An Astronomic VS: Black Hole vs. Neutron Star

Syke, Rika, Nurro, Eyewire, citizen science, competition, arm wrestling, Elena Daly

Did you enjoy our Great Galactic Voyage? This month we’re briefly revisiting the world of astronomy to bring you a gravitational heavy hitter! If you were a collapsing star, which would you rather become: a black hole or a neutron star? The choice may be as complex as astrophysics itself!

Read on, choose your starry fate, and then get ready: the competition starts at 11 AM EDT on 9/6 and goes for 48 hours!

Your teams:

Black Hole

  • If a star is roughly twice the mass of our Sun, it surpasses the Tolman–Oppenheimer–Volkoff limit, such that when it reaches its collapse phase, nothing in the universe can stop the star’s gravity from total collapse, resulting in the black hole: a region of spacetime so dense that even light can’t break free. A perfect void! Sounds metal.
  • Until 2019, when the Event Horizon Telescope finally imaged the supermassive black hole at the heart of galaxy Messier 87, there was never any published “visual proof” of black holes existing. Our awareness of black holes had previously been based on raw mathematics, predictions from Einstein’s general relativity, and various indirect observations.
  • There are still all kinds of things we don’t really know about black holes, because their very structure makes it impossible to learn their internal behavior. One hot topic is whether they emit “Hawking radiation,” a possible (and paradoxical-sounding) thermal electromagnetic radiation that might still be produced by a totally opaque, non-reflective body. If Hawking radiation is real, this means black holes could gradually evaporate over the course of, say, a googol years.

Neutron Star

  • Are you not quite up for becoming the densest, darkest thing in the universe? A neutron star might be more your style. Formed after certain forms of supernovae, the star’s remaining mass becomes primarily neutrons, packed so closely together that the total object is barely a dozen kilometers across! Strong force and neutron degeneracy pressure then prevent the star from collapsing any further. This means that even after the dazzling glory of going nova, neutron stars continue burning incredibly hot. How hot is hot? Try 600,000 Kelvin.
  • At such heat, you’d think astrophysicists would have no trouble locating neutron stars. However, their radiation doesn’t always emit in an easily detectable way, and over time they cool down. One of your best bets is when the stars’ angular momentum causes their radiation emissions to become regularly detectable “pulses”— in other words, when a neutron star is also a pulsar.
  • Unlike black holes, neutron stars can disappear comparably “fast.” Some ways this can happen include drifting close enough to another star to form a binary system that itself eventually collides and collapses— or as a neutron star’s rotation slows, it can no longer resist enough to do anything but continue full transformation into a black hole.


  • Starting Lineup – top 3 players on each team, who earn 75% of their score in bonus points
  • All Other Players – earn 50% of their score in bonus points
  • Winning Team – 20,000 additional points
  • Each Team’s MVP – 5,000 additional points

The winning team is determined by average points per player, with 2x weight given to Starting Lineup players. To qualify for any of the above bonuses or affect the team score, players must earn a minimum baseline of 2,000 points.

Artwork by Elena Daly