25 posts • joined 14 Mar 2012
Re: Run that by me again...
12 billion light years = 8 billion years?
Is that right? If so, why?
Because the Universe is constantly expanding, which affects how far the light must travel even while it is en route, and the effect gets ever more pronounced the further away you look. If you take the galaxy in question here it has a redshift of 4. That means we are seeing it as it was 12 billion years ago, because the light has had to travel that many light years. However when that light set off we were only 3 billion light years away. The galaxy itself is now roughly 23.6 billion light years away.
Don't worry if it makes your head hurt - at these kinds of distances astrophysicists use redshifts almost exclusively, in part because it's a single metric that avoids these kinds of ambiguities.
One final point to clarify my original post - the actual paper is perfectly correct, it's the press release that is wrong.
Yet another paper made meaningless in popular science coverage...
...although in this case the error lies squarely with the press office of the Carnegie Institution for Science rather than the re-reporting of it.
12 billion light years away? That'll be a little over 8 billion years ago then, when the universe was already 5 billion years old and fairly mature, not a mere 1.6 billion years. How did that get through peer review? DID it get through peer review? No: let's have a look at the paper and we see they quote a redshift of 4, which correlates to 12 billion years ago but a distance of almost double that, once you correct for expansion during the interim.
Sigh. How much work went into this? How many hundreds of thousands of dollars? And then at the final hurdle the publicly announced results are Bowdlerized by some English or Media Studies graduate working at the press office.
Re: Don't see how this helps any
a Jupiter-mass object out to 1 light year (63,000 AU), where it would still be within the Sun's zone of gravitational control. A larger object of 2–3 Jupiter masses would be visible at a distance of up to 7–10 light years."
Is that the sum total of your evidence? Quoting Wikipedia verbatim about the technical capabilities of WISE, rather than what is has actually been used for to date?
In other words you are completely ignoring the work that the WISE team have done, which they have announced now, restricting their claims to what may legitimately be claimed based on that work. Instead you have substituted what WISE is theoretically capable of, as if once you have the instrument you don't even need to turn it on to observe the null result. That isn't a scientifically robust argument, you wouldn't even accept that in everyday conversation.
Nemesis remains a fringe theory because zero evidence has been turned up in its favour. And it will rightfully remain a fringe theory.
You are overlooking several factors here. Firstly you choose to ignore the fossil evidence that led to the hypothesis being proposed in the first instance. You ignore the geological evidence to the same effect - sure it is a little sketchy but it is highly suggestive. You are completely ignoring the fact it has been published repeatedly in peer reviewed journals. You ignore that process of expert review, who concluded the theory had merit in order for it to be published, because you know better than them.
So, you ignore or dismiss evidence that is contrary to your position. You throw in irrelevant factors that do nothing to support your case as if they were final trump cards. You ignore the opinions of experts. Those are the hallmarks of a scientifically illiterate crackpot theory, not a properly published, legitimate proposal. Just because the theory naturally appeals to the "end of the world is nigh" brigade doesn't make it any less credible.
Don't see how this helps any
One thing the Nemesis hypothesis has always been very clear on is the size of the orbit - in order to get the period right it needs a semi-major axis of around 95,000 AU. These chaps can make meaningful assertions up to only 42% of that distance and less than 7.5% of the volume of space, and this is somehow "proof"?
Yes, Nemesis is unlikely but it is a legitimate minority opinion, dismissing it as crackpot science is in itself a demonstration of scientific ignorance, since the whole idea is surprisingly and annoyingly difficult to conclusively disprove. In their eagerness to "prove" the falsehood of the theory they are guilty of far worse junk science.
Re: "alert the victim that something had happened"
There's a few ISPs out there whose authentication procedure is "ah, you're coming from that wire. You must be genuine."
Perhaps on cable, but nowhere for DSL modems. That's the wonder of local loop unbundling, DSLAMs and MPLS. Without the correct virtual circuit indicator (not set by default, except possibly for ISP own-brand - as opposed to ISP supplied - stuff) it has no idea where to go. VCI 0 is generally a BT Openworld default "Your router is misconfigured" thing.
