15 September, 16:07

# The Milky Way Galaxy is moving at about 600 km/s relative to the cosmic microwave background. How does this compare to Earth's speed in its orbit and

+5
1. 15 September, 19:52
0
This speed is greater than both Earth's speed inits orbit and the solar system's speed.

Explanation:

Earth's mean orbital speed is the speed at which the Earth revolves around the sun. It is calculated as follows:

We take the quotient of the circumference of Earth's orbit around the Sun and the time it takes the to revolve around the sun which is one year.

The circumference of the Earth's orbit is approximately 2π (6.283185) times the radius of its orbit. This radius is also known as the astronomical unit (AU), and is about 1.4959787 x 10¹¹ meters (m). Therefore, the circumference is about 9.399511 x 10¹¹ m

Earth's orbital speed is:

v = (9.399511 x 10¹¹) / (3.155815 x 10⁷)

= 2.978473 x 10⁴ m/s

To get this to be in km/s we divide by 1000

Thus,

v = 29.78 km/s

The orbital speed of the solar system is determined as follows:

The distance from the centre of the solar system to the galactic centre is 28000 light years. The circumference of the solar system's orbit around the galactic centre is

C = (28000*9.46x10¹²) x2π

= 1.66 x 10¹⁸ km

(To convert from light years to km we multiply by 9.46 x 10¹²)

Thus, taking the quotient between the circumference and one galactic year we get

v = (1.66 x 10¹⁸) / (225 x 10⁶x 3.15 x 10⁷)

= 234.8 km/s

Therefore, the Milky Way's speed is greater than both Earth's speed inits orbit and the solar system's speed.