Fabian Walter

Imagine a city where a skyscraper and a huge park are being built at the same time. The skyscraper grows upward, and the park expands outward. Both processes are fast and get in each other's way, but in the end they are meant to become a single whole. That's the situation in galaxy GNz7q: a black hole grows at the center while new stars burst to life around it.

In the grand hall of the cosmic masquerade, quasars are the most skilled actors. They don disguises, change their makeup, and pass themselves off as something they are not. Two such impostors caught astronomers' eyes: both claimed to be gravitationally lensed quasars in the early Universe, but scrutiny unmasked them.

In the first few hundred million years after the Big Bang, the universe was a dark ocean in which the first stars and black holes ignited. Some of those black holes shot out narrow jets of plasma traveling at nearly the speed of light. If such a jet points straight at Earth, we see it as a bright spot: a blazar.