* Posts by John Mangan

92 posts • joined 14 Aug 2007

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Boffins' gravitational wave detection hat trick blows open astronomy

John Mangan

Re: So . . . . .

Scott, bear in mind that I am working from near thirty year old memories here but broadly yes.

I remember seeing graphs with a range of postulated sources; Big Bang, supernovae, merging black holes and others thatI've forgotten. Each had predicted ranges for strain and frequency. I'm pretty sure that the Big Bang was low frequency and amplitude because of the elapsed time/intervening expansion of the universe. The longest wavelength/lowest frequency waves will require a space-based detector with 'arms' thousand of kilometres long, see LISA.

I'll have to dig out my thesis to see compare how the predictions from back then compare with the current thinking on the subject (if I can still understand any significant fraction of it).

Other stuff I remember is that the gravitational waves were quadrupoles with two polarisations usually represented as + and x (similar to photons with l and - ). The 'best' signal would be with the wave travelling perpendicular to the detector (up/down into the ground) with the polarisation aligned with the two arms. This gives maximum 'stretch' to one arm with maximum 'squeeze' to the other alternating as the wave propagates.

Exciting times.

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John Mangan

Re: So . . . . .

To get to the oldest waves, and therefore the lowest frequency, will not be possible with ground-based detectors.

That's where LISA comes in . . .

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John Mangan

Re: So . . . . .

I'm well out of date here (and the memory is foggy) but this analogy may be helpful (or completely wrong).

If you drop something into a pool the ripples spread out until they hit a boundary, then they reflect, rinse and repeat until the energy has been evenly distributed around the pool, the boundary, etc. No more ripples.

These waves haven't hit any boundary, they haven't reflected. They suffer from the dissipation of energy as they move from a 'point' source into a larger and larger volume but they are not absorbed, reflected or otherwise homogenated (word?) before reaching us.

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John Mangan

Excited and sad . .

I worked with the Glasgow team as a Postgrad <mumble> years ago and so I am thrilled that this has finally come to fruition. I realised during my studies that I didn't have the patience required to make a career of it (along with other limitations).

I was interviewed by Ron Drever for the post (and worked with him briefly before he moved to Caltech) and I'm desperately sorry to hear he he may no longer be capable of realising his work was so successful.

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Ex-TalkTalker TalkTalks: Records portal had shared password. It was 4 years old

John Mangan

Re: Not just Talk Talk

Actually, I've been called by my bank (First Direct) on two occasions for the purposes of fraud prevention and on both occasions as they started the 'for security purposes . . .' spiel I interrupted with 'You called me, prove who you are." And they did!

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Silent Nork satellite tumbling in orbit

John Mangan

Always an upvote available . .

for a Tom Lehrer reference.

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LIGO boffins set to reveal grav-wave corker

John Mangan

Re: How many events ?

But it depends on what you mean by 'signal'. If you are just talking a 'blip' then yes coincidence would be difficult to rule out. However if you are talking timing, amplitude and signal characteristics (shape, frequency, rise and fall) then it is possible to be very confident with one even from two detectors.

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After-dinner Mint? Stylish desktop finale released as last of the 17 line

John Mangan

Re: Linux & Games

I haven't tried it yet but isn't that what Steam are doing?

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John Mangan

Re: Improvements in the bowls?

I knew there was a joke in there but I couldn't quite find it. Upvote for you.

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Getting metal hunks into orbit used to cost a bomb. Then SpaceX's Falcon 9 landed

John Mangan

Re: Why the unnecessary snark?

Maybe you've got the money but not the time for the several months of training required for a true orbital experience . . . .

Still doesn't make you an idiot for wanting to go.

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John Mangan

Why the unnecessary snark?

"allowing rich idiots the chance to experience freefall for a few minutes before returning to Earth"

I suspect that a large part of the readership of this article are not idiots but if they were rich would be lining up for this sort of experience. Jealous much?

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Hillary Clinton says for crypto 'maybe the back door is the wrong door'

John Mangan

Thor's Hammer

Maybe the solution to this is to show these people the episode of the 'Big Bang Theory' where the ladies are arguing about how 'only the worthy' can wield Thor's Hammer and asking who decides "Who's worthy?". How can a hammer decide?

It might bring the discussion down to a level they can comprehend.

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Lock up your top-of-racks, says Cisco, there's a bug in the USB code

John Mangan

Re: Not the biggest threat

. . . but people do inadvertently pick up the wrong stick, forget what they MEANT to do/WERE doing, not realise that they've picked up some malware, etc. etc. The information doesn't provide any information that specifies associated user actions which implies that just inserting the USB stick may be enough.

