Cosmic rays are incredibly powerful invisible particles, and we can’t be sure where they come from. Not much in the way of a comforting thought, but it makes for a cosmic mystery that astronomers have been trying to solve for decades. And now they have come one step closer. Here’s what we do know. Cosmic rays are energetic atomic nuclei travelling at near the speed of light. They hit our atmosphere and rapidly interact with the molecules there to break into billions of smaller, less energetic particles that shower down on the life on Earth, without giving us much notice...
One of the largest and brightest star clusters in the Milky Way galaxy is the Arches cluster, and its easy to see why. Lying only 100 light years away from the supermassive black hole that lies in the heart of our galaxy, it formed in an incredibly dense environment. It lies 25,000 light years from Earth in the constellation Sagittarius, and contains thousands of massive stars, including 160 that are hot, young, and exceptionally more massive than the Sun. Only 1 in 10 Million stars in the galaxy are as bright as these massive central 160 stars. Though it is...
In Canis Major, nearly 12,000 light years from Earth, lies an emission nebula that always makes me think of a particular comic book character. NGC 2359 is 30 light years across, and is colloquially known as Thor’s Helmet. The complex structure of Thor’s helmet consists of bubbles and filaments, and is due to a series of bursts from the massive star HD 56925. This star is a rare Wolf-Rayet star, which consistently expels its outer layers of gas at high velocities, and is characterized by its very high temperature. The blue bubble in the above image is a result of...
