Dark or black stars may have been the most influential celestial bodies in the universe, although no one knows for sure that they existed. They may have existed before conventional stars were able to form. They would be the oldest stars in the cosmos , twinkling long before these other stars, at least as we know them now.
So why is there no evidence for them?
Because they could have literally faded to black, into a black hole. At least that’s the theory put forward by the physicist at the University of Michigan (USA), Katherine Freese.
Freese suggests that dark stars are actually the seeds of the supermassive black holes that lurk at the heart of every galaxy. After all, even the regions of space that bend time and absorb light have to be born of something. And that something could be a dark star.
But how does a bright and glowing celestial body take such a dramatically extreme and dark turn? For one thing, a dark star, unlike the stars we know and occasionally see, would already have darkness literally running through its veins.
What differentiates the dark stars?
The stars we see today adhere to the same general rule of nuclear fusion. The great mass of a star means that it is always in a state of collapse on itself. But that kind of constant pressure on your core also produces energy that is radiated outward. The result is a perfect balance of inward attraction and outward radiation.
Our sun, for example, has struck that perfect balance, building gravitational pressure in the giant battery that essentially powers the solar system.
Dark stars, on the other hand, do things a bit differently. They have hydrogen and helium yes, but also, a touch of dark matter. Yes, it is that other material that no one has seen or detected, which makes the dark star theory even more diffuse.
The theory
About 13 billion years ago, when dark stars were forming, the universe was a very different and much denser place. They likely incorporated dark matter into their DNA, in the form of weakly interacting massive particles or WIMPs (hypothetical particles that could explain the dark matter problem, as we see).
Even as a microscopic ingredient in a star, dark matter could sustain a celestial body for a billion years thanks to a unique process called dark matter annihilation.
Essentially, dark matter gives a dark star its “superpowers”: it could expand and radiate energy without having to rely on that delicate process known as nuclear fusion. That would also unload the dark star from its core, allowing it to spread outward and, despite its name, shine even brighter. They could continue to grow as long as there was dark matter fuel.
There would be no limit, in principle. Later, at some point, a star with this mass would have to collapse, turning into a black hole.
How do we check this hypothesis?
The James Webb Space Telescope could give us the answer. Scheduled for launch in March 2021, the space eye will be “the largest and most powerful telescope ever put in space.” While astronomers are excited about the possibility of countless discoveries of new planets, Webb will also get a glimpse of the most elusive and ancient celestial body known as the dark star.
