“There are hints of a novel object ("Planet 9") with a mass 5−10 M in the outer Solar System, at a distance of order 500 [astronomical units]."
Thus begins a new paper by a renowned theoretical physicist who believes the “hints” of Planet 9 can be found and identified using spacecraft currently under development. He himself hints that this “Planet 9” may not be a planet at all, but something even more theoretical and “exotic.” More exotic? Like a planet of prehistoric women?
“Searches for this object are in progress. On the other hand, it has been suggested that Planet 9 might really be a primordial black hole (PBH) or other exotic compact object.”
In a new paper published in arxiv.org but not yet peer-reviewed, Ed Witten, a theoretical physicist at Princeton’s Institute for Advanced Study, proposes that where there’s hints of smoke, there’s likely hints of fire, but not necessarily of the planetary kind. Witten certainly has the creds to present this kind of theory – he’s worked on the mathematics of quantum field theory and developed string theory's unifying "M-theory" which proposes 11 dimensions (9 space dimensions, 1 time dimension, 1 energy dimension) and is the closest thing so far to a “Theory of Everything,” even though no experimental support for it exist.
Witten stays in theoretical mode by proposing that Planet 9 might be a primordial black hole – hypothetical black holes thought to have formed shortly after the Big Bang, meaning they aren’t collapsed stars like conventional black holes. If Planet 9 is a black hole in our solar system (a scary thought), it can’t be seen with conventional telescopes. Fortunately, Witten proposes a soon-to-be-conventional alternative.
“A possible alternative is to probe the gravitational field of this object using small, laser-launched spacecraft, like the ones envisioned in the Breakthrough Starshot project.”
Breakthrough Starshot is the project – founded by Yuri Milner, Stephen Hawking, and Mark Zuckerberg – to build a fleet of tiny light sail spacecraft that would be pushed by lasers at speeds approaching 20% of the speed of light to distant locations. A trip to the Alpha Centauri star system 4.37 light-years away would thus take 20+ years, but one to the edge of the solar system where this Planet 9 or Primordial Black Hole 1 might live would take far less time.
According to LiveScience, each craft would contain just an atomic clock and a radio transmitter. That simple pairing would tell Earth researchers when the craft was affected by the gravity of a large space object, where it is and, depending on the force, whether it’s a planet, a prmoridal black hole or something more exotic. A planet of prehistoric women?
“Think “quark nugget.””
The unimaginative LiveScience proposes a quark nugget (or strangelet), which is a theoretical object composed of approximately equal numbers of up, down, and strange quarks. Whatever the “hint of a novel object” might be, Witten’s proposal is a good news/bad news idea. Tiny light sails are low cost, but their completion, deployment and arrival are still decades away – far too long for those who want their Planet 9 questions answered now.
For those people, I suggest passing the time with viewings of “Voyage to the Planet of Prehistoric Women,” a 1968 sci-fi film directed by Peter Bogdanovich and starring the lovely Mamie Van Doren as Moana, a prehistoric woman living on Venus. Not exactly string theory or even string bikinis, but a fun romp based on a Roger Corman film.