1. I read in an article announcing the detection of gravitational waves by LIGO that it will be possible to detect them from the Big Bang. Is this true?
  • $\begingroup$ What article is this? Please put a link. $\endgroup$ Feb 11 '16 at 21:45
  • $\begingroup$ @SirCumference There's a reference to the beginning of the Universe in this article though it seems like a science writer than an actual physicist answered it msn.com/en-in/news/techandscience/… . There's another one about an earlier claim about gw from the Beginning that was proved false: washingtonpost.com/news/achenblog/wp/2014/09/22/… $\endgroup$
    – signsgeek
    Feb 15 '16 at 23:08

Gravitational waves from the big bang may be "heard" but not by LIGO. The waves emitted at or around the inflationary epoch of the big bang are expected to be at much lower frequencies (milli-Hz or lower) than those announced today by LIGO. There are various sources of noise that make LIGO insensitive to GWs at frequencies below about 10 Hz.

It will take space-based interferometers like the proposed LISA, with longer interferometer arms and well away from terrestrial sources of noise to stand a chance of detecting such GWs.

If they are detected - they might "sound" something like this (if upshifted into the audible range) - from the LIGO website. It sounds like white(ish) noise because of the broad continuum of frequencies expected.

  • $\begingroup$ By mHz, you mean milli-Herz? $\endgroup$ Feb 13 '16 at 2:07
  • $\begingroup$ Yes he means mili-Herz $\endgroup$ Feb 13 '16 at 9:25
  • $\begingroup$ @wayfaringstranger Yes. $p$ pico, $n$ nano, $\mu$ micro, $m$ milli, $k$ kilo $M$ mega, $G$ giga, $T$ tera. $\endgroup$
    – ProfRob
    Feb 13 '16 at 9:25
  • $\begingroup$ Actually I mean milli-hertz. ! $\endgroup$
    – ProfRob
    Feb 13 '16 at 9:28
  • $\begingroup$ @RobJeffries I added a "duplicate" question that I probably should have just added here, but it is a little different. It was about the locality of the signal. LIGO detected gravitational waves from a localized source. Wouldn't Big Bang GW come from "everywhere"? How would this effect detection? $\endgroup$ Feb 13 '16 at 15:59

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