LIGO Events and Earth Tide Ripples
LIGO was designed to detect a tiny ripple in Earth's crust caused by a gravitational wave.
There are coincidences between LIGO detections and earth tide events. From this observation, the ripple from an Earth tide is triggering a response in the LIGO system looking for a small signal in the noise, the ripple in the crust from a gravitational wave.
The LIGO system uses templates for 4 event types to detect; they are binary inspiral events. Each report is one of these 4 types.
The reliability of the LIGO system depends on the accuracy of this pattern matching software.
None of the templates has been validated by a test of the actual event.
The celestial events causing an earth tide in this time period: Full Moon, New Moon, PeriGee, PeriHelion, MJ = Moon-Jupiter alignment.
On 2019-04-23 was an alignment separation of the Moon and Jupiter of only 1 degree, 38 minutes, at the same RA. This is the MJ event.
More than one LIGO event has been detected in the ripples from one earth tide event. There are more LIGO events than earth tide events in the following list.
There are 45 LIGO events associated with 24 earth tide events.
There are 11 robust GW events (with a higher probability of a match) in the LIGO list of 45. 34 remain only candidates with a probability.
This list has the LIGO events in chronological order but preceded by the associated earth tide event. LIGO events can be reported before or after the earth tide event whose effect is over a span of time.
The lines starting with GW or S are the LIGO events.
GW150914 _ event 1 day after NM
GW151012 _ same day as NM
GW151226 _ 1 day after FM
GW170104 _ same day as PH
GW170608 _ 1 day before FM
GW170608 _ 1 day before FM
GW170729 _ 6 days after NM
GW170809 _ 2 days after FM
GW170814 _ 4 days before PG
GW170817 _ 1 day before PG
GW170818 _ same day as PG
NM-17-08-21 _ solar eclipse
GW170823 _ 2 days after NM
S190408an _ 3 days after NM
S19040412m _ 4 days before PG
S190421 _ 2 days before MJ
S190425z _ 2 days after MJ
S190426c _ 3 days after MJ
S190503bf _ 1 day before NM
S190510g _ 6 days after NM
S190512at _ 1 day before PG
S190513bm _ same day as PG
S190517h _ 1 day before FM
S190519bj _ 1 day after FM
S190521g _ 3 days after FM
S190521r _ 3 days after FM
S190602aq _ 1 day before NM
NM-19-07-02 _ solar eclipse
S190630ag _ 2 days before NM
S190701br _ 1 day before NM
S190706ai _ 4 days after NM
S190707q _ 5 days after NM
S190720a _ 2 days after FM
S190727h _ 4 days before NM
S190728q _ 3 days before NM
S190814bv _ 1 day before FM
S190828j _ 2 days before NM
S190828l _ 2 days before NM
S190901ap _ 2 days after NM
S190910d _3 days before FM
S190910h _ 3 days before FM
S190915ak _ 2 days after FM
S190923y _ 5 days before NM
S190924h _ 4 days before NM
S190930s _ 2 days after NM
S190930t _ 2 days after NM
S191105e _ 7 days before FM
S191109d _ 3 days before FM
Only GW170817 has an apparent independent confirmation.
GW 170817 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 17 August 2017, originating from the shell elliptical galaxy NGC 4993. The GW was produced by the last minutes of two neutron stars spiralling closer to each other and finally merging, and is the first GW observation which has been confirmed by non-gravitational means. Unlike the five previous GW detections, which were of merging black holes not expected to produce a detectable electromagnetic signal, the aftermath of this merger was also seen by 70 observatories on 7 continents and in space, across the electromagnetic spectrum, marking a significant breakthrough for multi-messenger astronomy. The discovery and subsequent observations of GW 170817 were given the Breakthrough of the Year award for 2017 by the journal Science.
The gravitational wave signal, designated GW 170817, had a duration of approximately 100 seconds, and shows the characteristics in intensity and frequency expected of the inspiral of two neutron stars. Analysis of the slight variation in arrival time of the GW at the three detector locations (two LIGO and one Virgo) yielded an approximate angular direction to the source. Independently, a short (~2 seconds' duration) gamma-ray burst, designated GRB 170817A, was detected by the Fermi and INTEGRAL spacecraft beginning 1.7 seconds after the GW merger signal. These detectors have very limited directional sensitivity, but indicated a large area of the sky which overlapped the gravitational wave position. It has been a long-standing hypothesis that short gamma-ray bursts are caused by neutron star mergers.
An intense observing campaign then took place to search for the expected emission at optical wavelengths. An astronomical transient designated AT 2017gfo (originally, SSS 17a) was found, 11 hours after the gravitational wave signal, in the galaxy NGC 4993 during a search of the region indicated by the GW detection. It was observed by numerous telescopes, from radio to X-ray wavelengths, over the following days and weeks, and was shown to be a fast-moving, rapidly-cooling cloud of neutron-rich material, as expected of debris ejected from a neutron-star merger.
The hidden story.
Earth tide is the displacement of the solid earth's surface caused by the gravity of the Moon and Sun. Its main component has meter-level amplitude at periods of about 12 hours and longer.
A new moon or full moon cause a significant earth tide with the Sun also aligned. A perigee does an earth tide regardless of the Sun.
Many of the LIGO events were just a day or two before or after the earth tide event.
All 43 LIGO events were within 6 days of an earth tide event.
For those questioning whether LIGO really detects a ripple in spacetime, this observation suggests the LIGO system detects the ripples of an earth tide.
Each search method produces a list of candidate events which are ranked in terms of their signal strength with respect to the detector's noise — a quantity called the "signal-to-noise-ratio" (SNR) — and their statistical significance, quantified by the false alarm rate (FAR), i.e. the rate at which one might expect such a candidate event to have occurred by chance, due simply to the noise characteristics of the detector data mimicking an actual gravitational-wave detection. By setting a FAR threshold of less than 1 per 30 days (about 12.2 per year) in at least one of the two matched-filter analysis algorithms, we restricted the list of candidate events and eliminated many candidate signals that are very likely to have been simply artefacts of the detector noise: within these candidates we found 11 events with a probability larger than 50% of having an astrophysical origin, rather than being instrumental noise. These candidates are labeled with the prefix 'GW' followed by the date of the detection (i.e. GW150914). The other candidates are considered as 'marginal' events, unlikely to be of astrophysical origin.
another definition from wikipedia:
In signal processing, a matched filter is obtained by correlating a known delayed signal, or template, with an unknown signal to detect the presence of the template in the unknown signal.
LIGO needs independent confirmation for credibility of its claims.
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Last updated (10/09/2019)
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