I can't believe...
... nobody's asked whether this affects their speed in a vacuum.
Nope. Just me then?
55 posts • joined 15 Nov 2007
Cherenkov radiation is emitted directly by a neutrino travelling faster than the local speed of light - no collisions are necessary for this to happen. Compare with sonic booms of supersonic flight.
Simply detecting two in two years implies no collision rates with humans, only passing harmlessly through them.
Note: 1 PeV is approximately equal to 0.16 Joules - which is the amount of energy released when you let a mass of 16 grams drop vertically 1 metre to impact the ground under earth's gravity.
It might just be me, but that is far easier to comprehend than some nonsense about thousands of trillions times the energy of visible light. Could you have found a more obscure and ridiculous example?
I may have erroniously caught the wrong end of the stick, but I was under the impression that all but a nanognat's fart of antimatter was already gone by t = 1 second. The traditional method of "banging the rocks (or particles at least) together, guys" is usually the easiest way of attempting to recreate this critical epoch, where there was clearly enough disparity for just matter to prevail thereafter.
Getting your antimatter cool enough to form atoms is a nice party trick, but it's not really relevant to the real problem. What this team hope to achieve by allowing them now for a few mere minutes at a time is quite frankly a mystery to me.
Good work on getting funding for such impressive toys, though.
Oh, I sometimes wish that you'd state where you get these figures from, or at least qualify it more meaningfully (viz. timescales).
Not telling us only makes me want to not stick my fingers in my ears and yell "LALALALALA I'm not listening" for the remainder of the article.
Come on Orlowski, your cause is flagging a bit with all this negative press about it being "about as greenhouse gas emitting as coal".
In all truth, hydrogen is an excellent energy storage medium. People just assume it's going to be wildly inneficient, hazardous, bulky, or all three. This really is rather unjustified. ~700 bar storage vessels are slowly becoming standardised for vehicular applications, so it is only a matter of time before somebody does something useful with it.
You don't need to be as loopy as DARPA to see this.
You need to be careful, Mr Page, not to give the honest law-abiding snake-oil salesmen of this world a bad reputation.
"Debates" as per the above comments are sound proof as to why science is, and never should be, democratic or even on the side of those who shout loudest.
I do still prefer that you enable comments to your articles. Provides me with much entertainment, reading all this drivel.
I'll go back to selective hearing mode now.
Please go back to school.
Einsteinian relativity, if that is it's real name, is a theory primarily regarding gravity. It is about objects travelling relative to each other and those in different gravitational fields. Perhaps you are confusing it with our little friend "quantum mechanics", which does indeed struggle with anything gravity-related.
Both of these theories are extremely accurate within their own domains, however. Accuracy of predicted effects for both of these theories is well into nine significant figures for many cases. They are, therefore, the best and most widely used boffinry tools of the trade, despite being nearly one hundred years old in parts.
A considerable boffinry effort has, in the last three decades or so, looked into all sorts of ways of combining the two, which you quite rightly call "string theory". Unfortunately, it requires many additional dimensions to be present (11 in total if you include time). These, if the nearly unproveable theories are correct, must be rolled or looped up so minutely to be undetectable to even our mightiest atomsmashers (LHC bread-roll-incident permitting).
It is unfortunately the aim of scientists to study things we do not fully understand. If we understood everything perfectly, we might as well all go home and waste our time on pointless pursuits like commenting on websites and cursing our least favourite operating systems, but why would anybody in their right mind want to do that?
Nice to see NASA have finally realised that you get nowhere in space under a democracy. The Russians, were always more innovative for this reason. Even the International Astronomical Union were sly enough to vote out Pluto from the league of extraordinary planets before the nay-sayers could get to the relevant conference.
In Soviet NASA, Colbert run on You! Oh no wait...
Why, of course you can generate hydrogen on offshore windfarms, pipe it on shore and deal with it in any number of worthwhile ways.
This is extremely beneficial as you use direct current 'leccy to electrolyse, whereas currently the 'leccy produced offshore has to be converted to fit in with the grid A.C., 50 Hz, timed just right. This incurrs all sorts of losses.
Piping hydrogen ashore from such windfarms may not be the most efficient system in the world, but at least it would be emissions free (after construction et al). Given enough storage facility, it would also be able to iron out those calm days/weeks, and meet demand peaks.
Why is everyone so negative about hydrogen energy? Scared of a little investment are we?
Thank goodness some people are at least trying to make it work. I like the thought of a fuel that can be made anywhere with a source of electricity and water. Goodbye petrol tankers and the like.
Mine's the one with the detonation-proof lining. A bit of exploding gas never hurt anyone.
Surprisingly, if you are after an all-singing-all-dancing picture as to the climate trends over the entire planet you will have to wait quite a number of years whilst the data are being recorded. In addition to this, climate science is a field still in its infancy. Rigorous water-tight science of a system so complex is bound by the pace at which the data either verify or disprove any theories. And, since the data can only be gathered in real time, a 30-year old field has precious little to go on (yes, I realise data can be surmised from older weather stations, tree-rings, ice bores and the like, but these are largely indirect measures, and rarely apply worldwide).
Why do I have to be bombarded with such sensationalism at every slightest event, and every event being construed almost beyond belief to suit the agenda of increasingly vocal groups of questionable authority? No other science would put up with it. It almost seems like opinions borne entirely from imagination are given equal or greater precedence than anything based upon sound science and unbiased quantitative analysis.
