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New NASA image reveals a strange bend in Saturn's rings

New NASA image reveals a strange bend in Saturn's rings NASA's just released a glorious new image of everyone's favourite ringed planet, Saturn, captured by the Cassini spacecraft last month. But if you take a closer look, you'll see that two of the planet's rings appear to be warping strangely as they approach the body of the planet. Fortunately, there's nothing physically messing with Saturn's rings (not like a few weeks ago, when astronomers spotted something denting one of the rings). What you're actually seeing is an optical illusion in space, which is possibly even cooler. In the photo, it looks as though Saturn's A and F rings are bending because the atmosphere of the planet acts like a very big lens, as NASA's media team explains. A little background here: Saturn's rings reflect a huge amount of light - more than any of the stars around them. That's why there are never any stars in photos of Saturn. Cameras aren't able to capture both the stars and rings without being saturated with too much light, so they need to use a shorter exposure time - which isn't able to pick up the stars. But it also means that the upper region of Saturn's atmosphere is bombarded with light, and while it absorbs quite a lot of it, some also passes straight through and back out into space, refracting as it travels through the atmosphere.  "When the light passes through, the atmosphere acts like a lens, bending it as it moves into space," writes Ria Misra for Gizmodo. The result is that the picture that's beamed back to us looks warped, even though Saturn's rings are as straight and incredibly flat as ever. What's even cooler is that this photograph was captured on June 9 by Cassini's on-board camera from a distance of more than 1.8 million kilometres (1.1 million miles) away, which is pretty incredible. And for a little scale, each pixel in the original image is 11 kilometres (7 miles). Yep, space is awesome.  NASA/JPL-Caltech/Space Science Institute 来自:VOA英语网 文章地址: http://www.tingvoa.com/html/20170717/New-NASA-image-reveals-a-strange-bend-in-Saturns-rings.html