( edit ) I also note that the pointing precision is of the order of milli-arc-seconds per visit, but over a decade this will be driven down especially in the area of parallax and proper motion. It is really going to nail down our near-space positions and thus by extension affect calibrations up the distance ladder.
Plus by then there will be results from the Gaia mission (if everything works out as expected) which has astrometry accuracy in the double digit micro arcsecond [sic!] range.
I may have mentioned this in other threads, but I feel is worth placing here. The Voyager Space Sounds.
The Voyager craft have long left the solar system proper, but as they were passing through the planetary part many things were recorded and downloaded to Earth. We probably remember the various stunning images the most. On board was a long boom which among other things functioned as a magnetometer ie. measured magnetic field strength from moment to moment. Some clever fellow noted that the usual frequencies of fluctuation for this mode of measurement were similiar to that which human ears are tuned to ( only for us it is sound wave pressure on our eardrums, not magnetism ). So the magnetometer record was simply converted into sonic form. I suspect there must have been some frequency shift ( upwards ) applied though.
Caveat : Now if you are the least bit unnerved by various sound effects in some movies eg. Alien(s) and the like, then don't listen! It spooks a bit as the vibrato in the upper registers is of the spine tingling type. However if you can suppress that you will enjoy the experience. :-) :-)
For myself I just listen while imagining that my ears are magnetometers, so like some vacuum swimming space beast I'm tooling around, say, Jupiter and Saturn listening for changes in the magnetic field. Thus you would have a background 'hum', soft and slowly changing indicating not alot ( business as usual ) but then the sounds rapidly change and clearly something is on the go. Perhaps a 'magnetic storm' ?
In any case it is an interesting alternate 'sense' to use/substitute.
Cheers, Mike.
( edit ) I might add that according to JPL Voyager I has left the solar system, judged upon measurements of magnetic field by that very same magnetometer ! :-)
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Yup, LIGO Magazine Issue 3 is out, and I for one am pleased to see this valuable resource continue. Call this one the Squeezing Edition! :-)
It begins by outlining studies at the Australian National University ( with substantial Hannover/GEO connections ) in 1990 that demonstrated this light squeezing business ( 'phase dependent noise de-amplification' ) and subsequent developments. Also mentioned are some music and wildlife aspects ( it is DownUnda, OK ? ).
Then is described some work at MIT and later at Hanford in actually seeing if squeezing works where it has to : at the interferometer. They nearly succeeded in the aims of their experiment, in between all the upgrade work ( to AdLIGO ) going on, passing trucks, seismic noise and the usual lock depriving suspects.
There is an interview with one of the squeezing pioneers, Carlton Caves, which describes what was then controversial a mere 20 years ago, is now standard dictum.
Quote:
I find this intensely reassuring as I first learnt quantum mechanics some 10 years again before that, so this is really a new area ie. that's why I reckon I don't understand it. Yet. So here is me thinking it was my ordinary stupidity, when in fact it was my finely honed stupidity instead! One day I may conquer this topic ....... aaarrghh if I thump my head against the wall a few more times maybe it will lodge correctly. :-)
Anyhows it is pointed out that the vacuum is not an empty, bland and inactive substrate. Even if the laser in one's interferometer is turned off the vacuum just be a bubblin' and a cracklin' all by itself. To wit : such fluctuations can subtract from the noise in a laser if you set things up right, when you turn it on, and forms the basis of squeezed light behaviours. This is absolutely a quantum domain phenomenon, classical stuff will not cut it here at all. I wish Richard Feynman was about to explain it, or alternatively to say that he doesn't understand it either !! :-) :-)
There is an article by Hartmut Grote, whom I met in 2011 at GEO ( and to whom I promised to fund GEO extravagantly if I ever became suitably rich! ), describing the very important AstroWatch function that GEO performs while everyone else is busy upgrading and thus not taking data at all. The idea is to have an IFO on duty regardless in case something in the sky goes bang. It'd be a shame if this instance was missed. Hartmut wonders if the interferometer has a will of it's own ! Deus ex machina ?? :-)
There is an article covering the new 200W stabilised laser system which has been developed in Hannover and delivered to be installed at LIGO sites.
