vbloke © 2006

This scheme ignored the actual stars themselves, but uniformity was more important than fussing about star positions.

Since then, precession has caused the celestial equator to wobble so as to cause the intersection point between it and the ecliptic to move westward along the ecliptic by 36° or a tenth of the way around.

Your birth sign ignores the effect of precession. What a horoscope calls “Aries” is the 30° segment along the ecliptic that is east of the current location of the vernal equinox – but today, most of it is in Pisces. The next 30° segment (called Taurus in the horoscope) is mostly in Aries. The astrological signs are directions in space that no longer correspond to the constellations that bear their names.

Precession causes the position of the sun on the vernal equinox to move as the earth wobbles on its axis – then again, the position of the sun varies on every date (analemma). This means that it is not only the names of the zodiac signs that are now wrong, the names of the tropics are also inaccurate!

This all dates to when the sun is within the constellation of your birth sign. According to astrology (corrected for precession – although these dates will vary slightly from year to year), you may find that you’re actually a different birth sign.

If you were born between November 30th and December 17th, you’re actually an Ophiuchus.

What happens in astrology is that the sun travels through the traditional 12 signs of the zodiac over the course of the year. Whatever sign the sun is in when you’re born is the sign you “are”. However, over the past 2,600 years (since the charts were drawn up), the precession of the earth has shifted the ecliptic westwards and now the sun visits the constellation of Ophiuchus during November/December. I very much doubt you’ll find a horoscope that takes this into account.

Capricorn: January 20th to February 16th
Aquarius: February 17th to March 11th
Pisces: March 12th to April 18th
Aries: April 19th to May 13th
Taurus: May 14th to June 21st
Gemini: June 22nd to July 20th
Cancer: July 21st to August 10th
Leo: August 11th to September 16th
Virgo: September 17th to October 30th
Libra: October 31st to November 23rd
Scorpio: November 24th to November 29th
Ophiuchus: November 30th to December 17th
Sagittarius: December 18th to January 19th

Since I’m no longer Cancer and am now Gemini “all of a sudden”, does this mean I’ll have to change my character and I can sue astrologers for giving me wrong information?

vbloke © 2006

Gravity obeys what is called the “inverse square law” – that is, it drops off rapidly the further you get, imagine standing next to a hot radiator – the heat is intense, but you feel it less the further you move away from it. True, the gravity of the planets reaches out for millions of miles, but in the case of Earth, the Sun and Moon overpower the combined gravity of every other planet in the solar system. Even the building you are standing in overpowers the gravity of Jupiter.

The electromagnetic force relies on the planets having an electric charge. Whilst the larger planets (Saturn, Jupiter, Uranus and Neptune) do, they are too far away for their relatively weak electric fields to affect us. The Sun’s electric charge dwarfs the entire electric output of all the planets. It’s like comparing a 1.5 volt battery to a power station.

So, this force must be something else. Something that does not diminish by distance and that helps tiny Pluto have the same effect as giant Jupiter.

Astrologers have sometimes said that there is a “quantum force” at work, neatly using Quantum Physics, something that is, let’s face it, very complicated and not easily understood unless you have a lot of PhD’s.

Here’s a quick note though. You might want to note this down for future reference. If something has “quantum” effects, it operates at the sub-atomic scale. Like the strong and weak nuclear force, quantum effects don’t work if you’re bigger than an atom. A lot of people claim “quantum effects” for all sorts of alternative therapies and products. Quantum effects operate on things so small, even the most powerful electron microscopes in the world cannot see them. Once you get to the size of a thousand thousandth of a millimetre, quantum effects no longer work. Write that down.

So, a “quantum force” would only work if Jupiter was an atomic nucleus and you were an electron.

When the zodiac was originally drawn up in around 600BC, astrologers knew about 6 planets – Mercury, Venus, Earth, Mars, Saturn and Jupiter. These were given arbitrary names and characters, as mankind likes to anthropomorphise things. Each planet was known to move around in the sky (the word “planet” actually means “wanderer” in ancient Greek) and appeared to follow the same line across the sky as the Sun and Moon – a line we call the Ecliptic. It is the constellations that lie on this line that we call the zodiac. Every planet passes through the constellations on their journey around the Sun.

So, so far we have six planets, the Moon and Sun and an unknown force. These were considered to affect your personality at the time of your birth.

Hang on, aren’t there nine planets?

All the planets past Jupiter are too far away to be seen properly without telescopes, so the ancients couldn’t have known about them. The telescope was invented around 1608 (not by Galileo, as often claimed, but by a Dutch spectacle maker that we don’t know the name of), this means that, whilst these planets obviously must be having an effect on your horoscope, they weren’t known about, so they couldn’t include them in their calculations.

