Why do you suppose there are no quasars relatively near our Galaxy?

At the heart of every quasar lies a supermassive black hole, a cosmic behemoth whose mass can be millions, if not billions, of times that of our Sun. The gravitational force of these black holes is inconceivably strong, pulling in dust, gas, and even light that ventures too close. Imagine a drain with water spiraling towards it; this is similar to how material gets drawn into the black hole’s accretion disc.

Quasars are astronomical highlights because they offer us insights into the workings of these enigmatic entities. They are the bright beacons powered by the physics of these black holes, serving as natural laboratories for studying extreme conditions that we're unable to replicate on Earth or our solar system.

The accretion disc of a quasar is the tumultuous region of space surrounding a supermassive black hole, where material is in the process of being consumed. It's here that the temperature becomes incredibly high, due to the friction and gravitational forces, heating the matter to millions of degrees. This heat causes the disc to emit intense light and other electromagnetic radiation, making quasars some of the brightest objects in the universe.

The swirling matter in the disc is on the ultimate one-way trip, destined to disappear beyond the event horizon of the black hole. However, before it does, it broadcasts a cosmos-spanning signal of bright, energetic light, offering an almost paradoxical spectacle: the most luminous objects in the universe being powered by the darkest ones.

Understanding the timeline of the universe is key to grasping why quasars aren't found closer to our galaxy. The Big Bang, roughly 13.8 billion years ago, was the explosive event that began it all. Following this, the universe has experienced different epochs. About 10 billion years ago, during a time often referred to as the 'quasar era,' these luminous objects were far more prevalent.

Today, we observe quasars as they were during this distant past, their light only now reaching us across the span of billions of years. Since quasar activity peaked so long ago, it is unlikely to observe them forming in our galactic neighborhood in the present era. Our Milky Way and its local group reside in a much more mature state of the universe’s evolution, where the peak conditions for quasar formation—such as the abundant supply of gas and dust needed for high rates of accretion—are no longer prevalent.