"The Dark Star Theory considers whether a binary failed star may be orbiting our Sun at a great distance."
https://darkstar1.co.uk/
"The 1987 New Science and Invention Encyclopedia, Volume 18 SHEE-SPAC
In a section on space probes, the encyclopedia shows the paths of the two Pioneer probes were to ‘triangulate’ on the gravitational affects. It shows the Earth, the Sun, a dead star (at 50 billion miles or 538 AU) and a tenth planet (at 4.7 billion miles or 50 AU)."
https://www.nibiruupdate.com/
"NIBIRU may have been uncovered more than 50 billion miles away, before being covered up by NASA, according to outrageous claims made in a conspiracy documentary."
https://www.express.co.uk/news/weird/1073550/nibiru-proof-scientists-planet-x-heat-50-billion-miles-spt
"Planet Nine’s average distance from the Sun should be about 56 billion miles away."
"If Planet Nine turns out to be Black Hole Nine instead, it’s probably about the size of a grapefruit but about 5 to 10 times the mass of Earth."
https://www.inverse.com/science/planet-9-location-orbit-distance-name-black-hole-news
"The object, which the researchers have nicknamed "Planet Nine," could have a mass about 10 times that of Earth"
https://solarsystem.nasa.gov/planets/hypothetical-planet-x/in-depth/
"Since 2016, some scientists have suspected that a massive, unseen world may be lurking in the outer solar system — a world called Planet Nine. The evidence comes from the strange orbits of some smaller objects past Neptune that all seem to be influenced by a bulky, hidden planet far beyond Pluto. But then, just last year, scientists thought of another explanation, and it’s straight out of sci-fi. The researchers proposed that the so-called Planet Nine isn’t a planet at all. Instead, they suggest that the solar system could be home to one of the universe’s earliest black holes: a primordial black hole."
https://astronomy.com/news/2020/07/is-planet-nine-a-black-hole-or-a-planet-harvard-scientists-suggest-a-way-to-find-out
"The hunt for Planet 9 has gone on for years, with astronomers using visual light and infrared telescopes to scan the outermost parts of the solar system.
"The thing that we realized is that the gravity is the important thing," said Jakub Scholtz, a physicist at Durham University in England and one of the two astronomers behind the idea. "It doesn't need to be a planet. The most mundane, or maybe the most sane explanation is that it's a planet. But as theoretical physicists, we know that early-universe cosmology can very readily introduce a range of very interesting new theoretical bodies — one of which… is primordial black holes.""
https://www.livescience.com/tiny-ancient-black-hole-planet-nine.html
"Though a Planet 9 has been hypothesized, we can't seem to find it, at least not yet. The strange orbits of distant bodies and weird gravitational anomalies beg for an explanation. Scientists propose a hunt for telltale gamma rays from a primordial black hole." https://bigthink.com/hard-science/planet-9-black-hole/
"gamma rays from an entity they know as the black sun."
http://www.starshipearththebigpicture.com/2017/07/17/benjamin-fulford-geopolitical-update-for-july-17-2017/
"gamma-ray bursts are the most energetic events to occur in the Universe!"
https://imagine.gsfc.nasa.gov/educators/gammaraybursts/starchild/page2.html