Finally there is a sudoku and a crossword to do ! :-)
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
A suggestion by Carlo Bradaschia, of VIRGO, chief editor of the VIRGO Newsletter.
In order to mitigate the efforts of our readers with the articles on tachyons and on Casimir effect, we suggest
“sneaking†a look at a very helpful book about all the challenges of modern physics: Giancarlo Ghirardi “Sneaking
a Look at God's Cardsâ€, Revised Edition: Unraveling the Mysteries of Quantum Mechanics – Princeton University
Press, 2004
Right, we have LIGO Magazine Issue 4 looking at the installation program for AdLIGO. I'd call it 'where the rubber meets the road' issue. Firstly :
Quote:
... to prepare for the first observing run in 2015 with the Advanced LIGO detectors ....
Quote:
... The first science data is expected to be from a 3 month run of the LIGO detectors in 2015 ...
which I find quite exciting! New data. My Precious. I think the articles might imply ( my wild guess only ) something for E@H in early 2016 ???? :-) :-)
Yes, that is another two years. But on the upside we will be more practised with our pipeline here by then. And I have more time to try to understand GR and tensors and stuff. :-)
There are high quality photos of the components from Livingston. Very optopunk equipment. They are going for modular arrangements called 'cartridges', I assume to ease the evolution of hardware upgrades down the track. There are certainly high order problems being addressed like differential heating of suspension wires due to stray light. Very detailed attention to particulate contamination.
The article on coatings demonstrates the importance of energy transfers at the very thin optical interface. Very high tech materials science, and very high chequebook too I'd say. DownUnda CSIRO got that contract ! :-)
Another article looks at the medium to longer term observational plans, plus linkages to EM astronomy. Plus how do you make a room clean - with the help of Mom and her sewing machine of course!
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
The publishing of LIGO Magazine Issue 5 has slipped under my radar despite being a regular & predictable occurence. Doh ... :-)
The big news is that AdLIGO @ Livingston has achieved full design lock for over two hours! Admittedly this is heterodyne lock whereas homodyne ( DC ) is what is ultimately the goal. But hey, what an outcome and with sensitivity over 15Mpc .... that is well outside our galaxy and represents a vast increase in sampled volume. Hanford is following this lead and no doubt benefits from the Livingston experience.The challenge now is to reduce noise 'budgets' ie. the impact of reasons for the interferometer to wiggle outside of the astronomical sources of interest.
What I hadn't known of was the change in lock acquisition tactics, which used to be by catching the resonant position as random excursions of the optics occurred. Sort of a sit and wait to grab it as it passed by, so to speak. Now the algorithms are more deterministic ie. rather less waiting for propitious moments. Due to the improved HEPI units less actuator strength is required to keep and maintain lock and in turn this reduces noise from those actuators, ergo better sensitivity.
There are some great articles on the experience of a young Japanese researcher living in Louisiana, the impact of LIGO experience upon young physicists and their subsequent careers, several bios, and the fun of the collaboration experience. This emphasises that LIGO is not simply a technical program but has a rich & important social flavour. For such a large enterprise this aspect is crucial to cohesion, organisational efficiency and of course enjoyment of the special pursuit that physics can be. And a wee bit of poetry to boot ... plus some hobbies up my street -> flying light planes, a crossword & sudoku.
