1512: Horoscopes

Explain xkcd: It's 'cause you're dumb.
Revision as of 11:17, 16 April 2015 by (talk) (OK, now that's true.)
Jump to: navigation, search
If you live in the Northern hemisphere, anyway. In the southern hemisphere, due to the coriolis effect, babies are born nine months BEFORE they're conceived.
Title text: If you live in the Northern hemisphere, anyway. In the southern hemisphere, due to the coriolis effect, babies are born nine months BEFORE they're conceived.


Horoscopes purport to predict someone's personality or future, depending on the position of planets and stars at the time of their birth and at present. Horoscopes commonly group people into twelve groups based on zodiac signs. The Zodiac signs are based on twelve constellations that follow the approximate path of the sun in our night sky. One's zodiac sign is determined by the position of the sun on their birthday, with each sign representing a specific approximately one-month period.

Today, horoscopes are admitted to be absolute rubbish which is why the comic jokes about the fact that its horoscopes at least may be true (at least for someone born after a full term pregnancy). Actual horoscopes are typically so vague that they could be true for almost anyone regardless of their sign. Note that this horoscope is tailored for an audience in the United States, as most cultural references are centered on "Western" culture, and several won't even work in Europe, for example. With the principle understood, it is easy to apply local traditions for more accuracy in non-Western cultures, however.

Since the 12 category zodiac signs in horoscopes are based on birthday dates, Randall can do some informed guess about the context of someone's conception (i.e., what was happening nine months before they were born, apart from the obvious), depending on the sign. For example, Virgo are born between August 23 and September 22, so based on a 9-month gestational period, they were likely conceived shortly before Christmas, leading to the guess "You may have been conceived while a Christmas song played". Randall also phrases his "predictions" as possibilities ("you may have") rather than declarations, acknowledging that unlike actual horoscopes, his don't necessarily apply to everyone. See detailed description in the table below.

The title text refers to the Coriolis effect which occurs to a body that is moving on an object that is spinning. Since the Earth is rotating this leads to the fact that something that is moving on Earth feels a force (the Coriolis force) which causes the moving object to be deflected to the right in the northern hemisphere and to the left in the southern hemisphere. This effect is the reason that weather systems (most clearly seen for hurricanes) rotate in one direction in the northern hemisphere and in the opposite direction in the southern hemisphere.

There is also a common misconception that the Coriolis force in respect of the Earth affects objects on a much smaller level, such as the direction water will spin down a drain in the two hemispheres (see also 843: Misconceptions). Randall plays on the misconception to make a joke involving reversing the flow of time. So whereas babies are born nine months after conception in the northern hemisphere (clockwise) the Coriolis effect is the reason why babies are being born nine months before in the southern hemisphere (counterclockwise).

Cf. the Weird Al song Horoscope for Today which also makes vague guesses, only they refer to bizarre events and tasks.

Table of Astrological signs

Here below is a table with data and explanation of the individual horoscopes:

