![\"https://upload.wikimedia.org/wikipedia/commons/c/c5/GW150914_Strain-diagrams_whitebg.png\"](\"https://upload.wikimedia.org/wikipedia/commons/c/c5/GW150914_Strain-diagrams_whitebg.png\")
i read that if there is indeed a gravitational wave, the measurement from LIGO Handford should coincide with that from LIGO Livingstone, after a time shift. Does this apply to this competition?
\nGiven the gravitational-wave measurement from one location, we should be able to predict the theoretical value from another location. By measuring the discrepancy, we can tell if it is noise or signal?
\nSo basically we are detecting if there are similar wave patterns (apart from the shift ) in the 3 locations?
\n
i read that if there is indeed a gravitational wave, the measurement from LIGO Handford should coincide with that from LIGO Livingstone, after a time shift. Does this apply to this competition?
\nGiven the gravitational-wave measurement from one location, we should be able to predict the theoretical value from another location. By measuring the discrepancy, we can tell if it is noise or signal?
\nSo basically we are detecting if there are similar wave patterns (apart from the shift ) in the 3 locations?
\n
i also read about 'characteristic strain':
\nhttps://cplberry.com/2015/01/10/1408-0740/
\n\"You might wonder why we don’t just directly use the amplitude of the wave? Gravitational waves are a stretching and squashing of spacetime, so you can characterise how much they stretch and squeeze things and use that to describe the size of your waves. The sensitivity of your detector is then how much various sources of noise cause a similar wibbling. The amplitude of the wave is really, really small, so it’s difficult to detect, but if you were to consider observations over a time interval instead of just one moment, it’s easier to spot a signal: hints that there might be a signal add up until you’re certain that it’s there. The characteristic strain is a way of modifying the amplitude to take into account how we add up the signal.\"
", "rawMarkdown": "i also read about 'characteristic strain':\n\nhttps://cplberry.com/2015/01/10/1408-0740/\n\n\"You might wonder why we don’t just directly use the amplitude of the wave? Gravitational waves are a stretching and squashing of spacetime, so you can characterise how much they stretch and squeeze things and use that to describe the size of your waves. The sensitivity of your detector is then how much various sources of noise cause a similar wibbling. The amplitude of the wave is really, really small, so it’s difficult to detect, but if you were to consider observations over a time interval instead of just one moment, it’s easier to spot a signal: hints that there might be a signal add up until you’re certain that it’s there. The characteristic strain is a way of modifying the amplitude to take into account how we add up the signal.\"", "votes": null }, { "id": "1490662", "postDate": "08/25/2021 19:05:35", "content": "\n\nGiven the gravitational-wave measurement from one location, we should be able to predict the theoretical value from another location.
\n
The competition host said in a post somewhere that the simulated GW signals in the data do indeed exhibit this time shift from detector to detector, based on the location of origin of the GW. The problem is, we have no data about the location of the origin a priori (just like in real life). So even though we know how long it takes GW to propagate from one detector to the other, there's no way of figuring out which way it's coming or going from except to find the chirps in the signal and then triangulate back.
\nAlso in the image you linked, the strain wave has already been preprocessed.
\n\n\nSo basically we are detecting if there are similar wave patterns (apart from the shift ) in the 3 locations?
\n
Depending on the orientation of the detectors and the point of origin, there might even be an inversion.
", "rawMarkdown": "> Given the gravitational-wave measurement from one location, we should be able to predict the theoretical value from another location.\n\nThe competition host said in a post somewhere that the simulated GW signals in the data do indeed exhibit this time shift from detector to detector, based on the *location of origin* of the GW. The problem is, we have no data about the location of the origin a priori (just like in real life). So even though we know how long it takes GW to propagate from one detector to the other, there's no way of figuring out which way it's coming or going from except to find the chirps in the signal and then triangulate back.\n\nAlso in the image you linked, the strain wave has already been preprocessed.\n\n> So basically we are detecting if there are similar wave patterns (apart from the shift ) in the 3 locations?\n\nDepending on the orientation of the detectors and the point of origin, there might even be an inversion.", "votes": null }, { "id": "1490711", "postDate": "08/25/2021 19:54:32", "content": "This is slightly unrelated, but this LTT episode discusses that once the LIGO experiment upgrades to using atomic clocks, the effective size of the LIGO experiment much will be larger and be able to study these delays at an accuracy not possible before :)
\nhttps://youtu.be/JK3eTGkX6qY?t=658
", "rawMarkdown": "This is slightly unrelated, but this LTT episode discusses that once the LIGO experiment upgrades to using atomic clocks, the effective size of the LIGO experiment much will be larger and be able to study these delays at an accuracy not possible before :)\n\nhttps://youtu.be/JK3eTGkX6qY?t=658", "votes": null }, { "id": "1560997", "postDate": "10/27/2021 09:03:35", "content": "Hey All,
\nThank you all for taking part in our competition. The participation has been overwhelmingly positive. We are currently conducting a survey to gauge the demographic and outreach achieved. Kindly spare 2min and fill in this survey https://forms.gle/QP9L16niPexozyhu5.
\nThank you all,
\nRegards,
\nChris
i also read about 'characteristic strain':
\nhttps://cplberry.com/2015/01/10/1408-0740/
\n\"You might wonder why we don’t just directly use the amplitude of the wave? Gravitational waves are a stretching and squashing of spacetime, so you can characterise how much they stretch and squeeze things and use that to describe the size of your waves. The sensitivity of your detector is then how much various sources of noise cause a similar wibbling. The amplitude of the wave is really, really small, so it’s difficult to detect, but if you were to consider observations over a time interval instead of just one moment, it’s easier to spot a signal: hints that there might be a signal add up until you’re certain that it’s there. The characteristic strain is a way of modifying the amplitude to take into account how we add up the signal.\"
", "votes": null, "replies": [] }, { "id": 1490662, "author_name": "authman", "author_url": "", "post_date": "08/25/2021 19:05:35", "content": "\n\nGiven the gravitational-wave measurement from one location, we should be able to predict the theoretical value from another location.
\n
The competition host said in a post somewhere that the simulated GW signals in the data do indeed exhibit this time shift from detector to detector, based on the location of origin of the GW. The problem is, we have no data about the location of the origin a priori (just like in real life). So even though we know how long it takes GW to propagate from one detector to the other, there's no way of figuring out which way it's coming or going from except to find the chirps in the signal and then triangulate back.
\nAlso in the image you linked, the strain wave has already been preprocessed.
\n\n\nSo basically we are detecting if there are similar wave patterns (apart from the shift ) in the 3 locations?
\n
Depending on the orientation of the detectors and the point of origin, there might even be an inversion.
", "votes": null, "replies": [] }, { "id": 1490711, "author_name": "anjum48", "author_url": "", "post_date": "08/25/2021 19:54:32", "content": "This is slightly unrelated, but this LTT episode discusses that once the LIGO experiment upgrades to using atomic clocks, the effective size of the LIGO experiment much will be larger and be able to study these delays at an accuracy not possible before :)
\nhttps://youtu.be/JK3eTGkX6qY?t=658
", "votes": null, "replies": [] }, { "id": 1560997, "author_name": "zerafachris", "author_url": "", "post_date": "10/27/2021 09:03:35", "content": "Hey All,
\nThank you all for taking part in our competition. The participation has been overwhelmingly positive. We are currently conducting a survey to gauge the demographic and outreach achieved. Kindly spare 2min and fill in this survey https://forms.gle/QP9L16niPexozyhu5.
\nThank you all,
\nRegards,
\nChris