

A major upgrade of the LIGO gravitational-wave detector is almost complete - alphanumeric0
http://www.nature.com/news/physics-wave-of-the-future-1.15561

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ISL
For clarity, as I'm close to LIGO (but not in the collaboration) and found the
title misleading:

A major upgrade of LIGO is almost complete. When it comes back online, if the
detectors reach design sensitivity, it's sufficient to make detection of
gravitational waves from neutron-star inspirals probable. As both LIGO and
Virgo are down for upgrades, there's no chance of a major new detection from
either until they're re-commissioned and running well (timescale of ~year+).

As reported at a workshop at the Institute for Nuclear Theory here at the
University of Washington a few weeks ago, the Advanced LIGO upgrades have been
going quite well; the riskiest work is coming toward a close.

The linked article makes no claims that there's anything new being dredged out
of past science runs on initial/enhanced LIGO (which remains possible, if
unlikely).

~~~
dang
Thanks! If you can suggest a better title, we'll use it. In the meantime, we
changed it to a sentence from your comment.

~~~
ISL
Sounds great -- I'm hesitant to wordsmith further. The previous title was
correct, too, it just led me to the wrong first impression. aLIGO is "on the
verge of detection", on timescales of years. For a project begun in 1992 or
earlier, that's real soon. Everyone in the experimental detection community is
excited and upbeat.

For the skeptic sibling comment -- there remains a non-negligible chance that
aLIGO will see nothing. If it reaches its design specifications and sees
nothing, it would force mainstream astrophysics to rethink a lot of widely-
held beliefs regarding neutron star abundances and merger rates.

~~~
mtdewcmu
>> For the skeptic sibling comment -- there remains a non-negligible chance
that aLIGO will see nothing. If it reaches its design specifications and sees
nothing, it would force mainstream astrophysics to rethink a lot of widely-
held beliefs regarding neutron star abundances and merger rates.

Thanks. I'm not so much a critic of LIGO, I just like science writing that
doesn't obscure the facts (as a sober scientist would assess them). It's odd
in any case to assert that a scientific instrument is on the verge of a
history-making observation (that implies being able to see the future). A
person with a genuine interest in scientific progress ought to be able to
handle the truth: the inescapable lesson that LIGO and other projects have
taught us so far is that gravity waves are difficult to detect by all known
methods. Science is about accepting truth as we are able to observe it.

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rghn
I actually got a chance to tour the LIGO facility in Louisiana recently. They
have an open house "Science Saturday" that, while somewhat kid oriented, is
pretty well put together. The control room was particularly fun to look around
in and I'd recommend a visit if in the area.

~~~
muaddirac
I went there in college (went for the physics, stayed for the fun science
room) - what I remember most was an exceptionally well-built Chladni plate
that you could control.

~~~
ISL
Whoa; hadn't heard of a Chladni plate before.

Here's a video:
[http://www.youtube.com/watch?v=lRFysSAxWxI](http://www.youtube.com/watch?v=lRFysSAxWxI)

Can't find one of anything at Livingston or Hanford, though.

At Hanford, they have one of Weber's original bar detectors in the visitor's
center lobby... So cool.

[http://www.ligo.caltech.edu/LIGO_web/0312news/0312one.html](http://www.ligo.caltech.edu/LIGO_web/0312news/0312one.html)

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platz
There was a huge thread on this a while back when bicepkeck made some
measurements.

[https://news.ycombinator.com/item?id=7416694](https://news.ycombinator.com/item?id=7416694)
(see parent)

I've been fascinated by ligo ever since learning about it.

Interferometers seem to me strange but wonderful instruments that seem simple
yet I think get at very fundamental properties.

~~~
InclinedPlane
There was a while where interferometry was the "next big thing*, but it's
proven to be considerably more difficult in practice than in theory. But
perhaps with time we'll see it reach some significant fraction of its
potential, which is enormous.

~~~
rprospero
I'm afraid that I don't follow what you mean by interferometry being the next
big thing. I was pretty well under the impression that it was the PREVIOUS big
thing. For example, when I was in undergrad, the oldest professor in the
department had done interferometry during his PhD thesis. His adviser, who
died before the moon landing, had done interferometry during his thesis.

Hell, I built an interferometer during my thesis. I tell myself that it's not
old hat because I was doing it with neutrons instead of photons and we had a
clever way of getting huge fluxes without drowning out our signal, but it's
also something that you can explain to a grad student in half an hour. Or an
to undergrad in ten minutes.

Anyway, I'm sure that I'm missing something here. In what area had you heard
that interferometry might be the next big thing?

~~~
InclinedPlane
There are different types of interferometry and different "waves" of
interferometry development.

The first wave started around the mid 19th century and saw the advent of lots
of new instrumentation that revolutionized science. Speed of light
measurements. The Michelson-Morley interferometry test which laid the
foundation for Relativity. Later FT-IR instrumentation. Fabry-Perot imaging.
Etc.

The second(?) wave happened in the late 20th/early 21st century and surrounded
visible light imaging, synthetic aperture interferometric telescope systems.
Most major large telescope installations built since the 1990s have
incorporated interferometric plans into them. The Keck 1 & 2 telescopes, for
example, and the Very Large Telescope array. Both were built with the idea
that interferometry systems would enable observations with "virtual"
telescopes having diameters on the order of 100m. However, that hasn't worked
out to be nearly as useful nor as practical as was imagined. The Keck
Interferometer has been mothballed due to lack of interest/funding and the
VLTI has been rarely used and has struggled to remain relevant. In fact, it's
been found that large telescopes aren't particularly advantageous for
interferometric unit telescopes.

Add to that the saga of space based interferometeric observatories, which have
so far come to naught. There was the long-planned, long-revised space
interferometry mission which was finally cancelled some years back. Then there
were several varieties of telescopic interferometer arrays or formation flying
fleets tasked mostly with detecting and observing distant planets (such as
NASA's "terrestrial planet finder" concept and ESA's "Darwin" concept along
similar lines). The idea of those was to use interferometry to both create
very high resolution imaging and also to deeply "null" the starlight of parent
stars. Over the last decade or two the limitations and difficulties of
interferometry have become more apparent and the competitive advantage of
alternate methods (such as large ground based telescopes using ordinary
coronographs coupled with adaptive optics and space-based telescopes using
coronographs) has more or less erased the promised future of interferometric
telescope arrays as a new major class of instrumentation that would open up
huge new realms of observation.

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stuartd
LEGO has come along a lot since I last played with it.

