Q: How can gravitational waves help mankind?

UPDATE:  [11 Feb. 2015] Gravitational waves have been detected!  Read more about it here.

@HughScot asked:

What do you hope to discover about gravitational waves that will help mankind in the future?

There are many things that we hope to observe through gravitational waves especially since they have the advantage of being able to travel through matter and come out the other side unchanged, unlike the different forms of light used in traditional astronomy.  This gives us the opportunity to observe things that do not emit light, like black holes or to observe systems that would otherwise be obscured by intervening material.

But this question asks how gravitational waves will improve mankind in the future - as in what are the applications of gravitational waves.  I get this question often when I am giving tours of the facility.  Well, the primary use of gravitational wave observations will be to understand our Universe better.  Most people's reactions to this are that our efforts can better used for other endeavors.  But this view is a little short sighted.  One of the things we forget is that when we understand more about the Universe in general, we know more about the world around us.  We are a very small part of the Universe, but we are a part of it nonetheless.

One of the direct uses for gravitational waves will be to use them to turn the Universe into our own laboratory.  There are many things that we cannot replicate on Earth, like the dense cores of neutron stars.  Under extreme conditions like this, nuclear physics and thermodynamics can theoretically do some interesting things.  However, we can't investigate those directly because we cannot create these environments ourselves.  That's when we turn to the Universe for our laboratory!  Prime candidates that will allow us to use gravitational waves to investigate this include pairs of neutron stars merging into one star, starquakes on these stars, or even rapidly rotating neutron stars with "mountains" on them (and I put mountains in quotation marks because neutron starts are believed to be so perfectly spherical that a deformation a few millimeters [a quarter of an inch or so] is 'huge').  Knowing the details of how nuclear physics and thermodynamics changes in these environments can have applications on Earth, although I can't tell you what they are yet.

Another application of gravitational wave observations will be testing Einstein's general relativity.  Even though gravity is the force that holds the Universe together, we have a very difficult time testing it since it since it is also the weakest force in the Universe (there is no negative mass to cancel the effects of positive mass like happens between positive and negative charge).  Since the mass needed to conduct experiments to test general relativity is so great, lab experiments are very few.  Again, we must turn to the Universe to be our lab.  Directly observing gravitational waves with LIGO and detectors like it will allow us to perform tests on general relativity that we have never been able to before.  For example, it is expected that gravitational waves travel at the speed of light but there really isn't anything in the theory that constrains them to that speed (they could travel slower).  Detecting gravitational waves with multiple detectors across the planet and observing light from the same source in the sky would allow us to test this.  (By the way, even though general relativity is difficult to test, every time it has been tested it has proven to be right!)

We already use an application of general relativity in our everyday lives: a consequence of special and general relativity is that time passes a different rates based on the speed of an observer or the strength of the gravitational field that the observer is in.  No matter what, your time will always be the same, but you may observe the clocks of others who are at rest or traveling slower than you ticking slower than yours (this tutorial does an excellent job of explaining how this time dilation works).  If corrections for this effect are not taken into account, the clocks on GPS satellites would quickly become out of sync and the GPS in you car, etc. would not be able to accurately locate you!

Besides the benefit to mankind due to the information the gravitational waves themselves will bring us, we have also developed a significant amount of new technology to make LIGO work.  We have developed new seismic isolation techniques that allow less than 1 billionth the energy of normal ground vibration into our instruments, we have required and received the most precisely polished mirrors, and we have developed new suspension and control systems to stabilize our optics.  These are just a few of the advancements the search for gravitational waves have made.  I am sure that there are many other applications for these new developments (although I haven't explored them myself).  Using technology developed for other purposes is a well known phenomenon in science and technology call spin-off technology.

In conclusion, we will never be able to commercialize or weaponize gravitational waves themselves.  However, they will carry information to us about some of the most extreme environments in the Universe which we can use as a laboratory for environments we cannot create here on Earth.  This information can tell us more about how the physics around us works in subtle ways that can have profound implications.  What those are are yet to be seen.  That's the exciting thing about science - you never really know the full potential of new discoveries until after the fact.

