[CurlyDave]

...It's 8,000 miles in diameter, certainly bigger than the Moon, but it's 300,000 miles distant...

I learned 240,000 miles in grade school (in the 1950s) and I do not believe it has changed since them.

But I do agree with you on the "insignificant shielding" issue.

[dayglored]

Yep, ~240,000 not ~300,000. I was misremembering.