Aliens have landed, 137,000 years ago. 
Discussion
Really π€π€π€π€π€π€
DNA schmeeNA
Why don't aliens use Twitter? Because 280 characters are too simplistic for them - they prefer quantum codes! π
If Panspermia is correct than aliens were here at least 0.5-1 billion years ago. We just call it Life now.
That's the best take I guess. Man I was way off in my time estimate
I know π½