Sunrise from West: The Possibility of a Planetary Shift

  • Context: High School 
  • Thread starter Thread starter Faizan
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Discussion Overview

The discussion centers around the concept of the sun rising from the west, exploring the implications of planetary shifts, Earth's rotation, and the possibility of retrograde motion. Participants examine theoretical and observational aspects related to Earth's and Mars' movements, as well as the effects of external forces on these dynamics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants question the possibility of the sun rising from the west, citing potential planetary shifts or catastrophic events as factors.
  • Others assert that Earth's rotation will not change direction barring a significant impact from a large object.
  • There are inquiries about whether Earth can change its orbital direction around the sun, with responses indicating that it cannot without external forces.
  • Participants discuss retrograde motion, with some suggesting that Earth cannot orbit in a retrograde direction under normal circumstances.
  • One participant describes the conservation of angular momentum as a reason for Earth's consistent rotational direction, likening it to a spinning ice-skater.
  • There is mention of the magnetic poles potentially flipping, which could lead to a redefinition of directional terms but not an actual change in the sun's rising position.
  • Another participant introduces the chaotic nature of the solar system and how resonance between planetary movements could lead to extreme changes over billions of years.
  • Some contributions reference encyclopedic facts about Earth's rotation, magnetic field, and the influence of other celestial bodies on its motion.

Areas of Agreement / Disagreement

Participants generally agree that Earth's rotation will not change direction without significant external forces, but multiple competing views exist regarding the implications of retrograde motion and the effects of magnetic pole shifts. The discussion remains unresolved on the broader implications of these phenomena.

Contextual Notes

Participants express uncertainty about the long-term stability of Earth's rotation and orbit, as well as the potential for future changes due to gravitational interactions and other external factors. The discussion includes references to complex astronomical concepts that may not be fully resolved.

  • #31
No because they move so much faster than the Earth in its orbit. Now on the backside of the Sun, when they are moving in the opposite direction to the Earth, they would appear to be moving backward, but at those times they are invisible to the naked eye.
 
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  • #32
selfAdjoint said:
No because they move so much faster than the Earth in its orbit. Now on the backside of the Sun, when they are moving in the opposite direction to the Earth, they would appear to be moving backward, but at those times they are invisible to the naked eye.

Are you sure of this? Venus has such a small apparent magnitude (i.e. it is so bright) and a fairly large maximum elongation (about 46 degrees) that I am almost certain that retrograde motion of Venus can indeed be observed with the naked eye.

Notwithstanding the issue of naked eye vs telescopic observations, it is still a fact that *all* the planets (inferior and superior) exhibit retrograde motion.


Coming back to the original poster, maybe a source of confusion is that books often talk about the motion of the sun from west to east when talking the motion *relative to a fixed background of stars*.

(Now I am addressing anyone who is interested, not necessarily selfAdjoint who probably knows all that).

The idea is that the Sun and the planets (and the stars) and everything rise in the East and set in the West over one day, but the Sun and stars don't quite move at the same rythm. The Sun takes 24 hr to get back (roughly) to its initial position whereas the stars take a bit less (about 23h56m). This is simply due to the revolution of the Earth around the Sun. Anyway, people then say that the Sun therefore moves *eastward* relative to *a fixed background of stars*. This means that if you plot the position of the Sun along the zodiac signs, you will see it moving eastward, accomplishing a full circle in one year. The planets do the same thing except that they sometimes revert directions, hence retrograde motion.

I just hope this might be a bit helpful.

Pat
 
  • #33
Just a quick question. Does the sun rotate about its center? Relative to a distant observer of course, say another star.
 
  • #34
Healey01 said:
Just a quick question. Does the sun rotate about its center? Relative to a distant observer of course, say another star.
Yes, the Sun takes about 25 days to rotate once around its axis, relative to the background stars. It's still a mystery as to why the Sun rotates so slowly.
 

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