Once We Were Deaf, Now We Can Hear… the LIGO Discovery

Can you make music out of cutting edge physics? It turns out that you can (see further below for the musical shortcut to gravitational wave experiments). Most people are probably not too excited about gravitational waves…it does sound like it might be a bit of a dry a topic. However, they involve extremely violent and powerful events in the universe.

 

e17_2_mediumA disturbance in the fabric of space-time – two massive black holes are merging at a distance of 1.3 billion light years from Earth

Image via Physical Review Letters

 

The LIGO array that recently discovered evidence of gravitational waves  (which represented an aspect of the general theory of relativity that had so far eluded observational or experimental proof), was “listening” to the effects of gravitational waves emitted by two extremely massive large black holes merging at a distance of approx. 1.3 billion light years.

One interesting thing about this is that one is actually looking into the distant past. It took 1.3 billion years for the information to arrive here, so the collision happened a very long time ago, although we could only see it now. So how does the LIGO experiment actually work?

 

High Energy Pulse

To this one must first consider what gravitational waves were actually expected to do. Gravitation is the result of a curvature in space-time caused by the presence of mass. The greater the mass, the greater the curvature effect. Without it, there would e.g. be no planetary orbits. Instead of revolving around a sun, the planets of our solar system would just wander endlessly through space.

When two masses are orbiting each other and accelerate, they cause ripples in space-time. These are gravitational waves, which should in theory be detectable. The problem is that gravitation is actually a very weak force. In order for such ripples to be substantial enough to make them measurable, one needs not only highly sensitive measuring equipment, but must observe ripples caused by truly staggering masses. Luckily there are actually numerous objects in the universe in possession of staggering masses.

Nothing has more mass than a gravitationally completely collapsed star, or what since 1967 is known as a “black hole”. When physicist John Wheeler asked an audience for suggestions to replace the cumbersome term “gravitationally completely collapsed star” (try saying this ten times – it gets old real fast), someone in the audience shouted out “black hole!” and the term has stuck ever since.

The following is a simplified explanation of how the effect of gravitational waves was detected by LIGO. On 14 September 2015, two LIGO detectors recorded a 0.2 seconds long “chirp” coming from the general direction of the Magellanic Clouds, increasing in frequency and amplitude in eight cycles from 35 Hz. to 150 Hz. (now known as the “GW 150914 event”).

 

G-wave-signalsThe identical gravitational wave signals captured by the LIGO detectors in Livingston and Hanford

Image credit: NSF / Ligo Collaboration

 

From the amplitude of the signal its luminosity distance could be calculated, which is how it is known that it originated at a distance of approx. 400 mega-parsecs or 1.3 billion light years. By analyzing the signal in combination with its inferred redshift it was determined that two orbiting black holes, one with approx. 36 solar masses and another with approx. 29 solar masses collided to form a new single black hole of about 62 solar masses (all numbers +/- 4).

In the 0.2 seconds of the merger, the two black holes accelerated from 30% to 60% of light speed (hence the increase in frequency in every cycle). The missing mass energy of approx. 3 solar masses radiated away as a burst of gravitational waves, with a peak power of 3.6×1049 watts, or 50 times the power of the light radiated by all stars in the observable universe. This is the kind of event that becomes measurable – barely!

Here is a computer simulation of the merger, slowed down to a speed perceptible by humans:

 

Computer simulation of the merging black holes that caused the signal

 

What happens when a gravitational wave reaches us is that space-time is lengthened in one direction and shortened in another. There would normally be no way to measure a lengthening or shortening of space time, since one’s “ruler” (and oneself!) would lengthen and shorten with it. However, luckily the speed of light is constant. A light ray traveling through space-time will in fact arrive later when the space through which it travels is lengthened and sooner when it is shortened.

LIGO uses two tunnels with mirrors at a right angle to each other in which laser light travels back and forth. A laser beam is split in two and sent into the two tunnels. Its two halves are out of phase, so when the two light rays are reflected back and recombined into one, they cancel each other out. However, when a gravitational wave hits this detector, the length of the tunnels changes, and with that the time required by the light rays to over the distance changes as well.

The tunnel lengths change by less than the diameter of a single proton. This is very little, but enough for highly sensitive laser interferometers to detect that the two light beams no longer cancel each other out. This is equivalent to measuring whether a 1 sixtillion meter (1,000,000,000,000,000,000,000 m.) long stick has expanded or shrunk by 5 millimeters.

Here is a schematic of the LIGO detector:

 

LIGOschematic-600px1A laser source, a beam splitter, two tunnels, mirrors and a light detector.

Image via millstonenews.com

 

Here is what one of the LIGO arrays looks like from outside:

 

LIGO_buildingLIGO gravitational wave detector in Hanford.

