Science was proved fallible once again, when NASA’s gamma ray telescope made a startling discovery: galaxies don’t emit as much gamma rays as was previously thought.
To put this into context, you first need to understand that the universe is literally glowing with gamma rays, a form of very high frequency electromagnetic radiation. While some of this radiation comes from gas clouds and pulsars, most of it — according to conventional wisdom — was spit into the cosmos by active galactic nuclei; black-hole-powered jets at the centres of galaxies.
Not so, according to Marco Ajello from the Kavi Institute for Particle Astrophysics and Cosmology (KIPAC) in California. According to their studies, after calculating the amount of radiation produced by an active galactic nucleus, they determined that these black hole jets could only account for about 30 per cent of the visible gamma radiation.
This discovery has left researchers with a bit of a puzzle: if galactic nuclei aren’t creating all this gamma radiation, just what the heck is? My own personal theory: Cylons.
Kinds of ionizing radiation
So, the universe is fraught with radiation. Alpha particles, beta particles, gamma and X-rays, it’s a pretty dangerous place, what with all that radiation floating around. Luckily for us, the Earth’s magnetic field keeps us pretty safe — but just in case it ever goes away, maybe you should brush up on ionizing radiation — the kind that can cause cancer and spider-men.
Alpha : Alpha particles, which are helium atoms stripped of their electrons, form alpha radiation, which is the main type of particle given off by radioactive materials, such as uranium. This type of radiation lacks the ability to penetrate skin, and is therefore relatively safe, unless alpha particle emitting materials are ingested or inhaled.
Beta: Beta particles are excited electrons released when the weak nuclear force — one of the four fundamental forces (the other three being: strong nuclear, gravitation and electromagnetism) according to the standard model of particle physics — causes a neutron to decay into a proton, and also to emit an electron and an antinutrino as beta radiation. Beta radiation has a greater ability to penetrate than Alpha, but can still be stopped by thin metal shields.
Gamma: Gamma radiation consists of very high-energy photons, with very short wavelengths and high frequencies, about 1 million times shorter than that of visible light. Due to its extremely high frequency — the wavelengths of which are smaller than atomic nuclei — gamma radiation is very good at penetrating shielding, and is therefore very dangerous. While the Earth’s magnetic field keeps the universe’s gamma rays at bay, sources here on Earth include radioactive materials and nuclear explosions.
