# All Questions

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### Is black hole solely responsible for hyper velocity stars?

I read that the stars orbiting around Sagittarius A a.k.a supermassive black hole located at the heart of milky way galaxy moves very fast(many times faster than our Sun across the galaxy) and it is ...
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### What are the most popular computer programming languages in observational astronomy?

I would like to work in the field of observational astronomy (not so much theoretical astronomy). I currently know two computer programming languages: C# and MATLAB. I have read that computer ...
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### Can recession rate denotes the age of galaxy?

Since the universe came into existence and matters is formed much later on, the space have been expanding ever since and by measuring the Doppler shift(to calculate the rate of space expansion) ...
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### Why is there no green stars?

So there's red stars, and orange stars, and yellow stars, and blue stars, and they are all good save the fact that there is a 'gap': THERE IS NO GREEN STARS. Is this because of hydrogen's chemical ...
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### Magnetar and black hole

What would happen if a magnetar and a black hole got close to each other?
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### How to calculate position of an unknown star knowing positions of some other stars from an image?

Suppose I know the coordinates (right ascension and declination) of the stars marked with red. How should I calculate the coordinates of an unknown star, marked with yellow? Searching over the web, ...
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### Examples of Equal Mass, Unequal Mass and Double Binary Star Systems

Can anyone give me an example of a star (ideally those with a common name e.g. Rigel, Sirius, etc) of the following multiple star systems. Equal Mass Star System, where two binary stars orbit round a ...
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### What are quasars?

What are quasars? Is there any difference between quasars and normal stars like our sun? How long will they live? When a quasar dies, will it be a black hole or a massive explosion? How strong is its ...
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### Astronomical databases for machine learning?

I was reading this question about open problems in astronomy. The bounty-receiving answer says that I have just left the field where some colleagues are trying to develop some software to use ...
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### Is there a legend for these 88 HST images?

Is there a legend for these 88 Hubble Space Telescope images? I have a 6000px x 4800 px version of this image (reduced & rotated to 480x600 here) that I use for an image slide show. I would ...
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### How much mass will the white dwarf sun have compared to our current sun?

In 4 billion years, when our sun sheds all of it's outer gas layers and turns into a white dwarf, how much mass will the white dwarf have compared to what the sun has today? Will the planets still ...
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### Variable and Multiple Stars in Hipparcos

Is there any way I can tell from Hipparcos catalog which stars are Binary/Multiple Stars and which are Variable stars?
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### If we built one hundred 3m telescopes and point them to a single star what would be the final resolution?

We'll mount all of them in a same location and connect them to each other (like VLT) so they will combined all the results and will produce some staggering images however my question is, would they be ...
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### Years, Months, Day, and Weeks?

Sorry if this is a basic question. 1 year = earth revolution around the sun 1 month = moon revolution around the earth 1 week = 7 days = ??? 1 day = earth rotation about its axis Why do we ...
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### How to calculate magnitude of a star in a triple star system?

I want to find a star's magnitude in a triple star. I already knew the the magnitude of the triple star and the other two star, but I don't quit know how to solve it. Is there a way to find it?
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### Does the Sun's light travel fast enough to have a straight path to Earth?

Hopefully this question isn't too silly. When we travel through space, we use a curved path following an orbit to reach our destinations. As far as I'm aware, we could take a more straight line ...
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### The fastest Probe we could build now

I found this at http://www.nature.com/news/the-exoplanet-next-door-1.11605 Even when launched by one of the most powerful rockets on Earth, boosted by a gravitational slingshot around Jupiter, ...
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### Do neutrinos have as much information as photons do?

If neutrino detectors keep improving so that a fair number of neutrinos can be observed, would they be as informative for astronomy as photons are? They are of course a very valuable complement to ...
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### How to differentiate between images of a gravitationally lensed object

The light coming from a distant galaxy or star can be distorted en route to Earth; this distortion is caused by the curvature of space when a massive object is present. My question is, how can we tell ...
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### Wouldn't the rings of Saturn experience tidal effect?

The "Lord of the Rings" has more than 60 moons, some of which are larger than Mercury. My question is, wouldn't the ring, which is mostly comprised of rocks, experience tidal effect whenever a moon is ...
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### What kind of scientific goals can we make if we send astronaults to the Moon today? [on hold]

Compared with Project Apollo, we have better instruments now. What kind of big discoveries are necessary to be made with the operation of a human being on the surface of the Moon?
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### What happens to the Gas Pressure when working out the Eddington Luminosity?

I am looking at how the Eddington Luminosity is derived and I do no understand why we only care about $P_{rad}$? When working out $L_{Edd}$ you take the ratio between $dP_{rad}/dr$ and ...
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### Time according to the gravity of Sagittarius A?

This may be a really dumb question (I'm more of a Biologist than an Astronomer) so I apologize in advance for my little knowledge pertaining to Astronomy, but, if I'm not mistaken, time is effected by ...
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### Why does Earth have more gravitational force than the Moon if I stand on it?

Perhaps this is a silly question but I am trying to understand Einstein's general theory of relativity. I would like to explain my question in more detail. The greater the mass of an object, the ...
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### Is there Dark Matter inside the Earth?

