# All Questions

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### Explanation for the first spinning neutron star detected in the Andromeda galaxy?

A new class of Neutron stars has been found in the Andromeda galaxy (M31), This is the first time a Spinning Neutron star has ever been detected by astronomers in M31. The article states- “pulsars” ...
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### If Venus had moon before and it fell back to Venus, why don't I see a unique, very big crater?

Does lack of a very big crater support the idea that Venus never had big moons before? If not, why can't I find a very big crater from the moon impact?
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### If “9 th planet” is ejected by Jupiter or Saturn, why does it have a very far perihelion?

If the "9 th planet" is ejected by Jupiter or Saturn, I think the perihelion should be near Jupiter and Saturn, but now the predicted orbit is very far away from Netpune, why would that happen?
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### How do we know that there is no border at the end of “infinite” space? [duplicate]

It has been suggested that space and beyond is infinite, but admittedly the same hypothesis was made by virtue of the fact that it is physically impossible to prove otherwise. How do we know that ...
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### Can dark matter be found in the shape of planets, galaxies etc.?

If dark matter has gravity just like normal matter, does that mean it can also form planets, solar systems and so on? Any answer will be appreciated.
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### Create heatmap from significance

I am working on my project in astrophysics and I would like to create my heatmap from the significance which is obtained by the gaussian fitting my histogram. I get this map : First picture : ...
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### Can you see the stars when it is trickling?

I am writing a book with the following scene in one chapter: It is trickling and my protagonists are outside looking into the night sky, looking to the stars. Reviewing the scene I am wondering: Is ...
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### Which class of objects in Solar System carries more mass?

Could you help me sorting this list in terms of total mass carried by these classes of objects? The star (Sun) - it's very big but only one. The planets (incl. dwarf planets). Certainly beaten by ...
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### Two body orbit of equal masses

Given two bodies of equal mass in an elliptical orbit: I know they will be orbiting about a common center of mass, i.e. the barycenter. But, do the velocities have to be equal in magnitude and ...
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### What was the flash I saw in the night sky?

On Saturday night (April 2nd) in Sydney, Australia, somewhere between 8:30 PM and 9:00 PM my partner and I saw three flashes in the sky. We were looking at Jupiter through a pair of 7x50 binoculars ...
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### Magnetic field in blazars

How such high magnetic fields are generated in Blazars? What is the orientation of magnetic field in accretion disc and jets? How magnetic field effects variability? How magnetic field causes shock ...
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### How to create synthetic test images of stars?

Is there any python/IDL code available to create synthetic test images of stars with and without background noise?
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### Can we tell how fast bodies are moving away by measuring their frequency?

It's clear the universe is expanding because light from distant bodies, like galaxies, are shifted towards the red side of the spectrum. In other words, the light measured is more red than it should ...
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### How was precision astrometry done before digital imaging?

Did they just put a ruler on the photographic plate? Quite some precision must have been required to discover Neptune from its influence on Uranus for example.
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### Could we verify the structure of a black hole by observing an orbiting object?

Can we determine the physical structure of a black hole by observing its gravitational effect on objects in orbit? There are three possibilities that I see, and would like to test: Singularity at ...
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### Unknown moving objects

Last night, I used my new Sony WX500 camera to get long exposure pictures of the sky from my backyard. I used the "Heavens Above" app to find out when satellite flares would happen, and I even got a ...
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### How the watches are showing perfect time?

The actual time for one day is 23hrs, 56mins, 4.1secs right? Then how can the clocks and watches can show perfect time? I mean, if I observe the sun rise at 6:00am this day, tomorrow I should observe ...
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### How does an absolute horizon form before the apparent horizon?

If I understand it correctly, the apparent horizon is the boundary between where light directed outwards will move outwards, and light directed outwards will move inwards. Even if light is moving away ...
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### Longitude of the Ecliptic

I originally went to math.stackexchange.com and they suggested I try here as well. I'm trying to figure out how to calculate times of moonrise and moonset for a given position on the earth on a ...
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### What is the definition of “deep space”?

I need to know the definition of deep space. I am an amateur astronomer, and am experiencing some difficulty understanding this.
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### Protocol for establishing longitudinal meridians on other heavenly bodies

When we first observe a new heavenly body (it could be a new star, asteroid, etc., but let's say a minor planet in our own solar system), are there any procedures set in place for establishing a ...
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### What happens over time as a neutron star cools?

My understanding of a white dwarf star is that, although it hasn't happened yet due to the age of the universe, eventually as it loses energy due to radiating heat and tidal forces, it will cool to ...
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### What happens if two or three stars collide with each other?

After finding out that there is a solar system with three stars, I did extensive research. I couldn't get a definitive answer. What would happen if they collided with each other? I know there would ...
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### Is it possible that Mercury was originally the moon of Venus after a giant impact?

Mercury looks like the Moon, and so it makes me think about a question: is it possible that Venus and Mercury were the a same planet originally, and a giant impact with that planet made it split into ...
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### My supernovae question [duplicate]

I understand the collapse of a star during a supernova, as the outward pressure cannot compete with the gravitational field. Is it conceivable, that a relaxation of the space-time curvature is what ...
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### Has the Kepler data been examined for light curves due to phase changes of non-transitting hot Jupiters and other?

