"Eric Albers" <eric@ericalbers.com> wrote in message news:cf4c422.0408151419.5aabf13@posting.google.com...

Since we know that stars are excellent at being seen from very far
away, would a civilization slightly more advanced use some kind of
modulation on their star to send a message out?

While this may seem silly, as even a 10km x 10km shutter is very tiny
relative to the size and surface area of our star, what size would be
needed to be easily detected from afar?

It's a nice idea, but I dont think it would be cost-effective as a communication device.
Thing is that you need a pretty darn big shutter.

Consider the fact that we still can barely detect earth-size objects around other stars, so the shutters should be at least
Earth-size. Probably Jupiter-size would be better.
And the data-rate would surely be slow (cannot expect 1kbit/sec from any Jupiter-size object), and detection chances diminish with
rapid shuttering too.
It's also very hard to rotate this 'transmitter'..

It is almost certainly cheaper for any civilization to build a good size antenna and use good-old microwave, or laser pulses.