Re: I'm confused!
No "small?" No "Big?" Can we at least have "massive" blackholes in between the "intermediate" and the "supermassive". After all, "super" implies bigger, better, above or higher in a sequence so tacked onto massive implies that massive must come before super while massive itself creates a mind image of something humungously bigger than some puny "intermediate" thing so we ought to have "big" in between them too.
You are missing a step between "micro" and "intermediate" which is stellar-mass black holes. Those are typically in the tens of solar mass range, as distinct from "micro" black holes (around molecular mass) which are purely theoretical but at the root of all those "end of the world is nigh" trolls whenever a new particle accelerator is built.
Nor is there any gap between "intermediate" and "supermassive". That is the scientific rather than everyday sense of massive, i.e. "has mass" as opposed to "very big". Thus a supermassive black hole has a lot of mass, but even the micro size is massive.
Re: Good Idea!
I've been in places where they relied on old programs because they were too tight to get a replacement written. I have warned managers of the need to migrate from DOS and 16-bit applications for safety and maintainability too - until I gave it away as a waste of time in 2004!
In my opinion, it is those managers who put their companies at such risk that should be fired, pronto.
In that case it's simple: we'd never hire you.
As a slightly different but essentially identical example: I work at a university where we have a telescope mount controlled from an old XENIX app. We were able to upgrade that to Openserver 5 but even that is 15 years old now. Anything more recent via XENIX emulation simply doesn't work since it needs semi-direct hardware access via ioctls. Cost of an new and equivalent mount? £130,000. Are you offering to stump up?
That's still small fry: for example Royal Mail have hundreds of millions tied up in Integrated Mail Processors. There's a fancy front end on some of the newer machines but underneath it all they are still DOS based. Are they supposed to scrap that investment on your whim too?
Remember, you haven't qualified your statement in any way so you are either ignorant of reality or chequebook happy. There are plenty of apps out there tied to one specific platform or other for any number of reasons. Simply wishing them away doesn't work.
You'll easily be able to point out which law prevents publicly accessible web-pages from being scraped then?
You mean, like, I don't know, the Berne Convention? It's only been law for 100 years or so. The law does not change according to what you want it to say.
The robots.txt protocol is indeed a bit coarse, but I understand that the propositions from Google to the EU included some sort of mechanism to give websites more control over what data Google can grab and display.
I don't know why I speaking up for Murdoch here but the law is clear - robots.txt has exactly zero legal clout.
Ah, two downvotes already for stating ".docx has been around since Word 2007, i.e. 3 releases, hardly changing "every version".
Can my downvoters can get both hands on the keyboard for a minute and let me know which part is mis-leading or inaccurate? :)
.docx is not a format. Neither was .doc which preceded it. It sprouts new bells and whistles every version which is why you have the problems using the same file between releases. You can't even trust pagination of the same document to be the same between two different versions.
Re: For those who can.
Why are people down voting you for pointing out that fact...The internet is a funny place.
So, the recommendation is to brick these routers by installing a firmware they are not capable of running? A sledgehammer is a quicker and functionally identical method of "fixing" this issue.
Although not responsible for the original downvote I get tired to this relentless "DD-WRT is great" bullshit. In particular this idea that a $50 consumer grade device becomes a $1000 enterprise router with a change of firmware - "See, it does everything that this more expensive router does".
Apart from simple performance of course - packet throughput is frequently less than 1% of the more expensive device. It's frequently much worse than even the original firmware - those extra functions don't come for free but take extra processing time. This is leaving aside that third party firmwares, DD-WRT especially, usually aim for device coverage as opposed getting it to work properly on any single device. That frequently means a less powerful wifi signal if the antennae is not optimally configured. How many open source developers wanting a cheap, capable router have access to an EMI testing lab? That'd be none of them.
