# All Questions

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### How much heat emanates from the planets after formation?

The 2nd answer to this question by MBR got me thinking about this. Is there some general guideline for residual heat a planet should emit, say 4.5 billion years after formation. I'm defining heat ...
57 views

### Is it possible for the year to have 11 full moons (i.e. the opposite of a blue moon)

A blue moon is so called for when we have 13 full moons in a year. https://en.wikipedia.org/wiki/Blue_moon Is it possible to have 11 fun moons in a year? (Maybe if we included calendar changes, for ...
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### Universal point for sky observation

Is there a place on Earth, where polar axis lies on the horizont and heaven equator is in zenit? If it exists, can I, in theory, see all the constelations available worldwide this night?
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### Tripod mount missing!

I have received a new Celestron Powerseeker 127 (a 5' short Newtonian), however it came without a tripod mount. Ideas or suggestions on how to procure the right mount our a suitable alternative ...
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### What is the simplest model of the Sun? [closed]

What is the simplest stellar structure model for the Sun? Well obviously a Polytropic model can't describe sun ( for now ). Can Eddington's model describe sun?
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### Appearance of the Cresent [duplicate]

Does the latitude of your position on earth change the appearance of the cresent like it changes the position of other objects visible in the sky? Does it rotate it?
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### Astronomy Calculations Tool

I took many images like the following: As many of you may recognise, this is a picture of Jupiter and its four Galilean moons. Using these images, I am aiming to calculate the mass of Jupiter by ...
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### Which is the largest planet ever observed?

I don't know much about planets outside our solar system. Do we even know the limit of the size of how large a planet or satellite can be? The largest planet I know of is Jupiter, but could there be ...
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### Adverse effects of urban growth on old astronomy observatories? Need article/book

I am looking to get some information on the adverse effects of urban growth/light pollution on the oldest/traditional observatories of the world (europe). Can anyone recommend me books or articles to ...
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### How does large body gravity affect planet formation?

If Jupiter's gravity is what kept the asteroid belt from forming a planet, then why didn't the sun's gravity keep the inner planets from forming?
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### Coincidence with Schwarzschild radius? [duplicate]

I was reading the article for Schwarzschild radius on Wikipedia and I noticed that the article states: The observable universe's mass has a Schwarzschild radius of approximately 13.7 billion light ...
1k views

### From which country or area is the new moon visible first?

Being able to see the Moon is dependant on various factors like sunset timing etc. Considering all these factors, which country or area of the world sees the new moon first? I am asking about the new ...
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### Direction Names Within a Galaxy

Are there commonly used names for objective directions within a spiral galaxy? Central and peripheral describe objective directions, because the observer's frame of reference doesn't affect whether ...
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### How to interprete function value of get_sun in astropy

As I know, spring equinox of 2016 is on 2016/3/20 4:30 GMT. I execute following statements in python: ` from astropy.time import Time from astropy.coordinates import get_sun t=Time('2016-03-20 ...
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### Wavelength-dependent limb darkening of the Sun - need approximations or sample images

I need an approximate analytical expression for visible light limb darkening of the sun viewed at large distance, either as a function of wavelength, or even just a few wavelengths from red to blue. ...
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### Will Earth lose the Moon before the Sun goes into supernova?

Ive read on some sites and saw on youtube videos that the moon is getting away from earth by 1-3 cm a year. Is this enough to make the Earth lose the Moon before the Sun goes into Supernova? Im ...
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### Is it possible for a virus to come from a meteorite?

So I am not a true scientist and I was just wondering if an extraterrestrial rock from space can have some dangerous unidentified virus or bacteria that can be deadly and wipe out the Earth if it not ...
2k views

### Is the Earth-Sun distance 1.012 AU?

Wolfram Alpha's query: Sun Earth distance in AU gives: 1.012 au (astronomical units) They definitely use this value in other places too - e.g. Earth-Sun $L_1$ distances from Earth and from Sun ...
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### How bad could we reasonably expect a solar flare to impact earth, and what can be done to mitigate the impact?

According to numerous articles, solar flares have done damage to the power grid on Earth in the past: http://science.nasa.gov/science-news/science-at-nasa/2008/06may_carringtonflare/ How bad can we ...
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### Where can I find a set of data of the initial conditions of our solar system?

As title suggests I'm in need of a set of data of our solar system. Similar to this http://bima.astro.umd.edu/nemo/archive/#iau25, specifically dubinsky milky way-andromeda data. I'm creating a ...
122 views

### Why can't neutron stars ignite and explode?

Beyond the Chandrasekhar limit, white dwarfs become extremely hot. As a result, previously unfusable carbon can become fusable, causing nuclear reactions. This leads to thermal runaway and ultimately ...
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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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### How can a naked singularity be possible?