On the last page is a quick & dirty summary of IFO locking. This is by Hartmut Grote, the main man at GEO whom I have enjoyed meeting. He very kindly gave myself and other volunteers a great tour of the GEO underground guts, at very short notice when he was under great time pressure ( I later discovered ). That was during the 2011 July public AEI event and I for one am forever grateful for his precious time then. Indeed Bikeman was there too, driving several of us out there in his Mini Cooper, not long before he graduated to E@H employee status. I remember casually commenting in the control room that their 1064nm CO2 laser was the same as the LIGO one, only to be politely told ( with some chuckling ) that this was due to GEO inventing and providing the gadget ! Was my face red ? If you are reading Hartmut then I have not forgotten my promise of massive funding boost at GEO should I ever become rich and famous. Or just rich will do it ... :-)
Anyhows I don't gain the impression that the early 2015 data taking estimate has slipped. And you know what that means for us ! :-)
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer. I expect that will keep me busy for a while. Having only finished the first - introductory/overview - chapter, the field reminds me of lepidoptery ie. the study of butterflies and moths. I don't mean that in any derogatory sense at all, but rather what a wonderful collection of objects in the pulsar category are out there, and boy are there some weird astrophysical gadgets operating ! I have this image in my mind of these fast, dense rotors just showering sparks all over the neighborhood ie. what a wild place must be the surface of a neutron star. I also note how hungrily one can study all meaningful aspects of the radio emission properties. So far it seems quite well written, not too much of a brain strain. I just have to quote this ( I'm assuming a wee bit tongue-in-cheek ) comment about galactic pulsar distributions :
Quote:
Although the clustering of sources around the Sun seen in the left panel of Figure 1.9 would be consistent with Ptolemy's geocentric picture of the heavens, it is clearly at variance with what we know about the Galaxy ......
In any event it has already settled my mind about dispersion effects. As this graphic illustrates :
the propagation delays can span several pulse cycles. The other thing that especially strikes me while reading is that neutron stars, being nearly black holes as it were, retain EM visibility for behaviours that may demonstrate really high gravitational field strengths ( yes, I know that is an obvious comment ).
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer.
Highly readable, and a bit like the "Bible" of the field I guess. Within a few weeks after coming to the AEI I noticed that there was this book that was lying around in quite a lot of offices.
I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer.
Highly readable, and a bit like the "Bible" of the field I guess. Within a few weeks after coming to the AEI I noticed that there was this book that was lying around in quite a lot of offices.
Cheers
HB
Yeah I sense that. It is quoted so frequently in many papers, and not just from AEI ....
FWIW : I've done chapter 2. I note that the very first extra-solar planet discovery was from around a neutron star ! B1257+12 reported in 1992 ( Wolszczan & Frail ) Roughly one Mercury and two Earths those latter two being in 3:2 resonance. I never knew that !
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: ( edit ) I also note
)
Plus by then there will be results from the Gaia mission (if everything works out as expected) which has astrometry accuracy in the double digit micro arcsecond [sic!] range.
http://www.esa.int/Our_Activities/Space_Science/Gaia_overview
Cheers
HB
I may have mentioned this in
)
I may have mentioned this in other threads, but I feel is worth placing here. The Voyager Space Sounds.
The Voyager craft have long left the solar system proper, but as they were passing through the planetary part many things were recorded and downloaded to Earth. We probably remember the various stunning images the most. On board was a long boom which among other things functioned as a magnetometer ie. measured magnetic field strength from moment to moment. Some clever fellow noted that the usual frequencies of fluctuation for this mode of measurement were similiar to that which human ears are tuned to ( only for us it is sound wave pressure on our eardrums, not magnetism ). So the magnetometer record was simply converted into sonic form. I suspect there must have been some frequency shift ( upwards ) applied though.
Caveat : Now if you are the least bit unnerved by various sound effects in some movies eg. Alien(s) and the like, then don't listen! It spooks a bit as the vibrato in the upper registers is of the spine tingling type. However if you can suppress that you will enjoy the experience. :-) :-)
For myself I just listen while imagining that my ears are magnetometers, so like some vacuum swimming space beast I'm tooling around, say, Jupiter and Saturn listening for changes in the magnetic field. Thus you would have a background 'hum', soft and slowly changing indicating not alot ( business as usual ) but then the sounds rapidly change and clearly something is on the go. Perhaps a 'magnetic storm' ?
In any case it is an interesting alternate 'sense' to use/substitute.
Cheers, Mike.
( edit ) I might add that according to JPL Voyager I has left the solar system, judged upon measurements of magnetic field by that very same magnetometer ! :-)
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
Yup, LIGO Magazine Issue 3 is
)
Yup, LIGO Magazine Issue 3 is out, and I for one am pleased to see this valuable resource continue. Call this one the Squeezing Edition! :-)
It begins by outlining studies at the Australian National University ( with substantial Hannover/GEO connections ) in 1990 that demonstrated this light squeezing business ( 'phase dependent noise de-amplification' ) and subsequent developments. Also mentioned are some music and wildlife aspects ( it is DownUnda, OK ? ).
