Speed of Sun Around Galaxy

[IsaacAsimov]

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

[michel123456]

Not bad.

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

[JohnStu]

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

[michel123456]

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, 2012 by michel123456

[IsaacAsimov]

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

[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

 

that is not a surprise since your input was

t=2.5E8 y