Questions regarding celestial bodies in orbit around a star.

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How long will it take Pluto to grow to planet size? [closed]

Pretty much everything in our solar system has collisions with smaller objects that lead to an increase in the mass of the larger. With Pluto being one of the largest things in the area of which it ...
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2answers
230 views

How did Jupiter form where it is?

Since Jupiter is the biggest planet in our solar system and is made up of mostly hydrogen and helium, (the gases the Sun uses to create energy), how come it didn't form as far out as say Uranus or ...
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Can there be an object with planetary discriminant between Ceres and Neptune?

The planetary discriminant is a measure of how dominant a body is within its region of the solar system. For (true) planets, it is >10000 and for dwarf planets it is <1. See this answer for more ...
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Do the planetary ring lasts? [duplicate]

Almost all gas giants in our solar system are observed to have a planetary ring comprises of ice, dust and rocks. My question is do these rings obediently sticks around their foster parent until our ...
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1answer
123 views

Where might a semi proficient amateur analyst participate in meaningful astronomical efforts

I am a retired engineer that has an ongoing interest in space efforts. In my youth I did work on the Apollo program but on propulsion and vehicle thermal control: not flight dynamics. I have ...
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2answers
116 views

On a log-log plot of surface gravity to planet mass, what is the meaning of the y-intercept?

I am playing around with data from exoplanets.org, and am interested in the plot of surface gravity to planet mass. I reproduced this plot after downloading their data and performed a non-linear ...
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2answers
171 views

Why does the Solar System have no (natural) satellites of satellites?

What are the conditions for a planetary moon to have a satellite of its own? How far do the Solar System's bodies fall from the necessary threshold?
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4answers
138 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 ...
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4answers
111 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 ...
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1answer
81 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 ...
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3answers
137 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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2answers
48 views

Can we know the orbital planes of extraterrestrial planetary bodies?

Astronomers can tell if there are any exoplanets orbiting its parent star using but not limited to the following methods: Transit As an massive object usually a planet passing in front of a star ...
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1answer
42 views

Equations for coordinates of solar system objects

I would like to write a program that visualizes the solar system. To do this, I would need equations for calculating the coordinates of each solar system object at a given time. Where could I obtain ...
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1answer
35 views

Are there any works discussing planetary bodies being forms of life?

I'm searching for works or individuals that consider and discuss the idea of planetary bodies being considered stand alone living creatures, rather than objects either capable or incapable of ...
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2answers
300 views

Open problems in astronomy that an amateur (with a PhD in some other field) would have a chance of solving?

What are some open problems in astronomy that an amateur would have a chance of solving? Suppose the amateur has a PhD in some other field, owns a basic telescope, a set of filters, diffraction ...
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0answers
17 views

are all the planet in the same plane? [duplicate]

are all the planet in solar system the same plane in the space or not ? if yes is there any especial reason ? and if no how do they orbits then ? as far as i know they are in the same plane , but is ...
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3answers
95 views

BIG CRUNCH Theory

Someday before i read about a article which explained about a phenomenon called BIG CRUNCH, according to it the way Big Bang happened because of which the remains moved away from one another forming ...
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2answers
77 views

Where is Mars in the night sky

I live around Houston, Texas and I'm taking advantage of Earth hour to look at the stars. I've found two objects that I think might be Mars. Both of them are in roughly the same plane as Venus and ...
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0answers
95 views

BIG Problem with the Planet definition [duplicate]

Ok, so Pluto is only ~1/13 the mass of the objects in "its orbit". This orbital region extends from 40 AU to 70 AU (semi major axes)- Now, just a minute. 30 AU is all the mass we are considering. Now, ...
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119 views

Lack of planets in the Oort Cloud

With the current news about the possibility of a planet in the Oort cloud, I was thinking, why is the matter in the Oort cloud distributed so? It makes sense that inside the planet region there is not ...
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1answer
46 views

Do astronomers and astrophysicists more often use diameters or radii when discussing about planets, dwarf planets, exoplanets and stars?

Mathematicians much more often use radii over diameters when discussing about circles and spheres, because in mathematics the radius is more fundamental than the diameter (the sphere is defined using ...
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1answer
124 views

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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1answer
135 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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31 views

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 ...
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97 views

Can Magnetars destroy planets?

Magnetars are the most magnetic things in our universe. Because of how powerful their magnetic fields are, they could split every single atom apart from each other in our body. Because of this could ...
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1answer
97 views

Difficulties in finding Jupiter

I am new to astronomy. Jupiter is now visible to the naked eye but I have difficulties in locating it with my (new Newtonian reflector) telescope. The lowest magnification I have is 36X, which I guess ...
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2answers
137 views

What astronomical observations would give conclusive proof of alien life?

There are several ways we are coming closer to answering the question "is there life elsewhere in the universe?". One is by first understanding very well the origin life on our own planet. Another is ...
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3answers
158 views

Why there are other planets in our solar system? [closed]

Why there are planets in our solar system other than Earth? Only Earth supports life. What is the significance of other planets? Earth receives sunlight from Sun; in a similar way, do we receive any ...
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2answers
81 views

Could there be another planet between Mercury and the Sun?

