- #1
robno9
- 1
- 0
how does the movement of stars compare to the movement of planets
Actually, the seasonal movement of the Earth around the Sun causes nearby stars to shift apparent position. This is called parallax, and it is the only direct means of measuring the distance to objects outside our solar system. This indeed makes the apparent positions of nearby stars wobble back and forth, though the variations are small and require careful observation and measurement.Mental Gridlock said:One more note about the difference between the apparent position of stars vs. planets is that a planet can appear to change the direction it's going and then go backwards and then forwards again. As far as I know a star can't do this, except for maybe the tiny wobble of a binary star which wouln't have been observed by the naked eye.
Louis B said:What causes the local group to move? I mean, in a galaxy there's a black hole in the center that causes the stars to orbit around it, but in a cluster of galaxies, is there anything that can cause them to move so fast?
Lymitra said:Yes, each galaxy exerts gravitational force on every other galaxy in the local group, just like the supermassive black hole in the center of our own galaxy that causes the stars to orbit around it. Also, a cluster of galaxies can be gravitationally attracted to other galaxy clusters, which causes it to move across space if space isn't expanding too fast.
Stars and planets both appear to move across the sky, but they do so in different ways. Stars appear to stay in fixed positions relative to each other, while planets appear to move in relation to the stars and each other.
The movement of stars and planets is due to their different orbits. Stars are much farther away and have a fixed position in relation to Earth, while planets are much closer and have their own orbital paths around the sun.
No, stars and planets move at different speeds. Stars have a relatively constant speed as they are much farther away, while planets have varying speeds depending on their position in their orbit.
The movements of stars and planets affect our view of the sky as they appear to rise and set at different times. This is also why we see different constellations and planets at different times of the year.
No, stars and planets have different types of motion. Stars have an apparent circular motion due to Earth's rotation, while planets have an elliptical motion due to their orbit around the sun.