Giant black holes can launch jets stretching tens of thousands of light years and blasting cleanly out of their host galaxies. These jets can last for tens of millions of years. Recently, astronomers discovered the first ray just forming and created a cavity in just twenty years.
It is believed that almost every galaxy has a huge black hole in its center. These black holes are so big that they have been given a new name: supermassive black holes. Not only do they consume anything that wanders too tightly, they also develop massive disks of material that swirl around them.
These accretion disks become incredibly bright as tons after tons of gas and dust try to push their way towards the black hole. This inward movement increases the density and the friction within the material causes temperatures to skyrocket.
As the gas and dust swirl in, it flattens out and forms a wafer-thin disk that spins at a healthy fraction of the speed of light. This disk generates extremely strong electric and magnetic fields, causing part of the gas to rotate around the black hole, eventually flying over the surface and blasting out in the form of double beams.
These jets are causing chaos. They can disrupt the formation of stars, blow holes in galaxies, and even escape into intergalactic space.
Astronomers have been observing these jets with radio telescopes for decades: the jets themselves are wrapped in strong magnetic fields like a straw around the soda you are sipping, and they generate extremely bright radio emissions.
And recently, astronomers at the US Naval Research Laboratory used the Karl G. Jansky Very Large Array to witness something remarkable: the birth of these jet systems.
A young radio jet taking off from a supermassive black hole in the center of a distant galaxy. (Photo illustration from the National Radio Astronomy Observatory, Photo Credit: Sophia Dagnello, NRAO / AUI / NSF)
They did this by conducting a radio sky survey, appropriately called the Very Large Array Sky Survey (VLASS). They then looked for bright sources that didn't exist in older polls. By comparing the two surveys, they were able to discover everything new that has surfaced over the past few decades.
The astronomers found several examples of jets flying out of galaxies where they had been silent twenty years ago. This is the first time astronomers have caught the formation of jets in the act. Further observations will show how these newborn jets shape and shape the surrounding galaxies and ultimately affect their evolution.