Supermassive black holes, lurking at the centers of most galaxies, possess masses ranging from 100,000 to tens of billions times that of our Sun. But just how big is Sagittarius A*, the supermassive black hole at the center of our own Milky Way galaxy, compared to our Sun? A new animation from NASA provides a stunning visual comparison.
, compared to our solar system. Its shadow is about half the diameter of Mercury’s orbit.
Credit: EHT Collaboration*
The size of a black hole is typically defined by its shadow, a dark circular region about twice the size of its event horizon, the point of no return. This shadow is created by the black hole’s intense gravity bending and capturing light. NASA’s animation scales 10 supermassive black holes relative to these shadows, offering a clear perspective on their immense sizes compared to familiar structures within our solar system.
Sagittarius A*, with a mass of 4.3 million Suns, has a shadow diameter roughly half that of Mercury’s orbit. This makes it dwarfed by some of the true behemoths featured in the animation. For instance, the black hole at the center of M87, with an updated mass of 5.4 billion Suns, has a shadow so large that light would take about two and a half days to cross it.
Credit: ESO/Voggel et al.
The animation also highlights the incredible density of these objects. The black hole in the dwarf galaxy 1601+3113, despite containing the mass of 100,000 Suns, has a shadow smaller than our own Sun due to the extreme compression of matter.
Furthermore, the animation illustrates the eventual fate of some supermassive black holes: merging with one another. The galaxy NGC 7727 hosts two such black holes, destined to collide and merge within the next 250 million years. This process, detectable through the low-frequency gravitational waves it produces, will be studied by future space-based observatories like the Laser Interferometer Space Antenna (LISA).
Credit: SDSS
The culmination of the animation showcases TON 618, a colossal black hole with over 60 billion solar masses. Its shadow is so vast that light would require weeks to traverse it, emphasizing the truly mind-boggling scale of these cosmic giants. While Sagittarius A* is a significant black hole in its own right, TON 618 underscores the immense range of sizes that exist in the universe. The comparison to our Sun truly highlights the “super” in supermassive black holes.
