1
vote
2answers
30 views

Can a comet orbit a planet?

Given that moons commonly orbit planets, why do we never encounter a comet orbiting a planet? What would happen (exactly, in detail) if a large one did settle into a stable orbit around the Earth? ...
3
votes
2answers
59 views

Why is the core of a gas giant supported by electron degeneracy pressure instead of nuclear fusion?

After a Sun-sized protostar forms, its core will become denser over time due to radiation. The core eventually gets dense and hot enough for hydrogen fusion to take place. In the late phases of the ...
0
votes
1answer
19 views

Warm and Hot dark matter density profiles

for Cold dark matter, density profiles are well known and easy to find information about - NFW,Burkert,Einasto, and others. but for some reason i couldn't find explicit expressions for the density ...
0
votes
1answer
20 views

R.A. and DEC. for Constellation area vertices

I'm developing a planetarium software and I need the R.A. and DEC that represents every constellation area in the sky. I think I only need R.A. and DEC for each vertex. Where can I find it? I'm ...
2
votes
2answers
73 views

Can I leave a planet without achieving escape velocity?

I know that if you exceed orbital velocity, you will never fall-back to the planet. My question is not about orbits. It's about brute-force propulsion to achieve altitude. I'm using an ...
6
votes
2answers
53 views

Why do we use FITS format for scientific images especially in astronomy? How is it different from formats such as JPEG, PNG etc?

I am new to astronomy and I found that the telescopic dataset can be stored in the FITS format instead of JPEG. Why do we have a special image format just for scientific images?
2
votes
1answer
96 views

Why do PMS stars on the Hayashi track remain at a constant temperature while they contract?

Why do pre-main-sequence stars on the Hayashi track remain at a constant temperature while they contract? I've read the Wikipedia article, so no need to repeat the derivation. What I took away from ...
1
vote
2answers
107 views

The multiverse spacetime paradox?

If there are indeed multiple universes, where do they exist? We "know" that outside our universe, consisted of spacetime, there is nothing - i.e. 0 dimensions, no space and no time. So "where" are ...
1
vote
0answers
34 views

Which stars do I have to use to join with a line to draw constellation figure?

I continue working on a planetarium software and I want to draw the lines that the draw the constellation's figure: Is there a catalogue or something similar with the stars which are the vertex of ...
1
vote
0answers
24 views

Where is Luna 1? [migrated]

Luna 1 was the first attempt by the Soviet Union to crash land into the surface of the moon but narrowly missed after a programming error becoming the first man-made object to escape Earth's ...
0
votes
1answer
26 views

How do astronomers detect gases that are in the atmosphere of exoplanets?

Exoplanets are just planets that are located outside our solar system - whether that be orbiting a star or drifting past one. Now, the closest star to us is Alpha Centauri which is just over four ...
0
votes
0answers
8 views

Does the dust around SMBH's protect habitable planets from jets?

The supermassive black hole in the Milky Way is covered by dust as seen from here. Is it common that SMBH's are covered in dust in their galactic disks? Would that dust absorb and disperse a jet from ...
10
votes
1answer
1k views

Could the 9th planet be virtual?

Astronomers recently claim that there is evidence for a 9th planet. As far as I understood it, this is mainly based on coinciding orbital parameters of a few Kuiper belt objects. Could the 9th planet ...
0
votes
0answers
15 views

How to calculate the total flux of a source from a fits file?

My fits file is a spire 250micron image that has data units of Jy/beam . I injected a source into it with a peak intensity 20Jy and fwhm(3,3). How can I calculate the total flux of the source? Please ...
1
vote
1answer
29 views

How large could gravitational waves get and what effect could they have on us?

The waves detected by LIGO were basically subatomic distortions of space-time. Could there be much greater distortions closer to a source. Would they become perceptible to a human in any way and what ...
0
votes
2answers
69 views

What could be a star-like object that shines at daytime for few seconds? What's the probability to see it?

