保护地球, 探索宇宙, 发现文明
2022年8月2日 A Moon Dressed Like Saturn Image Credit & Copyright: Francisco Sojuel Explanation: Why does Saturn appear so big? It doesn’t — what is pictured are foreground clouds on Earth crossing in front of the Moon. The Moon shows a slight crescent phase with most of its surface visible by reflected Earthlight known as ashen glow. The Sun di...
2022年3月13日 Colorful Airglow Bands Surround Milky Way Image Credit & Copyright: Xiaohan Wang Explanation: Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however — like an approaching storm — may cause noticeable rippling in the Earth’s atmospher...
2021年12月29日 Giant Storms and High Clouds on Jupiter Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill Explanation: What and where are these large ovals? They are rotating storm clouds on Jupiter imaged last month by NASA’s Juno spacecraft. In general, higher clouds are lighter in color, and the lightest clouds visible a...
2021年8月30日 A Fire Rainbow over West Virginia Image Credit: Christa Harbig Explanation: What’s happening to this cloud? Ice crystals in a distant cirrus cloud are acting like little floating prisms. Known informally as a fire rainbow for its flame-like appearance, a circumhorizon arc appears parallel to the horizon. For a circumhorizontal arc to be visi...
2021年06月08日 A Face in the Clouds of Jupiter from Juno Image Credit: NASA/JPL-Caltech/SwRI/MSSS/Jason Major Explanation: What do you see in the clouds of Jupiter? On the largest scale, circling the planet, Jupiter has alternating light zones and reddish-brown belts. Rising zone gas, mostly hydrogen and helium, usually swirls around regions of high pressure. C...
2021年06月05日 The Shining Clouds of Mars Image Credit: NASA, JPL-Caltech, MSSS Explanation: The weathered and layered face of Mount Mercou looms in the foreground of this mosaic from the Curiosity Mars rover’s Mast Camera. Made up of 21 individual images the scene was recorded just after sunset on March 19, the 3,063rd martian day of Curiosity’s on...
2021年05月30日 Aurora over Clouds Image Credit & Copyright: Daniele Boffelli Explanation: Auroras usually occur high above the clouds. The auroral glow is created when fast-moving particles ejected from the Sun impact the Earth’s magnetosphere, from which charged particles spiral along the Earth’s magnetic field to strike atoms and molecules hi...
2021年05月26日 The Outburst Clouds of Star AG Car Image Credit: NASA, ESA, STScI; Processing: Judy Schmidt; Text: Anders Nyholm Explanation: What created these unusual clouds? At the center of this 2021 Hubble image sits AG Carinae, a supergiant star located about 20,000 light-years away in the southern constellation Carina. The star’s emitted power is ov...
2021年03月23日 Mars over Duddo Stone Circle Image Credit & Copyright: Ged Kivlehan Explanation: Why are these large stones here? One the more famous stone circles is the Duddo Five Stones of Northumberland, England. Set in the open near the top of a modest incline, a short hike across empty fields will bring you to unusual human -sized stones that are unli...
2020年11月23日 A Jupiter Vista from Juno Image Credit: NASA/JPL-Caltech/SwRI/MSSS; Processing & License: Kevin M. Gill; Explanation: Why do colorful cloud bands encircle Jupiter? Jupiter’s top atmospheric layer is divided into light zones and dark belts that go all the way around the giant planet. It is high horizontal winds — in excess of 300 ...