保护地球，探索宇宙，发现文明
2020年9月28日 Filaments of the Cygnus Loop Image Credit: ESA/Hubble & NASA, W. Blair; Acknowledgement: Leo Shatz Explanation: What lies at the edge of an expanding supernova? Subtle and delicate in appearance, these ribbons of shocked interstellar gas are part of a blast wave at the expanding edge of a violent stellar explosion that would have been easily ...
2020年9月27日 Lightning over Colorado Image Credit & Copyright: Joe Randall Explanation: Have you ever watched a lightning storm in awe? Join the crowd. Oddly, details about how lightning is produced remains a topic of research. What is known is that updrafts carry light ice crystals into collisions with larger and softer ice balls, causing the smaller cry...
2020年9月26日 Moon Pairs and the Synodic Month Image Credit & Copyright: Marcella Giulia Pace Explanation: Observe the Moon each night and its visible sunlit portion will gradually change. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or synodic month is completed in about 29.5 days. They look full, but top left to botto...
2020年9月25日 Moon over Andromeda Composite Image Credit & Copyright: Adam Block and Tim Puckett Explanation: The Great Spiral Galaxy in Andromeda (also known as M31), a mere 2.5 million light-years distant, is the closest large spiral to our own Milky Way. Andromeda is visible to the unaided eye as a small, faint, fuzzy patch, but because its surface brig...
2020年9月24日 Enceladus in Infrared Image Credit: VIMS Team, SSI, U. Arizona, U. Nantes, ESA, NASA Explanation: One of our Solar System’s most tantalizing worlds, icy Saturnian moon Enceladus appears in these detailed hemisphere views from the Cassini spacecraft. In false color, the five panels present 13 years of infrared image data from Cassini’s ...
2020年9月23日 ISS Transits Mars Image Credit & Copyright: Tom Glenn Explanation: Yes, but have you ever seen the space station do this? If you know when and where to look, watching the bright International Space Station (ISS) drift across your night sky is a fascinating sight — but not very unusual. Images of the ISS crossing in front of the half-deg...
2020年9月22日 Equinox in the Sky Image Credit & Copyright: Luca Vanzella Explanation: Does the Sun set in the same direction every day? No, the direction of sunset depends on the time of the year. Although the Sun always sets approximately toward the west, on an equinox like today the Sun sets directly toward the west. After today’s September equinox...
2020年9月21日 Omega Sunrise Image Credit & Copyright: Juan Antonio Sendra Explanation: Capturing this sunrise required both luck and timing. First and foremost, precise timing was needed to capture a sailboat crossing right in front of a rising Sun. Additionally, by a lucky coincidence, the background Sun itself appears unusual — it looks like the Gr...
2020年9月20日 Breaking Distant Light Image Credit: VIMOS, VLT, ESO Explanation: In the distant universe, time appears to run slowly. Since time-dilated light appears shifted toward the red end of the spectrum (redshifted), astronomers are able to use cosmological time-slowing to help measure vast distances in the universe. Featured, the light from distant galax...
2020年9月19日 Orion in Depth Illustration Credit & Copyright: Ronald Davison Explanation: Orion is a familiar constellation. The apparent positions of its stars in two dimensions create a well-known pattern on the bowl of planet Earth’s night sky. Orion may not look quite so familiar in this 3D view though. The illustration reconstructs the relative ...