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When does the new decade begin ?

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jack martin's picture
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When does the new decade begin ?

There is some debate over this, is it 01-01-2020 or 01-01-2021 ?

Regards,

Jack

Essex UK

Robin Leadbeater's picture
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new millenium

 01-01-21. Same as with the new millenium. Since the first day of the Common Era was 1st Jan 0001 the 3rd millenium began  1st Jan 2001 but you probably will not convince the billions who celebrated the year before or similarly convince them that the new decade starts next year

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But are millennium and decades defined in the same way ?

This is the sort of question you only ask if you want an argument, and as no one else is biting.

While Robin is correct as regards millennium and centuries, in the mind of public opinion a decade is usually considered (whether right or wrong) as going xxx0 to xxx9. When you refer (say) to the 1920’s you tend to think of 1920 to 1929, perhaps because we’re lazy and only look at the “tens” figure, or because our brain starts to hurt when we try and workout how 1930 can possibly be referred to as being in the twenties.

It’s probably best to use whatever definition your target audience is happiest with, regardless of any legal or technical definitions, and if you’re having a “beginning of a new decade” party then you use the ambiguity to have 2 parties.

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This argument is analogous to

This argument is analogous to that been grammar descriptivists and prescriptivists. Oliver Kamm did, for some years, lay into the latter in his characteristically trenchant style in the Pedant column of The Times. IMHO, the community overwhelming thinks that 2020 is the first year of the new decade, and therefore it is the first year of the new decade. We are not talking about constants of the universe here. Nonetheless, I am willing to tolerate pedants who think otherwise. This isn't Twitter ;)

Robin Leadbeater's picture
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the first decade

 "Nonetheless, I am willing to tolerate pedants who think otherwise." 

 :-)

There is indeed no point swimming against the tide on this one but don't you find a decade lasting 9 years even a little unsettling ;-)

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Where's the fun in this?

Blimey - where did this spirit of toleration suddenly come from? Back in 2000 you could have a proper brawl about this...

Surely all Proper Astronomers measure their dates in Julian Day numbers, and so count in units of Julian decades (3652.5 days) from Jan 1, 4713 BC (Julian calendar). So, as everybody knows, the current decade started on 14 Jan 2018 (Gregorian calendar).

Does the BAA really allow people in who count their decades in lesser calendars? I shall write to the President directly about how standards are slipping...

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Mass-illogicality

Quite.

jack martin's picture
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When does the new decade begin ?

Thank you all for your explanations, its now clear and correct as to when this is.

But, I can see why others would disagree.

It also depends on your level of knowledge about the subject, which is after all of Astronomical significance.

Regards,

Jack

Essex UK

David Arditti's picture
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Do you want the full half-hour argument or only the 10 minute?

I'm not sure what Jack thinks is the 'clear and correct' answer, as he didn't say.

This is a matter of social convention, not calculation. No-one was actually counting decades after the beginning of the Common Era (the supposed year of the birth of Christ according to (probably erroneous) mediaeval scholars) in the years immediately after. Therefore there is no continuity here and no reason why we can't regard the first decade of the Common Era as having only 9 years, or extending from 1BCE to 9AD.

A decade is generally regarded as a grouping of years having the same three initial digits. Therefore the new decade has begun.

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"no reason why we can't

"no reason why we can't regard the first decade of the Common Era as having only 9 years".  I can think of an excellent reason and it is entirely a matter of etymology. "Deca", from the Greek Δεκα, meaning "ten".

If you wish to refer to the first few years CE as a nonade please go ahead and do so --- I will support you whole-heartedly.

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so that's settled

So that's settled. Let's hope the weather will calm down soon before we all go nuts!