Thursday, February 23, 2012

Q: Are there really Vegas odds on GW detection?

@Astroguyz  asked:

Are there really Vegas odds on GW detection?

The answer to this is yes, there were Vegas odds on the detection of gravitational waves.

This story starts in latter half of August of 2004.  Ladbrokes created a special category of wagering based on successful scientific discoveries by 2010.  These were the discovery of life on Titan, a fusion (rather than fission) nuclear power plant, finding the Higgs Boson, understanding the origin of cosmic rays, and the discovery of gravitational waves.  Originally, the odds were set at 500:1.  Well, those of us in the know thought that the broker was way off and we had a lot to gain by taken them up on their offer - so many that the broker realized the same thing.  Within just a few weeks (I cannot find the exact date but the news articles I've read implied it's between 2 and 3 weeks), the odds were slashed from 500:1 to 100:1, 10:1, 6:1, then 2:1 before they finally closed the bets.  If I wasn't a broke graduate student in 2004, I even I would have jumped on these!

Here is some of the news coverage of the betting:
   26 August 2004 - New Scientist
   31 August 2004 - BBC News
   29 July 2010 - The Economist

If you read through these, you will note that the same LIGO Science Collaboration member is quoted: James Hough from the University of Glasgow.   I asked him about this in an email and he wrote:

"I think my bet was for 25 pounds at 100 to 1 but the chair of the UK oversight committee had 50 pounds at 500 to one.
Unfortunately as you know we did not succeed.
But you can imagine my excitement over the Big Dog event!!  I was on tenterhooks for weeks!"
As James notes (and as I have mentioned on this blog many times), LIGO has yet to make the first direct detection of gravitational waves.  In the end, Ladbrokes cleaned up.  I do hope that they open bets like this again though since I know that Advanced LIGO will be able to reach 1000 times more of the Universe than it did during its last data run in 2010 (when we started the aLIGO upgrades).  Instead of maybe seeing gravitational waves, we expect to be able to see tens of gravitational waves every year after aLIGO reaches its design sensitivity.  I can't wait!

If you are interested in making bets on odd things, Ladbrokes does still have a "Specials" category with all sorts of odd things you can wager on.  If you have a gambling problem, please consider contacting the National Council on Problem Gambling at 1-800-522-4700.


P.S.  As I wrote this blog post, it is to the horrible background music of uninterruptable power supplies (UPS) in my and neighboring offices beeping due to a power outage here at LIGO Livingston (loving my office with a window!).  This is when our computer staff really gets called into action - all of the computers that run the instrument AND the supercomputer that is located here need to be powered down before their UPS fails (they are only supposed to be good for minutes to give you time to shut down) and then they get to power everything back up again once the power is back on.  And there is an order to powering the computers back on!  So I guess this blog post comes to you today courtesy of my laptop battery :) 

The picture above is looking down on the large assembly area (not far from my office) where systems like seismic isolation are being put together for Advanced LIGO.  The lights that you see are emergency lighting so no one hurts themselves trying to leave in the dark.  This is a view I've never seen before.

Friday, February 17, 2012

Q: Is there anything like LIGO outside of the USA?

I mentioned before that I've noticed in my blog visit statistics that some people find my site by searching questions that they have about gravitational waves.  They show up as the search keywords (don't worry - I have no way of knowing who searched and visited this site).  Many of the questions are great and I am not sure that my blog completely answered their question, at least in a concise way.  Today, I am answering one of these "searched for" questions:

"Is there anything like LIGO outside of the USA?"

Yes!  First, let me establish that there are 2 LIGO observatories in the United States.

Why are there 2 LIGO's?

Detectors like LIGO, gravitational wave interferometers, are sensitive to gravitational waves coming from nearly any place in the sky, including the sky that's above the other side of the planet.  The fact that gravitational waves can travel through matter and come out the other side unchanged is a huge advantage over doing astronomy using different forms of light and allows LIGO to have this amazing sensitivity.  It does have the downside that, given only a single detector, we cannot tell where a detected gravitational wave came from on the sky.  So, we built 2 detectors in the United States to ensure that, even if no other countries built gravitational wave detectors, we would be able to narrow down the location of any detections. 

LIGO Livingston's sensitivity to sources coming directly above locations on Earth.  Red is the highest sensitivity and blue is the lowest.  Since this is a flat map of a spherical object, sizes are distorted.  CLICK TO SEE DETAIL.
The time it will take a gravitational wave traveling at the speed of light to travel between the LIGO Hanford and Livingston observatories in seconds.  The black line is the circle on the sky the would produce a detection at both LIGOs at the same time.  CLICK TO SEE DETAIL.

