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You clearly knows more about this than I do; but calling the different neutrinos a mixture of the three flavours of neutrino seems a little lacking.

e, muon and tau neutrinos undergo flavour oscillation, ie change type, but they appear still to be different particles - the particles comprise a mixture of flavour eigenstates that interfere through a mismatch in the mass eigenstates. No I don't understand it fully but a simple mental-model analog might be beat frequencies produced by sound waves in constructive interference.

Incidentally when I was an undergrad neutrino mass was an open question, massive neutrino's (eg those with a mass) allows for flavour oscillation which accounts [to some extent!] for discrepancies in the number of ex solar electron neutrinos predicted in the standard model.

Wikipedia is ambiguous on this point but the question was solved (using a large vat of dry-cleaning fluid) in favour of a massive neutrino several years ago, http://physicsworld.com/cws/article/print/1497 . There are still questions as to the exact mass and whether other unobserved neutrino's (super-massive, non-interacting "sterile neutrinos") exist and could be a type of dark matter - indeed I didn't think that the 1eV bound had been established conclusively but that the mass differences had been.

I cannot provide proof for the reasoning behind it, just the common idea that in an almost infinitely large universe the probability of another earth like planet is almost guaranteed. Your post just stated it in a neat way I felt. Its more a matter of opinion the way I am describing it. I am sure it could be expanded upon and has been many times over.

I do not see how finding life on Mars would provide more solid proof since it could have been just as easily ejected from earth and landed on the martian surface.

If the life found on Mars did have different signatures due to atmospheric differences/mineral composition and the like, could we be sure that it was not ejected from earth millions of years ago and subsequently went extinct here? I am just thinking out loud, I can think of a few flaws to the line of reasoning... I just dont see how finding life on mars could be a sure indicator of life forming on other planets. Much like an earth like planet existing. Which one is more likely though remains distinct.

In regards to a meteor striking earth and killing all its inhabitants, I agree. A meteor is the least of our worries. However, when i said that we must avoid eradication I was thinking along the same lines as you. I am no expert, but would a gamma ray burst, no matter the size, have to be directed onto a said location to provide the levels of radiation and energy that would be lethal instantaneously if not crippling the atmosphere of the said planet?

Several groups of physicists have shown that the odds of a GRB eradicating life on earth is zero due to the spiral nature of our galaxy.
http://physicsworld.com/cws/article/news/24692

Going way into the future, if we did start to inhabit different galaxies the only thing I could see wiping out civilization would be either itself or the big crunch at the end of time as we understand it. If we ever do spread out to this unimaginable magnitude, we will be able to predict almost all phenomena in the universe with as much certainty as they allow. Even the precise moment when the inevitable will occur...

For that you need concentrated energy generation capacity

Distributed Nuclear power is on its way too. There was a demonstration of Cold Fusion in Japan in May.

I didn't mention it in my original posts because a lot of people believe that Low Energy Nuclear Reactions are unpossible, and they instantly stop thinking when the subject is brought up.

I talked a bit with a scientist who said his doctorate was applicable to Cold Fusion some 5 years ago. Like the article says, there is a core group of scientists who are plugging away at "impossible" technologies, and their discoveries have almost reached the point of commercial implementation. Soon, very soon, we'll be free of the Energy ball & chain.

Sorry. The last I checked, the record went to the Bose-Einstein condensate at a few nano-Kelvin. 1.9 K is boiling by comparison.

What you were thinking of is Transparent Alumina, an Aluminium Oxide Ceramic.

http://physicsworld.com/cws/article/news/20033

It does *NOT* conduct electricity (at least at room temperature) and if it's a superconductor at lower temperatures I don't know.

However, you *could* coat a window made from Transparent Alumina with a Photovoltaic ink ( http://physicsworld.com/cws/article/news/20033 ) and get a stronger, more durable window with photovoltaic properties. Maybe for those impractical windows shown in the 1950's concept art for habitations on the moon. ( http://moon.jaxa.jp/ja/gallery/moon_base/IMAGE/moon_base06_s.jpg ).

What you were thinking of is Transparent Alumina, an Aluminium Oxide Ceramic.

http://physicsworld.com/cws/article/news/20033

It does *NOT* conduct electricity (at least at room temperature) and if it's a superconductor at lower temperatures I don't know.

