What if Planet 9 is a Primordial Black Hole? (2019) User TheStartupChime, in the hypeurls subreddit, 28 Sep 2023
What if Planet 9 is a Primordial Black Hole? User volossaveroniki, in the SpaceNews subreddit, 15 Jul 2023
[1909.11090] What if Planet 9 is a Primordial Black Hole? User walt74, in the GOOOOODINTERNET subreddit, 21 Feb 2022
What if Planet 9 is a Primordial Black Hole? (2019) User PatientModBot, in the patient_hackernews subreddit, 13 Aug 2021
What if Planet 9 is a Primordial Black Hole? (2019) User qznc_bot2, in the Hacker News subreddit, 13 Aug 2021
What if Planet 9 is a Primordial Black Hole? User PatientModBot, in the patient_hackernews subreddit, 30 Jul 2020
What if Planet 9 is a Primordial Black Hole? User qznc_bot2, in the Hacker News subreddit, 30 Jul 2020
What if planet 9 is a Primordial Black Hole? A New Paper Investigates the Possibility That the Theorized “Planet 9” is Actually a Primordial Black Hole User SpunkySputniks, in the /r/space: news, articles and discussion subreddit, 27 Sep 2019
What If Planet 9 Is a Primordial Black Hole? User qznc_bot2, in the Hacker News subreddit, 26 Sep 2019
What if Planet 9 is a Primordial Black Hole? User pablojohns, in the /r/space: news, articles and discussion subreddit, 26 Sep 2019