Thursday, October 31, 2013
A Planet similar to earth
Scientists have found a new planet very close to the earth. Named Kepler-78b, this planet has 1.8 times the mass as that of the earth and is 400 light-years from the earth. It takes Kepler-78b 8.5 hrs to complete an orbit around its sun-like start in a radius of 900,000 miles. It does not rotate around its own axis. So I thought it will be interesting to compare the angular and linear speed of this new planet to earth. In order to calculate that, I assume it orbits in a circular path.
The orbit radius=900,000 miles*1609 m/1 mile=1.45*10^9 m.
time=8.5 hrs=30600 s.
w=2pi/30600 s=0.00021 rad/s
v=rw=0.00021 rad/s*1.45*10^9 m=3.0 *10^5 m/s.
The angular and linear speed of the plant can be compared to that of the earth, which has a linear speed
of 29780 m/s, which equals an angular speed of 29780 m/1.50*10^11 m=2.0*10^-7 rad/s. The planet rotates much faster than the earth around the star.