Then is described some work at MIT and later at Hanford in actually seeing if squeezing works where it has to : at the interferometer. They nearly succeeded in the aims of their experiment, in between all the upgrade work ( to AdLIGO ) going on, passing trucks, seismic noise and the usual lock depriving suspects.
There is an interview with one of the squeezing pioneers, Carlton Caves, which describes what was then controversial a mere 20 years ago, is now standard dictum.
Anyhows it is pointed out that the vacuum is not an empty, bland and inactive substrate. Even if the laser in one's interferometer is turned off the vacuum just be a bubblin' and a cracklin' all by itself. To wit : such fluctuations can subtract from the noise in a laser if you set things up right, when you turn it on, and forms the basis of squeezed light behaviours. This is absolutely a quantum domain phenomenon, classical stuff will not cut it here at all. I wish Richard Feynman was about to explain it, or alternatively to say that he doesn't understand it either !! :-) :-)
There is an article by Hartmut Grote, whom I met in 2011 at GEO ( and to whom I promised to fund GEO extravagantly if I ever became suitably rich! ), describing the very important AstroWatch function that GEO performs while everyone else is busy upgrading and thus not taking data at all. The idea is to have an IFO on duty regardless in case something in the sky goes bang. It'd be a shame if this instance was missed. Hartmut wonders if the interferometer has a will of it's own ! Deus ex machina ?? :-)
There is an article covering the new 200W stabilised laser system which has been developed in Hannover and delivered to be installed at LIGO sites.
Finally there is a sudoku and a crossword to do ! :-)
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
A suggestion by Carlo
)
A suggestion by Carlo Bradaschia, of VIRGO, chief editor of the VIRGO Newsletter.
In order to mitigate the efforts of our readers with the articles on tachyons and on Casimir effect, we suggest
“sneaking†a look at a very helpful book about all the challenges of modern physics: Giancarlo Ghirardi “Sneaking
a Look at God's Cardsâ€, Revised Edition: Unraveling the Mysteries of Quantum Mechanics – Princeton University
Press, 2004
Tullio
Right, we have LIGO Magazine
)
Right, we have LIGO Magazine Issue 4 looking at the installation program for AdLIGO. I'd call it 'where the rubber meets the road' issue. Firstly :
which I find quite exciting! New data. My Precious. I think the articles might imply ( my wild guess only ) something for E@H in early 2016 ???? :-) :-)
Yes, that is another two years. But on the upside we will be more practised with our pipeline here by then. And I have more time to try to understand GR and tensors and stuff. :-)
There are high quality photos of the components from Livingston. Very optopunk equipment. They are going for modular arrangements called 'cartridges', I assume to ease the evolution of hardware upgrades down the track. There are certainly high order problems being addressed like differential heating of suspension wires due to stray light. Very detailed attention to particulate contamination.
The article on coatings demonstrates the importance of energy transfers at the very thin optical interface. Very high tech materials science, and very high chequebook too I'd say. DownUnda CSIRO got that contract ! :-)
Another article looks at the medium to longer term observational plans, plus linkages to EM astronomy. Plus how do you make a room clean - with the help of Mom and her sewing machine of course!
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
The publishing of LIGO
)
The publishing of LIGO Magazine Issue 5 has slipped under my radar despite being a regular & predictable occurence. Doh ... :-)
The big news is that AdLIGO @ Livingston has achieved full design lock for over two hours! Admittedly this is heterodyne lock whereas homodyne ( DC ) is what is ultimately the goal. But hey, what an outcome and with sensitivity over 15Mpc .... that is well outside our galaxy and represents a vast increase in sampled volume. Hanford is following this lead and no doubt benefits from the Livingston experience.The challenge now is to reduce noise 'budgets' ie. the impact of reasons for the interferometer to wiggle outside of the astronomical sources of interest.
