保护地球，探索宇宙，发现文明
2024年1月13日 Circling the Sun Image Credit & Copyright: Radoslav Zboran Explanation: Earth’s orbit around the Sun is not a circle, it’s an ellipse. The point along its elliptical orbit where our fair planet is closest to the Sun is called perihelion. This year, perihelion was on January 2 at 01:00 UTC, with the Earth about 3 million miles close...
2021年8月29日 Orbits of Potentially Hazardous Asteroids Image Credit: NASA, JPL-Caltech Explanation: Are asteroids dangerous? Some are, but the likelihood of a dangerous asteroid striking the Earth during any given year is low. Because some past mass extinction events have been linked to asteroid impacts, however, humanity has made it a priority to find and cat...