Possibility dismissed because invisible in infrared searches. Likelihood of surrounding nebula from many collisions never considered. Strong statistical pattern of extinction events found at 27mm year intervals.
Melott, A.L.; Bambach, R.K. (2010). "Nemesis Reconsidered". Monthly Notices of the Royal Astronomical Society Letters.
Period considered too long for Nemesis orbit. ET orbital engineering overcomes objection.
The final chart is the money shot. Earth looks to be due for a big hit. Big ones come in pairs with about 50mm year separations, and Earth has been unusually quiet for 200mm years with only one big event 60mm years ago. We're due.
Sometimes I hate being right.
That chart is like looking at an x-ray of your brain and diagnosing terminal cancer.