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 is the primary focus of the Fermi Gamma-ray Space Telescope?

• Observing gamma rays in the universe

• Studying the sun's solar flares

• Tracking meteor showers

• Monitoring Earth's atmosphere

What are blazars known for?

• Producing large amounts of water vapor

• Orbiting around the sun

• Being the brightest stars in the universe

• Hosting supermassive black holes and emitting high-speed particle jets

What happens when gamma rays from blazars interact with starlight?

• They create a black hole

• They disappear completely

• They transform into two particles: an electron and a positron

• They become visible light

What is the Extragalactic Background Light (EBL)?

• Light from the sun

• Light from stars that have burned out

• Light from nearby galaxies

• Light from Earth's atmosphere

When did star formation in the universe peak according to recent studies?

• 15 billion years ago

• 10 billion years ago

• 20 billion years ago

• 5 billion years ago