Astrological sign English name Birthday range Expected conception Horoscope prediction Explanation
Aries The Ram March 21 - April 21 June 14 - July 14 You may have been conceived after a 4th of July fireworks show In the US the Independence Day is celebrated on the 4th of July, and this is customarily celebrated with huge fireworks. Fireworks are also often used in movies to depict the culmination of sex (i.e. the orgasm), and hence the potential for conception.
Taurus The Bull April 20 - May 20 July 13 - August 13 You may have been conceived on a hot August day In most of the northern hemisphere there are many hot days in August. Sometimes hot days increase lust, especially if it's too hot to go out or do anything else.
Gemini The Twins May 21 - June 21 August 14 - September 14 You may have been conceived as the leaves began to change In the northern part of the northern hemisphere the autumn starts at the end of this time period, so the leaves will begin to change color.
Cancer The Crab June 21 - July 21 September 14 - October 14 You may have been conceived by people trying on costumes This period ends 10 days before Halloween, so it is not unlikely that the people who conceived you (mom and dad) tried on their new costumes when they made you.
Leo The Lion July 22 - August 23 October 15 - November 16 You may have been conceived during thanksgiving Thanksgiving is celebrated in the US on fourth Thursday of November, which for only two out of seven years will lie before the 23rd of November. However many people are born before 9 months so it is not unlikely for someone born as a Leo to be conceived on this day.
Virgo The Maiden August 23 - September 22 November 16 - December 15 You may have been conceived while a Christmas song played It is very common for Christmas songs to be played in the month before Christmas
Libra The Scales September 22 - October 23 December 15 - January 16 You may have been conceived after a new year's eve party Since New Year's Eve always falls on December 31, and since the party goes on into the new year this fits with Libra. As it is very likely that people are together in a way that may lead to conception at this type of parties, there may even be rather more than a 30th part of the people that are Libra that are conceived at such a party.
Scorpio The Scorpion October 23 and November 22 January 16 - February 15 You may have been conceived by people stuck inside after a long winter This period is during the coolest part and towards the end of the winter in the northern hemisphere. People may even be forced to stay at home due to snow. When people have nothing else to do many babies are born 9 months later.
Sagittarius The Archer November 22 - December 21 February 15 - March 14 You may have been conceived during March madness Although originally the early part of the mating season for the European Hare, in which females fight off male suitors, in a US context this is an American college Basketball tournament [1].
Capricorn The Goat December 22 - January 19 March 15 - April 12 You may have been conceived during a sexy Easter Egg hunt Easter falls between March 22 and April 25 so most Easter Egg hunt, sexy or not, will fall in the relevant period to conceive Capricorn children. The goal of an Easter egg hunt can be to find as many eggs in a given time, or find a sequence of eggs, each containing a clue to the next. It is not difficult to think of adult variations on these themes. Most Egg hunts do not involve people who should make them sexy! On the other hand, the egg itself, as an Easter symbol, is a symbol of fertility.
Aquarius The Water Carrier January 20 - February 18 April 13 - May 11 You may have been conceived on Mother's day Mother's Day in the USA,and some other countries, is on the second Sunday in May, between the 8th and 14th of May.
Pisces The Fish February 19 - March 20 May 12 - June 13 You may have been conceived at someone's wedding It is not uncommon that people meet and even go so far as to risk conceiving a child at someones wedding, and June is widely reported as the most popular month for weddings in the United States. The tradition of a June Bride (late spring and beginning of summer in the northern hemisphere) may be an old one and hence explains the reference for Pisces which lies mainly in June. ABC claim that in the 15th and 16th century, May would have been the month for an "annual bath", and moreover June is named for Juno, goddess of marriage and childbirth.


[Above the frame:]
With an actual basis in fact
[A list with the name of each astrological sign in the first column (in gray) and a horoscope for each sign in the second column. Here given in table form]
Aries You may have been conceived after a 4th of July fireworks show
Taurus You may have been conceived on a hot August day
Gemini You may have been conceived as the leaves began to change
Cancer You may have been conceived by people trying on costumes
Leo You may have been conceived during Thanksgiving
Virgo You may have been conceived while a Christmas song played
Libra You may have been conceived after a New Year’s Eve party
Scorpio You may have been conceived by people stuck inside after a long winter
Sagittarius You may have been conceived during March Madness
Capricorn You may have been conceived during a sexy Easter egg hunt
Aquarius You may have been conceived on Mother's day
Pisces You may have been conceived at someone's wedding

comment.png add a comment! ⋅ comment.png add a topic (use sparingly)! ⋅ Icons-mini-action refresh blue.gif refresh comments!


So funny - especially the title text made me laugh :-) --Kynde (talk) 07:05, 15 April 2015 (UTC)

Nine months later, it would certainly eliminate the stress of wondering if you were gonna "get lucky" that night. - Equinox 16:13, 15 April 2015 (UTC)

The "coriolis effect" in the title text refers to the spin direction of vortices (rotating currents such as cyclones, whirlpools, and water draining from a basin), which is counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere. The title text is a joke extending the reversal to the flow of time.

The spin direction of whirlpools and basins is 'not' determined by the coriolis effect, on this scale its impact is way too small to make a difference. The title text refers to how the coriolis effect is often used to explain phenomena (especially with relation to the hemispheres), even when its wrong. -- 08:23, 15 April 2015 (UTC)

If the baby is born 9 months BEFORE they're conceived, would that account for the shift in seasons for the southern hemisphere? Born in March: Northern hemisphere -> conceived in June; Southern hemisphere -> conceived in December. June and December being summer respectively. If that's right, could someone add that to the wiki? User:none

The events described during which the conception of a person with a given birth month occurred assumes that the parents were in the United States at that time. The seasons would be shifted by six months in the southern hemisphere, and the holidays of the 4th of July (Independence Day -- Aries), Halloween (Cancer, conception in October), Thanksgiving (Leo, conception in November), Mother's Day (Aquarius, conception in May), and the NCAA (college) basketball playoffs ("March Madness" -- Sagittarius) , might either not be celebrated or celebrated on a different day. The Dining Logician (talk) 08:11, 15 April 2015 (UTC)