Photo credit: LIGO

 

A Song About Gravitational Waves

All you have read above has been packed into a 3.5 minute song by A Capella Science – and it’s actually quite good:

 

Yes, it is possible to sing about gravitational waves…and actually deliver all the necessary information packaged for dance floor use.

 

Addendum: Black Holes Are Singers Too

In the center of a galaxy in the Perseus Cluster, some 250 million light years from here, there is a super-massive black hole that sings, or rather hums. It is a one-note Johnny, and has emitted a single note, namely a B flat, 57 octaves below the middle C on a piano, for an estimated 2.5 billion years. We can state that this particular black hole is a basso very profondo.

This frequency is a million billion times below the limit of the range of human hearing. For some time it was considered the deepest sound ever emitted in the universe. Until another super-massive crooner was discovered in the M87 galaxy that is. This one is a less steady singer, but the note it emits is about 59 octaves below the middle C.  Kind of like Osmin’s low D on a galactic scale.

 

Osmin’s low D! If you want to hear something even more extreme consider these famous Russian octavists. The one from the Kochgev ensemble can presumably level buildings.

 

How does this sound actually propagate through the vacuum of space? The space surrounding these black hole is anything but empty – it is chock-full of gas molecules. Here is an optical representation of the sound wave propagating through the Perseus cluster as captured by an x-ray observatory:

 

sonic waves perseusA B-flat propagating through the Perseus Cluster.

Image credit: CHANDRA

 

Given that different black holes are singing different notes, with the precise note likely depending on the amount of mass in their vicinity, we imagine that all of the singing black holes out there must be producing a chord together. It will be interesting to find out what this interstellar harmony is, and whether it is a sad or happy sounding one.

 

Addendum 2: Happy Easter Holidays

We wish all our readers happy Easter holidays. Antonius Aquinas who occasionally contributes articles to Acting Man has posted an article on the topic, which may be of interest to some of our readers: Holy Week and the Decline of the West.

 

 
 

 
 

Dear Readers!

You may have noticed that our so-called “semiannual” funding drive, which started sometime in the summer if memory serves, has seamlessly segued into the winter. In fact, the year is almost over! We assure you this is not merely evidence of our chutzpa; rather, it is indicative of the fact that ad income still needs to be supplemented in order to support upkeep of the site. Naturally, the traditional benefits that can be spontaneously triggered by donations to this site remain operative regardless of the season - ranging from a boost to general well-being/happiness (inter alia featuring improved sleep & appetite), children including you in their songs, up to the likely allotment of privileges in the afterlife, etc., etc., but the Christmas season is probably an especially propitious time to cross our palms with silver. A special thank you to all readers who have already chipped in, your generosity is greatly appreciated. Regardless of that, we are honored by everybody's readership and hope we have managed to add a little value to your life.

   

Bitcoin address: 1DRkVzUmkGaz9xAP81us86zzxh5VMEhNke

   
 

One Response to “Gravitational Waves Explained In A Song”

  • SavvyGuy:

    > When two masses are orbiting each other and accelerate, they cause ripples in space-time.

    Strictly speaking, space-time ripples are caused by acceleration AND deceleration of two orbiting masses. Obviously, these perturbances in the space-time flux will be 180 degrees out of phase with each other, which is basically the definition of a ripple.

    On a parallel note, deflationary monetary regimes (e.g. as in Japan) seem to be monetary black holes where, soon enough, not the slightest monetary velocity will circulate. When two or more monetary black holes collide, I foresee severe ripples in human conditions worldwide, and a return to that shiny yellow metal which is the essence of zero monetary velocity!

Your comment:

You must be logged in to post a comment.

Most read in the last 20 days:

