There has been a lot of buzz about the large solar flare that was observed on March 7th (this is one of the strongest flares observed - read about this specific flare here). Most of the interest in this, other than it is an awesome thing to see, is that the material that was ejected from the Sun can interfere with satellites (like the GPS satellites you need to find your way around unfamiliar locales), power grids, and electromagnetic communications (like radio). Before I get started, below is a great video of the solar flare using different kinds of light (the Å symbol, called an angstrom, on the left side of some segments of this video is a unit of wavelength equal to 10-10 meters):
While this is truly an event to behold, there is more to it than just its beauty. Below is a short video on what you are seeing in this video and how the flare may affect us here on Earth:
The effects of astronomical events interacting with the Earth is called space weather. (NOAA even studies space weather and you can check the current space weather conditions anytime at NOAA Space Weather Prediction Center.) If you live north (or south) enough above the Equator (about 70o or so in latitude) , you may have seen the aurora (known as the aurora borealis [northern lights] if you are north of the Equator or the aurora australis [southern lights] if you are south). This light display is caused by charged particles from space interacting with the Earth's magnetic field (called the magnetosphere). This interaction directs the charged particles towards the north and south poles of the Earth. When the particles strike atoms of our atmosphere, they excite electrons in atoms that make up our air; light is produced when these excited electrons release this excess energy. Since our atmosphere is made up primarily of nitrogen and oxygen, the colors of this light are usually red (from nitrogen) or green (from oxygen). This recent solar flare is starting to interact with the Earth now and brilliant aurorae are expected. Since I am posting videos today, below is a spectacular time lapse video of the aurora borealis by National Geographic (there may be a short advertisement before it starts - sorry!):
I bring all of this up, not only because it is timely and interesting, but also because space weather affects LIGO. Space weather often produces particles that shower down on the Earth's surface called cosmic rays (even though most of the particles are not from space but are produced when very high energy particles from space smash into the atmosphere and produce showers of new particles from this interaction). Of particular concern to us is what would happen if a shower of particles are produced near or within one of our mirrors. Could this cause a vibration big enough for the detector to be sensitive to? If so, could the motion look like a gravitational wave signal? A paper published in 2008 investigated this (which you can read here if you are REALLY interested). It was determined that a strong shower could indeed move our mirrors enough for us to notice, but a strong shower like this is rare.
Even though the effect is rare, so is detecting a gravitational wave (at least until Advanced LIGO is completed). For the "Big Dog" event - when we last thought that we may have really detected a gravitational wave but it was later shown to be a blind test of our detection methods - the possibility that space weather could have affected our results was thoroughly investigated (along with many other things like one of us turning to the dark side and fraudulently adding this signal to the detector). As it turned out, it was a "clear" space weather day for that event.
Remember to check the NOAA Space Weather Prediction Center for updates on the effects of this recent solar flare here on Earth!
Thursday, March 8, 2012
Thursday, March 1, 2012
On Leap Years and Keeping Time
I hope everyone had a good leap day (I know it isn't a holiday, but it is even rarer since it only comes about every four years). In honor of this, I am discussing why we have leap days and different calendar systems. I'm not sure what you think, but while I find all of this fascinating, I'm happy this isn't something I study for a living!
There are many different calendar systems that base themselves on the periodicity of different things - most of them having an astronomical origin like the Sun, Moon, or even Venus. The system in most use today is the Gregorian calendar (at least for international commerce in countries that use a different system). This is a solar calendar that assigns a date to every cycle of day and night. This has the advantage of syncing up well with the normal human sleep cycle. However, the Earth does not revolve around the Sun in an integer number of days. While our normal year has 365 days in it, it actually takes the Earth 365.242374 days (and the length of a day is slowly increasing) to orbit the Sun.
If we did not correct for that extra fraction of a day, the seasons would slowly start changing later and later on the calendar. Over an average human lifespan, say 75 years, the equinoxes and solstices (start of seasons) will be a little more than 18 days later at the end of that 75 years than at birth. This year, the summer solstice is on June 20. If we never have another leap day, summer will start on Christmas (December 25 is 188 days after June 20) in 776 years. I know you and I wouldn't be around to see that, but on the human history scale of things this is very significant.
But our leap year every year that is evenly divisible by 4 system is overcompensating for that extra fraction of a day it takes Earth to orbit the Sun. So exceptions to the every 4-years rule must be made: every year divisible by 100 is NOT a leap year EXCEPT if it is divisible by 400. That is why 2000, even though it was divisible by 100, was not a leap year since it was also divisible by 400.
The reason I am going into this on this blog about LIGO is that keeping time is VERY important to us. It is also important to astronomers in general. There have been many revisions and changes to the calendar over the years (before the Gregorian calendar, most of Europe used the Julian calendar) and this can complicate figuring out how long it has been since something happened. So that we don't have to worry about these complications, astronomers use the Julian date system (which is different from figuring out the date on the Julian calendar mentioned above). This system assigns a date to every day consecutively (there are no months or years). For example, today is 2455988 (any fractional parts would correspond to the time of day). Day 0 is assigned to be January 1, 4713 BC (this is roughly around the beginning of human recorded history). This makes it is very easy to figure out how many days there have been between events; for example, I was born on 2443787 so I am 12,201 days old (today). Here at LIGO, we use a system called GPS time which counts the number of seconds since January 6, 1980 (I wrote a post about this here). In GPS time, I was born on -39489840... Now I feel prehistoric!