The person doesn't need to be malicious for bad things to happen.

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Beardy Branson bangs birds on Boeing

John Mangan

Launcherone?

For some reason when the video started I read it to ryhme with pepperoni.

And once I started I couldn't stop . . . . .

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GENUINE STARSHIP as used by PRINCESS LEIA sold for just $450k

John Mangan

"and Mr Asthma made his stride onto the ship"

I'm sorry, is that your breathing? I can hardly hear myself think.

My friend, can I offer a word of advice? Simplify.

There's simply too much going on; you're evil, you're ashmatic, you're a robot.

And what's with the cape? Are we going to the opera? I don't think so.

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Europe launches search for Einstein's space-time ripples

John Mangan

Re: Give us a wave

LISA will be looking in a lower frequency band than LIGO/VIRGO/GEO600 can observe. Different astronomical phenomena generate waves at different frequencies just as with optical/radio/x-ray/infra-red astronomoy.

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RSI Videofied is a 101 in how to build IP CCTV and alarms with zero security, zero encryption

John Mangan

I don't know about you . . .

but given how badly borked their product is - how much faith would you have in the patch?

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Astronomers catch first sighting of a planet's birth pangs

John Mangan

Phenomenal progress

I still remember when I was a young undergraduate that the whole issue of 'exoplanets' was based on the logical premise that ours was unlikely to be the only star in the galaxy with planets orbiting round it.

In the intervening years we have spotted 'hot massive Jupiters', 'hot Jupiters' and gone down the size scale to small-ish rocky worlds (although in danger of getting a severe roasting from their unstable little suns). We now have sufficient data to generate statistical models of the likely prevalence of habitable worlds throughout the galaxy - - - and only one man-made object has (arguably) yet left the solar system.

Not bad progress from 'banging the rocks together, guys'.

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GCHQ director blasts free market, says UK must be 'sovereign cryptographic nation'

John Mangan

Paging David Cameron

"First is the myth that the government wants to ban encryption," said the head of GCHQ. "We don’t. We advocate encryption."

Perhaps he should tell our beloved PM.

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Einstein's brain to be picked by satellites

John Mangan

Re: Sun and moon

"The Sun and Moon may distort the shape of the Earth, but Shirley it's the mass that matters?"

The distortion will mean that some of that mass will be closer to, or further from, the satellites than on average and therefore there will be variation in the gravitational field and variation in the relativistic effects.

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John Mangan

Re: Sun and moon

My suspicion is that the variation caused by the distortion would be much too small to register on this experiment. Given that the difference in time between two altitudes for the entire mass of the Earth is 140 parts per million I think any distortion will add the tiniest of variations to that.

But, I could be wrong.

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BlackBerry makes Android security patch promises

John Mangan

Re: Speaking as an android user (aka feeder of the chocolate factory)

"C'mon Wiley Fox! You're my other contender, make the same commitment."

Since WileyFox use CyanogenOs I believe that commitment is already there, i.e. not dependent on WileyFox for updates at all. I could be wrong, of course . . . . .

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Boffins build magnetic field cloak 'wormhole', could help MRI scanners

John Mangan

Re: Easy...

I really want to upvote that a lot more than once.

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Gas giant cores actually built from shedloads of gravel

John Mangan

Re: knowledgebase expansion

At least some of that has to be down to the increasing number of brains on the planet unencumbered by slavery, disease, local warlords/chieftains, etc. living in (reasonably) free societies. Now if we could just do the same for those souls struggling on less than $10/day imagine the rise on the resulting curve!

Of course there are those who believe we may get to the point where it takes so long for even a very bright human to get to the cutting edge of even a small area of knowledge that rpogress will effectively stop.

Better hope we have truly intelligent machines before we hit that wall.

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Galactic BIRTH: ALMA peers THIRTEEN BEELLLION years into Dawn of Time Itself

John Mangan

There is a limit . .

No matter what electro-magnetic radiation you choose to observe with you will reach a point where, due to the expansion of the universe, the horizon is receding at greater than the speed of light. This limit is the 'observable universe' and is independent of what radiation was or wasn't present at the time to be observed.

Projections for the (far) future of the universe describe the universe darkening as more and more galaxies pass this horizon leaving us stranded here with whatever is left of the Milky Way and the local cluster. I don't know if the long term predictions also tear the local cluster apart or gravity wins (in the 'short' term anyway) before the Big Rip.

