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Stand back, I'm going to try SCIENCE.
Yes, your zodiac sign is wrong! But my planetarium boss tells us now it's news, and none of us can figure out why. This has been happening for--well, forever, and your signs have been wrong probably for the last hundred years or so. According to my planetarium boss, this story just happened to hit the right spot at the right time, which is apparently what makes it news. The science world remains flummoxed by media and sundry.
Here's the super cool explanation my planetarium boss gave me. I made graphics, guys. You might not want to read it if you understand astronomy.
First of all, what is your zodiac sign? Well, your sign is the constellation the sun was in when you were born. So I give you:
. . . our solar system, with constellations outside our solar system, all on the same plane as our solar system (as we see them). So, anyone born on any give day, the earth is in a certain position relative to the sun. And if you could see the stars when the sun was out, the sun would look like it was in a constellation. So, if you were born when the earth was right here, your sign would be Young Alec Guinness. Lucky you.
Now, if you were born when the earth was right here, what would your sign be?
. . . if you answered Sign of the Hedgehog, you were correct!
Now, we learn in school that earth is tilted. Like this:
That pole coming out of it's head? That's the axis. And if you learned your stuff in school, it's always pointed in the same direction--right at the North Star! That's how come the north star is always north. So, here's a sad drawing of the earth and its axis, because I can't draw in 3d. The quiz is: what day of the year is this? It's a day that has a special name.
If you guessed winter solstice, you're mighty damn smart. The earth is tilted away from the sun. It's the shortest day of the year. This means if you are born December 21, you have the Sign of Young Alec Guinness. So, December birthdays equal Sign of Young Alec Guinness. Okay, another quiz. What day is this?
If you guessed vernal equinox, you're right! And what day is this?
If you guessed summer solstice, you're shore damn smart! It's the longest day of the year, and the earth is tilted towards the sun. But notice how the earth is always tilted in the same direction. Always right toward the north star.
But here's where they told you wrong. The axis actually doesn't stay still! It spins sort of like a top. Now, a top spins in a circle, with its axis straight up and down. But you'll notice that gradually, the spinning of the top itself causes the axis itself to spin in a circle. If you've ever had a top with a marker tip, if it just spun in one single circle, you'd just have 1 dot on your paper. But because the axis spins, you get tight little circles drawn on your paper (and then bigger and bigger ones as the top spins out of control). Those tight little circles are what the earth's axis is doing!
That one picture already ruined it for you, but if you didn't look at it because it didn't have Dana Scully on it, this is called precession. It takes the earth a long time to precess, 26,000 years (according to Planetarium Boss Lady) and that's why you don't hear about it much. Until now.
"26,000 years to precess" means it takes the earth's axis 26,000 years to go in one complete circle. That's 26,000 years to get back to pointing at the north star! So actually, thousands and thousands of years ago, the north star wasn't north. That means Polaris wasn't actually "the north star"--the north star in those days was in Draco! The constellation. Though if you want to write fic where Harry embodies the north star, go ahead, Dog's Body me. (Been there, done that.)
Anyway, the north star changing, that was because of precession. In another several thousand years, the north star will be inaccurate enough as a guide that we won't be able to use Polaris any more. So what does this mean? Well, one day, our axis won't be pointed at Polaris. It will be pointed somewhere else. Like here:
See, we have a new north star (I think it's supposed to be DianA Wynne Jones)! The axis is pointed toward a different star. And sure, someone born on this day will have the Sign Young Alec Guiness. But someone born on this day won't be born on December 21, because look, this is not the winter solstice! Winter solstice falls on the day the axis points us farthest away from the sun. Our calendars all have to do with us going around the sun--not with precession. So, December does not equal Sign of Young Alec Guinness. What sign is this person?
If you said Sign of the Hedgehog, you're right again! And now, this is the winter solstice, because the axis is pointed directly away from the sun. So, if you're born in December, your Sign is Hedgehog, not Young Alec Guinness! It changed: December does not equal Sign Alec Guinness any more. December is the dawning of the Age of the Hedgehog, the Age of the Hedgehog!
Now, you'll note that the axis has moved 90 degrees--a full fourth of its circle. If a full precess is 26,000 years, it would take 6,500 thousand years for our zodiac signs to get as off as I've drawn here.
Our zodiac was outfitted the way it is about 2,000 years ago. There are 13 constellations the sun looks as though it passes through as the earth moves around the sun (even though there are only 12 signs. No one liked Ophiucus):
26,000/13 = 2,000. This means every 2,000 years our zodiac signs all shift over one. If you were born in December and your sign was once Young Alec Guinness, you are now Sign Zuko. Or Anne of Green Gables; I actually don't know which way it's going.
