Calculating the distance between a "5 cent coin sized" sun to Proxima Centauri

[renormalised (Carl)]

Originally Posted by shelltree

It kept me very busy in my lunch break

These are the results I got, though again they are very likely a bit off

Rigel

810 light years and 85 solar diametres

810 x 9.4605284 x 10^18
= 7.66 x 10^12

85 x 1.391 x 10^12
= 1.182 x 10^14



19.41/1.182 x 10^14
= 1.642 x 10^-17

7.66 x 10^12 x 1.642 x 10^-17
= 1.257 x 10^14
= 1.257 x 10^8
= 1.25 x 10^2
= 125km

Betelguese

640 light years and 900 solar masses

640 x 9.4605284 x 10^18
= 6.05 x 10^12

900 x 1.391 x 10^12
= 1.251 x 10^7

19.41/1.251 x 10^7
= 1.55 x 10^-10

6.05 x 10^12 x 1.55 x 10^-10
= 9.377 x 10^13
= 9.377 x 10^8
= 9.377 x 10^2
= 937.7km

Sirius

8.64 light years and 1.71 solar diametres

8.64 x 9.4605284 x 10^18
= 8.173 x 10^13

1.71 x 1.391 x 10^12
= 2.378 x 10^12

19.41/2.378 x 10^12
= 8.162 x 10^-13

8.173 x 10^13 x 8.162 x 10^-13
= 6.67 x 10^17
= 6.67 x 10^11
= 6.67 x 10^2
= 667km

Gliese 581

20 light years and 0.36 solar diametres

20 x 9.4605284 x 10^18
= 1.892 x 10^11

0.36 x 1.391 x 10^12
= 5.007 x 10^11

19.41/1.892 x 10^11
= 1.025 x 10^-13

5.007 x 10^11 x 1.025 x 10^-13
= 5.132 x 10^12
= 5.132 x 10^6
= 5.132 x 10^2
= 513.2km

Alpha Cen A

4.395 light years and 1.23 solar diametres

4.395 x 9.4605284 x 10^18
= 4.157 x 10^13

1.23 x 1.391 x 10^12
= 1.710 x 10^12

19.41/1.710 x 10^12
= 1.135 x 10^-14

4.157 x 10^13 x 1.135 x 10^-14
= 4.718 x 10^14
= 4.718 x 10^8
= 4.718 x 10^2
= 471.8km

...maybe? I think I'm on the right track but so far I seem to get something wrong

You're way off again...check all your figures.

How do you get 810 x 9.4605284 x 10^18 = 7.66 x 10^12, when it should be 7.66 x 10^21????. Unless you're transposing the exponent for some weird reason!!!!

Check all your figures carefully.

[renormalised (Carl)]

Ah...I think I see what you're doing. You're converting that first figure to kilometres in your head and then writing it down as the answer. You're only confusing yourself and others by doing this....and not getting the right answers.

For instance, you got this for Alpha Cen A...

4.395 x 9.4605284 x 10^18 (assuming your answer was 4.158 x 10^19mm)
= 4.158 x 10^13 (km, not mm)

That answer is correct, but leave it at 4.158 x 10^19 (mm), which will give you the correct final answer.

But even still, when you get the calc' wrong in the first place...

(Rigel)

810 x 9.4605284 x 10^18
= 7.66 x 10^12 (should be 7.66 x 10^21mm)

You get 7.66 x 10^15km (not 7.66 x 10^12km)

What you've done here is multiplied it out but for some reason used 18 as the exponent instead of the correct answer, 21, and then did your conversion (which is unnecessary).