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Google robo-car in rear-end smash – but cack-handed human blamed

John Mangan

Re: Poor insurance risk

Well I would like to see how they weight those statistics. I have been using that car park for at least eight years so that's at least 1600 parks (allowing for holiday/training/illness/etc.) with one (consequence-free) impact.

But wait, they don't know what car park I use. That could have been the first and/or last time I used it. They don't know where I park and haven't asked.

What a pity they don't conclude that it is used by (infrequently) careless but principled people so even if it happens again it won't cost them anything next time either!

In fact their statistics give them no basis whatsoever for increasing my premium based on this one incident excepting providing a thinly veiled excuse.

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John Mangan

Re: Poor insurance risk

Somebody drove into my door panel in a car park at work. Fortunately s(he) was a decent human being and left a note with details.

Please tell me how this makes it more likely that I will have another accident (while not in the car) and justifies the insurers increasing my premiums (I shit you not!).

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Hey, Sand Hill Exchange. Shouting 'blockchain!' won't stop the Feds

John Mangan

Re: Regulations. . .

I presume the 'cautious approach' is what ends up with you losing first-mover advantage - and waiting for the regulators to decide to allow something new (together with the inevitable information leakage to potential competitors) probably gets that stuck in the box labelled "a mug's game".

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John Mangan

Regulations. . .

Interesting argument and certainly one I hadn't considered before.

But if regulation is bad -> it slows/inhibits/ innovation <- then no regulation must be good -> but that allows fraud <- so regulation must be good.

It leads to the really vexing question of how you have correct/sufficient regulation to stop criminals making us all destitute (and eventually killing the golden goose/economy) but not stopping beneficial innovation.

Now, if you can answer that, that would be a fascinating column!

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Limited edition Iron Man S6 sells for $91,000 thanks to ... serial number

John Mangan

Re: 66

You could argue that if the buyer had $91,00 to spend on this then he (for it will undoubtedly be a he)has already been quite lucky.

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John Mangan

"the Chinese have weird superstitions"

I suspect all superstitions look weird from outside the culture that originated them.

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Elon Musk: I'm neither a samurai nor a bastard

John Mangan

Spot on!

I enjoy my work (on the whole) but my 'job' is a compromise between the twin desires to live somewhere dry, warm and stocked with food and to have all of my time for me (even if I choose to spend that time doing no more than lying on a sofa watching reflected sunlight on the ceiling).

I don't expect to get paid for doing nothing and neither do I expect to work for nothing.

(That's not to say that I won't be flexible in the case of an emergency - but emergencies should not be happening every week or even every month).

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NASA probe snaps increasingly detailed shots of MOIST DWARF goddess

John Mangan

Re: Uh oh...

Every time someone posts a link to xkcd I lose half an hour clicking 'just one more before I stop'.

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Facebook worth more than Portugal? Hell, it's worth a LOT more than THAT

John Mangan

Tim says . . .

"Which is a bit weird, but then economics can be a bit weird at times."

And that's the bit that made the most sense to me!

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El Reg Redesign - leave your comment here.

John Mangan

Re: No change

@FartingHippo

- The site owners can change the site any way they please. It is their site.

- Visitors to the site can decide that the site does not meet their needs, is too irritating to look at, makes their eyes bleed, whatever and not come back.

That is not 'flouncing off into the sunset' it is exercising choice.

However I think the general tenor here is that:

- we presume that the site owners want to maintain (or even grow) the number of visitors to the site.

- most posters find the site content DOES meet their needs but the site is making access too difficult/irritating/whatever.

Said posters have tried to convey this to the site owners (with varying grades of bile/sarcasm/pleading/threats of violence) so that all parties can come to some accommodation that meets everyone's need.

However I, and others judging from the posts, are detecting a subtext of, 'we think it is fine and we don't know what you are moaning about' from the site owners.

They keep referring to the 'shock of the new' as though IT people are the most hidebound in the world and seem to be unable to grasp the 'shock of the crap'.

As others have pointed out; in terms of comments alone this is the single most important story on this site and has been for over a week! More commentards are united on this subject than has ever happened before.

The site owners can choose to let the site wither in terms of page views/ad revenue/etc. and visitors can choose to visit no more.

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John Mangan

Re: El Reg Redesign - leave your comment here.

Surely after ten pages of mostly vitriolic bile and horror the lead article on the home page should be 'Reg Readers HATE new design' - with a suitably humongous and irrelevant picture of course!

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Stars say relativity still works

John Mangan
Thumb Down

One slight problem with that . .

is that you have some circular logic there. The redshift gives you the distance if you know the Hubble constant. But you need to know the distance of some (non-triangulated galaxies to calculate the Hubble constant.

