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1500 questions
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Why isn't Earth a perfect sphere?
In general, almost everyone describes Earth as an perfect sphere, but in reality it isn't a perfect sphere.
Is there any specific reason why Earth is not perfect sphere ?
Hash
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Is the initial gravity of the black hole the same as the mass of the object that created it?
Is the gravity of a black hole the same or more than the original star that created it, before the black hole gets more matter? Is the gravity proportional to the initial mass?
Solo Man
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Daylight hours on Titan?
I still cannot seem to wrap my head around Titan's day and night based off of math. From what I understand, Titan has a day of 16 earth days (384 hours) in which it circles Saturn once (its day and also 1-year orbit around Saturn). But during one…
StarbuckM
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How close to escape velocity are most Oort-cloud comets?
User @antlersoft wrote a nice answer to my question on the difference between barycentric and heliocentric models of the solar system when applied to comets (edge cases of the systems). In a comment, @DavidHammen mentions that
Planetary…
WarpPrime
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What rotational speed would Mercury need to have to achieve a temperature comfortable for humans
I wondered what rotational speed would Mercury need to have to achieve a temperature comfortable to humans, let's say 20 °C.
EDIT:
My idea was that if Mercury is so cold on the night side and so hot in the daylight then if it rotates fast enough…
Piotr Golacki
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How do we know that objects that appear in duplicate or triplicate, etc. due to strong gravitational lensing aren't actually multiple objects?
If we are looking at faraway objects, there is no parallax view, correct?
So isn't there a chance that an object that appears multiple due to strong foreground gravitational lensing is actually several distinct objects?
Kurt Hikes
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How big would a telescope have to be to get a good look at the nearest neutron star?
It's my understanding of observational astronomy that the size of a telescope limits its effective angular resolution, which is why scientists needed to use radio telescopes all over the globe to look at the M87 black hole and Sagittarius A*.
For…
zucculent
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If a satellite is put into the same orbit of the Sun as Earth, how does it avoid hitting Earth?
If a spacecraft follows literally the exact orbit of Earth at a different speed to Earth then why doesn't it hit Earth at some point? I'm specifically thinking about this in relation to these spacecraft but I'm also interested in it more…
Jules
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Is Jupiter warming the Earth? (Earth, Sun Jupiter system)
If Sun-Jupiter baricentre is outside the Sun, does that mean the Sun is orbiting around that point too right?
Then the Sun shouldn't be nearer to the Earth at some point during the Sun-Jupiter orbit (and also farther at the opposite…
Enrique
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Hypothetical upper and lower bounds for Chandrasekhar limit based on composition?
Disclaimer: I'm going to be using the term "white dwarf" to refer to any spherical celestial body made of electron degenerate matter. If I had a better term, I would use it.
The Chandrasekhar limit for white dwarfs can be approximated with the…
zucculent
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Is the barycenter of the solar system usually outside of the sun?
I came across this picture on wikipedia:
Note: From a quick search I gathered that although there are slight differences between the limb of the sun and the accepted radius of the sun, these differences are rather tiny (~330km if I'm interpreting…
eps
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How can a black hole have a charge, or be charged?
So-called 'hairless' black holes (no-hair theory, or theorem?) , which is what real black holes are, can be described by just three characteristics: Mass, spin, and charge.
It is easy enough to contemplate size and rotation, but what made…
Kurt Hikes
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12
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Black Holes: More Than One Entry Point?
Most animations and drawings of Black Holes that I've seen usually depict some kind of funnel which is the "entrance" to the black hole; let's call this the front.
Are there more than one way to enter the Black Hole, such as the back side (180…
Thomas Matthews
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Why do sunspot rise in number "precisely" every eleven years?
Every eleven years (more or less precisely) sunspots are seen to rise in numbers. The magnetic field of the sun changes polarity over eleven years and this is the reason the number of spots can vary. But I'm not sure I understand why a flip occurs.…
Deschele Schilder
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Will Starlink deface the night sky?
There is some discussion (and there are some questions on this site) about the impact of Starlink on observational astronomy. I am not an astronomer, but I am amazed by the beauty an immensity of the night sky.
Must I be concerned, from an…
henning
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