I found this article http://www.epj-conferences.org/articles/epjconf/pdf/2011/01/epjconf_ohp2010_03005.pdf from 2011 announcing that two dozen secondary eclipses of "hot Jupters" have been seen in ...
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### Is nucleosynthesis responsible for the expansion of the universe?

Is it just a coincidence that the two major expansionary periods occur close to periods of nucleosynthesis? Big Bang nucleosynthesis occurred very close to the inflationary period. Supernova and ...
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### What is it that distinguishes one atmospheric layer from another?

The atmosphere of a planetary body (assuming it has an atmosphere) is described as being made up of distinct layers. For example, Earth, Saturn and Jupiter all have a stratosphere and a ...
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### What would happen if we changed Earth's orbit? [closed]

If one day we have enough technology to push the Earth away a bit further from the sun to reduce global warming, is it true that it will start to distort the orbits of Mars and Venus, giving them a ...
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### Stellar systems: what is the difference between virial, dynamical and thermodynamic equilibrium?

I'm currently going through Binney & Tremaine (2008) on my own to learn about stellar dynamics. I also have been perusing additional online resources such as this scholarpedia wiki. Often when ...
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### gravitational time dilation multiple sources

I wondered how time would be dilated for an object in the middle of 2 black holes, however https://en.wikipedia.org/wiki/Gravitational_time_dilation only provides a formula for one source of gravity ...
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### A good website for laymen to share their discoveries?

This is a wonderful Q&A forum, but I'm wondering if anybody knows of a good website where someone can let other people interested in astronomy know about new things that they have become aware of: ...
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### How can cosmic inflation make an infinite universe homogeneous?

As it is explained in this video, one of cosmic inflation's observable effects is the homogeneity of our universe. Inflation allows two points on the different sides of the observable universe to be ...
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### Could mirrors be replaced with CCDs?

Why do telescopes use mirrors that simply reflect photons, when they instead could be covered with large sensors to register them? Reflection is all good and well, all thanks to silver and beryllium ...
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### Are there events in universe which we receive first from their neutrino's instead of their photons?

Neutrino's are very small though they have mass. Because of that it is probably that the don't have a speed faster than photons. But is it in all events, like supernova's or else events, where it is ...
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### Simulates Orbit [duplicate]

I IT developer, and I would code a small program that simulates the orbit of two bodies, the problem of two bodies eventually. I have no problem on the part programming but I have a little trouble ...
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### How do we know background radiation does not come from undiscovered galaxies?

Each year while observing voids, astronomers discover more and more unexpected galaxies within them. How do we know the cosmic microwave background radiation is not the weak light from distant ...
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### Magnitude, satellite flare and the Heavens Above app

On the Heavens above app for Android and maybe iOS, it shows negative magnitude values for Iridium satellites, but for other ones, it shows positive. Here is a screenshot Why is this?
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### Photodetector Question: Does converting an RGB image to grayscale produce the same result as using a grayscale image detector?

FYI my application is not astronomy related, but I know astronomy folks have a lot of knowledge of photodetection and spectrometry instrumentation, so I am seeking this community's help. I'm ...
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### Are there any galaxies which fell out of sight horizon due to cosmic expansion?

If farthest galaxies run away from us with acceleration making them exceed speed of light, we should expect them to disappear from sky among time with increasing quantity. Did we observe this? Can we ...
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### Why are radar images of comets shaded only on one side?

NASA published a picture of a comet the other day. The image shows the comet being lit from above. See NASA's picture below. However, since it is a radar image, I would have assumed to get a ...
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### Gravitational field released during supernovae

During the collapse of a star at the commencement of supernovae, the intense pressures force fusion and fission to create the heavier elements and release vast amounts of energy. As this energy/mass ...
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### How do I modify redshifts to gain corrected line of sight velocities?

I'm currently trying to collect the data to run an N-body simulation for 11 of the galaxies in the Local Group where proper motions are known, however I don't understand how to get the required line ...
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### Did I see another planet?

A couple days ago, I zoomed in with my 30x optical zoom camera, and after some exposure adjustments, a bright star in the night sky turned into this: Are those other planets or other stars? Or is ...
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### Dark matter inertial mass

We know the existence of dark matter because we can test its gravitational mass (e.g. in gravitational lens) but, since we cannot see this matter, how we can be sure that it has an inertial mass, and ...
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### At the moment of total solar eclipse what are exact distances of Moon & Sun to the Earth

By total eclipse I mean the Moon and Sun are seen equal in size, neither of them is bigger. For example, the Moon's average distance is 384000 km and the Sun's average distance is 149.5 million km. ...
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### Why Milky Way and Andromeda are being drawn together if there was 'Big Bang'?

Scientists used to use following reasoning: most galaxies are red-shifted $\implies$ there was a 'Big Bang' Why this is being considered valid since not every galaxy has such property?
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### Calculating Right Ascension and Declination from Latitude / Longitude / Time

I have a latitude / longitude / time of a location on Earth, I need to calculate the Right Ascension / Declination that's overhead at the time provided. So far I've found out that Right Ascension is ...