Could there be another planet between Mercury and the Sun? Kepler found a lot of planets orbiting its star even 20 times closer than Mercury. If there were such planets in our system - would it be ...
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1answer
33 views

Recent origin of Saturn's rings

Saturn was formed around billion years ago along with Jupiter. After which it had enough time to form moon which can break into rings. Then why is it said that Saturn's ring are of recent origin - ...
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1answer
67 views

What is the process for vetting the 4,175 candidate planets Kepler has discovered?

In the National Geographic article about NASA's announcement of new planets discovered by the Kepler spacecraft, it states that there are 4,175 candidate planets. What is the process for vetting these ...
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2answers
179 views

Maximum and minimum gas giant & ice giant densities

I'm working on a star system generator for a game; I'd like its results to be plausible but they needn't be super-realistic. I've got the orbital distances and masses of each body in the system, and ...
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1answer
82 views

The role of gravity during planetesimal accretion

As far as I understand, during the formation of a planetary disc, grains of dust stick together due to collisions and chemical bonding. Considering the size of the grain - say, 1 mm - and the speed - ...
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3answers
461 views

Why, in the Solar System, all the mass seems to be concentrated at the centre?

Is this a consequence of planet formation in accretion disks ?
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135 views

Can a gas giant have an other gas planet as satellite?

Is it possible for a gas giant (A very big one) to have an other smaller gas planet as satellite?
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402 views

What would be the dynamics of a double-planet system, similar to Earth / Moon, but with both bodies nearly Earth-sized?

Researching a sci-fi story involving a "twin-planet" system. Is such an arrangement (however unlikely) physically possible? And if so, must they be tidally locked with each other, similar to the moon, ...
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3answers
231 views

Planets and Pluto? Neptune?

If one of the rules to be a planet is that it needs to clear ALL objects from their orbit, does this also make Neptune a non-planet? Since it has thus far failed to clear Pluto (and based on an answer ...
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2answers
145 views

How can a planet not rotate at all and yet have 1 year that is day and 1 year that is night?

A mercury day if you consider its solar day is 2 mercury years. Now if you consider just 1 half of mercury, in 1 of those years it is facing towards the sun and in another one of those years it is ...
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1answer
74 views

What day/night cycles, climate and seasons would experience Alpha Centauri Bb inhabitants?

Alpha Centauri Bb is an exoplanet orbiting Alpha Centauri B. It is asserted that given the close distance to the star the planet should be tidally locked. The orbiting period of the planet is about ...
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63 views

Is it possible that only one hemisphere of a planet has an atmosphere?

Suppose there is a tidally locked planet orbiting a star. The planet's surface consists of a global ocean, that is, liquid water. At the inner hemisphere the temperature is so high that the water is ...
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3answers
144 views

How would we detect a planet behind the Sun?

Let's assume hypothetically that Earth has a twin planet on the opposite side of Earth's orbit. Its orbital period would be exactly the same as Earth's and it would always be behind the Sun so ...
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36 views

Advancement of perihelion, data

I was looking for accurate and up-to-date data regarding the advancement of the perihelion of the planets in the Solar System, the only ones I've found so far are at least 90 years old bout I really ...
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1answer
54 views

Apocalypse on earth

What would it feel like on Earth if the Earth accelerated due to sudden changes in the solar system like ejection of another planet? Would there be giant tidal waves and other cataclysmic events?
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2k views

Is Pluto still a dwarf planet?

Recent news seem to suggest that astronomers are arguing about whether Pluto should become a planet again. However, I cannot find an official source for this. Is this actually true?
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101 views

Composition of planets' core

It is often possible to find a list of the materials that compose the cores and the mantle of plantes (often they are iron and/or nickel). How can these materials be determined in our Solar system? ...
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1answer
157 views

Planetary gas giants

I've read that a gas giant, like Jupiter, doesn't have a rocky surface. But planets must start as a rocky conglomerate of flotsam. Is the interior so hot that all the material is molten and there ...
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1answer
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How did scientists determine an estimate of the number of planets greater than Sedna's size to exist in the Inner Oort Cloud?

In the article, New Dwarf Planet Found at Solar System's Edge, Hints at Possible Faraway 'Planet X' (Wall, 2014) where they report on research and observations performed by astronomers that discovered ...
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2answers
210 views

Selecting a Telescope for Viewing Planets

I hope to observe planets like Jupiter and Saturn, and moons. I am a novice when it comes to telescopes and I know images in magazines are not taken with at least 12-inch telescope in a middle of ...
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1answer
631 views

Is a spotting scope or binoculars a better choice for astronomy?

I'm interested in observing the moon and planets, and maybe some nebulae and star clusters. I have a pair of binoculars: Nikon OceanPro 7x50 binoculars (around \$300) Celestron 20x80 binoculars ...
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2answers
89 views

any unique phenomenon when the cores of two planets are aligned with their star's core?

Imagine a line passing through the cores of two planets (in the same planetary system) and their star. Have we ever witnessed this - either with both planets on the same side of the star or on ...