# All Questions

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### How to calculate the expected surface temperature of a planet

I'm writing a program to generate solar systems but I'm having trouble calculating the expected temperature of a planet. I have found a formula to calculate this, but I haven't been able to get a ...
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### Could we detect an earth-like planet around another star?

Could we detect an earth-like planet (e.g. similar distance from star, and similar size) with current planet finding techniques? If an earth-like planet were orbiting our nearest star, excluding the ...
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### Is there any way a planet could form independent of a star?

I just recently heard that there are currently no theoretical models that support planet formation without a star, but I can't remember where. So, I thought I would request all of your expertises. ...
115 views

### How do the orbits of Nu Scorpii and AR Cassiopeiae work?

I apologize for the way this question is worded but I don't think I know the proper verbiage. Basically, I want to know how the stars orbit one another in the two septuple star systems. For example, ...
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### brown dwarfs and planets

As far as I know, a brown dwarf is a 'star' whose core never underwent a fusion reaction, so it never became a star. So I was wondering if, appart from orbiting a star, is there any difference between ...
544 views

### app to locate star by coordinates

I've named a star and would love to be able to find it in the sky - is there an app I can use to locate stars given a specific coordinate?
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### visualisation of the universe's expansion

in physics we were learning about the universe and the big bang. we were being told that everything came from one point and 'exploded' outwards, and is continuing to expand. I felt that this ...
31 views

### How to calculate the new orbit after a instantaneous change in a well defined initial one?

Say one has a simple two body system (and one body is much more massive than the other, for example a star, planet system) where all the quantities about it are know, that is the eccentricity, masses, ...
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### Statistics of elements abundance in exoplanets

Recently, I encountered the concept of carbon planets - planets, which would be, unlike the Earth, formed mostly by carbon, instead of oxygen, silicon and magnesium. (I am not counting iron, which is ...
346 views

### Why are Hubble images “Cut”

Whenever you take a look at a photo that is taken by hubble, Lets say M87 or Eagle Nebula or maybe Ultra Deep space field, The Image is always "Cut" Like this : or this I want to know reason ...
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### Why is there so much methane in space?

In school I learned that methane is organic matter and that it is a possible product of crude oil refinement. However, recently I read that Uranus has huge methane storms and the Saturn moon Titan ...
115 views

### Does rotation affect gravitational lines of force

I was reading about rotating pulsars and other more-massive objects spinning at absurd speeds (hundreds of revolutions per second), and there was one point of which I was not clear. Does a rotation ...
112 views

### Looking for help in understanding how black holes can move

I'm looking for help in understanding how black holes can move through space. This is probably a trivial question for anyone who knows astronomy, but probably due to my lack of education on the topic, ...
65 views

### Who discovered what set of factors is responsible for visibility of celestial bodies on Earth's daytime sky?

Visibility of a celestial body on the sky during the day depends on a number of factors - if I recall correctly: the body's magnitude, Seeing, Sky brightness, and probably some others I have missed. ...
210 views

### How long does it take Dawn to orbit Ceres?

I haven't been able to find the orbit time of Dawn around Ceres. Do you know how long it takes?
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### How can we see the Milky Way Galaxy when we are already in it? [duplicate]

How can we see the Milky Way Galaxy when we are already in it? I have seen lots of pictures of Milky way galaxy. Consider yourself being in a room, how can you see it from out when you are already ...
122 views

### Supernova explosion nearby

A nearby star has crossed Chandrasekhar's limit. How do we come to know when it will undergo supernova explosion? Or has it already undergone supernova explosion?
83 views

### Angular momentum in planetary disk formation

Reading about the formation of planetary disks, one of the major problems, it seems like, is the evacuation of angular momentum. Aparently planets can't form with the amount o angular momentum the ...
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### Calculating Postition of ISS / Hubble in space [closed]

How do I calculate the positions of above satellite in space ?
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### What is the term for astronomical objects outside the solar system that are smaller than dwarf planets?

Asteroids and comets only seem to refer to masses within the solar system, and it seems unclear whether planetesimal does.
119 views

### What's this red stuff in some astronomical photos, e.g. Centaurus A?

Sorry for the rookie question, but I've got no idea about that red "belt" crossing over center of the galaxy, in this photo. I've actually tried all sorts of google searches but I couldn't get ...
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### Do the planets, asteroid belt, kuiper belt, and scattered disc lie on the same plane?

If not, do any of the four groups in the title lie on the same plane as other members of the group? E.g. does the asteroid belt lie on the same plane as the planets do?
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### Assumptions necessary for the strong form of Olber's Paradox

From Wikipedia, here's Lord Kelvin's statement of Olbers' Paradox: Were the succession of stars endless, then the background of the sky would present us a uniform luminosity, like that displayed ...
53 views

### Detecting motion

In the television show " Ascension " they are supposed to be 50 years into a 100 year journey to another Star System but get this, they never left Earth . They are here on Earth in a huge biosphere . ...
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### How was Henrietta Leavitt's discovery important for star measurement? [duplicate]

Henrietta Leavitt discovered a relation between luminosity and period of variable stars, so it was possible to measure distance between two variable stars. I am curious to know how that was important ...
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### Is the conversion from proto-star to main sequence an event or a process?