Today's picture is of an engineer (my husband Derek Bridges) dressed in clean room garb (so as not to contaminate the equipment that will be placed into LIGO's interior vacuum).  The blue stands he is leaning on are part of the seismic isolation system mentioned in the text above and the big steel chamber behind him is one of the many used to contain LIGO instrumentation in its vacuum.  This picture was taken at the Advanced LIGO testing lab at MIT.

I hope this answered your question!  If not, please feel free to ask me more about this or anything else!

First Software Engineering Run for Advanced LIGO

Most of the visible work on Advanced LIGO has been revolving around the installation of new instruments that are needed to increase the sensitivity of LIGO about 10 fold.  While this is exciting, it can feel a little like being on the outside looking in for data analysts like myself.  But there is still much to prepare for!

The first step in that preparation starts in a few days with the first Software Engineering Run (which we abbreviate ER1 - there's longish, boring story on why it isn't being called SE1).  The goal of this is to start testing our computing infrastructure and data analysis methods with simulated data (remember, Advanced LIGO is still not complete).  For this first run, we will be simulating the channels of data that would contain information about a gravitational wave.

But what is a channel?  Just like channels on a TV, LIGO has many different data streams called channels that report on basically everything involving the instrument.  Besides the channel that will carry information about gravitational waves, we also have channels of data from seismometers that tell us how the ground is moving beneath us, channels from microphones placed around the detector that tell us about loud noises like thunder that can cause vibrations in the detector, and channels that tell us how different places on a mirror inside of LIGO is moving (and we can combine channels like this to tell if the mirror is moving up, down, sideways, front to back, rolling, etc.).  This is just the beginning of the channels we record at LIGO (there are hundreds per detector)!  We use these to cancel out unwanted movement and to double check if a potential gravitation wave is real or caused by vibrations in our environment (we would be less likely to claim a detection around the time that our seismometers indicate a train moving on the tracks a few miles away from the detector here in Louisiana).

So, we are starting out small with ER1 and focusing on just the gravitational wave channels (with simulated gravitational waves included to give the detection software a workout).  In the future, more of the Advanced LIGO channels will be simulated and included in the run.  We plan on having about 5 or 6 of these runs until Advanced LIGO is ready to give us all of the channels for real.  But, the transition from Software Engineering Run to Engineering Run should be seamless.  Engineering Runs precede Science Runs to allow us to work out any bugs in the real detector before we start using the data for science purposes - but data from engineering runs is handled like it would be if it were science data.  As more subsystems in LIGO are installed and producing data, the simulated data for those channels will be replaced with real data.  The only difference between the last Software Engineering Run and an Engineering Run will be that none of the data is simulated anymore.

It is anticipated that, by having these ER runs, that the computational infrastructure for Advanced LIGO will be ready to handle the new demands of the more sensitive detector.  We are entering a new era in LIGO where detections will be expected on a fairly regular basis (once the detector has been tuned into its design sensitivity).  We need to be able to respond quickly to potential detections to alert others in the astronomical community and for us to vet the detection in a time efficient way.  We want to be able to clear detections off of the table, so to speak, before others become backlogged.  Honestly, I am excited at the prospect of this since I have worked with LIGO since it took its first science data and I remember collaboration meetings being focused on how to make the data clean enough that we could see more than just instrumental artifacts or environmental contaminants.  Now I'm thinking about backlogged detections!

LIGO has several supercomputer clusters and one of them is located right here at the LIGO Livingston Observatory.  So, I went downstairs (from my office) and took a few pictures of our cluster today:

Above is a picture of the computers facing the front of the room.  Since these computers produce a large amount of heat and noise, they are isolated in their own room which also allows for the efficient use of extra air conditioning (and noise containment).  This is an odd room to be in because of the noise but also because of strong air currents moving the heat around.  The wind is noticeable and it can change quickly between a warm breeze to a cold one as you walk.