Since Dark Matter is assumed to interact gravitationally, it follows that the gravitation of massive regular matter bodies should have an effect on it. Even if it is otherwise weakly interacting with ...
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### How Does Black Hole Evaporation Look From the Inside?

Imagine you're inside a black hole event horizon. The curvature of spacetime is such that the direction towards the singularity becomes timelike, as reverse movement becomes literally impossible. How ...
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### Abundances of chemical determinations can be made from these observations cited bellow? [on hold]

Radial velocities of stars and galaxies are obtained from observations made with spectrographs. Abundances of chemical determinations can not be made from these observations instruments. Am I right?
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### Can stars be observed from space by x-rays, near infrared and radio wavelengths? [on hold]

I have a doubt. Can stars be observed from space by x-rays, near infrared and radio wavelengths?
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### Is the universe like the earth?

Is the universe much like the earth, in that if I were to travel in one and only one direction, I'd eventually end up where I started from?
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### why does venus flick?

I was watching Venus with the naked eye yesterday at about 7 pm and I noticed that it was flickering, almost like a star. I have always learned that planets don't flicker to the naked eye, only stars ...
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### Spectral analysis of AGN (velocity dispersion of galaxy absorption, doppler shifts)

I was wondering what parameters I need to know/measure to calculate the velocity dispersion of a galaxy, specifically an AGN. Also, I have spectra where there are blueshifted and redshifted ...
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### How was all the matter curled up inside a singularity during big bang ?

If the singularity had infinite mass, temperature and density, then it should curve space and time but there was no space-time before big bang. So where did the singularity come to existence without ...
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### What is the distance between 2 cities? [closed]

Both Quito and Kampala lie on the Equator. The longitude of Quito is 82°30'W and that of Kampala is 37°30'E. What is the distance from Quito to Kampala? A) along the shortest surface path B) along a ...
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### Planets orbiting Alpha Centauri

I read that a few years ago some planets were discovered orbiting Alpha Centauri. Has there been any more information since then concerning the possibility of life there? This is the closest star ...
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### How long until the stars are no longer visible by the human eye due to light pollution?

I was curious to how long it will be until the stars are not able to be seen due to light pollution. I started wondering this after reading Yummie's Flash comic Knite.
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### How often are new astronomical objects (variable stars, supernovae, comets, etc) discovered by amateurs?

How often are new astronomical objects (variable stars, supernovae, comets, etc) discovered by amateurs? Where could one report new findings?
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### Can we know the orbital planes of extraterrestrial planetary bodies?

Astronomers can tell if there are any exoplanets orbiting its parent star using but not limited to the following methods: Transit As an massive object usually a planet passing in front of a star ...
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### Is the sun too small to self-ignite?

I recently heard in a discussion that the sun is not massive enough to self-ignite via core-pressure. It simply has not enough mass to "generate" the gravitational force needed for that. The reason ...
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### Where to obtain Tycho Brahe's data?

I would like to obtain Tycho Brahe's data on Mars. What would be an authoritative source? One source I could find is this page (the data is given as an Excel file) but I have no idea can that be ...
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### Can the Universe be spatially closed and expand forever?

In the lambda-CDM model, the Universe is spatially flat, and will expand forever. Is possible that a spatially closed Universe expands forever?
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### In a spectrograph, photons follow the path: Screwdriver> Camera> Network / prism> detector? [closed]

I have a doubt. Can I say that in a spectrograph, photons follow the path: slit> camera> network / prism> detector?
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### Equations for coordinates of solar system objects

I would like to write a program that visualizes the solar system. To do this, I would need equations for calculating the coordinates of each solar system object at a given time. Where could I obtain ...
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### Are there any works discussing planetary bodies being forms of life?

I'm searching for works or individuals that consider and discuss the idea of planetary bodies being considered stand alone living creatures, rather than objects either capable or incapable of ...
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### How much do the mascons on the moon affect surface gravity?

The gravity anomalies on the moon (generally accepted to be caused by mascons) are powerful enough to affect the orbit of satellites. I'm trying to determine how much effect they would have on a ...
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### Will it be possible to just look out a window on a spacecraft? [on hold]

On a spacecraft, cruising through the void, will a regular piece of glass suffice to protect my eyes and skin from various forms of radiation? What sort of window will be sufficient to protect humans ...
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### Source of high energy cosmic particles

Earth receives shower of both solar and cosmic radiations every seconds. The Sun put up a heliosphere around the solar system and thus foreign high energy charged particles could not penetrate easily. ...
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### Can you assume atmosphere height for the purpose of surface pressure calculation?

Given that by definition of scale height an atmosphere thins by a factor of 1/e^x where x is elevation in terms of scale height multiples (See the table here: Definition of Scale Height), can we ...
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### If the 24 microarcsec parallax precision of the Gaia spacecraft is a 1-sigma value, what is the smallest parallax…?

If the 24 microarcsec parallax precision of the Gaia spacecraft is a 1-sigma value, what is the smallest parallax that could be measured to a 3-sigma confidence? What distance, in kiloparsecs, does ...