# All Questions

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### Is the motion of the Sun around the Galaxy a result of gravitational pull?

Does the orbit of the sun (and other stars within the Milky way) around the galaxy result directly from radial gravitational force toward the objects in the center of the galaxy, or is there ...
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### Which Planet/Star is it?

I live in north India. About 24° latitude. I can see a very Bright star in sky. Its towards east and high up. Is it Venus , Jupiter, star or anything else? Its not Sirius. I used Orion belt for that. ...
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### Would being ejected from the Milky Way Galaxy have any major impact on life on Earth? [duplicate]

I was reading about the impending collision of our galaxy with the Andromeda galaxy, and learned that there is a small possibility that our solar system could be ejected during the collision. ...
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### Why are planets round?

I was studying our solar system and all celestial objects are depicted as round objects, including black holes.. worm holes as hollow cylinders as a pathway across two universes.. even the galaxy is ...
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### Can a human land on Mercury? [closed]

Can a human in a normal astronaut suit designed for the moon, land on Mercury and walk on it's surface. If not what would happen to him/her?
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### Solar / lunar positions in ECEF using SOFA C libraries

I'd like to calculate the positions of the sun and moon in the ECEF coordinate system using the SOFA (http://www.iausofa.org/current_C.html) libraries given a Julian day input. So far, I've got this ...
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### Why is declination positive in the northern hemisphere?

Simple question -- why is declination positive in the northern hemisphere? Seems like it should've been called "inclination" since the word originated north of the equator.
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### Is the Drake equation based on a logical fallacy? [closed]

I often wonder why the Drake equation gets taken so seriously and why popular scientists in general say "it's probable' life exists elsewhere in the cosmos. My problem is that the mechanism for ...
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### Sun like star in our milkyway?

Is there any popular star or one which we can see with our naked eyes in our milky way that is atleast 90% sun-like(mass,radius,spectra,luminosity).The important thing is it must not be a binary. Its ...
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### How Soon Could a Waxing Crescent Moon Be Seen?

Question: Apart from a Solar Eclipse, How much time is needed until a Waxing Crescent Moon be seen following a New Moon? Would the time of year be significant? The Vernal Equinox + 1 Month. ...
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### Parabolic or hyperbolic trajectories

According to Newton's laws, the trajectories for the two-body problem are conics: either ellipses, or parabolas or hyperbolas. Of course periodic motions require Ellipses and in the Solar system these ...
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Imagine a photon reaching the Hubble Space Telescope today had originally been emitted from a star in the early universe 13 billion years ago. Einstein’s Special Relativity tells us, traveling at the ...
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### How big do comets get?

If my understanding is correct, Chury, the best explored comet so far is rather on the smallish side as comets go. Most comets observable with naked eye were so because they flew close to Earth, not ...
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### How does dark matter interact with black holes?

Is dark matter trapped near / in black holes, like regular matter is, or does something different happen with dark matter?
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### Could the sun burn a human floating next to it? [closed]

If a human was naked a few hundred feet from the sun, floating, with no atmosphere, not affected by the vacuum of space or UV radiation. Would the sun burn him/her? Or not have any effect?
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### Is there a map of the galaxies?

I see that there are many maps of a single galaxy, the Milky Way, showing the positions of the stars within our galaxy. I could not find a map of Galaxies, however. Is there such a map? In lieu of ...
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### Is it possible to know if a planet is located in the Habitable Zone knowing it's properties?

Is there an equation that can give me the possibile distance of the planet from his star knowing planet's temperature (or other datas)? I found this method for calculating the Habitable Zone but ...
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### Cluster of fast moving stars

We live in NW Tasmania in a country town and tonight out walking I pointed out a long cluster of stars to my sister as they made an unusual shape but then we realised they were moving really fast - we ...
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### Do accretion disks of black holes generate magnetic fields? [duplicate]

When a black hole's accetion disk rubs against each other it creates a static charge . Since the disk is in continual motion does it give rise to a magnetic field?
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### Is there a strict chronological order that determines the shape of galaxies?

Assuming no collision happens, do all elliptical galaxies eventually become spiral? also when a galaxy becomes spiral or barred spiral, can it switch between these shapes or is it set forever?
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### Declination change due to precession

I have this problem: I want to calculate the declination of the star in the year 5000. And I know RA (right ascension) and Dec (declination) of the star right now. How can I calculate it using ...
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### Can we apply Kepler's law of planetary motion to the moons motion around the earth?

I have been trying to understand Kepler's law of planetary motion for a while. So I was thinking, if it would even apply to the moon orbiting around the earth. Does the moon too orbit in an ellipse ...
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### Approximate distance from Earth to Mars at a given moment with reasonable (+/-100km) accuracy?

I've been scouring the internet for a straightforward way to approximate the distance between Earth and Mars at a given time. I hope to achieve an accuracy of about 100km.
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### Use every of our TV dishes as a radio-telescope?

