Breaking the Speed Limit: New Black Hole Discoveries Challenge Cosmic Theory

By Ian Wu

Choate Rosemary Hall, CT

Scientists have made two exciting discoveries about black holes — incredibly dense objects in space that have such strong gravity that not even light can escape them. These findings help us better understand how black holes work and how they grew in the early universe.

Image of a black hole

The first discovery involves a concept called "Light Echoes." Just like sound can echo off walls, light can echo around a black hole due to gravitational properties. When light travels near a black hole, it can take multiple paths to reach us on Earth: some light goes directly to us, while other light rays circle the black hole one or more times before reaching us. This creates a delay, similar to how you might hear an echo in the mountains.

To detect these light echoes, scientists from Princeton propose using a technique called interferometry. This is like combining multiple telescopes to act as one giant telescope. Imagine ripples in a pond - when two sets of ripples meet, they create a pattern where some waves add together to make bigger waves, while others cancel out. Interferometry works similarly with light waves. By observing at the same time from different locations and combining the signals, multiple telescopes can effectively function as one massive telescope, achieving much higher resolution than any single telescope could on its own. In this discovery, interferometry is conducted with telescopes thousands of kilometers apart. By studying these light echoes, scientists can learn important information about black holes, such as their size, how fast they spin, and how they warp space around them.

Image of the James Webb Space Telescope

The second discovery involves LID-568, a black hole detected by the James Webb Space Telescope. Scientists found it's consuming matter at an unprecedented rate. To understand this discovery's significance, imagine trying to drink a milkshake through a straw — there's typically a physical limit to how fast you can drink. However, LID-568 is consuming matter 40 times faster than what scientists thought was the theoretical maximum speed, called the Eddington limit. This limit is the point where the inward pull of gravity should balance with the outward pressure from heated, compressed matter. This discovery helps explain how early black hole “seeds” could have grown so massive, which current theories suggest arise either from the death of the universe’s first stars (light seeds) or the direct collapse of gas clouds (heavy seeds).

LID-568 lies 12.3 billion light-years away, offering us a glimpse into the early universe just 1.5 billion years after the Big Bang. Its rapid growth rate helps solve a long-standing astronomical puzzle: how supermassive black holes could form so quickly in the universe's youth. According to research team leader Hyewon Suh from the International Gemini Observatory, this discovery suggests black holes can gain much of their mass during brief periods of intense feeding, regardless of their original size. This finding bridges a crucial gap in our understanding of early black hole evolution.

Image of the LID-568 Black Hole

These discoveries extend far beyond black holes themselves. By studying these cosmic giants, scientists can test fundamental theories of physics and challenge our understanding of how the universe operates. The tools and techniques developed for black hole research have practical applications too, advancing fields like medical imaging and satellite navigation. Thus, unlocking the mysteries of black holes not only expands our cosmic knowledge but also drives technological innovation here on Earth.

Scientists plan to continue studying both light echoes and fast-growing black holes like LID-568. They'll use even better telescopes and new techniques to learn more about these mysterious objects. Each discovery brings us closer to understanding how our universe formed and evolved into what we see today.

----Works Cited

Suh, H., Scharwächter, J., Farina, E.P. et al. A super-Eddington-accreting black hole ~1.5 Gyr after the Big Bang observed with JWST. Nat Astron (2024). https://doi.org/10.1038/s41550-024-02402-9

Wong, G. N., Medeiros, L., Cárdenas-Avendaño, A., & Stone, J. M. (2024). Measuring Black Hole Light Echoes with Very Long Baseline Interferometry. The Astrophysical Journal Letters, 975(2), L40–L40. https://doi.org/10.3847/2041-8213/ad8650