Questions tagged [density]

Question 1

While looking for a parameter that represents the extent of a star cluster, I came across the King core radius ($r_c$). However, even after reading papers, I still don’t understand it. What does the ...

Question 2

Would matter stolen from the center of a planet like Jupiter be very hard or would it be soft or brittle or extremely tough? Could you use it for anything?

Question 3

Let say you were to teleport on earth 1 tonne of material from the center of Jupiter what would happen to this object density? Would it expend or stay the same? If it does expend does it disperse lot ...

Question 4

Starting with the continuity equation $$\frac{\partial \rho}{\partial t} + \nabla_r(\rho \vec{u}) = 0$$ making those substitutions. $$\nabla_r = \frac{\nabla_x}{a}$$ $$\rho(\vec{x},t) = \bar \rho(t)[1 ...

Question 5

There is a Fourier transform that I don't really understand in my textbook (p.218). I have the following equation: $$\ddot{\delta} + 2H\dot{\delta} -\frac{3}{2} \Omega_m H^2 \delta = 0 $$ Then using ...

Question 6

Theoretically, there could be a rogue planet made of iron or even osmium in large quantities, which can make it have 25 Earth masses within the volume of 1 Earth Radii. So if this object came near ...

Question 7

As far as I know, the critical density of our observable universe coincides with the density of a huge black hole of the same radius. It could be a BH expanding at the speed of light and growing in ...

Question 8

I have a question about planetary cores and their relation to the magnetic field. Around how massive (using this in the sense of mass, not size, for clarity) does a core need to be in relation to the ...

Question 9

Let's say we compare two elliptic/spiral galaxies with the bigger having a diameter 100 times the smaller. Now we count every separated object inside them and classify them into mass categories e.g. $...

Question 10

I want to recreate the figure . This comes from the Cosmological Boltzmann equation which can be modified as the number density equation as $$\frac{dY}{dx}=-\frac{s(m)<{\sigma}|v|>[y^2-Y_{eq}^2]}...

Question 11

Question Given the theorized exceptional formation of Luna, (Giant-impact Hyphothesis, Wikipedia), are there any similar animated models of how the other, much smaller, moons in our solar system ...

Question 12

In the solar neighborhood the stellar number density is about 0.14 stars per cubic parsec. This changes with a length scale of 220-450 pc as we move up or below the Milky Way disc, and 2.6 kpc ...

Question 13

What about astronomical observations makes scientists believe our universe is flat, at least as far as they can tell? Despite the critical Friedmann density being less than one, plus the existence of ...

Question 14

Is is true that the smaller a 'regular', stellar-mass black hole is, the denser it is inside of its event horizon? After all, if you look up (or calculate) the Schwarzschild radii of the Sun and the ...

Question 15

“Overdense" and "underdense" often appear in various documents to refer to high density and low density respectively. And I know that "overdensity" is defined as $$ \delta(x)=\...

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Questions tagged [density]

What is meant by the 'King core radius'?

Would the matter at the center of a planet like Jupiter be hard? [closed]

What happen if you were to take matter from the core of a gas giant and put it on earth how would its density be affected?

Newtonian theory of small perturbations: Continuity equation

Fourier transform of the density fluctuation

If a rogue planet entered near Jupiter planet could it tear the planet apart?

Is there evidence against a Universe Black Hole?

Question about the core mass fraction of planets and its relation to the magnetic field

Is the object mass distribution different for galaxies of different diameter?

How to plot the freeze out equation for massive particle species in Mathematica? [closed]

Besides Luna, are there any models of how moons become spherical and round?

What is the sharpest stellar number density variation known?

If the ratio of actual total mass to critical mass (Ω) in the universe is only about 0.3, why do cosmologists believe it is flat, as far as we see?

Does the density of a black hole decrease after releasing a large amount of Hawking radiation?

What do "overdense" and "underdense" mean in cosmology?

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