back to the New Deal.

http://www.staffingtalk.com/allowed-discuss-salary-co-workers/

You wonder why oral exams are not more common?

There were 279 students enrolled in this class. Assuming a ten minute oral exam for each and two minutes to grade the answers it takes 55.8 hours to examine all the students. This oral exam would take at least two weeks in a 14 week semester, and ten minutes is really too little time to judge the work of an entire semester.

If anyone other than the professor grades the student, then they cry foul.

If the exams begin in the fifth week of the 14 week semester, the students examined last cry foul since they must study significantly more material.

There should be only twenty students in a class? Good luck with that. I suppose you could raise tuition and hire more professors or have the classes taught by lecturers.

Actually, in the USA most classes are taught by lecturers, and the classes are still huge.