  • 21st Century Shoe-Shine Boys
      Anecdotal Flags are Waved   "If a shoeshine boy can predict where this market is going to go, then it's no place for a man with a lot of money to lose." - Joseph Kennedy   It is actually a true story as far as we know – Joseph Kennedy, by all accounts an extremely shrewd businessman and investor (despite the fact that he had graduated in economics*), really did get his shoes shined on Wall Street one fine morning, and the shoe-shine boy, one Pat Bologna, asked him if...
  • India: The Genie of Lawlessness is out of the Bottle
      Recapitulation (Part XVI, the Last) Since the announcement of demonetization of Indian currency on 8th November 2016, I have written a large number of articles. The issue is not so much that the Indian Prime Minister, Narendra Modi, is a tyrant and extremely simplistic in his thinking (which he is), or that demonetization and the new sales tax system were horribly ill-conceived (which they were). Time erases all tyrants from the map, and eventually from people’s...
  • Christopher Columbus and the Falsification of History
      Crazed Decision The Los Angeles City Council’s recent, crazed decision* to replace Christopher Columbus Day with one celebrating “indigenous peoples” can be traced to the falsification of history and denigration of European man which began in earnest in the 1960s throughout the educational establishment (from grade school through the universities), book publishing, and the print and electronic media.   Christopher Columbus at the Court of the Catholic Monarchs (a...
  • The Government Debt Paradox: Pick Your Poison
      Lasting Debt “Rule one: Never allow a crisis to go to waste,” said President Obama’s Chief of Staff Rahm Emanuel in November of 2008.  “They are opportunities to do big things.”   Rahm Emanuel looks happy. He should be – he is the mayor of Chicago, which is best described as crisis incarnate. Or maybe the proper term is perma-crisis? Anyway, it undoubtedly looks like a giant opportunity from his perspective, a gift that keeps on giving, so to speak. [PT] Photo...
  • The Forking Paradise - Precious Metals Supply and Demand Report
      Forking Incentives A month ago, we wrote about the bitcoin fork. We described the fork:   Picture a bank, the old-fashioned kind. Call it Acme (sorry, we watched too much Coyote and Road Runner growing up). A group of disgruntled employees leave. They take a copy of the book of accounts. They set up a new bank across the street, Wile E Bank. To win customers, they say if you had an account at Acme Bank, you now have an account at Wile, with the same balance!   BCH, son...
  • The United States of Hubris
      Improving the World, One Death at a Time If anyone should have any questions about whether the United States of America is not the most aggressive, warlike, and terrorist nation on the face of the earth, its latest proposed action against the supposed rogue state of North Korea should allay any such doubts.   Throughout history, the problem with empires has always been the same: no matter how stable and invincible they appeared, eventually they ran into “imperial...
  • Long Term Statistics on AAPL
      Introductory Remarks by PT Below we present a recent article by the Mole discussing a number of technical statistics on the behavior of AAPL over time. Since the company has the largest market cap in the US stock market (~ USD 850 billion – a valuation that exceeds that of entire industries), it is the biggest component of capitalization-weighted big cap indexes and the ETFs based on them. It is also a component of the price-weighted DJIA. It is fair to say that the performance of...
  • Tragedy of the Speculations
      The Instability Problem Bitcoin is often promoted as the antidote to the madness of fiat irredeemable currencies. It is also promoted as their replacement. Bitcoin is promoted not only as money, but the future money, and our monetary future. In fact, it is not.   A tragedy... get the hankies out! :) [PT]   Why not? To answer, let us start with a look at the incentives offered by bitcoin. We saw a comment this week, which is apropos:   "Crypto is so...
  • Janet Yellen's 78-Month Plan for the National Monetary Policy of the United States
      Past the Point of No Return Adventures in depravity are nearly always confronted with the unpleasant reality that stopping the degeneracy is much more difficult than starting it.  This realization, and the unsettling feeling that comes with it, usually surfaces just after passing the point of no return.  That's when the cucumber has pickled over and the prospect of turning back is no longer an option.   Depravity and bedlam through the ages. The blue barge of perdition in the...
  • To Hell In A Bucket
      No-one Cares... “No one really cares about the U.S. federal debt,” remarked a colleague and Economic Prism reader earlier in the week.  “You keep writing about it as if anyone gives a lick.” We could tell he was just warming up.  So, we settled back into our chair and made ourselves comfortable.   The federal debtberg, which no-one cares about (yet). We have added the most recent bar manually, as the charts published by the Fed will only be updated at the end of the...
  • Despite 24/7 Trading: Bitcoin Investors are Taking off for the Weekend on Friday Already
      Crypto-Statistics In the last issue of Seasonal Insights I have discussed how the S&P 500 Index performs on individual days of the week. In this issue I will show an analysis of the average cumulative annual returns of bitcoin on individual days of the week.   Bitcoin, daily. While this is beside the point, we note the crypto-currency (and other “alt coins” as well) has minor performance issues lately. The white line indicates important lateral support, but this looks to...
  • Precious Metals Supply and Demand
      Fundamental Developments There were big moves in the metals markets this week. The price of gold was up an additional $21 and that of silver $0.30. Will the dollar fall further?As always, we are interested in the fundamentals of supply and demand as measured by the basis. But first, here are the charts of the prices of gold and silver, and the gold-silver ratio.   Gold and silver prices in USD terms (as of last week Friday) - click to enlarge.   Next, this is a...

Support Acting Man

j9TJzzN

Austrian Theory and Investment

Archive

350x200

THE GOLD CARTEL: Government Intervention on Gold, the Mega Bubble in Paper and What This Means for Your Future

Realtime Charts

 

Gold in USD:

[Most Recent Quotes from www.kitco.com]

 


 

Gold in EUR:

[Most Recent Quotes from www.kitco.com]

 


 

Silver in USD:

[Most Recent Quotes from www.kitco.com]

 


 

Platinum in USD:

[Most Recent Quotes from www.kitco.com]

 


 

USD - Index:

[Most Recent USD from www.kitco.com]

 

 
Buy Silver Now!
 
Buy Gold Now!
 

Oilprice.com