2006-07-27 05:15:28 · 8 answers · asked by vignes 3 in Science & Mathematics ➔ Astronomy & Space
Earth's mean orbital speed is 30 kilometers per second (km/s), or 18½ miles per second (m/s). http://searchsmb.techtarget.com/sDefinition/0,,sid44_gci849653,00.html
it changes because it is moving in an elliptical orbit around the sun.. so at some points the gravity will be high and you can observe this in kepler's third law
2006-07-27 05:30:09 · answer #1 · answered by Prakash 4 · 0⤊ 0⤋
The true anomaly is an angle, subtended at the sun, from the perihelion of an orbit, measured in the plane of the orbit in the direction of motion to the current position of the planet.
The canonical velocity of a planet in an elliptical orbit around the sun, as a function of the true anomaly, Q, is given by a set of equations that can be considered the vector form of the Vis Viva equation.
Vx’’’ = -sin Q { GM / [ a (1-e^2) ] }^0.5
Vy’’’ = (e + cos Q) { GM / [ a (1-e^2) ] }^0.5
Where...
a = the orbit's semimajor axis
e = the orbit's eccentricity
Q = the true anomaly
GM = the solar gravitational constant
GM = 1.32712440018E+20 m^3 sec^-2
An astronomical unit is 1.49597870691E+11 meters.
For Earth's orbit,
a = 1.00000011 AU
e = 0.01671022
The speed of Earth in its orbit will be greatest at perihelion (Q=0) and least at aphelion (Q=pi radians).
At perihelion,
Vx’’’ = 0
Vy’’’ = (e + 1) { GM / [ a (1-e^2) ] }^0.5
orbital speed = 30.286 km/sec
At aphelion,
Vx’’’ = 0
Vy’’’ = (e - 1) { GM / [ a (1-e^2) ] }^0.5
orbital speed = 29.291 km/sec
2006-07-27 06:14:09 · answer #2 · answered by David S 5 · 1⤊ 0⤋
to many calculations had been made and they are all correct but one thing they had missed and that is if the orbital speed will change the earth orbital speed had dramatically changed it is not the same speed as it is billions of years ago meaning it is actually slowing down but it takes such a long time for any considerable change that would have effect on our daily lives but is really changing
2006-07-31 05:02:09 · answer #3 · answered by magneto077 2 · 0⤊ 0⤋
The actual speed depends on where the earth is in its orbit. When the earth is closest to the sun, it is faster than when it is further away.
2006-07-27 06:47:28 · answer #4 · answered by Bigfoot 7 · 0⤊ 0⤋
Around 67,000 mph. There is no substantial friction to change that speed.
2006-07-27 05:19:25 · answer #5 · answered by Anonymous · 0⤊ 0⤋
18 1/2 miles per second; about 66,000 mph
I do not know if it will ever change.
2006-07-27 05:20:42 · answer #6 · answered by 12BNBDA 3 · 0⤊ 0⤋
24 km/sec. so many things can chand this velocity like sun's gravity
2006-07-27 12:38:14 · answer #7 · answered by mabus 1 · 0⤊ 0⤋
use the facts of centripeal force, accelerate to calculate the velocity.
ok. i calculated it using my HEAD....
it is 29766.23176 meters/second.
or 18.6039 miles/s
or 66974.02147 mph
2006-07-27 05:29:59 · answer #8 · answered by cool nerd 4 · 1⤊ 0⤋