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1500 questions
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Is the Sun in our solar system moving or stationary?
When I was small, I read that Sun is fixed at the center of the solar system and that all the other planets rotate around it.
But later I heard that even the Sun is not fixed; it moves. Is this true?
Why had people previously thought that the Sun is…
Amruth A
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What is the final destiny of a neutron star?
As I understand, neutron stars are born as extremely bright, extremely fast spinning cores of stars dying in a supernova. However, several websites tell me that within a course of a few years, the surface temperature of a neutron star falls from…
Youstay Igo
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Why is the speed of light 299,792,458 meters/sec?
Ok, I am majoring in physics (4th year) and I never understood this fundamental (kinda) question. Maybe I haven't explored it enough.
For example, why does it take 8min20sec for the light from the sun to get to us?
I know the answer to this question…
sci-guy
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What would happen if a body were to fall into a neutron star?
We know neutron stars as a very massive object with extremely strong gravitational forces that composes mostly of neutrons.
I couldn't help but wonder, what would happen if an object fell into a neutron star, what would become of it? Will it turn it…
Yoda
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How does 2015 RR245 compare to the other KBOs predicting "Planet 9"?
2015 RR245 was recently announced, in a highly eccentric orbit in the KBO. From what I understand, the so called "Planet 9" was predicted because these objects tended to be pointed in a particular direction. How is this object pointed relative to…
PearsonArtPhoto
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Do stars of a galaxy change their positions relatively to each other?
Complete astronomy noob over here who would be happy if he get a simple answer (and who is also aware that this may be not possible)...
I've learned from a tv documentary that the stars at the edge of the galaxy are not traveling more slowely than…
MarMun
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4 answers
Do all objects get larger in an "expanding universe"?
I'm envisioning an analogy of the universe as a plane with marbles in that plane to represent different planets.
Now, if this plane expands how does this work? I assume that it is not like 'nothing' becomes 'something' then but rather…
hashier
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Why aren't ground-based observatories using adaptive optics for visible wavelengths (circa 2016)?
Adaptive Optics (AO) techniques allow ground based observatories to dramatically improve resolution by actively compensating for the effects of Astronomical Seeing.
The atmospheric effects are quite variable in both time and location. A parameter…
uhoh
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What happens over time as a neutron star cools?
My understanding of a white dwarf star is that, although it hasn't happened yet due to the age of the universe, eventually as it loses energy due to radiating heat and tidal forces, it will cool to become a black dwarf - essentially a black ball of…
David Smith
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Where is all the antimatter?
The universe supposedly started off with equal parts matter and antimatter and they are said to annihilate each other. Also, nature is famous for it's balance between everything. So all we see is matter and no antimatter (I guess that's a good…
Ranveer
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Why can we observe the Cosmic Microwave Background no matter the direction we look?
I often read that the CMB was released from everywhere in the Universe, in every direction.
If that statement is true, can someone elaborate what "everywhere in the universe, in every direction" means ? If not, why can we observe it in every…
fab
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4 answers
Why do planets tend to rotate in the same direction although they have formed from tumbling asteroids?
The axial tilts of asteroids seem to vary randomly (let me know if this premise is wrong), while the planets have a strong tendency to rotate in the same way. If planets were formed by colliding asteroids, shouldn't the sum of random tilts result in…
LocalFluff
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Why argon instead of another noble gas?
I noticed that the atmospheres of Earth and Mars have a little bit of argon in them (1% to 2%). I checked Venus, too, which has 0.007% argon, but that's still more than any other noble gas in the Venusian atmosphere.
I checked the 4 outer gas…
DrZ214
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How would parallax affect an object at 200-1000 AU (for example, the 9th planet)?
We know from this question that an object is hypothesized to be at between 200-1000 AU that is large enough to detect, known now as the 9th planet. It should move about 40 arcseconds per year. It seems to me that the parallax distance would be more…
PearsonArtPhoto
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Can a star have a ring system?
I often hear about planetary ring systems, and even some moons might have them, but how about stars? Can a star also have rings?
Gstestso
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