Questions tagged [solar-system]

Questions regarding the Sun and objects orbiting it.

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49
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5answers
7k views

Why hasn't the “9th Planet” been detected already?

In the comments to this question, there was considerable doubt placed as to the subject of if the so called "9th planet" really exists. That wasn't really the intent of the previous question, so I ask ...
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4answers
10k views

Why do (most of) the planets rotate counterclockwise, i.e. the same way the Sun does?

Referring to the mechanisms explaining the solar system formation and to the initial rotation of the gaseous cloud that collapsed, I understand easily why the planets orbit the Sun the same way this ...
28
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3answers
7k views

Why do the planets in our solar system orbit in the same plane?

(Yes I'm excluding Pluto from this the same way it was excluded for not being a planet) Observing the planets orbit of the Sun they all seem relatively planar and roughly all orbit along the same ...
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2answers
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How much magnification is needed to see planets of solar system?

I have a 3inch Newtonian reflector telescope with 300 mm focal length. I can use highest magnification of 75x using a 4mm eyepiece. But in 75x I can't see the details of Jupiter what was expected. ...
6
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2answers
297 views

Do astronomers generally agree that the distinction between comets and astroids is not so clear?

edit: I just saw this tweet and find it incredibly relevant :) begin question: First see this answer and then consider if there are known, or likely to be identified cases of solar system bodies that ...
15
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1answer
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Why is the solar system often shown as a 2D plane?

Whenever I have learned about the solar system I always see the orbits displayed as a virtually flat plane. Are all of the orbits in the solar system really like this? If so, why? It seems like a ...
53
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5answers
33k views

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 keep ...
18
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2answers
535 views

What are the current observational constraints on the existence of Nemesis?

Nemesis is a hypothetical companion to the Sun on a very eccentric, long-period orbit. The star supposedly returns every few tens of millions years, driving comets into the inner solar system and ...
23
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3answers
1k views

Are we made of the stuff of one star or more stars?

[T]his coincidence enabled stars in the late stages of their lives to turn helium into carbon, oxygen and most of the other atoms that you and I are made of. [...] [W]e're made of star stuff. Max ...
35
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5answers
5k views

9th planet location?

I've seen a number of news reports indicating there is likely a 9th planet in our Solar System, something with an orbital period of between 10k-20k years, that is 10 times Earth's mass. I haven't seen ...
10
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1answer
893 views

Best approximation for Sun's trajectory around galactic center?

What is the current best approximation for the path the Sun takes around the center of the Milky Way? I have found some information on the approximate position of the Milky Way's center, the speed of ...
6
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5answers
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Naming of the planets of the solar system

Planets of the solar system have been named with Roman mythology gods names. I have a few questions on my mind concerning that subject for a while: Who decided to name them like this? When did the ...
29
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3answers
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Pluto's orbit overlaps Neptune's, does this mean Pluto will hit Neptune sometime?

We know that the orbits of Pluto and Neptune overlap. This means that pluto sometimes crosses the orbit of Neptune; will Pluto hit Neptune in any circumstance?
38
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4answers
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Where does the Solar System end?

This is a question I've heard many times in the past, and a quick search of the site says it hasn't been asked here, so I figured I might as well ask (and answer) it. I know that it is rare for ...
14
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5answers
2k views

When will all eight planets in our solar system align?

Ignoring expansion of the universe, entropy, decaying orbits, and interference from any bodies colliding with or otherwise interfering with their orbits, will the eight planets known planets in our ...
37
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2answers
8k views

Do all stars have an Oort cloud or is it a rare occurence?

Do all stars have an Oort cloud like ours that will be filled with comets and other objects? If not, why are they not around every star?
14
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5answers
8k views

Does the gravity of the planets affect the orbit of other planets in our solar system?

When one planet passes near another during its trip around the sun, does their gravitational pull is strong enough to disrupt noticeably each other's orbit ?
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4answers
2k views

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 n-...
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3answers
2k views

What will happen if a black hole appears near our solar system?

We know that black hole possesses immense power and can destroy anything coming in front of it's path. If such a black hole appears near our solar system, are we going to survive? Is there any way not ...
33
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2answers
7k views

Why is our solar system “tipped” about 63° with respect to the plane of our galaxy?

Our own solar system is "tipped" by about 63 degrees with respect to the plane of the galaxy. Has it ever been researched or is there any scientific theory which could explain the reason why our solar ...
32
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2answers
11k views

Can our Sun become a black hole

Does every star become a black hole? Is there any probability that our sun can become a black hole? If yes then is it on its way to become a black hole? what is the current state of sun as per the ...
2
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1answer
376 views

Period of unique horoscopes?

What is the period of unique horoscopes? In other words how long does it take before any configuration of the classical planets repeats? The seven classical "wandering stars" are: Sun, Moon, Saturn, ...
17
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1answer
376 views

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 ...
15
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3answers
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What wavelength to best detect the “9th planet”?

We know that the reflected sunlight will make detecting the 9th planet very difficult in the visible light. Is there another band that will be more likely to detect it? What is the surface temperature ...
15
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2answers
298 views

Do any known exoplanetary/solar bodies have “annular” eclipses similar to Earth's?

