The report is due tomorrow
The report is due tomorrow. gas clouds but this one was born from a black hole and a massive gas cloud the black hole Star was born
Black Hole Stars may have been the largest stars that ever existed; they burned brighter than galaxies and were larger than any star today or that could ever exist in the future. But besides their scale, what makes them special and weird is that deep inside they were occupied by a cosmic parasite: an endlessly hungry black hole. How is that even possible?
Black Hole Stars take the weirdness of black holes and go beyond to break everything we know about how stars form and grow. They were only possible during a short window of time in the early universe, but if they existed they would solve one of the largest mysteries of cosmology.
Black Hole Stars were excessive anywhere you look at them. The most massive stars today may have about 300 solar masses; a Black Hole Star had up to 10 million solar masses of nearly pure hydrogen. Let’s take a moment to look at what this means visually: the Sun, Wesen Al Pegasi (the largest star), and finally the Black Hole Star. Its scale is beyond words: over 800,000 times wider than our Sun, 380 times larger than the largest star we know today. And far below its surface is a black hole growing rapidly as it devours billions upon billions of tons of matter per second.
Normally stars are born from gigantic clouds, collections of thousands or millions of solar masses of mostly hydrogen. In these clouds, matter starts to accumulate around the densest spots inside as these spots get denser, their gravitational pull intensifies and they grow faster. Eventually, they generate so much heat and pressure that they ignite fusion reactions and a new star is born. But this puts a limit on their size: nuclear fusion releases enough radiation energy that the surrounding gas cloud is blown away. The new baby star can’t gather more mass from now on. The star is living on the edge between two forces: gravity pulling in, trying to squash the star, and radiation created by fusion pushing outwards, trying to blow the star apart. After millions or billions of years, the core runs out of fuel and the balance breaks, destroying the star.
But Black Hole Stars were very, very different: the beasts of the other universe. Few hundred million years after the Big Bang, when the universe was much smaller, all the matter in existence was much more concentrated. The universe was much denser and hotter; dark matter was a dominant player, forming giant structures called dark matter halos. These Dark Matter Halos were so massive that they pulled in and concentrated unimaginably gigantic amounts of hydrogen gas, becoming the birthplaces of the first stars and galaxies. Epic clouds of hydrogen fought some as massive as 100 million Suns, more than the mass of small galaxies.
In this unique environment that will never exist again, the enormous gravitational pull of the Dark Matter Halos drew gas into its center and created extremely massive stars. As we said before, when a star is born it blows away the gas cloud that created it, but these Titanic gas clouds in the early universe were so large and massive that even after their birth more and more gas piled on the newborn star, making it grow to unbelievable proportions. The young star is forced to grow and grow and grow, getting more and more massive, until in some cases it reaches up to 10 million times the mass of our Sun.
Crushed by gravity, its core gets hotter and hotter, desperately pushing outwards, trying to blow itself apart. But to no avail, there’s too much mass and too much pressure; the balance is impossible to uphold, like a supernova. Run fast forward: the core gets crushed into a black hole. Normally that would be the end—today stars go supernova, a black hole forms, and things calm down. But in this case, the star survives its own death: a tremendous explosion rocks the star from the inside, but it’s not enough. The star is so large and massive, but not even a supernova can destroy it. But now it has a black hole for a heart—it’s tiny, a few tens of kilometers in the center of a thing the size of the solar system. The monster grows: stars are born from gas clouds, but this one was born from a black hole and a massive gas cloud. The Black Hole Star was born.