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The lowest possible mass for a star is about 8% of our Sun’s mass. Below this, the temperature and pressure at the core are not sufficient to sustain nuclear fusion (which is what defines a star) and the object is a large gas giant (like a large version of the planet Jupiter) known as a brown dwarf. Excluding black holes, a small number of stars are known ...


3

I would go about defining a centrifugal pressure : $$ P_{cent} = \frac {F_{cent}}{A_{surf}} = \frac {m\omega ^{2}}{4\pi r} $$ Then somehow you need to find out Ultimate tensile strength,- $\sigma_{ts}$ of a planet. Which may depend on a planet chemical composition, matter phase (gas, solid, etc), temperature and other factors. Then, when you'll know ...


3

I agree with Nickolas Alves answer, and can add the following: Particle physics experiments involve many physicists, and all their names are in all the papers usually, even though some have contributed only to the technical part, and few are really experts in the particular analysis of data published. If one wants to contribute to analysis for experiments in ...


2

It is a very rare event. But they are so powerful we can detect them across hundreds of thousands of galaxies. The first detection event was from a distance somewhere around 440 megaparsecs away. https://iopscience.iop.org/article/10.3847/2041-8213/aae377 estimates that near us the rate of mergers is 1 per year in a volume of space of 14 cubic gigaparsecs. ...


2

Part of the planet of mass $m$ is attracted to the rest with a force $\frac{GMm}{r^2}$, where $M$ is the mass of the planet. To be held on, the centripetal force acting on the mass needs to be $m\omega^2 r$, where $\omega$ is angular velocity. So parts of the planet will begin to be flung off, if $$m\omega^2 r \gt \frac{GMm}{r^2}\tag1$$ $$\omega^2 \gt \frac{...


2

The Earth as seen from the near side of the Moon is about four times wider than the Moon as seen from the Earth. This still takes up a very small amount of the “sky” and still allows plenty of directions from which an object could impact the near side of the Moon. Tycho, which has a prominent central peak, is only about 100 million years old, which is fairly ...


2

So, how can we be sure that complex structure formation is not taking place or is irrelevant in neutron stars and white dwarfs, and that it does not influence the prediction of the stellar evolution of these objects? These things probably do happen in both white dwarfs and neutron stars and are the topics of contemporary research. Your question is based on ...


2

It is the object of physics to answer questions like yours. In your example, the way this is done is to collect up all the relevant laws of physics, build them into a computer simulation, run the simulation, and then compare the results with astrophysical behavior we can observe with telescopes and other instruments. If the simulation does not comport with ...


1

If the collapse is spherically or axially symmetric, no gravitational radiation is emitted. If the collapse is less symmetric than that, emission of gravitational waves will occur. The more chaotic the collapse is, the greater the energy of gravitational radiation emitted. One would expect gravitational wave to be emitted in realistic collapses. Theoretical ...


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