Note that I said "narrow down".  Given 2 detectors and the detection time at each, we can start to triangulate possible sky locations of a gravitational wave to a circle on the sky that corresponds to the locations that could produce the observed difference in detection time (since we expect gravitational waves to travel at the speed of light, the maximum time it would take to travel between the 2 LIGO detectors is about 0.01 seconds).  With 3 detectors we can narrow the location to 2 points on the sky and with 4 or more we can find the 1 source.  Of course, if there was an optical event like a supernova on the 2-detector sky circle that for a gravitational wave detection at the same time, it would be probable that the optical event was also the source of the gravitational wave.

Another reason to have at least 2 detectors is eliminate the possibility that a local vibration is mistaken for a real gravitational wave.  LIGO is very sensitive to vibrations from our environment.  It is possible for a passing truck or a dropped hammer near the detector to make the mirrors inside vibrate in such a way that it "looks" like a gravitational wave.  In order to avoid making mistakes like this, we do not believe that anything is a gravitational wave unless we see the same signal in both detectors within the time it would take it to travel between detectors.  Therefore, we only consider a candidate detection if we see the same signal within +/- 0.01 seconds of when the signal is seen in one of the detectors.

Now, back to the original question:

Is there anything like LIGO outside of the USA?
There are several other gravitational wave interferometers in other countries.  The Virgo detector is located outside of Pisa, Italy, the GEO600 detector is located in Hannover, Germany, and the TAMA300 and the future KAGRA (formerly known as the LCGT) is located in Japan.  LIGO collaborates extensively with all of these detectors so that any time detectors are collecting data at the same time, that data is shared.  We also share technology so that all of the detectors are as sensitive as they can be.  The more observatories that see the same gravitational wave, the better we can localize it and the more we can know about it.

Thursday, February 9, 2012

King Cakes, Elevators, and More Questions!

On King Cake...

One of the great things about living in Louisiana between between the Epiphany and Mardi Gras is a wonderful sweet called King Cake.  Before I moved here, I'd never heard of it (although I did see something about it on the Food Network shortly after I moved here).  If you've never heard of it, let me tell you a little about it.

King Cake (from Wikipedia)

First, King Cake isn't a cake at all.  It is more like a very large cinnamon roll.  Instead of cutting individual rolls from a log of dough swirled with cinnamon, the log is turned back onto itself to make a circle (anywhere from about a foot in diameter to as large as the baker can handle).  Once the "cake" is baked, it is covered with icing (anything from a doughnut glaze type of icing to a cream cheese icing) and then covered in colored sugar, usually in the Mardi Gras colors of purple, yellow, and green.  Inside (or underneath) the cake somewhere is a trinket, usually a plastic baby.  Whoever gets the baby gets some sort of priviledge (in Mardi Gras tradition, the person who got the baby literally was the king for whatever their Mardi Gras celebration was).

Here at LIGO, King Cakes can usually be found in our kitchens (there is a full kitchen in the main observatory building and a kitchenette in the building across the street that houses the Science Education Center and other things - like my office).  If you get the baby, you get to buy the next King Cake.  But I've been noticing that there has been a shortage of King Cake in the kitchenette in the building were my office is!  Where has all the King Cake gone?


I have come up with a plan to increase the King Cake near my office.  Over the years, I have collected my own little orphanage of plastic babies.  This one has been living in my desk for a long while now (I almost decapitated this little fella when I cut into his cake):


I plan on seeding the kitchenette with a King Cake and stuffing it full of babies!  Mwa-ha-ha!!!  Today, 1 King Cake...  Tomorrow, MANY King Cakes!!!

Well, since I am writing about it in by blog I'm not really going to do this, but it was a thought. ;)

On Elevators...

One of the questions I get from students visiting LIGO is, "Wow!  You must be a genius!"  Not hardly.  I wasn't always a good student and even once I was, I always had a struggle to be the good student I wanted to be.  My elevator story below proves my "not a genius" claim.

