![More than 7.5 million Opal cards are now in circulation.](/web/20170222235227im_/http://www.smh.com.au/content/dam/images/g/k/8/3/q/p/image.related.square.80x75.gudakb.10rdjm.png/1487807233529.jpg)
![An artist's conception of the view from the fifth planet of the TRAPPIST-1 system.](/web/20170222235227im_/http://www.smh.com.au/content/dam/images/g/u/i/j/h/f/image.related.square.80x75.guidl3.11w2dh.png/1487798804942.jpg)
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