# All Questions

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### Why doesn't the New Horizons probe fly any nearer than 10,000 km from Pluto? [migrated]

New Horizons is intended to pass within 10,000 km of Pluto on its flyby on July 14. This will give a maximum resolution on the surface of 50m per pixel. This seems to me a bit of a waste, when it ...
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### Use Pluto's gravitation to reach the next dwarf planet [migrated]

Why doesn't New Horizons fly by nearer to Pluto so the gravitational pull would slingshot the probe to one of the next dwarf planets in the outer solar system (Eris, Haumea, Makemake,...)? I would ...
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### Tonight sky - deep sky objects

programmatically how can i get the list of Deep sky objects that will transit the meridian in my Latitude and longitude? Any online API?
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### Quantum entanglement; How many entangled particles can we find in the wild?

If not all particles are entangled in the universe, where there any entangle particles after the big bang; if so how many entangled particles are thought to occur naturally? (I am curious if a ...
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### Telescope Problems

I currently own a telescope, I'm an amateur astronomer and currently just trying to view the moon. I own the Celestron PowerSeeker 70AZ. Link for information on the telescope: ...
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### Cosmological deflation?

Wikipedia tells us: In physical cosmology, cosmic inflation, cosmological inflation, or just inflation is the exponential expansion of space in the early universe. The inflationary epoch lasted ...
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### On a log-log plot of surface gravity to planet mass, what is the meaning of the y-intercept?

I am playing around with data from exoplanets.org, and am interested in the plot of surface gravity to planet mass. I reproduced this plot after downloading their data and performed a non-linear ...
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### Why does the Solar System have no (natural) satellites of satellites?

What are the conditions for a planetary moon to have a satellite of its own? How far do the Solar System's bodies fall from the necessary threshold?
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### What is the most populated/numerous stellar system in which the orbits of all objects are known?

I posed a question or two on here a couple months or so ago about the orbital patterns of each of the seven stars in the two septenary star systems Nu Scorpii and AR Cassiopeiae. They remain ...
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### Is there evidence that what resulted from the Big Bang is “everything”? [on hold]

Asked this question in the physics forum before I realized there was this one: Do we have any observed evidence that the "known" universe truly is everything that is out there? (I mean everything ...
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### Faster than light [on hold]

Before explaining my view about light speed I must sorry at the beginning for my English, and lack of astrophysics background, I am just programmer. It is important, to be conversant with material in ...
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### What is the mass of plasma? [on hold]

I need to find the mass of plasma of the sun corona for may astronomy problem, but when I Google it, it didn't find it. what is the mass of plasma?
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### Smallest lunar probe that can be made using today's technology [migrated]

Suppose we want to do a lunar sample return mission. We can then launch a small rocket from the ISS that carries a small probe to the Moon. It will collect a sample and then return to the ISS. ...
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### Is there a way to tell what the surface of a planet is like?

Kepler-442b I'm doing a project in which I need to find a planet within our galaxy that might be habitable. I found this planet that is within its stellar system's habitable zone, and due to research ...
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### Would dark energy save the earth for a while as the sun heats up?

Would the expansion of space (e.g. dark energy) move the earth further away from the sun over time, possibly saving us for perhaps a few billion years as the sun heats up? Scientists now tend to ...
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### Star versus Black Hole

I'm making a simplified animation for college project on how a star reacts with a black hole. I had known that a black hole sucks in everything and thus should be doing the same for stars. But upon my ...
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### Could our Sun be a companion star of a massive black hole?

Can we track its orbit well now? There is any study that may indicate our sun may be a companion of a big black hole? What is the current constrain about its orbit now? There is a 1000 solar mass ...
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### Glowing ice in ceres [closed]

Do ice volcanos glow and maintain a regular shape as in the case of ceres? The 2 volcanoes should eventually merge into one, as they are in a common crater and close together.
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### How can a supernova affect black hole in a binary system?

Suppose in a binary stars system there is a dying star and a companion black hole as they orbit around each other. My question is what will possibly happen to the black hole if the partner goes ...
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### Determine the moons of Jupiter through a telescope

I was doing my own "space exploration" last night with a telescope. Being a space noob I can't visually determine stars or planets (I know the moon, though), but I focused on one particularly bright ...
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### Would a tablespoon of a neutron star remain intact?

I've heard people say that a tablespoon of neutron star would weigh over a billion tons. If we ever could take a tablespoon of one would it still remain intact with the same density?
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### Moment of falling in Black Hole if it can evaporate [duplicate]

If I understand correctly for outside observator object never cross event horizon. Then if black hole can evaporate this mean object never cross event horizon? How it could be right when for object, ...
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### Statistically speaking, what is the most commonly used operating system by astronomers worldwide? [closed]

Currently I'm in my third year of university. I would like to work in the field of observational astronomy (not so much theoretical astronomy). In about two weeks I'm going to buy a new laptop ...
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### Evolution of the Hubble parameter

In the lambda-CDM model describing an accelerating Universe, the Hubble parameter is currently decreasing with time. Will it continue to decrease forever?
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### Can close binaries have a very eccentric orbit?

