Here's a problem that I found a solution for:

 

How fast does the Sun travel around the Galaxy (Milky Way)?

 

Find: v

Given: radius from center of Galaxy to Sun, r (CS)=2.5E17 km, time it takes Sun to travel around Galaxy, t=2.5E8 y

 

s=2(pi) x r(CS)=2pi(2.5E17 km)=1.57E18 km

t=2.5E8 y (365 d/y)(24 h/d)=2.19E12 h

v=s/t=1.57E18 km/2.19E12 h

=717 258.6 km/h

Not bad.

The lowest estimation on this site is slightly more. About 782000 km/h (217 km/s)

How many spins around the centre of the galaxy has the solar system made in the last billion years?

How many spins around the centre of the galaxy has the solar system made in the last billion years?

 

in the last billion year:

4

or

4,5

 

and 1/1250 of a revolution since the origin of humans.

 

source: wikipedia

Edited April 22, 201213 yr by michel123456

Problem: How many times has the Sun revolved around the Galaxy in the last 1 billion years?

 

Solution:

Find: n

Given: Total time taken t₂=1 billion y=1E9 y (365 d/y)(24 h/d)=8.76E12 h

Time to travel once around Galaxy t₁=2.19E12 h

n=t₂/t₁=8.76E12 h/2.19E12 h = 4 times exactly

Problem: How many times has the Sun revolved around the Galaxy in the last 1 billion years?

 

Solution:

Find: n

Given: Total time taken t₂=1 billion y=1E9 y (365 d/y)(24 h/d)=8.76E12 h

Time to travel once around Galaxy t₁=2.19E12 h

n=t₂/t₁=8.76E12 h/2.19E12 h = 4 times exactly

 

that is not a surprise since your input was

t=2.5E8 y