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John Mangan
Happy

If I remember correctly . . .

the parallax method gives you a 'local' population of satrs with directly measured sitances. This allow you to calculate absolute magnitudes (how bright the *really* are) for a range of star types. Within this group are a class of stars known as Cepheid variables whose brightness changes with a period dependent on their size. These standard candles then allow you to calculate distances for more distant stars and 'local' galaxies. From the population of galaxies you get a scale of mass/brightness which can then be used to calculate equivalent values for more distant galaxies where you can't pick out the standard candles.

If I remember correctly . . . .

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Gravity wave detector gets more sensitive

John Mangan
Boffin

@James Micallef

That's not entirely correct - and I am dredging up a deep channel of memory here but:

Newtonian gravity doesn't predict gravitational waves; that is entirely a prediction of Einsteinian relativity. You also need to draw a distinction between direct measurements of gravitational radiation, as these detectors are designed to do, and indirect detection such as the changing orbits of neutron star or black hole binaries. The energy radiated away alters the orbits of the bodies involved. Pulsars in binaries are particularly useful in this case. It's a while since I looked it up but I think there was some good indirect evidence for gravitational radiation from these studies.

Gravitons have been proposed as the particle 'carrier' for the gravitational force but I've lost track of where they currently lie in the morass of Supersymmetry, string theory, Quantuim Loop Gravity et al.

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John Mangan
Happy

Ahh . . .memories

I used to be a Ph.D. student up at Glasgow working on this stuff more years ago that I want to admit. Back then we had a 10m prototype to play with, Argon ion lasers and and all the liquid nitrogen we could drink (don't try this at home!). Even then the sources of noise that would affect the detector were surprising. I finished my Ph.D. before Geo600 got properly started.

Quantum squeezing had been suggested back then but it obviously turned out to be a bit more difficult than expected.

(Sits back in armchair with slightly nostalgic look on face)

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Missile defence FAIL: US 'kill vehicle' space weapon flunks test

John Mangan

Reminds me of the scene in 'The West Wing'

where a scepticla President Bartlett received the results of the latest failed MD test with the immortal words, 'Good Grief Charlie Brown!"

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Shut up, Spock! – how Battlestar Galactica beat Trek babble

John Mangan

@Code Monkey

The gas is already dissolved in your blood stream and will be present in various body cavities, etc. With the drop in external pressure when 'entering' vacuum the gas expands.

Similarly with the bends; the Nitrogen does not come from the water but is already in the body.

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Moms stand firm against antenna madness

John Mangan

"emit radiation 800 feet in every direction"

Is that all? Blimey there must be even more of these transmitters than I realised!

Although . . . presumably if the range was just 800 feet the energy would be lower and nobody would have to worry? Reduce the range to 100 feet and put one in everyone's back garden and then all of the property values will be equally affected and everyone's happy, no?

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Tinfoil 'radiation shield' maternity wear hits 'Frisco

John Mangan
Happy

One ambition failed:

"Another product for folk with more brass than sense."

I always wanted to have more money than sense but it wasn't to be . . .

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What's the difference between an iPod and an iPood?

John Mangan

"That could have been worded better, don't you think?"

You know, I'm not entirely sure it could.

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End of Microsoft NHS deal means mass deletions

John Mangan

@Eddie

I can't say I've had those problems and I've used OOO on windows and Linux. Startup is always slow due to the Java dependence but usually after that I find things are pretty responsive.

Then again I may be less demanding than you - or you could be very unlucky.

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First true submarine captured from American drug smugglers

John Mangan

@Sooty

It did say in the article that deployment of active detection was very expensive over a wide area.

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3D TV: Avatar or Ishtar?

John Mangan
FAIL

Pros and Cons

Pro

More immersive with the right content

Cons

Family sitting around with their jamjars on

Non-interoperability of different specs so need a bag of 'spares' for when friends come around

Easy to lose one remote, what are the odds on losing/breaking expensive glasses

Not great/relevant for many types of content

possible restrictions on viewing angles/distances in modern, cramped houses

I left out expense since that will fall. Yes, internet access would be more useful.

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Amazon punts Kindleware for Androids

John Mangan

@Sid James

Erm . . . I think that was the joke.

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Laid-off public sector techies better get flexible to survive

John Mangan

@ Errr

"All those councils who stuck all their money in Icelandic banks when competent advice was saying to not do that and to also spread money around, spring to mind."

Well if you're going to start with a lie then you really can't expect me to read any further now can you?

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