Remember in the first paragraph when I mentioned the day is getting longer? One of the predictable reasons for this is the effect of the tides on the Earth cause it to rotate a little slower over time (this is called tidal breaking). Other factors that are not as predictable can also effect the length of a day, like the motion of the molten mass inside the Earth. A 2004 earthquake was so powerful that the length of the day became 2.68 microseconds shorter. There are also unpredictable reasons we don't understand that cause the length of the day to change (in 1999 it changed by about 1 microsecond and we don't know why). But, factors like this cause there to be such a thing as a leap second (there will be a leap second on June 30 this year). Date systems like Julian dates and GPS time are not affected by this unless you want to convert back into normal dates and times - here at LIGO we make sure that all of our computer programs keep up to date with the leap second corrections.
***
Yesterday (leap day) I was leaving work by way of a staircase in the back of my building. This faces the woods and there is a single light above them so you can see your way at night. This is a prime place to find the varied kinds of moths that are indigenous to the area because many of them are attracted to the light and some die during the night. I guess I got a leap day treat yesterday when I saw this moth I have NEVER seen before with beautiful pink and yellow colorings:
I looked this up later and discovered that this is a rosy maple moth.
There are many different calendar systems that base themselves on the periodicity of different things - most of them having an astronomical origin like the Sun, Moon, or even Venus. The system in most use today is the Gregorian calendar (at least for international commerce in countries that use a different system). This is a solar calendar that assigns a date to every cycle of day and night. This has the advantage of syncing up well with the normal human sleep cycle. However, the Earth does not revolve around the Sun in an integer number of days. While our normal year has 365 days in it, it actually takes the Earth 365.242374 days (and the length of a day is slowly increasing) to orbit the Sun.
If we did not correct for that extra fraction of a day, the seasons would slowly start changing later and later on the calendar. Over an average human lifespan, say 75 years, the equinoxes and solstices (start of seasons) will be a little more than 18 days later at the end of that 75 years than at birth. This year, the summer solstice is on June 20. If we never have another leap day, summer will start on Christmas (December 25 is 188 days after June 20) in 776 years. I know you and I wouldn't be around to see that, but on the human history scale of things this is very significant.
But our leap year every year that is evenly divisible by 4 system is overcompensating for that extra fraction of a day it takes Earth to orbit the Sun. So exceptions to the every 4-years rule must be made: every year divisible by 100 is NOT a leap year EXCEPT if it is divisible by 400. That is why 2000, even though it was divisible by 100, was not a leap year since it was also divisible by 400.
The reason I am going into this on this blog about LIGO is that keeping time is VERY important to us. It is also important to astronomers in general. There have been many revisions and changes to the calendar over the years (before the Gregorian calendar, most of Europe used the Julian calendar) and this can complicate figuring out how long it has been since something happened. So that we don't have to worry about these complications, astronomers use the Julian date system (which is different from figuring out the date on the Julian calendar mentioned above). This system assigns a date to every day consecutively (there are no months or years). For example, today is 2455988 (any fractional parts would correspond to the time of day). Day 0 is assigned to be January 1, 4713 BC (this is roughly around the beginning of human recorded history). This makes it is very easy to figure out how many days there have been between events; for example, I was born on 2443787 so I am 12,201 days old (today). Here at LIGO, we use a system called GPS time which counts the number of seconds since January 6, 1980 (I wrote a post about this here). In GPS time, I was born on -39489840... Now I feel prehistoric!
Remember in the first paragraph when I mentioned the day is getting longer? One of the predictable reasons for this is the effect of the tides on the Earth cause it to rotate a little slower over time (this is called tidal breaking). Other factors that are not as predictable can also effect the length of a day, like the motion of the molten mass inside the Earth. A 2004 earthquake was so powerful that the length of the day became 2.68 microseconds shorter. There are also unpredictable reasons we don't understand that cause the length of the day to change (in 1999 it changed by about 1 microsecond and we don't know why). But, factors like this cause there to be such a thing as a leap second (there will be a leap second on June 30 this year). Date systems like Julian dates and GPS time are not affected by this unless you want to convert back into normal dates and times - here at LIGO we make sure that all of our computer programs keep up to date with the leap second corrections.
***
Yesterday (leap day) I was leaving work by way of a staircase in the back of my building. This faces the woods and there is a single light above them so you can see your way at night. This is a prime place to find the varied kinds of moths that are indigenous to the area because many of them are attracted to the light and some die during the night. I guess I got a leap day treat yesterday when I saw this moth I have NEVER seen before with beautiful pink and yellow colorings:
I looked this up later and discovered that this is a rosy maple moth.
Thursday, February 23, 2012
Q: Are there really Vegas odds on GW detection?
@Astroguyz asked:
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:
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.
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:
Yes! First, let me establish that there are 2 LIGO observatories in the United States.
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.
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?"
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. |
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.
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?
AMBER'S DIABOLICAL PLAN FOR MORE KING CAKE...
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?).
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!
UPDATE:
@Astroguyz asked:
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?
AMBER'S DIABOLICAL PLAN FOR MORE KING CAKE...
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:
- Is there anything like LIGO outside of the USA? Answered on 17 February 2012
- Has LIGO seen anything yet?
- What does LIGO look like? Answered on 15 March 2012
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!
UPDATE:
@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 ligo.org - 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!
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!
Thursday, January 26, 2012
Q: How can gravitational waves help mankind?
UPDATE: [11 Feb. 2015] Gravitational waves have been detected! Read more about it here.
@HughScot asked:
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!
@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!
Subscribe to:
Posts (Atom)