This is a close look at the computers in the racks (as we call the large rectangular container).  Each one of the horizontal shelves is a computer.  Many computers are used simultaneously to search LIGO data for gravitational waves.

This is the back of the rack shown in the previous picture.  If you are ever chilly, this is the place to stand since the heat pushed through the fans from the computers is dumped here.

Broken New Year's Resolution and Priorities for 2012

I really do know better than to make New Year's resolutions.  Truly.  But there is one thing that I want to do more of and that is to make more blog posts.  I've noticed that it is easiest for me to make posts on Thursdays so I resolved to post weekly on Thursday.

Then last Thursday happened...

I woke up with the most painful migraine I've had (at least in recent memory).  I felt like my head was going to explode all morning and early afternoon and when I finally took the correct meds (when you are alone and trying to keep your brains in your skull, you tend to lose a lot of common sense) and felt better, but not well, I was thoroughly exhausted.  I think I was asleep more hours than I was awake that day.  Between that and the fact that I had to write a last-minute abstract to present some new LIGO results at the upcoming APS April Meeting, my blog post never happened.

But, today is a new Thursday and the first new blog post of the year!

I hope everyone had a pleasant holiday season.  I didn't murder any family members so I'm counting mine in the win column (I'm kidding - I would never harm my family!).

So, what have I been doing as a LIGO scientist this year?

1. I've had a few projects in the works that I am trying to wrap up and complete (I love starting new and exciting projects and documenting completed computer programs is not exciting to me).  One of the things that has been simmering for a long while now is a survey of the LIGO Scientific Collaboration to assess the members' feelings on its diversity and climate (working environment).  I created and administered a similar survey just for us who work at the LIGO Lab (I am on the LIGO Lab Diversity Committee).  The point of surveys like these are to identify areas that can be improved to make everyone's working experience better and to find out what we are going right.  This survey is in a fairly-mature format and should be ready to release in the coming weeks.
2. There is a paper I have half written on multi-messenger astronomy and LIGO that I am targeting to  publish in The Physics Teacher.  This has been half done for a while now because other life issues have gotten in the way.  Notably, work and making an application to move up the career ladder and secure myself something more permanent (all postdoctoral positions are temporary like medical residencies - I talk about this a little in my post about "Becoming a Physicist").  This is high on my list of priorities for the near future. 
3. There is a new initiative in LIGO to write outreach abstracts (summaries) of the scientific papers we publish (like this one).  The papers themselves are almost always on the arXiv server (I can think of only 1 exception) and anyone can read these for free.  That is all well and good, but these papers are meant to be read by other experts and are horrible to wade through for someone who doesn't do that sort of thing for a living.  We are trying to make our results more accessible to everyone and these abstracts are written so that everyone can know what science we are doing.  I've been working on the outreach abstract for the paper discussing the methods employed to rapidly alert telescopes to search for possible optical counterparts to gravitational wave detections (this is the link to the scientific paper).  I've talked about working on this project before here.  When this abstract goes live, I will write more about it and discuss the other abstracts that have been written.
4. There are also numerable data analysis and software simulation projects that need to be further developed, but I won't go into those here (if you really want me to, let me know in the comments - I may tell you about it later anyway even if you don't).
5. I also still work extensively with the Science Education Center here at Livingston.  Yesterday, I traveled to a elementary school in Amite, LA to talk to about 120 kindergarteners over the course of the day.  Besides the fact that they were adorable and very interested, I had the cutest ambush of my life - a 20 little kid group hug! :)  And only a few of them where taller than my hips.  Little things like this (besides getting to discover new things about the Universe) is what truly makes my job amazing!
6. Finally, I have only a few questions left to answer from my previous call for questions!  These will be answered in the coming weeks.  If you have anything you would like to know about, let me know.  Also, I was thinking about having guest blogs from other LIGO scientists, engineers, etc.  Is that something you would be interested in?  (My husband is an engineer at LIGO Livingston with me, so I have one person that I can probably bribe into doing this.)  There are many different specialties here so this may be interesting.  Let me know!

