What is the speed of Earth?

We all know the rotation and revolution of the earth. But do you know any other factors after revolution that affect the movement of earth in both direction of movement and speed of earth? Well is a lot and its seems quite complicated but it is not. You'll know yourself after reading this article because today we are going to calculate the speed at which the earth moves step by step. But before that, I want you to guess the speed, just randomly you know. Why not better comment the guess in the comment section and later check how much close you got it. Well lest start the discussion.

1. Rotation

The earth rotates in its axis which goes through north pole to south pole and rotates in counter-clock wise when viewed from north pole. The part of the earth moving towards and away from the sun makes day and night. The time taken by earth to complete one cycle of rotation and come to its original position is 23 hours, 56 minutes and 4.0916 seconds which is one sidereal day. However, during one rotation, it also travels some distance along revolution. So after each sidereal day, earth has to move some more angle to be in the same time with respect to Sun and our local time. Here, same time with respect to our local time means if sun rises at 6 in the morning today, it should always rise at about the same time always. This angle varies each day through out the year due to earth's elliptical orbit around the sun. This is the reason why September 18th is the shortest and December 22nd the longest day in the year. Revolution also affects a day. So, the average of the sum of time required for earth to complete a sidereal day and the time required to rotate that extra angle annually gives 24 hours which is Solar day.

When earth rotates, the person near the polar region covers the greater distance than the person near the polar region. Its something like wheel and axle-the further apart you go from the axis of rotation, the greater distance you cover in the same time, thus increasing the velocity.

According to the data updated by NASA on 23^rd December 2016,

Equatorial Diameter of Earth = 12756.274 km

Time = 24 hours

So,

Circumference (Distance Covered) = 兀 * Diameter = 兀 * 12756.274 km = 40075.017 km

Therefore,

Velocity _Rotation = Distance Covered/Time Taken = (40075.017 km)/(24 hrs)

                                                                             = 1669.792 km/hr

                                                                             = 4630.498 m/s

2. Revolution

Earth revolves around the Sun in a plane titled 23.4° causing different seasons in a year. According to Kepler's laws of planetary motion, earth moves around the sun in an elliptical orbit with sun in one of the foci.

Revolution of Earth around Sun according to Kepler's Law

The end part of the major axis near the sun is known as Periapsis and the other end is known as Apoapsis. The Aphelion measures 152.10 * 10⁶ km and Prehelion measures 147.10 * 10⁶ km. The eccentricity of the orbit of earth is 0.01671022 which is quite small. So, while calculating the circumference, for easiness, we take it as circle.

Semi-major axis of the orbit (Radius) = 149.6 * 10⁶ km
Time taken by earth to revolve around the sun (One year) = 365.2421891 days

So,
Circumference = 2 * 兀 * Radius = 2 * 兀 * 149.6 * 10⁶ km = 939964522 km

And,
Velocity _Revolution = Circumference/Time Taken = (939964522 km)/(365.2421891 days)
                                                                           = 29.78 km/s
                                                                           = 29780 m/s

3. Revolution of Sun around the Center Milky Way Galaxy

The Sun also revolves around the center of Milky Way Galaxy, the galaxy our solar system lies on. One complete revolution of Sun around the center of Milky Way Galaxy is known as Cosmic year or Galactic year. One Cosmic year equals to about 230 million years.

According to the latest NASA's statistical data of 23^rd December 2016, the average velocity of Sun during the Cosmic year is 720,000 km/hr which equals 200,000 m/s.

4. Movement of Milky Way within Local Group

Now, the Milky Way Galaxy also moves around other group of nearby galaxies called Local Group. Scientist say that Milky Way galaxy revolves around the Local Group and also moves towards the constellations like Hydra and Virgo. So, the average resultant velocity of the movement of Milky Way Galaxy as provided by the latest data of 2013 by http://space.com is 3.5792 * 10⁶ km/hr.

After This?

Scientists are trying to figure out the things after this too, but for now, we have only this much data. However, we all know the universe is expanding right? So, there are chances that there are more movements to affect the speed of earth. Damn! The whole universe is moving.

Total

So lets calculate the total velocity of the earth. Now, for the total velocity, it would be quite accurate if we considered all the directions of the velocity and did the addition in vector space. However, we lack the direction of most of the velocities. So, here we are just going to find out the total speed of the earth. Now, lets tabulate the calculated velocities in order and add them to get the total.

Speed of	Speed (m/s)
Earth’s Rotation	4630.498
Earth's Revolution	29780
Revolution of Sun	200000
Movement of Milky Way Galaxy	994222.222
Total	1228632.72

You can view the video of the calculation of the speed of movement of Earth below. Please SUBSCRIBE MY CHANNEL if you haven't already.

So, yeah, we calculated the speed of earth and 1.228 * 10⁶ m/s is too fast to imagine. Actually it seemed quite simple right? So, how much had you guessed? Is your guess correct? How much close did you got it? Please let me know in the comment below.