Halloween is starting to become common in Brazil, including the "Trick or Treat" stuff. Mother's Day is also celebrated at the same date. And I wouldn't be surprised if Thanksgiving became common here too, if not only for the sales... 19:47, 17 December 2015 (UTC)

"Today, horoscopes are admitted to be pseudoscience." Citation needed. But what rubbish. Horoscopes are not even pseudoscience, so who is it "admitting" they are? 08:36, 15 April 2015 (UTC)

Agree, I would like the citation for "today", as there were experiments disproving horoscopes in ancient Rome already (involving two babies born in same time, one rich, one slave). -- Hkmaly (talk) 12:48, 15 April 2015 (UTC)

The general trick to horoscopes is make them vague enough that anyone can think they're true, regardless of their sign. --PsyMar (talk) 10:34, 15 April 2015 (UTC)

"You will have an opportunity today, meet someone new and should take care of your finances. Family matters will continue as per the last few days." 13:41, 15 April 2015 (UTC)
It's the Forer effect. 21:55, 16 April 2015 (UTC)

I propose an addition to the "conceived during someone's wedding" -- it's more common that the conception is actually after the wedding, during the (somewhat expected) consummation by the actual married couple. Thus, "honeymoon babies"! --BigMal // 12:53, 15 April 2015 (UTC)

I read this as being conceived at someone else's wedding - attending weddings often being a trigger for romantic thoughts. 03:25, 17 April 2015 (UTC)

Wait, I though Superman goes back in time not by "going against earths rotation, but simply by going faster than light? 19:53, 15 April 2015 (UTC)

The expected conception column is off, therefore the explanations may be off. Length of a human pregnancy is 38 weeks after conception, or 9 1/2 months, not the 9 months that is commonly portrayed. I'm not sure if Randall took this into account or not. 20:40, 15 April 2015 (UTC)

This is true, except you must have meant 8½ month not 9½ since 38 weeks is less than 9 month. Actually it is very close to 8,75 month. But anyway you are correct, that all the dates should be fixed to go 38 weeks back, not 9 months!--Kynde (talk) 20:54, 15 April 2015 (UTC)
Yep, that is what I meant, sorry 05:26, 16 April 2015 (UTC)
Updated with the correct dates, but the explanations haven't been proofread to conform with the dates 05:34, 16 April 2015 (UTC)
Fixed explanations, then realized you went for 40 weeks, not 38, so changed them to 38 weeks and fixed explanations again ;) Nealmcb (talk) 17:58, 16 April 2015 (UTC)
Even 38 weeks is idealised - I have a niece and nephew who were born 22 weeks after conception (4 years old now and doing well!) And term isn't until 41 weeks (from last menstruation) in France. 38 weeks happens to be a useful average in many parts of the world, but even healthy term pregnancies in USA/UK/Australia(/others?) covers the range of 35-40 weeks from conception. Also, with the rise of babies conceived by IVF, it's no longer quite so obvious what was happening 38-ish weeks before birth! 03:30, 17 April 2015 (UTC)

No reference to the fact that November babies might be conceived on V day? Vkapadia (talk) 21:10, 15 April 2015 (UTC)

The real secret behind horoscopes and Nostradamus, is "vague shift"The Goyim speaks (talk) 01:36, 17 April 2015 (UTC)

In the second paragraph of the explanation, can we use either "i.e." or "for example," but not both? I don't have a particular preference for one or another; anyone who does is encouraged to make the correction. 06:32, 17 April 2015 (UTC)

I feel like there was a missed opportunity for Scorpio. Could have mentioned Valentines Day. (talk) (please sign your comments with ~~~~)

Aquarius could also, perhaps sadly/strangely, be prom babies. 22:29, 22 May 2016 (UTC)

Regarding about Gemini, which coincidentally I am one, doesn't apply to South-East Asian countries like Singapore(where I am born in), where the leaves doesn't change colors the whole year round. Same goes to the rest of the horoscopes as well. Boeing-787lover 13:56, 30 November 2017 (UTC)

Aries and to a lesser extent Cancer: kids went back to school, leaving house empty, or if your parents are in education (incl. college) they'd just started a new semester and met a bunch of new people. Singlelinelabyrinth (talk) 19:21, 26 July 2020 (UTC)