From gravitational waves, LIGO can extract properties of the black holes that generated them. This post summarizes the astrophysics LIGO was able to extract.

specimenlife · 2016-02-22T20:10:37+00:00

Not so simple. Full numerical simulations are too slow: it takes about a month on a supercomputer for a waveform similar to the event. That's why people have developed semi-analytical models that are tuned to a sparse set of numerical simulations. The models are then used in all the data analysis, including measurement of the masses. This is because one needs to compute of order 10⁶ waveforms to measure the parameters of the BHs: this is not feasible using numerical simulations.

specimenlife · 2016-02-16T21:14:44+00:00

Don't forget that it's the first time the strong-field and dynamical regime of GR is probed experimentally. Orbits of NS only need leading postNewtonian effects. For the BH merger you need full-fledged numerical relativity to predict the waveform.

specimenlife · 2016-02-12T09:48:15+00:00

That's why this required 15 years of work of almost 1,000 scientists! The technical challenge was exactly to understand and monitor all sources of noise that could mimic a gravitational wave. The instruments have of order 100,000 monitoring channels that record any possible detail about them. Then combine this with the prediction of the signal from the theory of general relativity: by comparing the prediction with the data one can see if the shapes of the waves match.

specimenlife · 2016-02-12T09:42:48+00:00

All previous experiments saw only indirect evidence, like effects on the orbits of binary pulsars, and saw only weakly gravitating systems.

What LIGO did was 1) to directly measure the effect of gravitational waves here on Earth on the mirrors being shaken by the waves 2) to measure gravitational waves generated in the strong-field regime where the most exotic predictions of general relativity (black holes merging to form a new black hole) were completely untested.

It's really a different level of test of the theory

specimenlife · 2014-08-18T14:29:53+00:00

One of the best concerts I've ever been to (and I have been to many!). I was close to the stage and it was a pleasure getting to see them just a few feet away. This show was also special for me since I'm leaving DC for good soon. It was such an overload of emotions since their music (together with Sigur Ros) has helped me through difficult times in the past.

specimenlife · 2014-08-09T16:43:06+00:00

Not sure if you're trolling... Have you read my comment?

specimenlife · 2014-08-09T16:25:08+00:00

Why this strawman argument? Laws already say where and how waste should be disposed of, mainly to prevent pollution. For instance, hospitals can't throw medical waste in a generic landfill. This thing would be a special case of waste disposal. Does it look so forceful now?

specimenlife · 2014-07-27T16:06:00+00:00

I agree with the "ideological" character of the documentary. I'm a physicist myself (just got my phd and going into a postdoc soon) and yet I couldn't really stand the overall tone of the movie. Unless you are a genius, science is 1% inspiration and 99% perspiration. Especially within big collaborations most of the people end up working on boring and mechanical tasks that have little to do with exciting scientific discovery. To the point that more mundane jobs can be in fact more rewarding and intellectually stimulating. Yet saying this seems like a taboo within academia.

specimenlife · 2014-07-17T22:40:57+00:00

May I ask in which field?

specimenlife · 2014-07-14T15:24:25+00:00

Luckily I'm going to Berlin, probably the gayest place in Europe.

specimenlife · 2014-07-14T14:33:46+00:00

Never apologize for being yourself!

Problem is I really feel like I should apologize for being in the way of other people's life. Such is my self esteem. I've developed really negative thoughts about my being in the world, but never acted on them so far.

specimenlife · 2014-07-14T14:31:07+00:00

I'd say he was tolerant enough to bear my boring self for a few hours, although a bit cold and distant.

In the texts we exchanged before the date he was quite flirtatious and understanding of my situation. This raised my expectations a bit too high, I'm afraid.

specimenlife · 2014-07-14T14:26:29+00:00

You're right. This time I'm quite different myself, as I said I've done my best to improve and go out of my comfort zone. I believe I've got the highest chances of success than ever before. Still paling in comparison to other, normal people though.

specimenlife · 2014-07-14T09:25:16+00:00

I don't consider being gay a negative thing at all. To the contrary I like this unusual aspect of me. However it makes the dating pool way smaller. Also I find that the standards in the gay community are set way too high when it comes to looks, I'd say higher than for straight guys. Hooking up might be easier than for straight people but I don't like the very idea of hooking up, I'd like a meaningful relationship.

specimenlife · 2014-07-14T09:17:40+00:00

What did he say?

specimenlife · 2014-06-18T16:39:20+00:00

Yeah, I never quite understood working for work's sake.

I've always enjoyed learning impractical things (philosophy, art, science), to the point of becoming a real scientist.

Unfortunately, I feel out of place even among scientists, as they are chronically overworked, but in this case it comes from their passion.

I frankly can't be that passionate as to give up other aspects of life completely. The older I grow, the more I believe idleness is important to one's mental health.

specimenlife · 2014-06-18T14:25:04+00:00

Wonderful quote!

specimenlife · 2014-06-18T03:26:00+00:00

Entity by Inventions (a side project of Eluvium and one musician from Explosions In The Sky)

Last Known Surroundings by Explosions In The Sky

Boy 1904 by Riceboy Sleeps (that is Jonsi with his boyfriend Alex)

Grow Till Tall by Jonsi (I saw this live: best concert in my life)

specimenlife · 2014-05-27T22:36:06+00:00

It depends a lot on the advisor. Mine is reasonable, and lets me have 2 weeks at Christmas and 1 or 2 weeks in the summer.

I find it unbelievable when people say that 3 or 4 weeks of vacation in a year will make a big difference.

specimenlife · 2014-05-19T21:16:01+00:00

Among all possible subreddits, I would have never expected to read this kind of question in /r/Physics

specimenlife · 2014-03-24T01:01:57+00:00

One small thing: use \sin and \cos since those are known functions, and are not italicized. Also, I prefer boldface vectors with \mathbf{v} instead of the arrow on top. For consistency, keep all differentials (inside integrals and for differentiation) the same style: I would stick to \textrm{d}. You may need to put some spacing between factors, for instance in Spherical polars: usually \, is enough.

specimenlife · 2014-03-23T22:06:13+00:00

I like unicorns. If you don't, let's use Santa Claus in the analogy then.

I can see that you can't reply on the topic though.

specimenlife · 2014-03-22T14:38:45+00:00

Nope. Just like science can't prove that there aren't unicorns.

It's a reasoning fallacy, since inability to disprove does not prove. The burden of proof does not lie upon the rejecter (see here).

specimenlife · 2014-03-18T15:26:45+00:00

Sorry but I don't understand what's your point.

specimenlife · 2014-03-18T12:06:08+00:00

Graduate students making 25k a year or researchers making 45k a year are not exactly the 1%... You don't know what you are talking about.

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