Wikipedia talk:WikiProject Physics/Archive July 2012

Thermonuclear weapon

Hello,

I started a requested move of Teller–Ulam design to Thermonuclear weapon. Feedbacks are very welcome. -- Taku (talk) 23:57, 30 June 2012 (UTC)

These are not exactly the same topic because there are other possible designs for fusion weapons. For example, the fission trigger could be built in a sphere around the fusion core. Or Lithium deuteride could be replaced by other substances capable of fusion.

So I would suggest a more general article on thermonuclear weapons with a link to this particular design (which is the most commonly used). JRSpriggs (talk) 19:11, 1 July 2012 (UTC)

Don't we already have a general article at nuclear weapon design? That article already mentions fusion-boosted fission weapons (the spherical type), and links to Teller-Ulam design (from its "two-stage thermonuclear weapons" paragraph). In fact, the article looks well-written enough to be worth trying to polish to featured status IMO.

Regarding fuels other than lithium deuteride, that was only tried once to my knowledge (the Ivy Mike test). LiD turns out to be by far the most practical fuel for weapons. --Christopher Thomas (talk) 19:35, 1 July 2012 (UTC)

Escape velocity - scalar or vector ?

As part of a rewrite of sections of the escape velocity article, Zedshort (talk · contribs) wrote

"Escape velocity is a velocity in that it is the radial speed an object must have as it is directed radially away if it is to escape another mass's) gravitational pull. The escaping object may have an additional component of velocity normal to its radial velocity but in order to escape the planet's gravitational pull, it must have a speed in the radial direction at least as great in magnitude as the mass's "escape velocity"".

This idea that escape velocity depends on direction seemed to me such a fundamental error that I reverted their rewrite, explaining why on the talk page. In response, Zedshort says

"You are incorrect. Escape velocity is not just a speed but has a direction making it a vector quantity. The component of the speed in the radial direction must be equal to the escape velocity in magnitude."

To avoid a pointless back-and-forth argument, I would welcome other editors' input at Talk:Escape velocity#Reversion of rewrite. Gandalf61 (talk) 14:59, 2 July 2012 (UTC)