How can we have a singularity, without a black hole around it? How would one form? What does it do?
6k views

### Why is the Sun's density less than the inner planets?

The density of the Sun is $1410~\frac{\text{kg}}{\text{m}^{3}}$ and Mercury's is $5430~\frac{\text{kg}}{\text{m}^{3}}$, but shouldn't the Sun be denser? Because when the Solar System was forming, ...
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### What would happen to a gas planet if its core mass goes beyond the Chandrasekhar limit?

Hypothetically, let's say we had a gas giant that continued to accrete mass. I've heard that the cores of gas giants are electron degenerate. So if the planet continued to accrete mass and the core ...
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### Solar Pressure and Gravity

I recently read some articles and pages on Solar Sails, and the possibility of using lasers to propel spacecraft, and I had a relatively outlandish idea. Would it be possible for a star to be ...
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### View HD images of space in linux [SOLVED] [closed]

I dont know if this is the correct place to ask this. (I apologize if it isnt) I like browsing through large HD images of space(a weird eccentricity I have), but I always have to go to NASA's image ...
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### How long can you be trapped orbiting around a black hole for?

I have a story I wanna write but I want to be sure it's not completely scientifically irrelevant. I know there is black hole modelisation called the Kerr black holes, in which there is a limit ...
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### Does the shape of a supernova remnant depend on the progenitor star's magnetic field?

The magnetic field activity in a star can be very chaotic and my question is are they somehow related?
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### What is meant by ionization states?

I am going through the theory of saha equation but I am not able to understand the concept of ionisation state? What are ionization states actually?
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### Why aren't people going to The Moon any more? [duplicate]

In 1969 America landed on the moon, and at that time our technology was not as good as it is now. So my question is, we have much more advanced technology than in 1969, so why are we not utilising ...
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### Stars repartitions

I'm looking for the stars repartitions in percent, in the Harvard Classification (from O to M) I have search every where but I found nothing. I'm not looking for exact values, but more generic ...
277 views

### Why haven't asteroid belts turned into new large bodies?

If gravitation (attraction of mass) is the cause of the formation of all celestial bodies then how come the numerous small bodies found in asteroid belts spread over an orbit instead of clustering ...
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### Mass limit of planetary ring

Is there a limit to how massive a planet's ring can be? If there is, how does it depend on the mass of the planet, presence/absence of moons, distance to the star or other parameters?
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### Can the theory of multiuniverse explain dark matter?

If there are many universes they must have an gravity effect on each other. Since dark matter is measured through gravity but we dont know the mass behind it, isnt it possible that it comes from ...
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### Why 2007 OR₁₀ is not a dwarf Planet yet?

Per definition a dwarf planet is: a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic ...
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### Has Science observed and recorded a stars birth?

Has Science observed the entire process of a star being created when the area of creation was just a void in space? Or is there still missing data that has not been entirely observed and recorded? ...
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### What is the most dense object in the universe?

Inspired by this answer to the question, Why is the Sun's density less than the inner planets?, what is the most dense object in the universe?
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### Reclaimed bodies in planetary formation?

This question on Worldbuilding.SE got me thinking... We currently think that many bodies that condensed during star/planet system formation, many bodies are ejected. I've heard it stated that there ...
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### The observation of changes barycenter of the solar system

Is it possible to observation changes in the barycenter of the solar system? There are graphics showing changes barycenter but they are made on the basis of computer simulation (E.g.: here and here). ...
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### Can we measure/detect GR light bending during solar eclipse using ordinary equipment?

Suppose an amateur astronomer finds himself watching Solar Eclipse. He can see the stars around totality. Is Sun's GR effect strong enough for the amateur astronomer to be able to tell that a ...
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### What is the effect of the axial precession on the orientation of the planet's orbits?

I am working on an online application to visualize the positions of the planets and to calculate their ephemerides (you find it here, but it is not complete yet). I do not have much knowledge in ...
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### Does weight influence Earth's spin? [closed]

If put enough weight on a particular point on Earth's surface disturbing the balance between hemispheres, is it possible that the Earth's spin could change like an unbalanced spinning top?
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### Population of excited H levels in a Strömgren Sphere

In chapter 2.2 of Astrophysics of Gaseous Nebulae and AGN Ostriker and Ferland claim that, as far as ionization is concerned, one can assume all atoms to be in the ground state in a Strömgren Sphere ...
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### Is there any proof of space being created?

Is there any proof for space being created? Because I guess an explanation for the dark energy (dark = our understanding of it) could be that there is a gigantic amount of matter/dark matter that we ...
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### How many planets are there in this solar system?

So, in school (that's a long time age) they have been teaching us there are 9 planets in our solar system. Mercury Venus Earth Mars Jupiter Saturn Uranus Neptune Pluto But every now and then I ...
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### In a finite universe, what happens when light reaches the boundary?

If a universe is finite and is not expanding at a speed equal to or greater than c, what happens when light or another form of electromagnetic radiation traveling reaches the boundary?
301 views

### Is there any real chance of getting hit with a meteorite if we build a base on the moon?

I've been reading an article today on how the European Space Agency (ESA) has an interest in building a space village on the moon which will be 3D printed and assembled by robots. Eventually people ...