Does anyone knows if it were possible to use all the ground bases TV dishes lots of people have on their homes be usable as a radio-telescope if we put all of them together? Would this have any ...
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### State vectors of “interesting” multiple stars

I'd like to show a demonstration of Runge Kutta integration of real systems using examples of interesting multiple stars, where "interesting" means you can see through a small telescope that they are ...
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### Why is the universe full of spinning objects?

Almost all celestial objects are rotating in some way about their axes. Why is this and should we expect the rotation to slow as the universe ages?
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### Pyramid shaped observatories

There are some pyramid shaped observatories around the world, like the Solar Lab Pyramid (1) in the Canary Islands or The Pyramid International Laboratory (2) in Nepal. (1) (2) I was wondering, ...
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### Why does the eclipse in this video look annular?

In this article about the AS870 flight that flew through the umbra of the March 8-9 2016 solar eclipse, there is a link to a YouTube video showing the eclipse recored by a handheld camera in the ...
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### Does Pi change when gravity changes [closed]

Will Pi have the same value on the surface of say Jupiter, compared to the value of PI on Earth. Or does Pi vary with gravity?
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### How to determine the mass of a runaway star?

I would like to know how do astronomers estimate the mass of a star that has been ejected from its galaxy. What kind of accuracy can be achieved?
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### How does gravity affect spacetime [closed]

Scientists say that gravity warps space and time. They also say that the more gravity there is the slower time moves. Why and/or how does gravity do this.
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### Light that travels eternally because of inflation?

What happens with electromagentic waves that are emitted into intergalactic space, but reach not any object because of inflation? Lets assume that photon A and photon B are emitted. Photon B hits ...
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### Are all the photos of the universe really so colorful or is it just visual effects that are added later?

Do the colorful pictures of the universe show how it looks like that in reality or is it just a visual effect that is added later.
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### What are the 10 most abundant elements in the universe by number of atomic nuclei?

I've seen websites that show the ratios of the 10 most common elements but they compare them by relative mass. I think it's more interesting to know the relative abundances of atomic nuclei because ...
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### How could a neutron star collapse into a black hole?

White dwarfs usually do not collapse, as they have electron degeneracy pressure due to the Pauli exclusion principle. However, if one accretes mass beyond the Chandrasekhar limit, it is energetically ...
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### Obtain tangent point (origin) of the Standard Coordinates system

In a previous question (Transform pixel coordinates (in FITS file) to equatorial), Rob supplied a great source that describes the process of obtaining celestial coordinates for objects in an observed ...
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### What's the proper terminology for nebula clouds?

I'm writing a research paper over outer space (yeah, yeah, broad topic) and I'm wondering what the proper terminology for nebula clouds is. This is an excerpt from my paper showing how I'm going to ...
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### Measuring star distance by parallax using a small telescope

I was wondering if it's possible to measure star distance using parallax at home with a small telescope (Something like a 3-inch reflector)? Or is this not really practical?
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### What is the distribution of organic compounds in the Milky Way Galaxy?

I imagine the answer is unknown for the entire galaxy, but I'd appreciate a notion of the scales and locations of regions where astronomers have ventured at least a guess as to the distribution of ...
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### Transform pixel coordinates (in FITS file) to equatorial

Say I have a FITS file with an observed field of stars, each one with x,y coordinates given in pixels. Assume the image is aligned so that the x axis is the right ascension, and the y axis the ...
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### Can we find rocks from Venus or Mercury on Earth?

As we know, we can find rocks from Mars on Earth, how about Venus and Mercury? Is that not found yet? Or it is impossible to find them because they are closer to the sun and derbis won't go far away ...
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### Why is space and time spoken of as one thing

I've never understood why it's spacetime and not space and time. In other words why aren't space and time spoken of as two different things. Can someone explain to me why this is
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### Create a Signal over Noise map from heatmap

Recently, I obtained my heatmap from a sky survey. But now, I'm trying to get a "Signal over Noise" map from my heatmap. My heatmap looks like : My colour bar indicates the number of stars per ...
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### Does conservation of energy make black holes impossible?

I was musing today about black holes, and came across what seems to be a contradictory fact about black holes. If any matter were to actually fall into a black hole, it seems like it would need to ...
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### How does gravity really work

I am only 12 years old and I'm constantly wondering and trying understand how gravity really works. On YouTube everyone always talks about objects warping space time around themselves and uses the ...
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### Equation of the Center constant factor

This questions concerns the longitudinal aspect of the Equation of Time, also called the Equation of the Center. In some sources the equation looks like the following: $\nu - M = 2\varepsilon \sin M$ ...
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### How can a low-mass star increase its mass to 1.4 Msun? [closed]

In my astronomy class I learned that a only low-mass stars (< 0.5 Msun) will contract, and then become degenerate, until it is a white dwarf. However, we also learned about the Chandrasekhar limit, ...
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### When Phobos collides with mars (or breaks up), will it have any noticeable effects on Earth?

When Phobos meets its predicted doom in a few 10s of millions of years, whether it breaks up or collides with the surface of Mars, will this change have any noticeable effects (permanent or temporary) ...