Before............................
Yes and no he said that all atoms of a given element are identical in mass and properties.
Use proportions.
1 lightyear = <span>9.4605284 trillion kilometers
</span><span>x light years </span>≈<span> 33.31 </span>trillion kilometers
<span>
33.31/9.46 = x/1
3.50 </span>≈ x<span>
</span>
