1
vote
4answers
130 views

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 ...
0
votes
2answers
45 views

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 ...
1
vote
1answer
77 views

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 ...
-4
votes
1answer
46 views

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 ...
1
vote
1answer
75 views

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 ...
7
votes
6answers
125 views

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 ...
4
votes
2answers
109 views

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?
-1
votes
0answers
52 views

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, ...
3
votes
1answer
79 views

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?
0
votes
1answer
45 views

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 ...
-2
votes
0answers
35 views

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 ...
0
votes
1answer
52 views

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?
4
votes
1answer
80 views

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 ...
0
votes
1answer
24 views

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, ...
0
votes
1answer
62 views

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 ...
1
vote
4answers
87 views

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 ...
3
votes
2answers
44 views

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, ...
0
votes
0answers
73 views

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 ...
0
votes
2answers
86 views

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 ...
1
vote
1answer
36 views

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 ...
0
votes
0answers
21 views

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 ...
0
votes
0answers
22 views

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 ...
1
vote
1answer
60 views

Can asteroids contain atmosphere?

Gas is abundance in the universe, can a massive asteroid draws in these gas forming a thin atmosphere?
1
vote
1answer
65 views

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 ...
0
votes
1answer
60 views

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 ...
0
votes
0answers
20 views

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 ...
2
votes
1answer
25 views

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?
3
votes
1answer
57 views

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 ...
2
votes
2answers
68 views

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, ...
1
vote
2answers
39 views

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 ...
1
vote
1answer
50 views

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?
0
votes
1answer
51 views

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 ...
1
vote
1answer
53 views

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 ...
2
votes
2answers
64 views

How long for a complete solar system cycle

Considering the solar system as a closed system, how long until all the planets pass twice by the same position relative to each other? I would say that you'd have to get the length of the year in ...
0
votes
1answer
22 views

How can I find out which known stars lie within or close to M8

I'm looking for a way to find stars within a certain region of space, the Lagoona Nebula in this case, based on what we currently know. Are there some databases that allow you to make such queries? ...
2
votes
2answers
691 views

Circular formation around the moon

I have seen a large circular formation of cloud around the full moon sometimes. Have anyone seen the same? What is the reason behind this formation? Due to lunar attraction? Most of the sky is empty ...
1
vote
2answers
59 views

Was the Universe expanding before the beginning of inflation?

My point of view is that first there was the Big Bang singularity, and then the period of inflation which resulted in the observable Universe becoming many times bigger. But was the Universe expanding ...
0
votes
1answer
43 views

How come, in our lifetime, we will see the first stars which ever formed?

Isn't it an unlikely coincidence that we live in such special times, that we will have observatories (JWST) that see all the way back to the first starlight in the universe? Are we dreaming, and is it ...
0
votes
3answers
109 views

Could there be a closer star to Earth than the Alpha Centauri triple star system, excluding the Sun? [duplicate]

Do we know for certain that the nearest star to Earth, excluding the Sun and the theorized Nemesis, is the Alpha Centauri multiple star system, at +/-4.4 light-years away? Have we been able to ...
3
votes
1answer
166 views

Are black holes solely responsible for hyper velocity stars?

I read that the stars orbiting around Sagittarius A* (a.k.a the supermassive black hole located at the heart of the Milky Way) move very fast (many times faster than our Sun moves across the galaxy), ...
4
votes
3answers
107 views

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 ...
9
votes
1answer
218 views

Why are there no green stars?

There are red stars, and orange stars, and yellow stars, and blue stars, and they are all understandable save the fact that there is a 'gap': There are no green stars. Is this because of hydrogen's ...
2
votes
1answer
55 views

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, ...
0
votes
1answer
16 views

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 ...
5
votes
1answer
58 views

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 ...
-2
votes
1answer
48 views

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 ...
3
votes
1answer
112 views

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 ...
0
votes
1answer
29 views

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?
1
vote
0answers
56 views

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 ...
1
vote
2answers
70 views

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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