Some years ago I looked up to the blue sky, around 2 PM, and I saw, for 2 or 3 seconds, something like a star fading out. Could it be a Supernova or another phenomena? Is it highly possible?
0
votes
0answers
41 views

LIGO gravitational wave chirp signal frequency

This question is about the LIGO gravitational wave signals' frequency, The signals start from about 35 Hz to peak at about 250Hz, giving evidence of gravitational waves, the question is about the ...
1
vote
1answer
164 views

What is the first recorded reference to the Moon being a satellite of the Earth?

I saw a list recently of the moons of the various planets and the discoverer(s) and date of discovery. Earth's Moon was listed as Unknown. I know you don't 'discover' a huge disc in the sky. But ...
3
votes
3answers
347 views

Do all the stars visible to the naked eye belong to Milky Way?

It is surprising that even late in 1920, people do not know there are galaxies besides the Milky Way. Does this mean that all the stars visible to the naked eye are near to us?
4
votes
1answer
254 views

What uncertainty does an error bar signify in astronomy?

When an astronomer talks about her/his topic and shows an X/Y-plot with error bars. What should one assume that those error bars represent? 1 standard deviation? Or 2? Or some specific significance ...
1
vote
1answer
50 views

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: $\nu - M = 2\varepsilon \sin M$ ...
6
votes
2answers
143 views

Are there real uses of abstract algebra in astrophysics?

It is known that a physicist must have, at least in general, a good level in mathematics in order to research and understand other people's works. Linear algebra is a good example, as ODEs and ...
1
vote
2answers
41 views

“Supernova” is the explosion or the resulting celestial body? Is it incorrect to call the explosion “supernova”?

Sorry for such a newbie question. I searched and read multiples sources about supernova but I'm not completely sure if what is called "supernova" is the explosion, the resulting celestial body or the ...
1
vote
2answers
110 views

Is solar wind a source of water?

Solar wind may contain some hydrogen and oxygen atoms which is the composition of water, some of them may move to the poles of earth, my question is, is solar wind also a source of water in earth?
5
votes
2answers
97 views

Difference in energy released in stellar mass black hole merger and supermassive black hole merger

Super massive black holes are usually millions of times more massive than stellar mass black holes. I have read on SE and over internet that 3M☉ worth of energy is released in black hole mergers (not ...
0
votes
1answer
38 views

Pinhole Projector: Can I use a specific solar optical eye piece to focus the Transit of Mercury?

The title pretty much explains this one. Can I use a specific solar optical eye piece, or other optical device, in conjunction with the pinhole projector method to focus the Transit of Mercury? ...
0
votes
1answer
44 views

Calculating azimuth from equatorial coordinates

I try to get the azimuth of an object from its equatorial coordinates using this formula: $a = \arctan2(\sin(θ - α), \sin φ * \cos(θ - α) - \cos φ * \tan δ)$ Where φ = geographic latitude of the ...
3
votes
1answer
52 views

Will the E-ELT use Adaptive Optics at visible wavelengths?

In this recent BBC article I read that the European Extremely Large Telescope or E-ELT is in final design and is planned to be on line by 2024, and that (of course) it will rely heavily on adaptive ...
0
votes
0answers
56 views

Objects are bigger closer to big masses

I usually heard that on surface of earth time pass slower than on orbit. As speed of light is constant it will not change based on your position or observed position. Then if we have big mass that ...
4
votes
2answers
126 views

What study profiles could land me the job of astronomer?

I realize there are very few to none universities that offer direct specialization of astronomy. If I aspired to be make astronomy my career choice, I'd likely have to pick something like physics and ...
4
votes
1answer
149 views

Is it possible to steer the sight of a Liquid Mirror Telescope using a plain mirror scheme? If yes, why hasn't it been done?

I have read about Liquid Mirror Telescopes in a number of places, and according to these sources, a major disadvantage of these telescopes is that they can only "see" straight up. In a nutshell, the ...
0
votes
0answers
29 views

How to orientate a telescope using an accelerometer and magnetometer?