For a start, this raises an interesting question – these planets had an effect, but couldn’t be included in horoscope calculations – why didn’t ancient astrologers notice this “extra” influence coming from somewhere? If, as they claim, astrology is a science, this effect should be measurable and quantifiable and the positions and sizes of these planets should be calculable by extrapolating from this extra influence. This never happened.

Uranus was discovered in 1781 by Sir William Herschel. Astrologers never saw it coming. Instead, Uranus was quietly included in their calculations. Suddenly, your horoscope changed to include this massive new planet that had always existed. Does the force that controls astrology only work when it’s seen? If we don’t know about something, does it have no effect? If so, you could cross a motorway safely, just by closing your eyes and wearing earplugs.

Neptune was discovered in 1846 by collaboration between Urbain Le Verrier, John Couch Adams and Johann Gottfried Galle. See above.

Pluto was discovered in 1930 by Clyde Tombaugh. Pluto is a bit of an anomaly though, it’s tiny. Also, it’s orbit is what astronomers call “eccentric”; it orbits at an angle to the sun – the other eight planets all lie roughly within the same plane, but Pluto sits at an angle of 17°. It’s also the only planet whose orbit takes it inside the orbit of another planet – for a part of it’s year, Pluto is closer to the Sun than Neptune, the rest of the time, it’s further away. Why does Pluto have the same effect as it’s giant neighbour? To put it another way, Neptune is nearly 58 times the volume of Earth, whereas Pluto is smaller than Earth’s Moon.

What about Sedna? 2002UB313, the recently discovered planet candidate? The asteroid belt? The Kuiper Belt? Comets? Do these have an effect? Some of the moons of Saturn and Jupiter are larger than Mercury and Pluto! Do they have an effect? Why not? Things are looking a bit dodgy for astrology.

So, that’s it for planets – isn’t it?

No.

You see, every dot of light in the sky (apart from the planets) is a star. Our sun is a star as well, it just so happens that we’re very close to it. Do other stars have planets?

Yes.

Since 1989, planets have been found around other stars. In total so far, astronomers have discovered 188 “extrasolar” planets. 188! That’s a lot of planets.

Most of these are huge. In our solar system, Jupiter is the king of planets. It is huge – 1321 times the volume of Earth! Most of these extrasolar planets are what are called “Hot Jupiter’s” – planets that make Jupiter seem small. Some of them are truly gigantic – measured at up to 11 times the mass of Jupiter. 11 times! That’s one big planet.

Astronomers recently discovered a “cold Earth” – a rocky planet around 5 times the mass of Earth orbiting a distant star in our own galaxy. Surely this should affect your horoscope?

If, as astrologers would have us believe, their force does not diminish by distance, then these planets should have a measurable effect on your horoscope. We can’t see them directly, so why should they have an effect? Well, we can’t see Pluto, Sedna or 2002UB313 without very powerful telescopes, but these have been included in horoscopes as having effects, so why not these massive extrasolar planets? You see, these planets haven’t been given “traditional” names like our solar system planets, they’re called things like 16 Cyg B b, HD 216435 b and 55 Cnc d. What does that tell you about their characteristics?

Astronomers have theorised that most of the stars we can see might have planets. We can only detect them by inferring them from how they effect their parent star, so the process is slow and laborious. There are definitely more than 188 out there.

One day, your horoscope will have to include all these planets, but where will the line be drawn? Theoretically, there could be billions of planets in the observable universe. Your horoscope will be very cluttered and probably the size of the Encyclopaedia Britannica every day to include the effects of all these other planets. Phew.

Is that it?

No.

What happens when a star “dies”? Well, some stars explode violently in a supernova, some expand into red giants and then shrink, slowly cooling over billions of years. What could happen is, if one of these stars had a planetary system, some of these planets could be thrown out of their orbits and sent flying through the universe. A planet without a star. These would be almost impossible to see, but it is almost certain that there are some out there. Would these “wanderers” have an effect as well?

Astrologers want to claim their profession is a science. If so, then they have to play by the rules of science. Their force should have a measurable and predictable effect. We should be able to infer and predict things based on this force. No astrologer ever predicted Uranus, Neptune or Pluto based on their calculations, even though they must have been having an effect by their force acting on us. No astrologer predicted extra solar planets or recently discovered comets based on their calculations of the zodiac. No astrologer will tell you that the planets were named arbitrarily by the ancients, these names are used by astrologers to personify them and give them characteristics. Mars was the god of war – hence it controls aggression. This is because it has a reddish colour in the sky and red is the colour of aggression. What would your horoscope be like if it had been called Diana, the Roman goddess of hunting, or Aphrodite, the Greek goddess of Love?

Uranus, Neptune and Pluto’s names were decided by a vote. There was no consideration of their “characters” when they were named. What does this say about their effect on your horoscope?