Hope to hear from you soon!

~~~

Today's picture comes from my office and its new vampy inhabitants:

From left to right: Vampire Julius from Paul Frank, Count Chocula from the cereal of the same name, and The Count from Sesame Street

You may remember from previous posts that not only do I have a nearly unhealthy love for vampire books, but I also have a collection of stuffed undead (do NOT call them dolls).  Here is a previously posted picture of my office with a few of the figures in the background:

And another of my name tag covered light (which really doesn't function so well as a light since I've added even more tags) with a few other figures:

Nerdy Fun for the Holidays!

Since I am not sure that I will be posting again before the end of the year (I hope so, but I also have the feeling that you will be busy with your own holiday events), I wanted to make this a fun post that will make you smile.


• Happy Helium Holidays

The APS Physics Buzz Blog team performed this wonderful rendition of Carol of the Bells using helium or sulfur hexafluoride to modify their voices and a harmonious, hilarious way!  Many people are familiar with the fact that if you inhale helium your voice becomes much higher pitched.  This is because the helium gas is so much lighter than air, it allows your vocal cords to vibrate at a higher frequency producing the high pitch.  Sulfur hexafluoride is sometimes known as the anti-helium since it is so much heavier than helium, if causes your vocal cords to vibrate much slower producing a deep, low pitch.

The beginning of this video features Becky Thompson-Flagg who is the Head of Public Outreach for the APS and is also the model for the Spectra superhero character comic books (read here about that).  She explains the physics behind the voice changes and the mild peril involved in this performance.  Then the concert begins :)

• Interactive Relativity Tutorial - Al's Relativistic Adventures

Al's Relativistic Adventures is an animated tutorial on special relativity.  While this is appropriate for middle school students, I found the lessons to be very accurate and the authors are talented at communicating complicated concepts in easy to understand ways (I even learned how to better communicate some concepts from working through this activity).  Once you are done, you are even awarded a certificate - I printed mine out and hung it in my office :)

• Play the GRB Lottery

Gamma ray bursts (GRBs) are the most luminous events to be observed in the Universe and their origins, other than that they are produce from extraordinary energetic events), are still not certain.  They play a vital role to LIGO since whatever produces them could have produced gravitational waves and observe these gravitational waves may uncover the cause of these explosions.

There are several satellites currently in orbit around the Earth detecting these GRBs.  One of these is the Swift satellite and they have a fun GRB Lottery to play on their website (free to play, of course).  You are presented a map of the sky that has locations of past detected GRBs (notice that there is no area on the sky that is favored over another so any guess is really as good as another).  You then click on an area that you would like to select as your own and if you are the closest guess to a GRB within the two weeks, you win!  "What do you win?" you say...  Well, you get a nifty certificate commemorating your good fortune and the Swift outreach staff will send you a small gift (I got a nice package of education materials including a poster).

I played the GRB Lottery once and I won!  I decided that I would retire from my glorious reign so that the rest of you can have a chance!  :P  Below is the certificate I earned which is hanging proudly in my office:

• Physics Carols

This webpage (www.PhysicsSongs.org) has an amazing collection of covers to well known songs with physics lyrics.  They even have a special page of physics related carols!  I have to admit to getting lost on the page and chuckling to myself (and feeling even more nerdy than usual)!

Bittersweet: The End of A Professional Service Term

I have mentioned many times on this blog that I feel that performing service to my profession is just as important as the research and public outreach that I do; in a way, this is a form of professional outreach.

I have had the uncommon honor to serve on the American Physical Society (APS) Council and then, half way into my four-year term, I was elected to serve on their Executive Board.  I have met many new colleagues whom I would have never met otherwise since we don't work in the same field of physics.  Even better, some of them have become friends (good enough friends that I will even discuss my Impostor Syndrome issue with them - I wrote a whole post about this).

As far as contributing to the profession, I have had the opportunity to work extensively on strategic planning for the next decade of the society and represented young physicists' concerns on many issues.  Even more than that, I am now able to better understand the workings of my professional society, understand the concerns of physicists who work in industry, outside of the United States, etc. and learn more about the politics (inside and outside of physics) that make research happen (or not).

