Finally, scientists have found a well-verified gravity wave with the LIGO instruments. This is a tremendous technological achievement, requiring over 40 years of developing more sensitive instruments. For the official announcement, see:
The Einstein@home site wrote:
|Exciting news: Gravitational Waves detected!
We want to share our excitement about the first-ever direct detection of gravitational waves! The event happened right before the beginning of the first observing run of the advanced LIGO detectors, on 14 September 2015. The waves were generated as two black holes merged into a single black hole about 1.3 billion light years from Earth. In astronomy units this is 410 Mpc, approximately 10% of the way across the visible Universe!
Just as exciting: this is also the first-ever observation of binary black holes. In fact, since black holes are black, and emit no light or electromagnetic radiation, this is the only way we can see them.
Until yesterday, this has been (mostly) a well-kept secret since the signal was received last September. It was somewhat unexpected, as the LIGOs had just been restarted after a major upgrade and were not yet considered fully operational as scientific instruments. It appears that the team wanted to be quite cautious before announcing any result.
Very cool! It's hard to understand what exactly is going on though
We are so happy:
All what we studied in school with blood sweat and tears. It is true. Thank You Einstein.
Just to be clear, we did have indirect evidence of gravitational waves for quite some time. But this is the first direct evidence of gravitational wave.
Obviously that doesn't take away anything from the achievement of LIGO. Now what would be interesting is to see is what all information can we drive through gravitational waves of past. Will we be able to make instruments so sensitive that they can detect not only gravitational waves for such massive objects like black hole but for relatively smaller objects as well.
P.S.: XKCD has a great comics on this discovery: http://xkcd.com/1642/
I found some information about other events seen by LIGO since the "big one".
Apparently several significant events have been observed, one of which is a likely gravitational wave:
|Although the signal from "LVT151012" is much weaker than the confirmed “GW150914” event, the LIGO team says it most likely has an astrophysical source and arose from two coalescing black holes. |
LIGO scientist Amber Stuver described their best candidate as being “clean and clear”. Nevertheless it has not yet met statistical standards to be considered a detection. The article goes on to say that:
|These events suggest that the rate of binary-black-hole mergers is higher than expected, between six and 400 per cubic gigaparsec per year. |
I found an old thread about a theory of quantum gravity:
Since that thread mentions that their theory might be testable, I thought it might be worthwhile to see if the recent GW event is evidence for or against that theory.
I was talking about LIGO for years and only about 5% of people cared, but hooray now it's on TV and people care lol. Weird thing actually, my friend was randomly looking up information on gravitational waves the day before the announcement and he hadn't looked into it in years.
And the other ideas will be proved later also.
The LIGO / Virgo teams have published another paper! There was another event on Dec. 26; this time it appears to be the merger of two black holes of about 8 and 14 solar masses.
The article mentions that there is one other significant event from the first science run, which is still being analyzed. The event just reported was not obvious like the first one, but required substantial analysis to find at all. After thoroughly verifying the data, one researcher commented that an event this significant should not occur as an accidental noise pattern oftener than once in a million years.
Stay tuned for the third shoe to drop. I'm pretty sure they will either publish a paper on the remaining event, even if only to conclude that it is most probably noise, or else will save it as a major portion of a summary paper of the six months or so of listening which ended on Jan 19.
Based on the (very limited) data from theory and observation I'd venture a random guess that events as strong as the September wave do not occur more often than once every 20 years or so.
Did You think about the consequences of that to daily life?
Einstein lived in the reality.
|loveandormoney wrote: |
|Did You think about the consequences of that to daily life?
Einstein lived in the reality.
Consequences of gravity? Huge! I am floored by it every day. Consequences of gravitational waves? It appears they've been going right by us, "over our heads" so to speak, for centuries. Joseph Weber began looking for them back in the 1970s at the University of Maryland. I shared in the excitement when he got vibrations on both of his aluminum cylinders at the same time that had no explanation, therefore could have been gravity waves. Apparently Weber continued to believe his experiment was working, while almost everyone else thought there was some other explanation.
When the first LIGO discovery was made, I'm pretty sure they were concerned lest it turned out it was a never-to-be-repeated event that would cause skepticism for decades to come. The December event should be more typical of events which will continue to be seen on a regular basis.
An analysis of all three events, described as a summary of the six-month observation period, has now been published. As stated earlier, the December event had an assumed probability of one in a million of being accidentally seen due to random noise patterns (five sigma, which is the usual scientific limit for reliability). The "marginal" event had about a one in ten chance of appearing due to random noise, so would be considered way short of a confirmed sighting if seen by itself.
LIGO has spotted another black hole merger. This one was observed in January; the paper was published June 1.
If you look at Fig. 2 (have to click on a couple of plusses to get there), you can see a comparison of the black hole masses in the four events observed so far. The "questionable" event, LVT151012, looks a lot more real when you see it on the same graph and fitting in nicely with the others. The new event is the second largest yet seen, about 50 solar masses total.
Waow ! a gravity wave ? what were its intensity ?
More interesting is the amplitude?
Can You tell us something and the quantity of the energy?
The wavelength of the ones discovered at ligo is 43 Km to 7000 Km. The amplitude is very low in general cases, you need a massive object to produce a vibration strong enough to be detected, such as a supernova or two black holes orbiting each other (LIGO's experiment).
So it's true: all we learned with Newton's theory seems to be somthing that fit very well the reality, but realty is something else...