When a proto-star becomes a main sequence star, is that something that happens in an instant when a certain threshold is met, or is it a process that takes a few thousand/million years?
123 views

### Do all stars have the potential to have life supporting planets?

Regardless of how big or small, how hot or cold, do all stars have a goldilocks zone, and if so, could any given planet in this zone (with the right configuration) support life?
106 views

### How much light does Jupiter project onto the surface of Ganymede?

I suppose the answer would be a range as the Jupiter-facing side of Ganymede passed from Jupiter's light side to its shadow side. I'd also like to know how much light the sun projects onto the surface ...
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### Help w/ Hubble's Law + Doppler Effect.

I had a question about the following chart. What mathematical observation or equation could be made about the data given in respect to the doppler effect? I'm confused if this means that planets are ...
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### How do astronomers estimate the total mass of dust in clouds and galaxies?

As I understand it astronomers estimate the mass of stars by studying the orbits of their companions (other stars or planets). This helps them to derive relationships between the luminosities and ...
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### Better than Earth habitability [closed]

Earth undoubtly has very good conditions for supporting life. Although it is expected that many other planets on the outer space have conditions at least as good as Earth, the vast majority doesn't, ...
287 views

### Mass distribution in the early universe

The latest big quasar find at ~12.8 bn LJ with an estimated mass of 12 bn M☉ (see e.g. http://www.newscientist.com/article/mg22530104.000-ancient-black-hole-had-an-inexplicable-growth-spurt.html) puts ...
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### How can a galaxy in-between our view and the galaxy behind it have a 'lensing effect'?

In this article, the author writes: This galaxy is so distant that it would have been invisible without the gravitational lensing effects of a large galaxy cluster called Abell 1689, located ...
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### What's the mass of the interstellar neighborhood of the Sun?

What's approximatively the mass of the interstellar neighborhood of the Sun ? (for example the neighborhood of radius 50 light-years). Remark: The mass of the observable matter should be completed ...
119 views

### Free source of printable star charts in the format of the Millennium Star Atlas?

I've been looking for sources of printable electronic star charts - there seem to be many different ones available, either as part of planetarium software or just plain charting packages. But there's ...
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### What are the cloud-like blobs in the Martian southern hemisphere?

In a very recent edition of New Scientist, an article Mystery cloud-like blobs over Mars baffle astronomers (16 Feb, 2015), detailed that on 12 March 2012, amateur astronomers around the world ...
242 views

### Nebula and galaxies using 70mm scope

Telescope: Orion 09843 SpaceProbe 3,3 inch aperture(76mm), 700mm focal length, eyepieces - 25mm and 10mm focal lengths. Please tell me whether it is possible to see nebula and galaxies.
368 views

### Does the Sun turn around a big star?

The moon turns around the Earth. The Earth turns around the Sun. Does the Sun turn around a big star? If so, does this big star turn around a very big star? ... etc ... What are all the intermediate ...
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### Internal heat and differentiation

I was reading an article on planetary differentiation, and apparently internal heat producction plays a mojor role. There are several sources of such heat described, such as tidal heat, radiogenic ...
300 views

### Exoplanet Temperature Calculations

I was given an exoplanet similar in size and distance to host star to our own earth. It's orbiting a star with luminosity six times our sun, the greenhouse coefficient 0.3, bond albedo 0.3. I need to ...
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### How can we tell that a short-period binary is tidally locked?

Observationally, how can this be established? What is known theoretically about the process? Are there any reference papers to read?
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### How do I soundproof a Meade ETX-90 telescope?

I'd like to start using my Meade ETX-90 this summer in my backyard, but I'm worried that my neighbors will start complaining due to high noise this telescope makes when operating. How do I soundproof ...
127 views

### When will a day on Earth & Mars be the same length?

I read on Wikipedia that: As on Earth, the period of rotation of Mars (the length of its day) is slowing down. However, this effect is three orders of magnitude smaller than on Earth because the ...
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### What are the positions of the Earth, Moon, and Sun at a time when there is the least difference between high and low tides?

Does this happen when there is a full moon?
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### Is there any man-made satellite orbiting our moon?

I am just wondering whether any man-made satellites are currently orbiting our Moon. If there is one, would I be able to see it using my telescope?
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### When we see the Sun, do we actually see its past?

The Sun's rays hit our eyes around 8 minutes after they are emitted from the Sun. Does this mean that the Sun that we see is always the Sun as it was some 8 minutes before? I strongly think this must ...
208 views

### Is gravitational energy released when a body contracts?

Kelvin stated that gravitational energy released due to contraction was responsible for the energy radiated in the stars. Although the theory was wrong, was the assumption practically right? If it's ...
245 views

### Temperature of the Sun's rays

What is the temperature of the light that leaves the Sun towards the Earth and does it cool down during it's journey here ? If it doesn't cool down then how come it isn't frying the Earth ? Is it our ...