Yes, DD-WRT has it's place but all too often it is advocated in an axiomatic fashion by the relentless fiddlers. Like here for instance where the router does not support it. Too often it simply devolves to the point of "See, look what I've done, aren't I clever?" when the reality is no extra functions were needed so it is actually "I've made my router slower and less powerful to show how clever I am".
Re: Excuse me?
Even state-owned universities in the US get most of their income from tuition fees, endowments and alumni. Very little state subsidy - it's anti free market, you know. What there is tends to be in the form of grants for specific research projects in the same way as many companies sponsor research.
Re: Sounds like Nemesis all over again
No, as I said, do the sums. That is all that is needed for a parallax measurement of a single star. According to the Tycho-2 catalogue here there are 5,227,058 stars between 9th and 12th magnitude. That makes 10,454,116 observations which is obviously a very small needle in a very large haystack.
Look at the list of nearby stars - they were generally detected not by parallax but by proper motion, and parallax only then used to measure the distance to the star in question, i.e. once it had already been identified. The problem with Nemesis is that it would have the same proper motion as our own solar system, and therefore not moving with respect to us, save for a very small orbital movement which to all intents and purposes looks the same as a much more distant star.
As for the detection of that brown dwarf recently that is precisely what I alluded to in my earlier post: you can detect those "easily" by looking for a bright IR source with no corresponding visible source. You can't do that for stars on the main sequence.
Re: Sounds like Nemesis all over again
Both red and brown dwarves have been proposed at different points. The brown dwarf alternative is increasingly difficult to defend since infra-red sky surveys should have picked it up by now. The red dwarf alternative is much more difficult to dismiss since a nearby red dwarf to all intents and purposes looks identical to a much more distant red giant. To distinguish between them needs full spectroscopy of each candidate star individually, which is both costly and time consuming.
The magnitude range for a red dwarf has been estimated at between 9 and 12. That covers millions of stars. You can dismiss a lot of those immediately because they are the wrong overall colour (i.e. not red) but it still leaves you with tens to hundreds of thousands of possible candidates.
Sounds like Nemesis all over again
A lot of people have been very dismissive of the Nemesis hypothesis over the years but personally I've always found it unlikely, but been unwilling to entirely rule it out. You do the sums and a red dwarf could in fact be very close by, but next to impossible to distinguish from all the other background stars.
Re: Why did nobody found out that Enigma was cracked
There was an awful lot of double-bluff going on. Letting Coventry be bombed to bits was the most notable one but there were plenty of others: One tactic was to thoroughly depth-charge an area of sea that was presumed to be empty. This had the the effect of a) suggesting faulty intelligence at work and b) the co-ordinates so bombed, which they made sure it was within sight of German intelligence, could be used as a fresh crib to break a new day's codes.
Re: That's naughty...
The SDK and kernel are two separate bodies of code. The what the kernel's licence says is a complete irrelevance to the licensing of something else.
Re: Oh dear...
I've just given you another one. If you'd read the comments you'd have seen someone had found the exact device around an hour after this went up. It's an ethernet transformer. You don't get a thumbs up for going to the Delta website and plumping for the first thing mentioned on the front page with a "that's close enough" attitude.
Re: Security @RICHTO
Actually NT 3.x was a relatively pure microkernel system with external device drivers. It was only with NT 4.0 that the video driver was moved back into the kernel to boost performance.
Re: DSLR for planetry imaging
The CCD cells are on a 4.3µm pitch but they are binned for movie mode - you only get 1080p resolution. Have a nice time enjoying those three pixel images.
Re: DSLR for planetry imaging
I was one of the thumbs down. I didn't comment at the time simply because I couldn't be bothered to go through the sums to show why.
DSLRs _are_ completely unsuited to planetary imaging. It isn't just the lack of movie mode on many models - sensor size is an equally important factor that is endemic to the format.
