When you look at stars in the night sky, you’re not only seeing light from another place, but another time. Space is so vast that even light, moving at the fastest speed we can imagine, takes ages to reach our planet from other parts of the universe. So if you look at our solar system’s closest neighbor, Alpha Centauri, you’re seeing the light emitted by that star over four years ago. Bigger distances thus yield bigger gaps in time, which is how astronomers recently found evidence of a black hole from 13 billion years ago, long before the Earth, or most other planets, even existed.
Finding darkness in ultrabright objects
The light that was detected by wasn’t coming directly from the black hole itself, as those intensely massive objects don’t emit or reflect any light to see (hence their name). Any object that gets too close gets pulled into the black hole, but all that gravity is good for collecting a looser assortment of material in the immediate space around the black hole as well. In the case of this ancient black hole spotted by astronomers, they knew it was there it was surrounded by an ultrabright quasar, a cloud of energy-emitting particles orbiting the black hole at close to the speed of light.
By analyzing the light coming from quasar J1342+0928, the following profile of the black hole was put together. The supermassive black hole was around 800 million times the mass of our Sun, which isn’t surprising since it would have to be large to support a quasar around it. However, when combining that size plus its age, scientists started scratching their heads. How did such huge collection of mass exist only 690 million years after the Big Bang created our universe?
What existed in the early days of the universe?
As far as everyone could understand, there shouldn’t have been that much material in one place to form a giant black hole that early in our universe’s history. The current model is that after the Big Bang occurred, matter was first very energetic, but then calmed down into mostly neutral hydrogen atoms. Each proton and electron pair was balanced, and had no need to interact with its neighbors, meaning no energy was being released anywhere. This time in the universe’s history is known as the Cosmic Dark Ages, because no stars yet existed to emit any light. Everything was essentially inert.
Eventually, gravity started stirring things up. Particles began to clump and collide, forming larger atoms and reactions. New elements were created for the first time, as did collections of mass with enough nuclear activity to start emitting energy, becoming the first stars. As it happens, the light from the newly discovered quasar J1342+0928 was emitted at this time, meaning it existed when the entire concept of “stars” was just getting started.
Too old to be so big?
Which brings us back to how weird this timing is. The nuances of the light from quasar J1342+0928 help narrow down the date of the so-called Cosmic Dawn, but also raises new questions about what the state of the universe was at that time. If stars were still forming for the first time, how was enough matter somehow rounded up already to form a black hole 800 times bigger than our Sun? Smaller black holes are normally created from the collapse of a star, not congealing dust. This doesn’t necessarily contradict the model for the universe’s maturation, but instead has astronomers looking for new ways for black holes to form.
My four-year-old asked: What would happen to a person sucked into a black hole? To a car? To a house? To a… (etc.)
In almost every case, once that object got close enough to the black hole, crossing the so-called event horizon, it would be ripped and stretched to the center of the gravity-producing mass. For instance, if you fell in feet first, your feet would be yanked downwards harder than your head, although overall the experience would probably be very short, as you’d be pulled apart into a molecular “piece of spaghetti” before being crushed into the black hole itself. You’d technically be adding more mass to the black hole too, making it ever-slightly bigger than it was before.
Source: Scientists observe supermassive black hole in infant universe, Phys.org