Oh, sure there's plenty of open ocean one year, and plenty of sea-ice the next, and yes, I'm concerned. I just can't make head nor tail of it until I understand what's happening in the long term and more importantly what mechanisms are responsible for these effects. Nobel prizes cannot be won by anecdotes... No actually, scratch that. They can.
Thanks for an interesting and well researched article. I just wish wish more people could base their ideas and publications on sound data, and not a photograph of a fluffy creature looking sorry for itself in some slightly-less icy wasteland.
...has become yet another conspiracy theory.
Please. It's a bit of rock, when viewed from one orientation, has a feature that looks a little like a head and a pair of shoulders.
No miracles were harmed in the making of this comment. Well, maybe one or two.
There's already plenty of categories of objects that don't quite make the grade of being a planet. I think I understand them all... except this one.
Asteroids - Inner solar system objects, mostly rocky, and not cleared their own orbit, the largest of which is Ceres.
Centaurs - Relatively small icy/rocky bodies orbitting between Jupiter and Uranus.
Trans-Neptunian object - an object that orbits partly or entirely outside the orbit of Neptune.
Kuiper Belt object (KBO) - Relatively small icy-rocky objects orbiting 30-50 AU from the Sun with relatively small inclination.
Resonant KBOs, or "Plutinos" - a KBO with an orbit in resonance with Neptune, which includes Pluto.
Classical KBOs - non-resonant orbit and generally lower eccentricity, and generally slightly farther from the Sun than the resonant variety.
Scattered disk objects - generally farther again (48-70 AU), but with greater eccentricity and also greater inclinations, Eris is a member of this group.
Oort cloud - über far away (50 k AU), and surrounding the Sun in a shell, the source of long period comets.
Now, is it me, or is "Plutoid" not really needed, as everything has already been covered in some category or other?
Since air is a fairly ideal gas (particularly if you vastly reduce the pressure), the speed of sound is governed largely by temperature. As any avionic expert knows, you are going to encounter large inefficiencies running near or in excess of the speed of sound.
In air, for the speed of sound to increase above 1500 km/h, one would have to hike up the temperatures well in excess of 160 deg C, whereas in hydrogen, the speed of sound is already 4740 km/h even at room temperature. It is therefore much more efficient to fly through hydrogen at 1500 km/h, and you wouldn't be creating such great mechanical stresses as a sonic boom in a confined area.
Also, large Hydrogen pipelines already exist. They are safe. One of these tube vehicles running the breadth of the USA would require less than 1% of our annual hydrogen output. Keeping the pressure constantly a jot above atmospheric would mean that it is easy to detect any leaks externally, and no high-integrity seals or engineering would be necessary, unlike the high-vacuum tube case. Oh, and you can easily power all the electrolysers you want to produce your low pressure hydrogen using the solar cells you mentioned coating the tube (neat idea, if I may say so).
Sure, a maglev train in a vacuum tube is possible now without much research, but if one is to look more than a few years ahead, there are massive running cost cuts attained with the hydrogen tube vehicle.
Next you'll be telling us it falls out of the sky too...
Is it me, or is it becoming increasingly obvious these so-called saviours are too good to be true? Of course it doesn't grow in fully-fledged desert. Nothing does really, which is why they are so empty and sandy. Nature has learnt this after several billion years of trying.
If the west is that desperate for so-called greener and non-oil based solutions to long-haul transportation, why can't some big research-based companies look into such gems as the hydrogen-fuelled tube vehicle: http://www.fuelcellpropulsion.org/PublicOutreach/Websites/Publications.htm
/gets coat. The one with the oil-tight sealant-lining and attached waders.
"threw material over an area 50km across"
Does this mean that the ejecta reached 25 km away from the impact?
What about the Silverpit crater? Or has this been discredited as an impact crater? That crater alone is 3 km wide, with rings extending out to 10 km. Usually ejecta from an impact crater reaches distances hundreds of times the crater diameter.
Maybe I've misunderstood something...
PH, as she knows how to make an impact.
"The U.S. has just demonstrated that it can knock out anything in orbit from a ship fired weapon, at will".
Shoot the moon!..
Also, I significantly remember concerns about the first attempt due to bad weather from the launch site. So, yes, the U.S. can indeed knock out anything in orbit from a ship fired weapon, so long as it's a nice pleasant day, and it's smaller than the moon. Those evil spysats are fine so long as they get a helping hand from inclement weather conditions...
Charge conjugation changes a particle into exactly the same particle with the opposite charge (eg: +1 -> -1). Parity conjugation, on the other hand, changes exactly that: the handedness, or "spin" of a particle. It is like reflecting it in a mirror. When one conjugates both the charge and the parity of a particle, this converts said particle into its antiparticle nemesis. Hence if there is some asymmetry in CP, there is some definable difference between particles and antiparticles.
Sheesh, when will some basic degree-level particle physics ever be set out straight? Some would say it is confusing enough as it is...
Mine's the coat with the paper note saying "kick me" being hastily ripped off.
Great! 5000 of the 2 million cows in California put to use generating enough stench for 1200 homes.
The population of California is 36 million...
Do they have many goats or sheep there??? Shame they don't have too many elephants... Maybe, everyone in California should walk around wearing personal gas collecting kits. Now that would be the future!
*awaits Arnie to pass the bill implementing this*
Mine's the one made from a synthetic fabric coalesced from bovine methane based hydrocarbons... eww.
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