Since we're talking about the Canon 550D consider that it uses a 22.3mm sensor. This is a comparatively large sensor that is great for photographers since it reduces the cropping factor, but is a positive disadvantage in this application. The pixels are arranged on a 13.8µm pitch. A prime focus image of Ganymede at opposition (the most favourable time) is 25µm diameter even at the relatively generous 2400mm focal length of a Celestron C11. That makes a prime focus image area of less than 3 pixels. No amount of post processing can do anything with such limited information - even calculating the Strehl ratios (the first stage of the staking process) is more speculation than concrete mathematics.
Compare with one of the webcam derived imagers such as the NexImage 5 with a pixel pitch of 2.2µm. That gives you an image area of 101 pixels. That's enough for the stackers to begin working profitably with the data collected. The effective resolution can then be boosted by perhaps a factor of 10 or more as a side effect of the stacking process, depending on how many images you have to work with.
In practice however, you'd want to use eyepiece projection on both imagers rather than prime focus to get a decent resolution in the first place. Not a problem with the small sensors of the webcam imagers but if you extend the image over the much greater area of the DSLR sensors the curvature of the focal plane is magnified and completely takes over. The CCD sensor is flat, but the resulting focal "plane" is not. As a consequence only a portion of the image can be in focus at any given focus setting.
The OP's comments do not suggest a suggestion of appropriate tools based on knowledge and experience, but a case of techno-lust - looking around for relatively high-end equipment and assuming it must be exceptional regardless of the circumstances. I wouldn't knock that camera for wide field work, but it is a patently ridiculous suggestion for something like this.
Re: The race to the moon started when?
There was no race to the Moon. After they had men in orbit the Russians looked at their next goals and decided against a manned mission to the Moon. It is only American propanga that portrays a "race" to the Moon - a race with precisely one competitor. A race which ultimately led nowhere - it was 40 years since they were last there, they couldn't go there today and haven't been anywhere else since.
In contrast ventures such as the ISS would have been completely impossible if it was not for decades of Russian experience and expertise developed on their own space station programme.
Re: Whoever designs system that have changable clocks will always have problems
No, it is not me that has missed the point: if you define an internal representation in terms of a monotonic counter that is no longer UTC, even if the epoch is defined in terms of UTC: that simply calibrates the meaning of the counter against the real world: it is _not_ itself UTC and immune to this kind of snafu. Windows uses such a monotonic timer internally, not UTC. Nothing uses UTC, at least you haven't given an example of a system that does yet.
Re: Whoever designs system that have changable clocks will always have problems
"Storing and processing in UTC removes >99% of the complexity."
You've obviously never done any of this work. How does defining everything to UTC solve the problem of six different units in customary use - seven if you include the week (which you need to to accomodate daylight savings)? Determining a time offset from UTC or any other time zone is a matter of one extra term in an expression referring to a lookup table. Add automatic detemination of daylight savings and you are still only looking at a dozen or so lines of code.
Compare that dozen lines to the amount needed simply to deal with all those units. Leap years and leap seconds notwithstanding, months are still not the same length, and yes handling leap years alone (yet alone leap seconds) takes vastly more than that 0.1 line of code that is allowed for in your 99% assertion. An assertion now shown as the ignorant crap it really is, to the extent that you have demonstrated that not only do you not understand the problem, but fail to grasp even its dimensions.
As a final case in point: how many systems actually deal in UTC internally? I'll give you a clue - it isn't ALL "real" systems, in fact I can't think of any more recent than MS-DOS. Windows doesn't and Unix certainly doesn't, both use simple synthetic escalating timers of the nature suggested by Refined Chap. They convert to natural units as and when needed. What do you know that the designers of those systems don't? Or more realistically, what did they realise based on factors that you haven't even considered?
Re: Re cortezcortez
Sorry, but you can't simply make up constitutional law like that. They are nothing to do with the UK and Westminster has absolutely NO powers over them. The only connection is as the nam implies through the crown, not Westminster.
It's always a good idea to ensure you yourself have a basic grasp of the facts before accusing others of ignorance and pontificating.
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