8

No they didn't. The deduction that (very) heavy elements are being produced is somewhat indirect and involves creating a theoretical model of the expanding "fireball" and comparing that model against measurements of brightness vs time at a range of wavelengths and against spectra (mostly in the infrared) as the afterglow faded. Normally, when we view a ...


6

I think it is generally expected that the merger of two neutron stars will lead to the formation of a black hole. What is more uncertain is whether that black hole forms straight away, or an intermediate state of a hyper(/supra)massive neutron star forms (see, e.g. Sec IIC of Hotokezaka et al, PRD, 044026, 2013 for a definition of hypermassive and ...


4

Any of these phenomena would be visible to the naked eye if they occured in the Milky Way, or a neighbouring galaxy (such as the Magellanic clouds) and was not obscured by dust. At the distance of stars, all of these would appear star-like. Supernovae have been seen, most recently in 1987, when there was a supernova in the Large Magellanic cloud. It had a ...


4

WD+NS collision cannot leave nothing behind. Gravitational mass defect of NS is ~10% of its rest mass -- thus whatever energy released in the collision cannot disrupt the NS. The energy released is basically the nuclear energy of the WD material burning into heavier elements as it gets heated in the process of collision. That amounts to at most ~0.2% of the ...


3

This is a kind of silly question because you are dealing with object (stars, etc) that cannot exist in an atmosphere so treat the whole below as a bit of a lark. The decibel scale is logarithmic. 120 dB is one joule of sound energy. 130 Joules is ten times more: 10 Joules, 140 is 100 Joules etc. (Source) The loudest sound on Earth is said to be Krakatoa at ...


2

When two neutron stars collide, the resulting supernova is called a "kilonova," producing much more energy than a regular supernova. Additionally, heavier elements are formed, such as gold, platinum, etc. Other effects of this collision include a gamma-ray burst and/or gravitational waves. The object formed after the event can either be a heavier ...


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