Definition: In this task, you are given a news article. Your task is to classify the article to one out of the four topics 'World', 'Sports', 'Business', 'Sci/Tech' if the article's main topic is relevant to the world, sports, business, and science/technology, correspondingly. If you are not sure about the topic, choose the closest option. Note that URLs in the text have been replaced with [Link].
Input: NASA To Slam  #39;Hammer #39; into Comet Tempel 1 The high-speed impact will wallop the pickle-shaped comet Tempel 1 with energy equivalent to 4.8 tons of TNT, said Michael A #39;Hearn, another university astronomer and principal investigator on the \$311 million mission.

Sci/Tech