For anyone interested in things like this, I'd recommend "Deep Time" by Gregory Benford[1]. It has a chapter devoted to WIPP[2] and this messaging.

[1] Amazon link: https://www.amazon.com/Deep-Time-Humanity-Communicates-Mille...

[2] Seems to be online, albeit poorly formatted, here: https://www.physics.uci.edu/~silverma/benford.html

The concept that you are interested in is known as deep time (https://en.wikipedia.org/wiki/Deep_time) and there is a book by the same name by Gregory Benford (http://www.amazon.com/Deep-Time-Humanity-Communicates-Millen...) that explores the idea in greater depth.

There's a great discussion of this project in Deep Time by Gregory Benford, which is where I first learned about it.

http://www.amazon.com/Deep-Time-Humanity-Communicates-Millen...