I got on the elevator this morning (they are painting the exterior stairs so they are temporarily off limits).  I have been in this elevator many times before, but today I stop and look at the control panel:


This elevator only goes between 2 floors and yet there is a button for each floor.  Wouldn't it make sense just to have a single button that took you to the "other" floor?  Really, if I am on the first floor and just entered the elevator, where else would I want to go.  While I am having these deep thoughts, the door closes and after about a minute or so I am standing there wondering why the elevator isn't moving.  It turns out that pushing any button is a good start but that was a mental leap I simply didn't make.  (Of course, I did eventually push 2 and it delivered me there directly.)  At least I was alone in a elevator so no one knows the depths my brilliance can plunge (except for you and I am sure you won't tell anyone, right?). 

More Questions Please! 

So, I am starting to run out of questions from you, my wonderful readers!  Please send me more!!!  (In the comments below or on Twitter to @livingligo.)  However, I have figured out a "sneaky" way to start digging up those questions you are wondering about but never asked.  You tend to Google them and you may end up on my site.  When this happens, the terms you Googled show up in my statistics for how people found my blog.  Here are some of the questions I have found this way:

Starting next week, I will begin answering these questions (and the few that I have left over from the last time I made a call for questions).  Please ask me more!  If you are a teacher and you have students who may have questions, please have them ask (or you can for them).

I look forward to hearing from you!


@Astroguyz asked:
  • Where do you see gravity wave/astronomy & physics a decade from now? 
  • Are there really Vegas odds on GW detection?  Answered on 23 February 2012

Thursday, February 2, 2012

Science Summaries on - FEEDBACK WELCOME!

A new initiative the LIGO Science Collaboration (LSC) is undertaking is composing science summaries of all of our newly published papers so that everyone can keep themselves up to date on what new science LIGO and her sister observatories produce.  Today's post gives you a look into my experience writing one of these summaries.

One unfortunate thing about science is that almost all publications are written for an audience of other experts in the field.  This allows us to communicate to one another in efficient terminology that is all but alien to non-experts.  Some research is so specialized that it can be difficult for experts in a related sub-specialty to understand papers without careful study.  However, most physical science research is funded through government agencies - that means with your tax payer dollars.  LIGO is funded by the National Science Foundation (that's right kids, the same people who pay Elmo pay me!).  So, for the same reasons that I write this blog (to let everyone see inside of LIGO) the LSC is publishing these science summaries of recent publications.

There have been several already published (click on "science" and then on "science summaries"), but I wanted to talk about my experience writing one on the a paper titled "Implementation and testing of the first prompt search for gravitational wave transients with electromagnetic counterparts".  Of course, the title for the summary is a bit more succinct, "Optical, X-ray, and Radio Telescopes Seek Explosive Sources of Gravitational Waves".  This is that paper that outlines the development of the procedures and software needed to alert optical telescopes when we think LIGO may have seen a gravitational wave (I wrote about working on this in a previous blog post).

Before I started writing this summary, I re-read the paper.  Wow.  This paper wasn't too difficult to read because of jargon, but there were so many details that I thought were important (... of course I did!).  So I sat back and asked myself how I would explain this to my mother, who is a real estate appraiser and not an expert on what I do (even though she always smiles and nods when I ramble on about work).  What are the most important points I would want her to know?  The first is that we were successful in creating a system that would give us a good chance of imaging the source of a gravitational wave if we were to have a real detection.  The other was that we made partnerships with scientists who operate telescopes around the world (and they are just as excited to work with us as we were with them - but we don't talk about that in the paper).  After I determined these 2 major points, I made sure to detail the who, what, when, where, why, and how as well.  Then my draft went to the rest of the group who did the work described in this paper for their opinions.

I got many helpful comments from the project group.  There are so many small changes I was advised to make so that my prose would be better understood (I am sure my regular readers can tell me many ways that, if I just changed the way I said this or that, my blog would be improved).  Once everyone was comfortable with the summary draft, it then went to the Education and Public Outreach (EPO) group in the collaboration for review.  This is where all of us who are interested in sharing LIGO's work with the public get together to plan events, etc.  The comments I got from this group had me doing some major reworking of the summary.  You see, I answered most of the who, what, when, where, why, and how questions in a few very long sentences right at the beginning.  Instead of this, it was suggested that I give a more introductory paragraph that established background instead of a flood of facts.  After these major revisions, my summary wasn't any longer and still contained all of the same information but in a much more digestible manner.

Now that the summary has been published, I am wondering what your thoughts are on it.  What could I have said better?  I've learned so much from my colleagues in writing this, but in the end, they are still experts that are just as biased as I am towards jargon.  I would love to learn from you!  Please feel free to leave comments below!