Kategorie: UserBlog

Just by determining how circular a given crater is – using pi and the crater’s perimeter and area – planetary geologists can reveal clues about how the crater was formed and the surface that was impacted. via NASA http://ift.tt/2IncexY

What might you see in the night sky over the next few months? The featured graphic gives a few highlights. Viewed as a clock face centered at the bottom, sky events in March fan out toward the left, April toward the top, and May toward the right. Objects relatively close to Earth are illustrated, in general, as nearer to the cartoon figure with the telescope at the bottom center — although almost everything pictured can be seen without a telescope. Sky highlights this season include a bright Venus in the evening sky during March, the Lyrids meteor shower during April, and Jupiter entering the evening sky during May. As true in every season, the International Space Station (ISS) can be sometimes be found drifting across your sky if you know just when and where to look. via NASA http://ift.tt/2GoUphs

Not everyone gets to become a part of history, but mathematician Billie Robertson is one of the lucky ones. In this image taken on Nov. 27, 1972, she was running a real-time simulation of Translunar Injection (TLI) Go-No-Go for the Apollo 17 lunar landing mission. via NASA http://ift.tt/2FS6VIG

Cassini captured this striking view of Saturn’s moon Dione on July 23, 2012. via NASA http://ift.tt/2p6YbUu

What would it be like to orbit the Earth? The International Space Station (ISS) does this every 90 minutes, and sometimes the astronauts on board take image sequences that are made into videos. The featured time-lapse video shows many visual spectacles of the dark Earth below. First, as the video begins, green and red auroras are visible on the upper left above white clouds. Soon city lights come into view, and it becomes clear you are flying over North America, eventually passing over Florida. In the second sequence you fly over Europe and Africa, eventually passing over the Nile River. Brief flashes of light are lightning in storms. Stars far in the distance can be seen rising through the greenish-gold glow of the Earth’s atmosphere. via NASA http://ift.tt/2HrQDTJ

Look at the Moon every night and its visible sunlit portion gradually changes. In phases progressing from New Moon to Full Moon to New Moon again, a lunar cycle or lunation is completed in about 29.5 days. Top left to bottom right, these frames show the range of lunar phases for 25 consecutive nights beginning on January 18, following an almost complete lunation. They skip the 2 days just after and 2 days before New Moon, when the lunar phase is at best a narrow crescent, close to the Sun and really hard to see. Of course, mostly clear Arizona night skies and a little help from a friend were required to complete this lunar cycle project, imaging in early evening for the first half and late evening and early morning for the second half of the lunation. For extra credit, the cycle was centered on the Full Moon of January 31. That was the second Full Moon in January, when the Moon was near lunar orbit perigee and took on reddish hues during a total lunar eclipse. via NASA http://ift.tt/2FvmdzH