Briefly describe the motions of Earth with respect to other bodies in the Universe.?

Answer 1

The actual motion of the earth through space is very complex. It is the combination of the various relative motions of the earth with respect to other gravitating bodies in the universe superimposed on one another. The motion also depends on the your selected "frame of reference" (or vantage point). The sun and moon are most "influential" gravitationally on earth's short period motions, the sun because of its large mass, the moon because of its relative closeness, though the other planets exert a small but detectable gravitational effect on these motions (called perturbations) and the Milky Way because of its stupendous mass. The earth and moon "orbit" about their common center of mass, and the earth/moon system together "orbit" the sun. The moon's motion can be simplified by taking the earth as fixed or stationary, with it "orbiting" the earth in an ellipse (a flattened circle) with the earth at one focus once every 28 days. With the sun taken as stationary, the earth (or earth/moon system) "orbits" the sun in an ellipse with the sun at one focus over a period of one year at a velocity of roughly 18 miles per second. From this vantage point, the earth and moon seem to perform a spiral dance (earth tight, moon larger) along the earth's orbit as they move together around the sun. The description of planet and satellite motions as ellipses in astronomy texts and popularizations (web, magazines, popular books) is a simplification. The "orbits" are really unclosed approximate (or pseudo) ellipses, whose parametric axes vary and/or rotate over decades to millenia. The sun moves in an "orbit" about the center of the Milky Way galaxy, 30000 light years from the center, at roughly 200 miles per second over a 200 million year period. Further, the Milky Way is approaching/orbiting the Andromeda galaxy (M31) at roughly 500 miles per second. The last two are LARGE velocities, but are to a HIGH approximation linear and do not change over thousands if not millions of years. When the sun's motion is taken into account (with the center of the Milky Way as fixed), the earth's orbit becomes yet another spiral dance around the sun's roughly linear path around the galactic center (with the earth/moon spiral on top of THAT!). Lastly, the motion of our Milky Way galaxy through space just changes the direction and overall look of the now torturous spiral motion of earth through space. How are the velocity numbers obtained? The earth's speed is derived simply from the orbital period of one year and the distance of the earth from the sun (93 Megamiles) and is known accurately. The sun's velocity in the galaxy is obtained from painstaking statistical analyses of many measurements of neighboring stars proper motion (ACROSS our line of sight) and of their radial velocities (ALONG our line of sight) from doppler measurements, while the Milky Way's is obtained from analysis of many external galaxy doppler measurements and that of the cosmic background radiation. Finally, because of the geometry of our Universe, all of the external galaxies appear to be rushing away from us as the "center", the speed at which they rush away is proportional to their distance away from us, the proportionality constant being called the Hubble constant. The velocity values of last 3 motions mentioned above have large uncertainties due to uncertainties in the many measurements made in order to obtain them.

Answer 2

The Earth is the 3rd planet from our Sun and orbits it once every 365 days. Our Sun, in turn, is merely an average-sized star on the outer arm of our Galaxy, which we call the Milky Way. Our Galaxy also rotates like a giant pinwheel, taking millions of years to complete a rotation. Additionally, there are billions of other glaxies in the Universe, all rotating and also expanding away from each other. If you took a ballon and painted dots on it representing galaxies and then inflated the balloon you would get an idea of how the Universe is expanding. The whole Universe began about 13 billion years ago as a single point of incredible energy which exploded in what is referred to as the Big Bang.

Answer 3

The Earth and the Sun rotate around a barycenter, the barycenter is not actually in the center of the Sun so to say the Earth orbits the Sun is not technically correct. The obit of the earth around the sun is elliptical in nature rather than a circle. The Earth and the Moon also rotate around a barycenter, this barycenter is actually beneath the surface of the Earth but not in the center of the Earth. The other planets have their own orbit which are in three dimensional space so they don't obit in the same plane as the Earth. Our solar system is just one in the spiral milky way galaxy. So our entire solar system is rotating around the barycenter of the milky way galaxy. The milky way galaxy is traveling though space as the universe continues to expand, theoretically traveling away from the origin point of the big bang.

Now for fun and games with gravity. Everything in the universe with mass exerts force on everything else in the universe with mass, this is called the universal law of gravitation. The strength of these forces are proportional to the mass and inversely proportional to the distance between them. So in theory the Earth exerts influence on everything else in the universe, but in practice this force is negligible for most bodies due to distance.

Answer 4

(1) Earth orbits around the sun at an average velocity of 67,108 mph;
(2) Sun and earth orbit around the Milky Way galactic center at about 559,234 mph. Also, the sun and Earth currently move relative to the cosmic microwave background radiation (CMBR) at 829,008 mph
(3) The Milky Way and the Andromeda Galaxy are approaching each other at about 1.34-million mph
(4) The Local Cluster of galaxies of which the Milky Way and Earth are a part are moving towards an immense cluster of distant galaxies (..called "The Great Attractor"..) at 1,342,161 mph

Answer 5

1. Earth rotates (spins on it's axis day and night)
2. Earth revolves or orbits (around the sun years)
3. Earth tilts on it's axis (seasons quartersly)
4. Earth wobbles on it's axis (precession thousands of years)
5. Earth and sun rotate in the Milky way (time and speed ?)
6. Milky way, Earth and sun travel outward from the Big Bang to the outter fringe. (time and speed ?)
7. Earth and sun maybe wobble in the Milky way (unknown ?)
8. Earth and sun are moving away from some stars and towards others (time and speed ?)

7 is totally unknown postulate but the EArth and Sun couls see-saw or undulate in their orbits around the milky way, it is possible and probably, but hard to pin down or prove.

Answer 6

Earth moves in an elipse about the Sun. In relationship to nearby stars the earth moves in something like a spiral. It makes a different shape from almost every different point of view. All of the various shapes are relatively smooth.

Answer 7

The Earth moves in all possible directions and speeds with respect to other bodies in the Universe. You just have to choose the bodies.

Which you have not done here, FYI.

Answer 8

the LOCAL GROUP has its motions, the MILKY WAY has its motion. the sun, has its PROPER MOTION, THE EARTH orbits the sun. in its orbit, it turns on its axis, and wobbles once approximately every 26,000 years, this is known as PRECESSION OF THE EQUINOXES