I’d been hearing a lot about Betelgeuse lately, and I hadn’t realised how immensely huge it is. So I decided to make this short video which shows the size of Betelgeuse as compared to our Sun and the Solar System. I know VY Canis Majoris is bigger (actually even larger stars have been discovered), but this video isn’t about the largest star; I made it because Betelgeuse specifically was in the news.
As nighttime arrives, previously obscured light sources begin to dazzle the eye. City lights sprawl across Earth’s surface. A constant glow hovers in the upper atmosphere. Beyond Earth, starlight fills in the darkness of the cosmos.
From the vantage point of space, we can get a unique view of each of these nighttime spectacles. On October 7, 2018, an astronaut aboard the International Space Station (ISS) shot this photograph while orbiting at an altitude of more than 400 kilometers (250 miles) over Australia. In this view, stars appear more numerous along the image center, where the plane of our disk-shaped Milky Way galaxy extends into space.
The oranges (above) and greens (in the video below) enveloping Earth are known as airglow—diffuse bands of light that stretch 50 to 400 miles into our atmosphere. The phenomenon typically occurs when molecules (mostly nitrogen and oxygen) are energized by ultraviolet (UV) radiation from sunlight. To release that energy, atoms in the lower atmosphere bump into each other and lose energy in the collision. But the upper atmosphere is thinner, so atoms are less likely to collide. Instead they release their energy by emitting photons. The result is colorful airglow. [leggi tutto]
Scientists studying what amounts to a computer-simulated “pulsar in a box” are gaining a more detailed understanding of the complex, high-energy environment around spinning neutron stars, also called pulsars. The model traces the paths of charged particles in magnetic and electric fields near the neutron star, revealing behaviors that may help explain how pulsars emit gamma-ray and radio pulses with ultraprecise timing.[…]