My term comes to a close (on both the Council and the Executive Board) at the end of this year and I have just traveled back from my last meetings in Salt Lake City, UT.  I am sad about not getting to meet the new people who will be elected to replace all of us rotating off this year (I do recognize if we never left, there would be no new people!).  A big relief to me is that I won't have to travel so much - if you serve on the Council, that is 2 trips a year and then if you serve on the Executive Board that is an additional 3 trips (or 4 trips next year).  Since I HATE to travel, this will mean more nights in my own bed <contented sigh>.

The view from my hotel room in Salt Lake City.  This is facing Temple Square and the LDS temple is visible between the 2 red-orange buildings.

If you are reading this and are not a physicist (I hope some of you aren't since it is for you that I really write this blog), I hope that I have given you a little peek into the physics community outside of LIGO.  If you are a physicist, I urge you to consider expanding whatever service work you do to the APS, AAPT, OSA, etc.  It can be a lot of work, but I would definitely do it all over again.  Of course, service isn't all work (just mostly):

Wine tasting during the APS Executive Board Retreat, Santa Barbara, CA (Photo: Ken Cole)

Special thanks to Ken Cole for permission to use his picture of me (above).  Ken is the APS Special Assistant to the Executive Officer (and has done a great job a wrangling me these last years) and is also a gifted photographer.  You can view more of his photos here.

2 Questions: "Can there be a gravitational wave detection before Advanced LIGO?" & "What does it mean if gravitational waves aren't detected with aLIGO?"

Sorry for being away from the blog for as long as I have.  What has been keeping me away from you, you say?  Well, I got sick :(  The one thing that I am very susceptible to is sinus infections (ever since I was a kid) and autumn is prime time for me to catch one.  That kept me basically in bed for about 4 days with a few days before and after still feeling miserable but ambulatory.  My waterfall of post-nasal drip has begun to slow down but my coughing is starting to taste funny again.  I'm off to the after-hours clinic tonight to see if I need antibiotics to clear this up.

There was also a meeting at the LIGO Livingston Observatory where I work that brought astronomers and LIGO scientists together to discuss what data of ours they would like to have access to and what is the best way for them to get the data.  This is all in an effort to make the data the the American taxpayer has paid for available to other scientists.  This is an interesting topic because most of us here at LIGO have neuroses about making a detection claim that later turns out to be false.  Because of that, we tend to keep our data close to the vest until we are certain what is in it.  Anyway, I will talk about this more in a later blog post.

Now, back to answering reader questions!  Since I have been away so long I figured I would answer 2:

QUESTION #1

@AstroGuyz asked:

You know the question on every science bloggers' mind is the Big One; "When will LIGO discover gravity waves?"  Are the prospects for gravitational wave detection good before AdLIGO goes online?  Think we'll nab it before the Higgs?

First off, there is very little probability of detecting gravitational waves before Advanced LIGO is ready.  Notice I didn't say it was impossible.  There are 2 situations that could produce a pre-Advanced LIGO detection.

The first possibility is a joint run between two or more detectors outside of the United States.  This happened over this past summer when GEO and Virgo were both operational and while we are still looking at this data, we haven't seen anything yet.  Now that Virgo has commenced its upgrade efforts in earnest, there isn't really another chance for a joint run until Advanced LIGO is ready.  (FYI: you can see what gravitational wave detectors are operating right now on the GWIstat page, which is always displayed under my "Interesting Links" to the right.  Note that not all of these are interferometric (laser) detectors.)

The second chance for detection is going to rely on a single detector, mainly GEO, to be operating when a significant astronomical event is observed using other astronomy observations.  For example, if a supernova is detected in the sky at the same time a very strong event is detected in GEO, then chances are that these two events are related and there is a real gravitational wave detection.  That is why GEO is continually running while LIGO and Virgo undergo their upgrades - so that we don't miss something that is basically obvious.