What I hadn't known of was the change in lock acquisition tactics, which used to be by catching the resonant position as random excursions of the optics occurred. Sort of a sit and wait to grab it as it passed by, so to speak. Now the algorithms are more deterministic ie. rather less waiting for propitious moments. Due to the improved HEPI units less actuator strength is required to keep and maintain lock and in turn this reduces noise from those actuators, ergo better sensitivity.
There are some great articles on the experience of a young Japanese researcher living in Louisiana, the impact of LIGO experience upon young physicists and their subsequent careers, several bios, and the fun of the collaboration experience. This emphasises that LIGO is not simply a technical program but has a rich & important social flavour. For such a large enterprise this aspect is crucial to cohesion, organisational efficiency and of course enjoyment of the special pursuit that physics can be. And a wee bit of poetry to boot ... plus some hobbies up my street -> flying light planes, a crossword & sudoku.
On the last page is a quick & dirty summary of IFO locking. This is by Hartmut Grote, the main man at GEO whom I have enjoyed meeting. He very kindly gave myself and other volunteers a great tour of the GEO underground guts, at very short notice when he was under great time pressure ( I later discovered ). That was during the 2011 July public AEI event and I for one am forever grateful for his precious time then. Indeed Bikeman was there too, driving several of us out there in his Mini Cooper, not long before he graduated to E@H employee status. I remember casually commenting in the control room that their 1064nm CO2 laser was the same as the LIGO one, only to be politely told ( with some chuckling ) that this was due to GEO inventing and providing the gadget ! Was my face red ? If you are reading Hartmut then I have not forgotten my promise of massive funding boost at GEO should I ever become rich and famous. Or just rich will do it ... :-)
Anyhows I don't gain the impression that the early 2015 data taking estimate has slipped. And you know what that means for us ! :-)
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I decided to bite the bullet
)
I decided to bite the bullet and get a copy of the 'Handbook Of Pulsar Astronomy' by Lorimer & Kramer. I expect that will keep me busy for a while. Having only finished the first - introductory/overview - chapter, the field reminds me of lepidoptery ie. the study of butterflies and moths. I don't mean that in any derogatory sense at all, but rather what a wonderful collection of objects in the pulsar category are out there, and boy are there some weird astrophysical gadgets operating ! I have this image in my mind of these fast, dense rotors just showering sparks all over the neighborhood ie. what a wild place must be the surface of a neutron star. I also note how hungrily one can study all meaningful aspects of the radio emission properties. So far it seems quite well written, not too much of a brain strain. I just have to quote this ( I'm assuming a wee bit tongue-in-cheek ) comment about galactic pulsar distributions :
In any event it has already settled my mind about dispersion effects. As this graphic illustrates :
the propagation delays can span several pulse cycles. The other thing that especially strikes me while reading is that neutron stars, being nearly black holes as it were, retain EM visibility for behaviours that may demonstrate really high gravitational field strengths ( yes, I know that is an obvious comment ).
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
RE: I decided to bite the
)
Highly readable, and a bit like the "Bible" of the field I guess. Within a few weeks after coming to the AEI I noticed that there was this book that was lying around in quite a lot of offices.
Cheers
HB
RE: RE: I decided to bite
)
Yeah I sense that. It is quoted so frequently in many papers, and not just from AEI ....
FWIW : I've done chapter 2. I note that the very first extra-solar planet discovery was from around a neutron star ! B1257+12 reported in 1992 ( Wolszczan & Frail ) Roughly one Mercury and two Earths those latter two being in 3:2 resonance. I never knew that !
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
http://www.amazon.com/Astrono
)
http://www.amazon.com/Astronomy-Cambridge-Observing-Handbooks-Astronomers/dp/0521828236
I wondered what size that bullet was so I had to take a look.
I wouldn't mind getting it but at the same time it makes me think I could buy more RAM for that much too.
I guess if my memory was the way it used to be I would buy and read the book
Maybe I will find a free version.
Edit: I found some of the book
http://books.google.com/books/about/Handbook_of_Pulsar_Astronomy.html?id=OZ8tdN6qJcsC