Down-votes are not for factually correct or incorrect comments. They are for comments that either do or do not contribute to the discussion.
Saying that he believes that "aliens created a solar sail-powered pancake-shaped spacecraft 600,000 years ago just so it could fly by us and say hi" is incredibly dismissive, and also a misrepresentation of his views, and his point.
Those are his views. I didn't misrepresent them, I stated them plainly. As a result, it sounds like a stupid idea. That is my contribution to the discussion. Not liking this contribution, or not agreeing with it, doesn't mean it's not a contribution. The downvotes are because people don't like it.
In this article, he mentions a dead alien civilization sending it. He also mentions the pancake shape.
In this other article[1] he mentions it taking 600,000 years to reach us from Vega.
In this article[2] he mentions the solar sail.
You can find it all on the Wikipedia page[3]. But thanks for the downvotes, guys.
[1] https://www.skyandtelescope.com/astronomy-news/astronomers-s... [2] https://www.haaretz.com/world-news/.premium.MAGAZINE-if-true... [3] https://en.wikipedia.org/wiki/ʻOumuamua