April 1, 2009--The sun's face is spotless(没有污点的) in an image taken by the Solar(太阳的) and Heliospheric(日光层的) Observatory on March 31, 2009. An unusually low number of sunspots(太阳黑子) since the start of the year has prompted(促使) NASA to conclude that our normally stormy star is at its lowest cycle of activity(活动循环) in almost a century.
The last time the sun experienced such a deep solar minimum was in 1913, when it had 311 spotless days.
NASA：National Aeronautics and Space Administration <美>国家航空和宇宙航行局
April 7, 2009--A lacy(花边的) web of dust encircles(包围，环绕) galaxy(银河系) NGC 7049, shown backlighted(背后照明的) by millions of stars in this Hubble Space Telescope image.
Astronomers are studying a family of globular(球状的) clusters that appear as glittering(闪耀的) spots around the dusty halo(光环) to learn more about the formation and evolution of the galaxy, which sits within the constellation Indus(印第安座) in Earth's Southern Hemisphere sky.
NGC：New General Catalogue (of Nebulae and Clusters of Stars) （星云星团）新总表
April 1, 2009--Fanlike(扇状的) features create unusual patterns on Mars's permanent south polar ice cap(冰帽，冰冠) in a new image released by the Mars Reconnaissance Orbiter(火星侦察卫星).
The ice cap at the Martian south pole covers an area the size of Texas. Its thick layer(层) of water ice is topped by another, thinner layer of frozen carbon dioxide(二氧化碳).
April 2, 2009--The most detailed survey yet of galaxies near our own will help astronomers(天文学家) uncover how matter--both seen and unseen--is distributed. Within our cosmic neighborhood, the survey counted more than a hundred thousand galaxies, seen above as dots in a computer simulation(计算机模拟).
"It's like taking a snapshot(快照) of wildebeest(羚羊的一种) on the African plain.We can tell which waterholes they're heading to and how fast they're traveling," study leader Heath Jones, of the Anglo-Australian Observatory, said in a statement. Knowing galaxies' speeds and directions can help researchers map the gravitational forces that show where matter lurks(潜伏).
April 3, 2009--An infrared image(红外图像) shows bright areas in Hotei Arcus, a region on Saturn's moon Titan that may be the site of current volcanic activity--possibly the first active ice volcano to be seen on Titan.
Over the past four years NASA's Cassini probe has snapped several shots of Hotei Arcus that show changes in brightness. The changes match the signature of ammonia(氨) frost, which could be the product of cryovolcanism(火山活动).