Category: structure formation

What Was It Like When The First Supermassive B…

What Was It Like When The First Supermassive Black Holes Formed?

“The earliest galaxies and quasars we’ve ever found are among the brightest, most massive ones we expect to exist. They are the great winners in the gravitational wars of the early Universe: the ultimate cosmic overdogs. By time our telescopes reveal them, 400-to-700 million years after the Big Bang (the earliest quasar comes from 690 million years), they already have billions of stars and supermassive black holes of many hundreds of millions of solar masses.

But this is not a cosmic catastrophe; this is a piece of evidence that showcases the runaway power of gravitation in our Universe. Seeded by the first generation of stars and the relatively large black holes they produce, these objects merge and grow within a cluster, and then grow even larger as clusters merge to form galaxies and galaxies merge to form larger galaxies. By today, we have black holes tens of billions as massive as the Sun. But even in the earliest stages we can observe, billion-solar-mass black holes are well within reach. As we peel back the cosmic veil, we hope to learn exactly how they grow up.”

One of the great challenges for modern astrophysics and cosmology is to explain where these behemoths at the centers of galaxies, the supermassive black holes found throughout the Universe, came from. How did they get so big? And how did they get so big so fast? It might seem reasonable to get a few billion solar mass black holes by today, 13.8 billion years after the Big Bang. But how could you get something nearly that large when the Universe was just 5% of its current age? Through the physics of the first stars, first galaxies, and gravitational attraction and collapse, of course! 

Come get the cosmic story of where these ultimate objects come from, and learn how it really is possible without any new physics!

What Was It Like When The Universe Made The Ve…

What Was It Like When The Universe Made The Very First Galaxies?

“The first galaxies required a large number of steps to happen first: they needed stars and star clusters to form, and they needed for gravity to bring these star clusters together into larger clumps. But once you make them, they are now the largest structures, and can continue to grow, attracting not only star clusters and gas, but additional small galaxies. The cosmic web has taken its first major step up, and will continue to grow further, and more complex, over the hundreds of millions and billions of years to follow.”

For millions upon millions of years, there were no stars in the Universe. As the first one finally formed, the star clusters that birthed them became the largest structures in the Universe. Yet these were too small and limited to be considered galaxies. For that, we need more than one massive star cluster in the same place. We need for them to merge, triggering a starburst and creating a larger, more luminous object. It takes much longer for that to happen than to merely form stars, and the Universe was a very different place by then. The Big Bang may have started everything off uniformly and without anything more than the seeds of structure, but gravity, and time, are awfully powerful tools.

Come learn what the Universe was like when we made the very first galaxies. It’s a story you won’t soon forget!