However, you *could* coat a window made from Transparent Alumina with a Photovoltaic ink ( http://physicsworld.com/cws/article/news/20033 ) and get a stronger, more durable window with photovoltaic properties. Maybe for those impractical windows shown in the 1950's concept art for habitations on the moon. ( http://moon.jaxa.jp/ja/gallery/moon_base/IMAGE/moon_base06_s.jpg ).

The smallest known exoplanet is the fourth planet of the pulsar B1257+12, with a mass considerably smaller than Earth. Many of the pulsar planets are Earth sized and smaller.

MOD PARENT UP!

Thanks for commenting. It's good that you took the time to help others understand.

This story about the same researcher mentioned in the Slashdot story is far more sensible: Cold-fusion demonstration "a success".

Except that if you read the papers published by the scientist, they show that there was Helium production; they measured the ambient Helium in the atmosphere and proved their experiments generated up to 28 times the amount of present helium. (papers are referenced here: http://physicsworld.com/blog/2008/05/coldfusion_demonstration_a_suc_1.html) Furthermore, they also measured excess heat beyond that capable of happening from surface chemical reactions, which is conclusive evidence towards Nuclear Fusion. The only missing piece is reproducibility and peer review, which is probably why we're just hearing about it now, even though the experiments have been happening over the past decade, one of which was over two years long and generated excess heat for the entire duration.

This article cover the news better: http://physicsworld.com/cws/article/news/33926

It also contains a link to the original paper: http://arxiv.org/abs/0804.2202

This article cover the news better: http://physicsworld.com/cws/article/news/33926

It also contains a link to the original paper: http://arxiv.org/abs/0804.2202

Right, because Einstein wasn't just a math-loving, nobody patent clerk when he published some of the most important papers in the history of physics.

Beware of making universal generalizations.

Eyes rolling...

One cannot "mine" helium. It comes dominantly from radioactive decay in the earth of Uranium and its decay products. But because it is so light, it generally leaks out of the ground, and escapes. Also because it is so light, it is not retained in the earth's atmosphere at all, and leaks into space (at which point it is irretrievable). Our supply right now comes from radioactive decay (over the last 5 billion years) which produced helium that accidentally got trapped in the earth (mostly in the same underground reservoirs as oil -- it is mixed in with natural gas). The half-life of Uranium is about 4.5 billion years, so the Helium is produced very slowly.

The problem is that it has widespread industrial and scientific uses, and its loss will have a severe impact on our science and industry. In particular it is used as a coolant (gets down to about 4K, and is the best way to get things to that temperature). Also it is used in any application requiring high field superconducting magnets. The fancy new High-T_c magnets generally cannot support large fields, so in fields like particle physics which require big magnets, they generally use simpler materials (e.g. Niobium-Titanium for the main LHC magnets) that only superconduct at temperatures much lower than the liquid Nitrogen boiling point.

-- Bob

Another interesting alternative to the dark matter theory is the TeVeS (Tensor Vector Scalar) theory of gravity. It is powerful enough to explain gravitational lensing, and the Bullet cluster as well.

pulse length is ~10 fs or 3 microns at the speed of light. Since most of the stuff one looks at is at thermal velocities, this is certainly a macroscopic freeze frame. To look at steps of chemical reactions, sub-femtosecond pulses are desirable. Google "energy recovery linac" (ERL) for information on a mechanism for getting such short pulses. UK was hoping to build an ERL-based light source at Daresbury but the budget news out today http://physicsworld.com/cws/article/news/32163 suggests this won't go ahead for a while.

maybe its an optical illusion and one glaxy just passing through the corner of a universe sized kaleidescope... http://physicsworld.com/cws/article/news/18368

Second thought is a bit more speculative (is that possible?), but might make sense... If 4 galaxies are to merge then predictably, they will contain and feed the largest super massive black hole in the universe. Then maybe they will be able to attract more and more galaxies. Then maybe (when it's at a ripe old age) the universe will implode at the point of that hole. Then maybe there will be another big bang (the same size as the one we know).

I know this is pure speculation and not nearly as funny as the post I'm responding two, thanks.