PDA

View Full Version : Hmmmm...that's funny.



trinitree88
2017-May-01, 02:02 PM
The background noise that's referred to as Earth's Hum...is characterized by the author, as emanating from Sag A, and a likely companion. Hmm, interesting.
SEE:https://arxiv.org/abs/1704.08983 pete

Squink
2017-May-01, 11:01 PM
GRASERs from the galactic core?

Cougar
2017-May-01, 11:26 PM
Abstract: A number of earth’s tremor spectral peaks show a persistent narrow bandwidth incompatible with any geophysical or instrumental origin. These peaks, located at frequencies lower than a few mHz, are in principle consistent with the earth strain waves induced by monochromatic gravitational waves. Exploring this hypothesis under the current cosmological constraints yields that the tremor peaks below 2 mHz are in apparently significant coincidence with the theoretical emission of two binary systems each consisting of a small main sequence star with mass ∼ 10−1 M⊙, captured by Sgr A* in a close orbit.



In other words, first, this signal might result from certain gravitational waves;
then, such waves could come from a couple of small stars in particular orbits around Sgr A*.

Seems to be some precarious cogitating going on here. :razz:

BigDon
2017-May-03, 03:58 PM
Can somebody define monochromatic as it's used here?

01101001
2017-May-03, 05:46 PM
Can somebody define monochromatic as it's used here?

Single frequency. Just like monochromatic visible light.

publiusr
2017-May-05, 06:04 PM
This will be on Coast to Coast AM for sure.

BigDon
2017-May-05, 08:07 PM
Single frequency. Just like monochromatic visible light.

Thank you 110. I guess that's what I asked for.

But as I am no further enlightened than I was before, can somebody explain "monochromatic gravity waves from Sagittarius A" then?

Shaula
2017-May-05, 08:34 PM
Thank you 110. I guess that's what I asked for.

But as I am no further enlightened than I was before, can somebody explain "monochromatic gravity waves from Sagittarius A" then?
Essentially any system capable of radiating gravitational waves that has a minimal inspiral (so the components are not getting closer to each other quickly as was the case for the black hole mergers detected with LIGO) will radiate gravitational waves over a narrow frequency range (hence monochromatic). The claim in this article is that the narrowband components of the hum are due to such a system, and identifies some near SagA that he believes are a good fit.

The animation here (https://en.wikipedia.org/wiki/Gravitational_wave#Astrophysics_implications) shows an example of this - two neutron stars in orbit generating a fairly simple, single frequency, gravitational wave.

The animation here (https://www.ligo.caltech.edu/page/what-are-gw) shows a system with inspiral evolving from a fairly monochromatic/single frequency emitter to a 'chirping' emitter as they merge.

BigDon
2017-May-05, 09:09 PM
Wow.

That wasn't so painful after all.

Thank you Shaula. I'm enlightened. (But not quite illuminated yet. :))