That's my fun science I learned today.
Here's the super cool explanation my planetarium boss gave me. I made graphics, guys. You might not want to read it if you understand astronomy.
First of all, what is your zodiac sign? Well, your sign is the constellation the sun was in when you were born. So I give you:
. . . our solar system, with constellations outside our solar system, all on the same plane as our solar system (as we see them). So, anyone born on any give day, the earth is in a certain position relative to the sun. And if you could see the stars when the sun was out, the sun would look like it was in a constellation. So, if you were born when the earth was right here, your sign would be Young Alec Guinness. Lucky you.
Now, if you were born when the earth was right here, what would your sign be?
. . . if you answered Sign of the Hedgehog, you were correct!
Now, we learn in school that earth is tilted. Like this:
That pole coming out of it's head? That's the axis. And if you learned your stuff in school, it's always pointed in the same direction--right at the North Star! That's how come the north star is always north. So, here's a sad drawing of the earth and its axis, because I can't draw in 3d. The quiz is: what day of the year is this? It's a day that has a special name.
If you guessed winter solstice, you're mighty damn smart. The earth is tilted away from the sun. It's the shortest day of the year. This means if you are born December 21, you have the Sign of Young Alec Guinness. So, December birthdays equal Sign of Young Alec Guinness. Okay, another quiz. What day is this?
If you guessed vernal equinox, you're right! And what day is this?
If you guessed summer solstice, you're shore damn smart! It's the longest day of the year, and the earth is tilted towards the sun. But notice how the earth is always tilted in the same direction. Always right toward the north star.
But here's where they told you wrong. The axis actually doesn't stay still! It spins sort of like a top. Now, a top spins in a circle, with its axis straight up and down. But you'll notice that gradually, the spinning of the top itself causes the axis itself to spin in a circle. If you've ever had a top with a marker tip, if it just spun in one single circle, you'd just have 1 dot on your paper. But because the axis spins, you get tight little circles drawn on your paper (and then bigger and bigger ones as the top spins out of control). Those tight little circles are what the earth's axis is doing!
That one picture already ruined it for you, but if you didn't look at it because it didn't have Dana Scully on it, this is called precession. It takes the earth a long time to precess, 26,000 years (according to Planetarium Boss Lady) and that's why you don't hear about it much. Until now.
"26,000 years to precess" means it takes the earth's axis 26,000 years to go in one complete circle. That's 26,000 years to get back to pointing at the north star! So actually, thousands and thousands of years ago, the north star wasn't north. That means Polaris wasn't actually "the north star"--the north star in those days was in Draco! The constellation. Though if you want to write fic where Harry embodies the north star, go ahead, Dog's Body me. (Been there, done that.)
Anyway, the north star changing, that was because of precession. In another several thousand years, the north star will be inaccurate enough as a guide that we won't be able to use Polaris any more. So what does this mean? Well, one day, our axis won't be pointed at Polaris. It will be pointed somewhere else. Like here:
See, we have a new north star (I think it's supposed to be DianA Wynne Jones)! The axis is pointed toward a different star. And sure, someone born on this day will have the Sign Young Alec Guiness. But someone born on this day won't be born on December 21, because look, this is not the winter solstice! Winter solstice falls on the day the axis points us farthest away from the sun. Our calendars all have to do with us going around the sun--not with precession. So, December does not equal Sign of Young Alec Guinness. What sign is this person?
If you said Sign of the Hedgehog, you're right again! And now, this is the winter solstice, because the axis is pointed directly away from the sun. So, if you're born in December, your Sign is Hedgehog, not Young Alec Guinness! It changed: December does not equal Sign Alec Guinness any more. December is the dawning of the Age of the Hedgehog, the Age of the Hedgehog!
Now, you'll note that the axis has moved 90 degrees--a full fourth of its circle. If a full precess is 26,000 years, it would take 6,500 thousand years for our zodiac signs to get as off as I've drawn here.
Our zodiac was outfitted the way it is about 2,000 years ago. There are 13 constellations the sun looks as though it passes through as the earth moves around the sun (even though there are only 12 signs. No one liked Ophiucus):
26,000/13 = 2,000. This means every 2,000 years our zodiac signs all shift over one. If you were born in December and your sign was once Young Alec Guinness, you are now Sign Zuko. Or Anne of Green Gables; I actually don't know which way it's going.
That's my fun science I learned today.
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