Treaty of Tordesillas Portuguese expansion Brazil line

Portugal expanded Brazil across the treaty line

The 1494 Treaty of Tordesillas split overseas lands between Spain and Portugal along an imaginary line. Because people could not measure longitude accurately, the line was not strictly enforced, allowing Portuguese expansion of Brazil across it.

Submarines can navigate without GPS

An inertial navigation system works out a submarine’s position from its motion sensors, without outside information once aligned. Weather and jamming do not disrupt it. But small errors build over time, so the system needs occasional position fixes.

Plastic waste could become hydrogen and graphene

Researchers have demonstrated a way to heat polyethylene—the plastic used in many bags and containers—so it breaks down into hydrogen gas and graphene, a form of carbon just one atom thick. The approach could turn waste plastic into two useful materials, although scaling it up remains a challenge.

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Treaty of Tordesillas Portuguese expansion Brazil line

Portugal expanded Brazil across the treaty line

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