Changes

#:

#:

#''Despite wasting millions of taxpayer dollars searching for gravity waves predicted by the theory, none has ever been found.  Sound like global warming?''

#''Despite wasting millions of taxpayer dollars searching for gravity waves predicted by the theory, none has ever been found.  Sound like global warming?''

#:True, the ''direct'' searches for gravitational waves have not yet yielded any clear results, though indirect observations have been made (the Hulse/Taylor observations.)  Before people dismiss indirect observations, recall that no one has ever seen an electron.

#:True, the ''direct'' searches for gravitational waves had not yet yielded any clear results at the time that item was written (September 2012), though indirect observations had been made (the Hulse/Taylor observations.)  Before people dismiss indirect observations, recall that no one has ever seen an electron.

#:The Earth-based LIGO detectors have, so far, not detected any unambiguous gravitational wave signatures from such events as a black-hole merger.  It is barely sensitive enough to find such things in the Milky Way or very nearby galaxies.  It is being upgraded in a plan that should complete in 2014.  It is hoped that, after the upgrade, it will be able to see these events clearly and unambiguously.

#:The Earth-based LIGO detectors had, at that time, not detected any unambiguous gravitational wave signatures from such events as a black-hole merger.  It was barely sensitive enough to find such things in the Milky Way or very nearby galaxies.  It was upgraded in a plan that completed in 2014.  It was hoped that, after the upgrade, it would be able to see these events clearly and unambiguously.

#:The space-based LISA detectors have not been built yet, and the original proposal has been scrapped because of budgetary problems.  A new version, called "eLISA" has been proposed, and should be sensitive to events as far away as redshift 15.

#:The space-based LISA detectors have not been built yet, and the original proposal has been scrapped because of budgetary problems.  A new version, called "eLISA" has been proposed, and should be sensitive to events as far away as redshift 15.

#:Whether these experiments are a good use of money is another question, one that has no bearing on whether relativity is correct.

#:Whether these experiments are a good use of money is another question, one that has no bearing on whether relativity is correct.

#:::The results are only partly negative.  The scientists knew all along that a certain amount of luck would be involved in finding a sufficiently strong signal within the time frame of the experiment.  The failure so far does not mean that black-hole mergers do not emit gravitational waves; just that they haven't been lucky enough to find them.  They will continue to search.

#:::The results are only partly negative.  The scientists knew all along that a certain amount of luck would be involved in finding a sufficiently strong signal within the time frame of the experiment.  The failure so far does not mean that black-hole mergers do not emit gravitational waves; just that they haven't been lucky enough to find them.  They will continue to search.

#:'''Update:'''  Another, much more commonplace observation of gravitational wave emission has been reported.<ref>http://www.bbc.co.uk/news/science-environment-19408363 BBC article</ref>  The article suggests that, since it shows detectable gravitational waves are more common than previously thought, there is optimism that the eLISA detector, when completed, might find one source per week.

#:'''Update:'''  Another, much more commonplace observation of gravitational wave emission has been reported.<ref>http://www.bbc.co.uk/news/science-environment-19408363 BBC article</ref>  The article suggests that, since it shows detectable gravitational waves are more common than previously thought, there is optimism that the eLISA detector, when completed, might find one source per week.

#:

#:

#:'''Update 2:'''  Gravitational waves have been detected directly through LIGO: the Laser Interferometer Gravitational-Wave Observatory.

#:'''Update 2:'''  Gravitational waves have been detected directly through LIGO: the Laser Interferometer Gravitational-Wave Observatory.

#:

#:

#:First detection on 14 September 2015. See LIGO Scientific Collaboration and Virgo Collaboration, "Observation of Gravitational Waves from a Binary Black Hole Merger," Physical Review Letters, 116, 061102 – published 11 February 2016.

#:*First detection on 14 September 2015. See LIGO Scientific Collaboration and Virgo Collaboration, "Observation of Gravitational Waves from a Binary Black Hole Merger," Physical Review Letters, 116, 061102 – published 11 February 2016.

#:

#:

#:Second detection on 26 December 2015 (the "boxing day event").  See LIGO Scientific Collaboration and Virgo Collaboration, "GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence," Physical Review Letters, 116, 241103 – published 15 June 2016.

#:*Second detection on 26 December 2015 (the "boxing day event").  See LIGO Scientific Collaboration and Virgo Collaboration, "GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence," Physical Review Letters, 116, 241103 – published 15 June 2016.

#:

#:

#:Third detection on 4 January 2017.  See LIGO Scientific and Virgo Collaboration, "GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2," Physical Review Letters, 118, 221101 – published 1 June 2017.

#:*Third detection on 4 January 2017.  See LIGO Scientific and Virgo Collaboration, "GW170104: Observation of a 50-Solar-Mass Binary Black Hole Coalescence at Redshift 0.2," Physical Review Letters, 118, 221101 – published 1 June 2017.

#:

#:

#: So, in this respect, gravitational waves ARE like global warming: both are true, verified, factual phenomena, which exist whether or not any particular person wants them to exist.  As John Adams pointed out in 1770, "Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts."

#: So, in this respect, gravitational waves ARE like global warming: both are true, verified, factual phenomena, which exist whether or not any particular person wants them to exist.  As John Adams pointed out in 1770, "Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts."