My dad told me this the other day and, if it is true, it seems like a remarkable fact. I haven't been able to support it with anything other than that the galactic plane is roughly 63 degrees and earth's axial tilt is roughly 28.5 degrees, which is nearly orthogonal if both tilts were in the same direction.
Yet another way to word is if January 1st occurs in the same position relative to a hypothetical fixed point on the sun.
I have two questions about the interactions of black holes with dark energy.
How does expanding space work inside black holes? Most are rather small so I would imagine that the effect is negligible but if we consider a black hole with a radius of 5 billion light years where the expansion of space would be significant. Would an object falling through such a black hole take a longer time to reach the singularity due to said expansion? Any noteworthy effects?
Additionally, can black holes grow in mass and size from dark energy? I've read that the density of dark energy is 7 *10-30 g/cm3, could there be a point where a black hole of sufficient size gains more energy from this than it loses due to hawking radiation and thus keeps growing forever?
Obviously, any such definition would be mostly arbitrary... but I feel that such standardization would be necessary especially as we start exploring other astronomical bodies.
I'm sure that for our own solar system, we probably just designate the side of the ecliptic plane with Earth's North on it as the "North side"..
But what about something like Uranus whose rotation is basically perpedicular to the plane?
What about other star systems? How would we determine, for example, Proxima Centauri B's North Pole?
This question has gotten me very confused since sometimes I’ve heard as little as 15 solar masses or as much as 20. One scenario puts a star like Rigel (17 or 18 solar masses) in a situation where it will become a black hole and the other just leaves it as a neutron star or magnetar at most.
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