Tracing the History of Starlight with NASA's Fermi Mission

NASA's Fermi Gamma-ray Space Telescope has been pivotal in studying the universe through gamma rays, the highest energy form of light. Over the past decade, Fermi has observed nearly 2,000 blazars, galaxies with supermassive black holes that emit high-speed particle jets. These gamma rays interact with the Extragalactic Background Light (EBL), formed by starlight traveling across the universe. When gamma rays collide with starlight, they transform into particles, weakening the gamma ray signal. A recent study of the EBL, looking back 12 billion years, confirms that star formation peaked around 10 billion years ago. Stars are crucial for creating light and heavy elements in the universe. Understanding star evolution is key to comprehending cosmic history, and Fermi brings us closer to this understanding.

What role does the Fermi Gamma-ray Space Telescope play in studying the universe?

How do gamma rays from blazars interact with starlight?

What is the Extragalactic Background Light (EBL) and how is it formed?

What effect does the EBL have on the gamma ray signals from blazars?

Why is understanding star formation important for understanding the cosmos?