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This article makes a number of incorrect statements. First of all, all observed FRBs so far are at cosmological distances, well outside the Milky Way. Second, e
by dsqrt 10y ago
This article makes a number of incorrect statements. First of all, all observed FRBs so far are at cosmological distances, well outside the Milky Way. Second, even before the discovery of a repeating source, neutron star collisions have already been ruled out as being a primary source of FRBs because of their rate. Only a very small fraction of neutron stars collide with another neutron star or black hole in the lifetime of the Universe (of the order of 1 every tens of thousands). On the other hand, the FRB rate inferred from the observations is around several percent of the core-collapse supernova rate, ie, the rate at which neutron stars are formed.
EDIT
Also the energy estimate given in the article are way off. The energy released by FRBs are of the order of what the Sun emits in 1 year not 1 day (assuming that FRB emit energy isotropically and that the distances estimated from the dispersion measurement of FRBs are correct).
- Animats 10y agoThe energy released by FRBs are of the order of what the Sun emits in 1 year not 1 day (assuming that FRB emit energy isotropically and that the distances estimated from the dispersion measurement of FRBs are correct). Each burst lasts only a few milliseconds. What does the energy consumption look like assuming the FRBs emit RF directionally and aim at plausible targets in their sky? That's what an attempt to communicate would probably do.
- dsqrt 10y agoThe energy requirements are proportional to the beaming angle, so if we assume FRBs to be beamed, then the energy required decreases significantly. For example assuming a beam of 10 deg^2, this would give a reduction of a factor 648.
- Animats 10y agoAssume the sender has an antenna at least as good as Arecibo. That antenna has a beam width of 4 minutes of arc.[1] That's 0.066 degrees, or about one ten millionth of the sky. So you get to divide the power requirements by 10^7. [1] http://egg.astro.cornell.edu/alfalfa/ugrad/backgrnd/intro2arecibo.pdf http://egg.astro.cornell.edu/alfalfa/ugrad/backgrnd/intro2ar...