how could earth maintain its speed?

Question

earth is orbiting the sun in a orbit. its oval in shape. then doesnt it make any speed difference.

Answer 1

The Earth does change its speed over the course of the year. However, the eccentricity of the Earth's orbit is only about .0017. That's pretty circular.

At perihelion (first week of January), the Earth is traveling about 29.835 km/sec and at apohelion (first week of July), the Earth is traveling about 29.734 km/sec.

Rather than confuse people with the minor variations, the mean motion (average angular velocity) is just multiplied by the satellite's average radius (semi-major axis of the orbit) to get a mean speed of about 29.785 km/sec. That's pretty close to both its fastest speed and its slowest speed.

All of the planet's orbits are pretty circular. Pluto (e=.248) and Mercury (e=.206) are the most elliptical orbits.

If you're interested, the average radius of the Earth (1 astronomical unit) is 149,597,870.691 km. This is the semi-major axis (a).

Perihelion (closest point to Sun) is rp=a(1-e) (rp is radius of perihelion)
Apohelion (furthest point from Sun) is ra=a(1+e) (ra = radius of apohelion)

Speed in the orbit is: s=sqrt[GS (2/r - 1/a)]
where GS is the Sun's gravitational constant (1.327 124 420 76 x 10^11 km^3/sec^2); r is the current distance from the Sun; and a is the average radius (semi-major axis).

The same equations are used for the Moon and satellites, except the Earth's gravitational constant (3.986004418 x 10^5 km^3/sec^2) is substituted for the Sun's gravitational constant.

Answer 2

There is no other force to act upon the earth to slow, or speed up the earths movement arround the sun. Orbit doesn't change speed, only the direction the speed is directed. In a way the earth has sped up to it's maximum falling speed, and keeps falling within the suns gravitational pull but, it's falling at such an outward speed that it misses hitting the sun continuing on the same ovular orbit untill acted upon buy an outward force enough to ruin it's orbit. (Hitting a large mass the size of the moon)

Answer 3

The distance is so great, that is is almost like walking in a straight line. (Imagine you are in a car. There is a road all around the Earth. You can drive at 300 MPH. Even though the Earth is round, the road will seem always flat!)
Most planets of the Solar System have an oval shape orbit paths, which is optimal to keep planets at a certain distance from the Sun.

Answer 4

The orbit of the earth is the result of inertia and gravity. Inertia causes the earth to move forward, and gravity causes the earth to "fall" into the sun. Since neither inertia or gravity overcome one another, the result is an orbital path. The orbit of the earth is slightly elliptical, or ovular, because inertia and gravity are not in perfect balance.

In answer to your question, the earth does speed up and slow down throughout its orbit. As the earth approaches the sun, it speeds up, and as it travels away from the sun, it slows down, just as when you throw a ball in the air, it slows down until it reverses direction, and then speeds up again.

The difference in speeds is very small, but it is responsible for our northern winters being slightly shorter (about 4 days shorter) than northern summers. During northern winter, the earth is closer to the sun, and thus, moving faster in its orbit.

Answer 5

The earths orbit is slightly oval. At apogee (furthest) it's going slightly slower than at perigee (closest). And the orbit always sweeps the same amount of arc at any speed. Also remember that the earth is essentially always falling toward the sun but kept in orbit by it's own centrifical force caused by its orbital speed. With nothing to slow it, it just keeps falling.

Answer 6

Newton's first law says that an object in motion will tend to stay in motion unless acted on by a force. In every day life there is always a force from friction with the air or ground that is slowing everything down. Ice skaters can slide much longer than people just sliding on the floor because friction on the ice is less than on the ground, but even on the ice there is some friction and the sliding slows gradually. But in outer space, with no air and no ground, there is no friction, so the motion never slows down.

Answer 7

All physical systems that lose energy through friction, as the earth does, eventually slow down. Some day the earth will spiral into the sun.
A joke:
A professor of astrophysics was giving a public lecture about the beginning and end of the solar system.
Towards the end he said:
"The Earth will fall into the Sun in ten billion years or so."
In a panic, a man shouted "WHAT DID YOU SAY??"
The professor calmly repeated,"In approximately ten billion years, the Earth will fall into the Sun."
"Oh, I'm relieved, I thought you said ten million!"
Budda Bing!

Answer 8

Astronomers proved that Earth's orbit is (almost) a perfect ellipse. In such an orbit, Earth's speed is the highest when it is at the closest to the Sun, and the lowest when it is at the farthest.

Answer 9

the earth orbit is very close to circular... I am not sure of the exact numbers but if i remeber it correctly the ammount that it is off from being exactly circular is about 1% or so...

The differance in its speed as it its at its closest to the sun and its farthest is about 19 miles/second to about 18.5 miles/s

not too much of a differance but it in noticable when proforming very precise measurments

Answer 10

OOhhhoo hahaa what a question?Think the other way round what's stopping earth from rotating?There isn't a force that is acting against earth's rotation because it's in vacuum.