So, unless one of these two situations happens, we will all need to wait for Advanced LIGO to be done.  And I wouldn't expect a detection as soon as we turn it on either...  It will take a while for us to get all of the new equipment "tuned-up" to the point that it is working to the best of its abilities.  Don't quote me on this, but I wouldn't expect anything until 2016-2017.

As far as detecting gravitational waves before the Higgs particle, I can't say but I am thinking about writing a post about what all the excitement over this particle is about in another post!

QUESTION #2

@EclipseMaps asked:

What are consequences for theory of gravity/relativity if null results for gravitational waves after extended observations?

From my last question, I mentioned not to expect a detection of gravitational waves until about 2016-2017.  Even if that time comes and goes, I still wouldn't get too worried.  However, if 2020 or so comes by (remember, this is just my opinion and not that of LIGO) and we firmly see no evidence of a detection, then this does have some implications.

The first thing most people would think is that LIGO has been a failure.  Actually, that is very far from the truth.  I, along with over 800 scientists in the LIGO Scientific Collaboration, have dedicated our careers to this as well as used taxpayer dollars to search for gravitational wave and we haven't done this on a hunch.  The 1993 Nobel Prize in Physics was awarded for proof that gravitational waves exist by observing their affects on an astronomical system.  We simply want to detect them affecting our own detectors so that we can do astronomy with them.

Not detecting gravitational waves after we have detectors that clearly should be detecting them tells us that there is something we don't understand about general relativity (the theory where gravitational waves originate) or that we don't understand enough about the composition of our universe, namely how many of those things we expect to produce detectable gravitational waves exist.  This would be extraordinarily interesting (although a bit disappointing to me).  So much so, that there would be whole conferences of physicists and astronomers debating the populations of gravitational wave sources to exotic interference such as gravitational waves leaking into separated universes (see my discussion about how gravitons behave in string theory here).

PICTURE FOR THE DAY:

My "Lucky Yen"

This is my "Lucky Yen".  There really isn't anything special about it other than it was given to me by my first physics professor in college, Dr. Plitnik, who gave this to me on my birthday in 1997.  It was just after the Fall semester started.  I know it is kind of dumb, but it meant a lot to me and I have carried it in whatever bag I used through college, grad school and now.  It has even earned its own coin case (which has a higher market value than the coin).

Living LIGO 1 Year Anniversary!

Today is the one year anniversary of the Living LIGO blog!  Thank you to everyone who has ever read my blog and followed me on Twitter.  It has been an exciting year and I hope that the next one is even better for you.

I've learned many things through writing this blog.  The first thing I found was my voice.  Originally, I was targeting this blog to middle and high school teachers and students to give them an insight into the science of LIGO and what it is like to be a scientist.  While I think that this blog has served that role to a point, I also found an audience drawn from a great community of science enthusiasts and I've been able to engage them with all of the things that I love about my job.

By far, it is my readers who have made Living LIGO what it is (and I personally think it is great).  A high point for me came back in March when it was revealed that the "Big Dog" blind injection was not a real gravitational wave.  I wanted to share it on my blog since this was a rare peek into how science is done.  One of my readers shared it on his blog (here) which got the attention of a popular "Cosmic Variance" blog (here) and the story was then picked up by places like Discovery News (here) and various other blogs.  The number of readers went from a few a day to over 1000 on that particular day (and many of those reader have now become regulars).  This is something I never expected when I started writing my blog but it is very exciting for me and I hope that it has at least been interesting for you.

I usually like to post a picture with every post, but I didn't have anything particularly relevant to this so I decided to give you a peek into where I create my blog post and most of my other brilliant research - my office.  It's small but it's all mine!  I even have a window (which is great since fluorescent lights give me migraines) and a door:

If you look closely, you can see some of my collection of stuffed vampire/creepy things.

*Thank you again to every reader out there.*  As always, please let me know what kinds of things you would like to know about.  I'll answer almost anything - from science questions to how to become a physicist or whatever!  Ask in the comment section of any blog post or contact me on Twitter as @livingligo.