NASA Explains Fermi Telescope Does Not Detect Gamma-Rays From Nearby Supernova

Space.com

NASA’s Fermi Gamma-ray Space Telescope "detected none of the high-energy gamma-ray light" from a nearby supernova. NASA explains.   Credit: NASA Goddard Space Flight Center

Transcript

00:00 NASA's Fermi Gamma-ray Space Telescope

00:04 watches the sky for gamma rays, the highest energy form of light.

00:08 These detections help scientists learn more about the most powerful

00:12 events in the cosmos. However, a recent absence

00:16 of gamma ray detection may have been just as informative.

00:20 Cosmic rays are small particles like protons and helium nuclei

00:24 traveling at nearly the speed of light. It takes a lot of energy to

00:28 accelerate them to that speed, so scientists assume they're driven by

00:32 powerful events like exploding stars, called supernovae.

00:36 Because cosmic rays are charged particles, they interact with magnetic

00:40 fields as they travel. These interactions mean they don't follow a

00:44 straight line from their sources, and so scientists can't trace where they came from.

00:48 But when cosmic rays smash into other particles, they produce gamma rays.

00:52 And gamma rays do travel to us straight from their sources.

00:56 Fermi has even detected such gamma rays from supernova

01:00 remnants, which are thousands of years old.

01:04 If supernovae and their remnants really are a key source of cosmic rays,

01:08 then calculations tell astronomers how many gamma rays Fermi should detect.

01:12 But so far, the telescope hasn't seen enough gamma rays

01:16 from these sources. Scientists had suspected this was

01:20 because the supernovae were too far away, or observations began too late,

01:24 well after peak production.

01:28 In May 2023, Fermi observed the most luminous nearby supernova

01:32 seen since the mission launched 15 years ago. It captured

01:36 data from the first few weeks of the explosion, when scientists anticipated

01:40 the greatest production of cosmic rays. But Fermi didn't see

01:44 any gamma rays from the explosion. Scientists aren't yet

01:48 sure what this means for the link between cosmic rays and supernovae.

01:52 There's still a lot of work left to do. But Fermi's non-detection

01:56 has added a very important new piece to this high-energy puzzle.

02:00 [music]

02:04 [BLANK_AUDIO]

Category

Transcript

Recommended