分类： 天文·每日一图

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 ...

2020年9月17日 Solar Cycle 25 Has Begun Image Credit: NASA, SDO Explanation: The general trend of monthly sunspot data now confirms that the minimum of the approximately 11 year cycle of solar activity occurred in December 2019, marking the start of Solar Cycle 25. That quiet Sun, at minimum activity, appears on the right of this split hemispherical view. In con...