For example, are there binaries with an orbital period < 5 day and that are very eccentric? What kind of factors could slow down orbital circularisation? Are ...
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### Astronomy-themed names, wordplay, connotations

I use an astronomy theme for naming my main computer and parts thereof. It started with a machine named Cassini, build while watching the arrival of the exploration mission and Saturn Orbital ...
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### Space time and aging

Would a more significant curvature of spacetime relative to earth (i.e. time on jupiter) effect the aging process? Basically would you age at a slower rate? Or age faster on the moon?
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### Missing Terms in Weinberg's treatment of perturbations on Newtonian Cosmology

I was reading Appendix F of Steven Weingberg's book "Cosmology". In this Appendix he works out the perturbations to a cosmological fluid described by non-relativistic hydrodynamics and Newtonian ...
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### How to orient ESO's Milky Way Panorama in a 3D model

I have been trying hard to find the star "Polaris" in the following image from ESO and Serge Brunier: From peering at other maps and simulation apps, I think it should be in the top-left quarter, ...
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### What are the equations for an orbit with time as parameter?

I am preparing a talk on the Equation of Time, and I want to produce an animation of the movement of the earth around the sun, in an exaggerated ellipse, to illustrate the speeding up and slowing down ...
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### Image sets for testing stacking algorithms?

I am looking for sets of astronomical images for testing different kinds of stacking algorithms. The idea is simple: if one has $N$ images of the same object, the signal-to-noise ratio of the ...
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### What decided how the Kepler space telescope was pointed?

I suppose that the Kepler field was well chosen. It is rich in stars and has minimal background light since it is pointing out from the disc. But other things could have been considered. For example, ...
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### How strong does a light source on the Moon have to be to be visible from Earth?

Flashes from some meteoroid impacts on the Moon can be seen with the naked eye. How much light must a future lunar base emit in order to be visible as a dot in the lunar night (like the flag of ...
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### Is the North star going to stay in the North sky?

Considering how the our solar system, and how every other star in the galaxy is traveling through the cosmos, it seems like it's a miracle that the stars and constellations in the sky stay as constant ...
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### Were magnetic monopoles created before, during or after inflation?

In the case that magnetic monopoles exist, when were they created? I thought that all particles were created after inflation, but I've read some comments recently that hint at a pre-inflationary ...
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### How are errors on X-ray photon index propagated to X-ray spectral index?

I have seen that in X-ray astronomy, astronomers often talk in terms of photon index $\Gamma$, which is related to spectral index $\alpha$ by relation $\Gamma$ = $\alpha$ + 1. Are the errors on ...
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### X-ray flare questions

I search the reference papers about flare, but nobody said something about below clearly. Could anyone give some help? If a single X-ray decay without eclipse or other irrelevant factors is not able ...
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### Can asteroids contain atmosphere?

Gas is abundance in the universe, can a massive asteroid draws in these gas forming a thin atmosphere?
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### Would a human body float in the dense atmosphere of Venus?

To survive high in the atmosphere of Venus, all you would nead to wear is suit that protects you from the sulfuric acid vapors in the air and a supply of breathable air. Assuming (for simplicity) that ...
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### Is there a theory / equation showing whether or not two passing bodies will go into orbit around each other?

I am looking for a theory that shows whether or not two passing celestial bodies will go into orbit. I assume there would have to be a critical point where the gravitational attraction is stronger ...
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### How can we derive photometric redshift?

Is there any good tool than can derive photometric redshift or good reference paper? We need to assess photometric redshift based on GALEX(Fnu and Nuv), Sloan(ugriz) and 2mass(jhk) magnitudes. Could ...
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### How are boulders formed on asteroids?

For example: Are they soft landed meteorites? Or do they form from melted material during a violent impact? Or are they the result of some kind of erosion process?
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### Calculating RA/dec from JPL ephemeris data

I'm using JPL planetary ephemerides to calculate the position of planets. Using DE405 ephemeris (using a parser provided by Project Pluto with all tests passing). I am fetching the position of Mars ...
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### How to tell a nebula from a galaxy?

Not all galaxies are spiral in shape[1][2], some nebulae are huge[3] and nebula are the nursery of stars[4]. How to tell them apart? Note I have already compare the contents for galaxy and a nebula, ...
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### Habitable Planet around Red Dwarf

Is there the possibility for a habitable Planet around a red dwarf? It is not required that the whole surface is habitable, but it shouldn't be a tiny spot. After reading a bit I assume the planet ...
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### What's the difference between grism and grating?

In spectroscopic observations, sometimes you meet grism, sometimes grating. Both of them could cause light dispersion, but what is the difference?
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### Concerning fate of Milky Way Galaxy

Andromeda Galaxy is the largest galaxy in the galaxy cluster[1] called Local Group[2] and our Milky Way Galaxy as well as some satellite/dwarf galaxies are orbiting around each other within Local ...
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### When the universe expands does it create new space, matter, or something else?

I am wondering what exactly is meant when it is said the universe expands. Does it simply create new space for matter to fill, does it also create new matter/dark matter to fill that space, or am I ...