For a project with my astronomy professor, we are hooking up an array of 4 smaller telescopes to observe objects in space together. To do this, we wanted to put an accelerometer and magnetometer on ...
0
votes
0answers
38 views

Converting ecliptical to equatorial coordinates

When looking for a formula to convert polar ecliptic geocentric coordinates of an object to equatorial coordinates I find various sources that give these formulae (like Wikipedia): Declination $δ = ...
1
vote
1answer
39 views

Question regarding the Milky Way when calculating galactic space velocities for galaxies

I have been calculating galaxy space velocities (where proper motions are known) in order to measure their orbits of the Milky Way using the method proposed in the appendix of ...
6
votes
1answer
79 views

What is a quaternary mirror and why does the E-ELT need one?

In this recent BBC article I read the one-sentence paragraph: "Development on the mirrors - in particular, a very complex quaternary mirror - continues apace." and became interested in the ...
7
votes
1answer
313 views

How can one explain the apparent motion of the Sun from a heliocentric point of view?

From a horizontal frame of reference, the path of the Sun looks like a part of a circle in a tilted plane, as shown in this picture: ...
-1
votes
1answer
73 views

Communicating with distant planet with life possibility

So, telescopes are like time machines. If we get an image and data for analysis from a planet say 1000 light years away, we are essentially looking 1000 years back in time. Now, if we notice presence ...
5
votes
2answers
114 views

What's the name for [the other kind of planet] in a binary star system?

This XKCD what-if talks about rainbows on planets in a binary star system. It points out that there are two types: circumbinary planets, where the planet orbits far from and around both stars ...
7
votes
3answers
566 views

What qualifies as a good place for stargazing, i.e. with least light pollution?

I know that minimal light pollution is a must for stargazing, and a place which is away from civilization is better. Does altitude of a place matter for light pollution? Does it affect the quality ...
6
votes
3answers
625 views

I'd like to become an astronomer. What experience do I need? [closed]

I think I'd like to become an astronomer. What degrees and training/experience do I need to become one? I've heard I should take science and mathematics, but I don't know which specific courses I ...
2
votes
0answers
96 views

Good Introductory Textbooks [closed]

I have a more mathematical background but have always been interested in astrophysics, cosmology, astronomy, etc. There are a lot of popular books on the subject, but I am getting more interested in ...
1
vote
0answers
224 views

Class presentation on the Sun, ideas? [closed]

Tomorrow I have to give a [high school] class presentation on a topic of the solar system. I have thought of the Sun, as I have always believed it to be the central part of the Solar System. So I am ...
2
votes
3answers
87 views

What must/do astronomers reveal beyond their academic papers?

Academic papers often make claims about observational data and results from computations. The papers only refer to names of data sources (such as an observatory) and of mathematical methods without ...
3
votes
2answers
232 views

Help in determining the features of an unusual, fictional star system

(Hope this is the right Stack-exchange site for this question) I'm working on a sci-fi RPG campaign, set on a very atypical location. Since this is a work of fiction, there's enough room for ...
4
votes
1answer
63 views

meaning of p-wave charmonia

What exactly does p-wave mean when referring to particles, like charmonia states. For example, see the following reference: http://arxiv.org/abs/hep-ph/9208254 My doubt is - p wave in scattering ...
6
votes
1answer
928 views

Are there more stars than all the words ever spoken by humans?

A while ago I saw Neil deGrasse Tyson comparing the number of stars in the universe with the number of words spoken by all of humankind, ever since. I realize both of these numbers are not strictly ...
3
votes
3answers
77 views

Good textbooks for a descriptive astronomy course

Brief tale of woe My department at a small public university in the US has decided to begin offering a descriptive astronomy general education course for the first time in a couple of decades and we ...
1
vote
1answer
90 views

Mass of Star Collapse

Does a star, when collapsing into a neutron star, or even a black hole, pick up any significant relativistic mass due to its rapid collapse rate?
0
votes
1answer
37 views

How ready are we to deal with a asteroid/comet/giant-meteor on a collision course with Earth?

I keep hearing astronomers saying there are observatories scanning the skies all day and night looking for near-Earth objects, extrapolating their trajectories. My questions are If we were to get ...
-9
votes
0answers
137 views

Does Sun speaks Om? [closed]

In india on whatsapp people forwards a pic that shows that Nasa says Sun has a voice and it is ancient om. Is it true or just fake cheating idea of Indian people?

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