Celebrity astrophysicist Neil deGrasse Tyson is denying sexual misconduct allegations, offering his own account of encounters with three women. After Fox and National Geographic announced they were investigating the Cosmos host following a Patheos report, Tyson initially declined comment. But in a Facebook post this weekend, he said, “Clearly, I cannot continue to stay silent.” In connection with two allegations from within the last decade, he apologized for making the women uncomfortable but suggested no harassment had occurred. Responding to an allegation of sexual assault from the 1980s, he said the woman was an ex-girlfriend who had apparently created a “false memory.” Tyson said he welcomed the investigation. “Accusations can damage a reputation and a marriage,” he wrote. “Sometimes irreversibly. I see myself as loving husband and as a public servant—a scientist and educator who serves at the will of the public.”