B Shapes and gravitational radiation

AI Thread Summary
A perfect sphere does not emit detectable gravitational radiation because it lacks spherically asymmetric motion, which is necessary for gravitational wave production. In contrast, an ovoid or deformed body can create a changing quadrupole moment, leading to the emission of gravitational waves. Spinning neutron stars typically remain nearly spherical due to their dense mass, but minor surface deformations can introduce asymmetry and generate detectable gravitational radiation. The mechanism for this emission relies on the presence of a changing quadrupole moment, which a simple spinning sphere does not possess. Understanding these principles is crucial for detecting and studying gravitational waves.
wolram
Gold Member
Dearly Missed
Messages
4,410
Reaction score
555
IIRC , a perfect sphere will not be detectable with a gravitational detector, but an ovoid shaped body will, why is this so? or am i wrong.
 
Space news on Phys.org
wolram said:
IIRC , a perfect sphere will not be detectable with a gravitational detector, but an ovoid shaped body will, why is this so? or am i wrong.
Why do you think what you think?
 
I found this on wiki
Vhttps://en.wikipedia.org/wiki/Gravitational_wave#Rotating_neutron_stars

As noted above, a mass distribution will emit gravitational radiation only when there is spherically asymmetric motion among the masses. A spinning neutron star will generally emit no gravitational radiation because neutron stars are highly dense objects with a strong gravitational field that keeps them almost perfectly spherical. In some cases, however, there might be slight deformities on the surface called "mountains", which are bumps extending no more than 10 centimeters (4 inches) above the surface,[45] that make the spinning spherically asymmetric. This gives the star a quadrupole moment that changes with time, and it will emit gravitational waves until the deformities are smoothed out.
 
So it seems you have answered your own question.
 
phinds said:
So it seems you have answered your own question.

No, I do not understand the mechanism for the production of gravitational radiation.
 
Last edited by a moderator:
In order to have gravitational radiation, you have to have a changing quadrupole moment of the field. A simple spinning sphere won't have that.
 
  • Like
Likes wolram
Abstract The Event Horizon Telescope (EHT) has significantly advanced our ability to study black holes, achieving unprecedented spatial resolution and revealing horizon-scale structures. Notably, these observations feature a distinctive dark shadow—primarily arising from faint jet emissions—surrounded by a bright photon ring. Anticipated upgrades of the EHT promise substantial improvements in dynamic range, enabling deeper exploration of low-background regions, particularly the inner shadow...

Similar threads

Back
Top