Why cold salty seawater sinks and drives ocean circulation

Cold, salty seawater can sink through the ocean

Seawater gets heavier when it becomes colder or saltier. In places where surface water becomes cold and salty enough, it sinks beneath the water around it and helps drive deep ocean currents.

3–6%

Plants turn only a small share of light into stored energy

Plants usually turn only about 3–6% of incoming light into chemical energy. Most of the rest that they absorb becomes heat, while a small amount is given off again as a faint glow from chlorophyll.

Some galaxies are already beyond the reach of any signal we send

Because the universe's expansion is accelerating, light emitted from Earth today will never reach certain sufficiently distant galaxies. The space between us and those galaxies expands in a way that prevents the signal from ever catching up. We can still observe light they emitted long ago, but seeing a galaxy does not mean we can ever communicate with it.

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Why cold salty seawater sinks and drives ocean circulation

Cold, salty seawater can sink through the ocean

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