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Old 06-02-2018, 07:29 PM
 
Location: PRC
3,250 posts, read 3,365,783 times
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It seems we dont orbit the Sun but kids are told in school that we do.

This is obvious for some of you but I learned something new the other day.
I think I have understood this correctly, but please elaborate or set me straight if necessary.

Technically, the planets of the Solar System do NOT orbit the Sun. They orbit a point in space determined by the difference in mass between themselves and the Sun - a combined center of gravity.

It appears as if they do orbit the Sun, due to the huge difference in masses between the Sun and the other planets. The exception is Jupiter which is so large that its mass is significant compared with the Sun.

There is a point in space around which all the planets of the Solar System revolve, even the Sun. According to the mass of the other planets, it appears as if this point is within the circumference of the Sun, but for Jupiter, this point is outside of the circumference of the Sun and so both the Sun and Jupiter can be shown (from their orbits) to be revolving around this point in space, their combined center of gravity.

Explanation and gif video
Quote:
The gas giant is so big that it pulls the center of mass between it and the sun, also known as the barycenter, some 1.07 solar radii from the star's center— which is about 30,000 miles above the sun's surface.
What I want to know is what keeps the Sun at a particular point in space? Maybe no-one can answer that one yet.

Last edited by ocpaul20; 06-02-2018 at 07:52 PM..
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Old 06-03-2018, 09:28 AM
 
22,794 posts, read 17,268,975 times
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Quote:
Originally Posted by ocpaul20 View Post
It seems we dont orbit the Sun but kids are told in school that we do.

This is obvious for some of you but I learned something new the other day.
I think I have understood this correctly, but please elaborate or set me straight if necessary.

Technically, the planets of the Solar System do NOT orbit the Sun. They orbit a point in space determined by the difference in mass between themselves and the Sun - a combined center of gravity.

It appears as if they do orbit the Sun, due to the huge difference in masses between the Sun and the other planets. The exception is Jupiter which is so large that its mass is significant compared with the Sun.

There is a point in space around which all the planets of the Solar System revolve, even the Sun. According to the mass of the other planets, it appears as if this point is within the circumference of the Sun, but for Jupiter, this point is outside of the circumference of the Sun and so both the Sun and Jupiter can be shown (from their orbits) to be revolving around this point in space, their combined center of gravity.

Explanation and gif video
What I want to know is what keeps the Sun at a particular point in space? Maybe no-one can answer that one yet.
Well, you're not wrong. Any time one object orbits another object, the gravitational pull of each object on the other creates a barycenter (a center of gravity) around which both objects revolve.

But in casual conversation we just say that the earth orbits the sun. Just like we say, ''I just watched the sunset,'' instead of saying, ''I just watched as the rotation of the earth carried me out of line of sight of the sun due to the earth itself getting in the way.'' There are times when it's just not practical or desirable to be exactingly correct when conversing.

The Sun is not kept at a particular point in space. The Sun moves through space as it orbits the galaxy. Its relative rate of speed as it moves through space is roughly 43,000 mile per hour.
''Relative to the local standard of rest, our Sun and the Earth are moving at about 43,000 miles per hour (70,000 km/hr) roughly in the direction of the bright star Vega in the constellation of Lyra. This speed is not unusual for the stars around us and is our "milling around" speed in our suburban part of the Galaxy.''

https://astrosociety.org/edu/publica...1/howfast.html
No object in the Universe is truly at rest. Moons, planets, comets, asteroids, stars, galaxies, everything is in motion.
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Old 06-03-2018, 01:01 PM
 
7,168 posts, read 3,920,595 times
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Quote:
Originally Posted by ocpaul20 View Post
It seems we dont orbit the Sun but kids are told in school that we do.

This is obvious for some of you but I learned something new the other day.
I think I have understood this correctly, but please elaborate or set me straight if necessary.

Technically, the planets of the Solar System do NOT orbit the Sun. They orbit a point in space determined by the difference in mass between themselves and the Sun - a combined center of gravity.

It appears as if they do orbit the Sun, due to the huge difference in masses between the Sun and the other planets. The exception is Jupiter which is so large that its mass is significant compared with the Sun.

There is a point in space around which all the planets of the Solar System revolve, even the Sun. According to the mass of the other planets, it appears as if this point is within the circumference of the Sun, but for Jupiter, this point is outside of the circumference of the Sun and so both the Sun and Jupiter can be shown (from their orbits) to be revolving around this point in space, their combined center of gravity.

Explanation and gif video
What I want to know is what keeps the Sun at a particular point in space? Maybe no-one can answer that one yet.
The sun is not kept in a point in space. Our solar system is traveling at something like 500,000 mph around the galaxy. And our galaxy is traveling around 1.3 million miles per hour.

As to orbits, Pluto and Charon also orbit outside of Pluto’s surface.

