Recent content by DrMik

Waveform is right. Get yourself a good astronomy magazine and look in the small ads. You can pick up a decent 6" to 8" (150 mm to 200 mm) Dobsonian for little money, probably less than a new 76 mm you mention. (Dobsonian is the type of 'swivel-based' mounting a Newtonian can come with). The...

Self replication.

Yes I use a couple of 12V pc fans to cool both a laser and the LM317 attached to a CPU heat sink. I drilled a hole in it and mounted the laser and then attached the LM317 metal tab to it with a self tapping screw. The two 12V fans were mounted either end so the air is blown through the heat...

Calculus, James Stewart, ISBN 0-534-13212-X, 2nd Ed. Primer for partial diff, (Chapter 12)

Yup. I was taught first angle in school 'technical drawing class', but was told of 3rd. When working as an engineer all the drawings of the stuff I made came in 3rd angle *(both European and US). I thought this blog deserved noting in the 22nd decade.

Err yes. I was not using the term instantaneous so literally, I meant it as if you actually did it using the tube of sweets. Why was this so different from the pencil analogy? But you are correct anyway (apart from drift velocity in copper I though it was about tenths of a mm per sec). I must...

Hear Hear! I must apologise for the references given for antiparticles. The Ginzburg book is on my shelf. They gave the two references for the antiprotons and antinuclei being primary cosmic rays. I have re-read the sections and it is not exactly clear if they are the references for...

It was the same 'laymans' terminology as the pencil analogy given earlier. I don't think this question is above the level of 'high school' so that was the level of answer I gave. If you have a better analogy why don't you just give it to the questioner then?

YES! Primary cosmic rays can be antiprotons and antinuclei. Antiprotons where E>1.8GeV make up about 0.1% and antinuclei where Z \geq 2 not more than 0.23%. So total around 0.1% to 1% maximum. Original data from Aizu,H et al Physical Review vol116, p436 (1959) and Jain,P.L., Lohrman, E. and...

Imagine a cardboard tube full of sweets. If you push in another sweet at one end another drops out of the opposite end, no matter how long the tube is. That shows that the sweet put in only travels a couple of millimetres yet its action can be seen instantly at the other end of the tube which...