What are we actually seeing?
During one of the movie’s highlightsclimactic moments, a dark disk is shown, surrounded by a bright red-and-white ring. It strongly resembles the EHT image of the supermassive black hole M87*. In that image, we see glowing gas swirling around the black hole, with light being bent dramatically by gravity. The dark shadow appears because light can no longer escape. Even the color scheme in the movie seems to mimic that of the EHT photo, despite the fact that those colors are artistically chosen — the famous image was based on radio waves, not visible light.
At first glance, it looks like a textbook black hole —, until one of the characters says it’s actually a massive neutron star. Another adds that this is “practically the same as a black hole.” But how accurate is that?
Black Hole vs. Neutron Star
Both are remnants of collapsed stars. When a massive star runs out of fuel, it collapses under its own gravity. If the mass is great enough, it forms a black hole: — an object from which even light cannot escape. Slightly lighter stars are just barely held up by the pressure of neutrons. This results in a neutron star: an extremely compact, hot sphere about the size of a city, but more massive than the Sun. Both objects are so dense that relativistic effects become visible, leading to impressive distortions of light in both cases.
There is, however, a crucial difference: a black hole has no surface, while a neutron star does. Because this surface is extremely hot, it emits light. It’s also illuminated by incoming gas that crashes into it. So a neutron star can never appear completely black.
Still redeemable?
Should we then dismiss the scene? Not necessarily. This is where the concept of dynamic range comes into play: how well we can perceive differences in brightness. If the accretion disk is extremely bright, it can outshine the neutron star’s surface and make it appear dark — just as we can’t see stars during the day. Heat the disk enough, and the surface fades from view.
One problem remains: gas falling onto the surface should light up. But this, too, is addressed later in the movie. We see a collision with the surface that releases a huge amount of energy, which is — exactly what you’d expect from a neutron star, and not from a black hole. So it ends up being surprisingly accurate.
Conclusion
‘The Fantastic Four: First Steps’ doesn’t go with a black hole, but with a neutron star — and they pull it off quite well. While neutron stars often look different from black holes, it’s certainly plausible that under some conditions, the difference is barely visible. The result is a visually striking scene, supported by the story. Definitely worth watching. Now let’s hope that the next appearance of a neutron star or black hole comes not from Hollywood, but from real astronomical observations.