Recent content by shelanachium

Thanks for references, Humanino! I did know about free neutrons, though minutes rather than hours. My main point was that if the long-lived stau does exist, it should already have been found in secondary cosmic rays. It hasn't, so probably does not exist.

In the New Scientist of 5 July 2008 is an article 'Crucible of Creation' on pp 28 - 31. Part of it concerns the ratio of the isotopes Li-6 and Li-7 which formed just after the Big Bang. They discuss the work of Maxim Pospelov of the Perimeter Institute in Waterloo, Ontario. Pospelov proposes...

St Augustine of Hippo sorted this one 1500 years ago. He was asked 'What was God doing before Creation?' Most would have answered 'Creating Hell for those who ask such questions'. St Augustine answered 'Time and Space were created together. Therefore it is meaningless to ask what happened...

That's my point. Mersenne primes must be a tiny subset of all primes. Many cryptographical systems depend on the use of multiples of vast primes. It is not computationally feasible to factorise such numbers, which keeps these systems secure. Yet if the known vast primes are a minute subset...

Absolutely enormous primes are known these days. It is not possible that all primes are known up to the largest ones one sees mentioned. So how far up is EVERY prime known?

Just I think Cosmology is getting a bit like Ptolemy's epicycles. We got inflation, then dark matter, then a resurrected cosmological constant - and what next? I know it is only an act of faith to believe like Dirac that the fundamental rules of the Universe are simple. (I prefer RULES to...

Well now, from the avalanche of responses to my original posting, haven't I made my earlier point: NOBODY AGREES! Or are you all saying the same thing? - and this non-mathematical guy mostly into biology and chemistry, but who at 57 still asks questions like a ten-year-old, fails to understand...

I have lost count of the number of times I have raised this matter at Astronomy bashes and before eminent astronomers and cosmologists (living in Cambridge, England, helps.) Not only can I not usually make sense of their answers (which can be put down to insufficient intellect on my own part)...

According to Einstein, there is no absolute frame of reference; no such thing as 'absolute rest'. But does not the Cosmic Background Radiation provide an absolute frame of reference? An object for which this radiation is totally isotropic is at absolute rest; I gather we move relative to it at...

Fair enough, but at what distance does universal expansion outride gravity? Universal expansion should have SOME effect even at intragalactic distances, producing an apparent weakening of gravity so that it no longer follows the 1/r^2 rule. In fact inside galaxies and galaxy clusters the...

Space expands. So we are told. But why only intergalactic space? I asked Stephen Hawking once (I happen to live in the same town), and he replied 'gravitationally bound systems (such as the Local Group of galaxies) do not expand'. Why not? Does gravity have a limited range? An expansion...

As a photon travels at the speed of light, it does not experience time. For a photon the beginning and end of time are simultaneous. However then does anything ever happen to a photon, as events must happen in time?

Thanks! That's what Wikipedia said - but gave no explanation. I thought it had to be Jupiter's rotation; were the energy coming from the orbits of the satellites continuously changing in one direction, they would alter radically over geological time. Jupiter's rotation is a much larger source of...

Thanks guys (and gals?) for all your feedback. If Janus is right the system can evolve in a reasonable time (few billion years). Only remaining worry is that if orbit began quite large (e.g. 100,000km+) it might have been nearly coplanar with the ecliptic like that of our own moon. It would then...

Our own moon rotates synchronously, but has an elliptical orbit. It therefore doesn't EXACTLY keep the same face to the Earth all the time - it appears to 'rock' a little from side to side. (look up 'lunar librations'). This indeed causes stress within the Moon and is thought to be one of the...