保护地球, 探索宇宙, 发现文明
2022年11月25日 NGC 6744: Extragalactic Close-Up Image Credit: NASA, ESA, and the LEGUS team Explanation: Beautiful spiral galaxy NGC 6744 is nearly 175,000 light-years across. That’s larger than the Milky Way. It lies some 30 million light-years distant in the southern constellation Pavo, with its galactic disk tilted towards our line of sight. This Hubbl...
2022年3月6日 Venus and the Triply Ultraviolet Sun Image Credit: NASA/SDO & the AIA, EVE, and HMI teams; Digital Composition: Peter L. Dove Explanation: This was a very unusual type of solar eclipse. Typically, it is the Earth’s Moon that eclipses the Sun. In 2012, though, the planet Venus took a turn. Like a solar eclipse by the Moon, the phase of Ve...
2020年10月3日 Driving to the Sun Image Credit: Solar Dynamics Observatory, NASA Explanation: How long would it take to drive to the Sun? Brittany age 7, and D.J. age 12, ponder this question over dinner one evening. James also age 7, suggests taking a really fast racing car while Christopher age 4, eagerly agrees. Jerry, a really old guy who is used to estimati...
2020年8月19日 The Sun Rotating Video Credit: SDO, NASA; Digital Composition: Kevin M. Gill Explanation: Does the Sun change as it rotates? Yes, and the changes can vary from subtle to dramatic. In the featured time-lapse sequences, our Sun — as imaged by NASA’s Solar Dynamics Observatory — is shown rotating though an entire month in 2014. In t...