"Advanced imaging technology enhances security by safely screening passengers for metallic and non-metallic threats including weapons, explosives and other objects concealed under layers of clothing without physical contact, " Soule said.

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The harpoon is clearly aimed at capturing the larger objects but many other solutions have been proposed, including the use of lasers to nudge space junk out of the way, or using giant nets and space tugs.

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Other well preserved objects were also found in the cave, including large containers, many of which held wheat and barley, apricots and other edible plants.

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