This was somewhat inspired by this question but is a bit different: I am interested in if there are any known systems in which the angular size of the eclipsing object is almost the same as the ...
13
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4answers
1k views

How did the Earth come to be in orbit around the sun?

I'm not sure if this post should be in the physics subject forum, but this seems to fit here too. I have been reading a book about chemistry and how the universe came to be with the theory of stars ...
3
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1answer
527 views

What is the orbital period of our sun around its barycenter?

In years, what is the time it takes our sun to orbit around our solar system's barycenter?
16
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1answer
918 views

Do we get any benefit from being in a galaxy?

If our solar system were to somehow be created outside of a galaxy as a single star in the vast nothingness between galaxies, would life on Earth change any? Does being a member of a galaxy actually ...
10
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2answers
4k views

Why are most planetary orbits nearly circular

In our solar system, with the exception of Pluto all planets follow a relatively circular orbit around the Sun, at the same inclination. They also all rotate in the same direction, none are '...
3
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1answer
526 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 ...
2
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2answers
2k views

What would happen if a planet is removed from the solar system? [closed]

More exactly what would to happen to us/Earth in general if any of the gas giants is removed by magic from the solar system ? How long would it take after such change before we notice it ? How major ...
6
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1answer
261 views

What is the format of the data from the JPL's HORIZONS system?

I'm looking for accurate positions and velocities of the planets in the solar system over several decades. I want to simulate their trajectories using Newtonian laws of motion, and compare the ...
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2answers
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How did the authors of Surya Siddhanta find the diameters of other planets in the solar system?

The Surya Siddhanta, "a Sanskrit treatise in Indian astronomy from the late 4th-century or early 5th-century CE" is truly a great work. But how was it possible for the writers to find the exact ...
3
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2answers
187 views

What is the future of our universe?

Is the universe heading towards a Big Freeze, a Big Rip, a Big Crunch or a Big Bounce? Or is it part of an infinitely recurring cyclic model?
3
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2answers
433 views

What would happen if a Sun-like star were to consume a Jupiter-like planet?

A substantial number of discovered exoplanet systems are likely contain more than one gas giant with distances far closer to the star than in our solar system. It is known that in solar system ...
2
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2answers
129 views

What measures are currently in place to detect asteroids on possible collision courses with earth?

I know some measures must exist, but I have no idea what the programs are, what organizations are involved, or how effective they are.
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1answer
1k views

Can Pluto and Neptune collide anytime in future? [duplicate]

We know that, the orbit of pluto ambiguously cuts the orbit of Neptune. I want to know, whether the revolving speed of Neptune is equal to the revolving speed of pluto. If not, is there a possibility ...
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3answers
632 views

Brown Dwarf transcending past the sun with the naked eye [closed]

I seen with my naked eye in mid 2014 from Ca. right after sunrise a black spot in front of the Sun.I observed it for about a hour with my naked eye. Here is a picture that closely resembles what I ...
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2answers
618 views

If the planets only attract, then how can they stay in their orbit?

Gravity is related to mass, and gravity is an attracting force on every body. Then what happens when bodies only attract each other..without repulsion they may strike the sun. I think there must be a ...
22
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2answers
14k views

Why do the planets orbit in the same direction?

Theoretically, planets would have an approximately equal chance of going one way in their orbit or another but in reality, this is not the case (at least in our solar system). Why is this?
14
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2answers
676 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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2answers
274 views

Planetary reference systems and time

I am researching into how coordinate systems of solar systems objects are created by reading some of the reports written by the Working Group on Cartographic Coordinates and Rotational Elements (e.g. ...
31
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6answers
10k 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, ...
19
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2answers
619 views

Hypothetical trans-Neptunian planets orbiting the Sun

The planet HD 106906 b was found at 650 AU from its home star, a star not so different from the Sun. Fomalhaut b is also a young planet that is orbiting very far away from its star. These two planets ...
14
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3answers
4k views

Is the Jupiter-Sun system considered a binary system of some type?

Since Jupiter is very massive, it is the only planet (in our solar system) that has a center of mass with the Sun that lies outside the volume of the Sun. (Source) If Jupiter was a star, they would ...
12
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1answer
305 views

Why do planets and satellites in the Solar system look so wildly different if they came from more or less the same matter?

First, the planets. We have Mercury, which is rocky, no atmosphere. But then we have Venus, which is completely different: thick atmosphere, very hot, geologically active. Then Earth - blue, full of ...
8
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1answer
423 views

As viewed from Mars, what are Jupiter's and Saturn's maximum brightness in apparent magnitude?

From Earth, Jupiter's maximum brightness is -2.94 and Saturn's is -0.24. But what about from Mars? They should be brighter, but by how much? There are equations at the obvious wiki entry but I'm not ...
8
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1answer
519 views

Stability of orbital resonance

Recently I've become more interested in the topic of the stability of planetary systems. I have been reading about it and it seems that orbital resonances play an important role in the stability of ...
6
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1answer
141 views

Planets positions (azimuth, altitude) API

I'm looking for a simple API that will allow me to get positions of planets and the moon for a given date, location and time. Does anyone know an API like that? Any suggestions or alternatives would ...
3
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2answers
598 views

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 ...