why are the tropic of cancer and tropic of capricorn named after the zodiac sighns ?

Answer 1

only those who name it knows.

Answer 2

They're actually not... they're named for constellations, Capricorn and Cancer. Apparently, Cancer was the exact latitude of the summer solstice in the northern Hemisphere (when the constellations were first named about 2000 years ago), and the exact latitude in the sky during the winter solstice was Capricorn. But there's been a shift since then, as there so often is in exact positioning of the stars... now the northern hemisphere is in Gemini during the summer solstice and in Sagittarius during the winter solstice.

All the zodiac signs are named for constellations, as I'm sure you know. I think it's naive NOT to believe that the universe exerts an effect on people. Look at the way the moon affects tides. Check with your local emergency room and ask if they don't have a drastic increase in traffic right around a full moon.

Still, I also think it's naive to believe that we can quantify that effect of the cosmos on people, even with lots of study. Look at all the new planetoids and other celestial bodies are being found all the time! How could we quantify that?

Answer 3

From Wikipedia:
The line is called the Tropic of Cancer because when it was named, the sun was in the constellation of Cancer when it appeared directly overhead at this latitude during the June solstice. However, due to precession of the equinoxes, the June solstice is now in the constellation Gemini.

The Tropic of Capricorn is so named because about 2000 years ago the sun was entering the constellation Capricornus on the December solstice. In modern times the sun appears in the constellation Sagittarius during this time. The change is due to precession of the equinoxes.

Answer 4

Both the tropics and zodiac signs are named from constellations

Answer 5

Because those are the constellations that can be seen from those points on earth