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Old 06-06-2018, 05:59 PM
 
10,169 posts, read 10,495,907 times
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Quote:
Originally Posted by Mike555 View Post
Well, you're not wrong. Any time one object orbits another object, the gravitational pull of each object on the other creates a barycenter (a center of gravity) around which both objects revolve.
For the Earth–Moon system, where the barycenter is located on average 2,902 miles from the Earth's center, well within the planet's radius of 3,963 miles. We say that barycenter is inside the Earth.
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Old 06-08-2018, 09:08 PM
 
6,994 posts, read 6,743,583 times
Reputation: 5188
Quote:
Originally Posted by ocpaul20 View Post
It seems we dont orbit the Sun but kids are told in school that we do.

This is obvious for some of you but I learned something new the other day.
I think I have understood this correctly, but please elaborate or set me straight if necessary.

Technically, the planets of the Solar System do NOT orbit the Sun. They orbit a point in space determined by the difference in mass between themselves and the Sun - a combined center of gravity.

It appears as if they do orbit the Sun, due to the huge difference in masses between the Sun and the other planets. The exception is Jupiter which is so large that its mass is significant compared with the Sun.

There is a point in space around which all the planets of the Solar System revolve, even the Sun. According to the mass of the other planets, it appears as if this point is within the circumference of the Sun, but for Jupiter, this point is outside of the circumference of the Sun and so both the Sun and Jupiter can be shown (from their orbits) to be revolving around this point in space, their combined center of gravity.

Explanation and gif video
What I want to know is what keeps the Sun at a particular point in space? Maybe no-one can answer that one yet.
The Sun is supposedly revolving around the black hole in the center of the Milky Way. And the Milky Way and all the other galaxies are supposedly moving relative to each other somehow as well.
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Old 06-09-2018, 09:08 PM
 
2,960 posts, read 1,127,390 times
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Quote:
Originally Posted by UrbanAdventurer View Post
The Sun is supposedly revolving around the black hole in the center of the Milky Way. And the Milky Way and all the other galaxies are supposedly moving relative to each other somehow as well.
That is correct. The galaxies in the Local Cluster are all gravitationally bound to one another.
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Old 06-13-2018, 08:30 PM
 
Location: Ohio
20,723 posts, read 14,670,694 times
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Quote:
Originally Posted by UrbanAdventurer View Post
The Sun is supposedly revolving around the black hole in the center of the Milky Way. And the Milky Way and all the other galaxies are supposedly moving relative to each other somehow as well.

The Sun and a cluster of stars in this region of the galaxy are revolving around a central point in the spiral arm of this region of the galaxy, and the spiral arm in turn revolves around a central point in the galaxy, which is believed to be a black-hole.
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Old 06-16-2018, 01:46 AM
 
2,960 posts, read 1,127,390 times
Reputation: 2006
Quote:
Originally Posted by Mike555 View Post
Well, you're not wrong. Any time one object orbits another object, the gravitational pull of each object on the other creates a barycenter (a center of gravity) around which both objects revolve.

But in casual conversation we just say that the earth orbits the sun. Just like we say, ''I just watched the sunset,'' instead of saying, ''I just watched as the rotation of the earth carried me out of line of sight of the sun due to the earth itself getting in the way.'' There are times when it's just not practical or desirable to be exactingly correct when conversing.

The Sun is not kept at a particular point in space. The Sun moves through space as it orbits the galaxy. Its relative rate of speed as it moves through space is roughly 43,000 mile per hour.
''Relative to the local standard of rest, our Sun and the Earth are moving at about 43,000 miles per hour (70,000 km/hr) roughly in the direction of the bright star Vega in the constellation of Lyra. This speed is not unusual for the stars around us and is our "milling around" speed in our suburban part of the Galaxy.''

https://astrosociety.org/edu/publica...1/howfast.html
No object in the Universe is truly at rest. Moons, planets, comets, asteroids, stars, galaxies, everything is in motion.
Correct me if I'm wrong, but I do believe that the barycenter of the Solar System will always be located within the Sun, as it accounts for over 99.8 % of it's total mass.
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Old 06-16-2018, 06:21 AM
 
Location: 912 feet above sea level
2,270 posts, read 936,140 times
Reputation: 12519
Quote:
Originally Posted by Milky Way Resident View Post
Correct me if I'm wrong, but I do believe that the barycenter of the Solar System will always be located within the Sun, as it accounts for over 99.8 % of it's total mass.
The Sun-Jupiter barycenter is slightly outside of the Sun.

It is not simply a function of mass but of distance. On average, Jupiter is nearly 500 million miles from the Sun. If it was much closer, the barycenter would be within the Sun. And were it much further out, the barycenter would similarly be even further outside of the Sun.
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Old 06-16-2018, 10:39 AM
 
11,591 posts, read 8,287,030 times
Reputation: 12764
What do you mean may be wrong. You mean they may be mentally ill or slow adults?
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