April 23, 2019

Traveler’s Tales of Gravitational Waves

We brake for gravitational waves…

(all photos by author)

This past week the science community held its breath, as rumors swirled once again that researchers had accomplished direct detection of gravitational waves. Sure, we’ve been down this road before, but with Advanced LIGO (the Laser Interferometer Gravitational-wave Observatory) resuming operation in late 2015, there’s good reason to believe said detection could come at any time.

And perhaps, by the time our weekly Friday column comes out, it has. Our science writing career has grown up with LIGO and the hunt for gravitational waves, and we’ve been fortunate enough to visit both the Livingston and Hanford detectors that compose the detector in our travels.

Adventures at LIGO Livingston (top) and LIGO Hanford (bottom)

This is therefore a sort of ‘Schrodinger’s post,’ a letter to a future in which gravitational waves may or may not have been discovered by astronomers. A positive detection will serve as a vindication and open a new field of astronomy, a method to probe the cosmos completely off the electromagnetic spectrum. For our money, the hunt for gravitational waves is at least as compelling an odyssey as the Large Hadron Collider’s quest for the Higgs-Boson. Of course, a non-detection would cause the science community to hold its breath, and maybe move on to the Shark Week topic of the moment.

Hey, its happened before. Remember, this excitement came from one tweet, albeit a presumably informed one. Perhaps another ‘blind-injection’ was placed in the system to keep researchers on their toes, though potential bean-spiller physicist Lawrence Krauss also Tweeted that this wasn’t the case, though he’s cried wolf before.

Constructing large physics experiments such as LIGO serve as some of the greatest feats humans are capable of. Heck, we just think its awe-inspiring that smartwatch-wearing apes like ourselves can construct such globe-spanning devices, all on a hunch that gravitational waves must exist.

Of course, a long term non-detection could be just as bewildering, though a headline reading ‘Astronomers Fail to Detect Gravitational Waves Again’ just isn’t sexy. Likewise, LIGO doesn’t produce any splashy pictures akin to the Hubble Space Telescope… we therefore suspect that, if the announcement of the detection of gravitational waves comes to pass this week, a large segment of the Yahoo! front page reading population will simply say ‘what are gravitational waves? What’s LIGO?’

In the ‘belly of the beast’ at LIGO Hanford

We’ve stood in the heart of both detectors, and watched as controllers at both LIGO stations diligently struggled to attain a lock. Assuming that you, future reader, are now reading the breathless headlines exclaiming ‘Gravity Waves Discovered!’ in the future near or far, here are some pitfalls to watch out for, as we boldly scold future science news reporting:

-LIGO did not discover gravitational waves: I know. Again, ‘First Direct Detection!’ just doesn’t hook those eyeballs in the modern, SEO-driven world. Truth is, we already know that gravitational waves exist, and Russell Hulse and Joseph Taylor won the Nobel Prize in physics in 1993 for their indirect detection seen in the measurement of the timing of the binary pulsar system PSR B1913+16. Again, LIGO’s detection will serve as a first direct measurement.

-LIGO vs BICEP: Sure, as science writers, we all want to go there. The BICEP-2 news of a detection vindicating inflation theory and the subsequent controversy is the sort of thing science journalism loves. We’ll all try our best to link the BICEP story and LIGO, sure. But the truth is, both searches operate at very different frequencies.

-LIGO isn’t the only detector out there: It’s enough to watch mainstream journalism switch from Donald Trump coverage to realize there’s there are two LIGO gravitational wave detectors on ‘merican soil. But wait, there’s more: Germany has the GEO-600 detector, Italy has VIRGO, and Japan has the KAGRA detector. And hey, even India may host a third LIGO detector soon… did any of them witness the alleged signal as it passed through the Earth? Did any news outlet care to check?

-LIGO versus the Big Bang: In a somewhat congruent topic to BICEP, lots of pundits will most likely attempt to link LIGO’s announcement to ‘proof of the Big Bang,’ with the usual Conservapedia backlash. Truth is, the Big Bang theory of cosmology has numerous lines of evidence supporting its bulwark. The non-detection of gravitational waves during the original LIGO run a decade ago actually already placed constraints on the Big Bang, but again, negative results just don’t seem to bring ‘em in.

-Gravity Waves (or not): here’s a fun experiment; watch how many times talking heads say, ‘gravity waves’ instead of ‘gravitational waves’ following the rumored press release. Do a brief Google search and see how many headlines scream ‘Gravity Waves Discovered!!!’ Sure, I’ve caught m’self wanting to say the same on occasion. ‘Gravity waves’ just wants to roll off the tongue, and hey, its six characters shorter, very tweet-able. But gravity waves are an atmospheric phenomena, and have nothing to do with merging pulsars. Even Neil deGrasse Tyson, who rightly pointed out to Colbert that his globe spins backwards, gets this one wrong on occassion.

So there you have it, our two cents on a historic discovery. Congratulations: you now live in a world, be it next week or in the next decade, where gravitational wave astronomy is now a mature science.

I envy you.

Comments

  1. Torbjrn Larsson says:

    Lovely sum up!

    [Though my idiosyncratic self want to ask every time the vague 'direct vs indirect' distinction is made how it would be testably defined. My hunch is that it signifies "in my opinion likely observation vs too many constraints to be palatable".]

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