Binary Dates in 2010 and 2011
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http://www.exploringbinary.com/binary-dates-in-2010-and-2011/
People have been tweeting about the upcoming dates that look like binary numbers. 10/10/10 seems to be a favorite, both because of its symmetry and because 101010 = 42 in decimal (you know, the answer to the ultimate question of life, the universe, and everything). Here are the nine dates in each year, interpreted as binary numbers, and with their decimal equivalents:
| Date | mm/dd/yy | Binary | Decimal |
|---|---|---|---|
| January 1st, 2010 | 1/1/10 | 1110 | 14 |
| 1/01/10 | 10110 | 22 | |
| January 10th, 2010 | 1/10/10 | 11010 | 26 |
| January 11th, 2010 | 1/11/10 | 11110 | 30 |
| October 1st, 2010 | 10/1/10 | 10110 | 22 |
| 10/01/10 | 100110 | 38 | |
| October 10th, 2010 | 10/10/10 | 101010 | 42 |
| October 11th, 2010 | 10/11/10 | 101110 | 46 |
| November 1st, 2010 | 11/1/10 | 11110 | 30 |
| 11/01/10 | 110110 | 54 | |
| November 10th, 2010 | 11/10/10 | 111010 | 58 |
| November 11th, 2010 | 11/11/10 | 111110 | 62 |
Here they are in dd/mm/yy format:
| Date | dd/mm/yy | Binary | Decimal |
|---|---|---|---|
| January 1st, 2010 | 1/1/10 | 1110 | 14 |
| 1/01/10 | 10110 | 22 | |
| January 10th, 2010 | 10/1/10 | 10110 | 22 |
| 10/01/10 | 100110 | 38 | |
| January 11th, 2010 | 11/1/10 | 11110 | 30 |
| 11/01/10 | 110110 | 54 | |
| October 1st, 2010 | 1/10/10 | 11010 | 26 |
| October 10th, 2010 | 10/10/10 | 101010 | 42 |
| October 11th, 2010 | 11/10/10 | 111010 | 58 |
| November 1st, 2010 | 1/11/10 | 11110 | 30 |
| November 10th, 2010 | 10/11/10 | 101110 | 46 |
| November 11th, 2010 | 11/11/10 | 111110 | 62 |
2011
The same days also look like binary in 2011:
| Date | mm/dd/yy | Binary | Decimal |
|---|---|---|---|
| January 1st, 2011 | 1/1/11 | 1111 | 15 |
| 1/01/11 | 10111 | 23 | |
| January 10th, 2011 | 1/10/11 | 11011 | 27 |
| January 11th, 2011 | 1/11/11 | 11111 | 31 |
| October 1st, 2011 | 10/1/11 | 10111 | 23 |
| 10/01/11 | 100111 | 39 | |
| October 10th, 2011 | 10/10/11 | 101011 | 43 |
| October 11th, 2011 | 10/11/11 | 101111 | 47 |
| November 1st, 2011 | 11/1/11 | 11111 | 31 |
| 11/01/11 | 110111 | 55 | |
| November 10th, 2011 | 11/10/11 | 111011 | 59 |
| November 11th, 2011 | 11/11/11 | 111111 | 63 |
Here they are in dd/mm/yy format:
| Date | dd/mm/yy | Binary | Decimal |
|---|---|---|---|
| January 1st, 2011 | 1/1/11 | 1111 | 15 |
| 1/01/11 | 10111 | 23 | |
| January 10th, 2011 | 10/1/11 | 10111 | 23 |
| 10/01/11 | 100111 | 39 | |
| January 11th, 2011 | 11/1/11 | 11111 | 31 |
| 11/01/11 | 110111 | 55 | |
| October 1st, 2011 | 1/10/11 | 11011 | 27 |
| October 10th, 2011 | 10/10/11 | 101011 | 43 |
| October 11th, 2011 | 11/10/11 | 111011 | 59 |
| November 1st, 2011 | 1/11/11 | 11111 | 31 |
| November 10th, 2011 | 10/11/11 | 101111 | 47 |
| November 11th, 2011 | 11/11/11 | 111111 | 63 |
And in case you were wondering, 2010 = 11111011010 in binary, and 2011 = 11111011011 in binary.
(If this blog existed in 2001 — if blogs existed in 2001 period — I would have made tables for those dates as well.)
Palindromes
Considering dates as numbers leads you to wonder which are number palindromes. Numbers written with leading zeros are not palindromes, so numbers ending with zeros are not palindromes either. This means no dates in 2010 are palindromic. In 2011 however, there are palindromic dates. There are several consisting of all 1s, like 1/1/11, but those are not interesting. That leaves two palindromic dates made up of both 0s and 1s:
- January 10th, 2011, in mm/dd/yy format: 1/10/11.
- October 1st, 2011, in dd/mm/yy format: 1/10/11.
Both are the same binary number: 11011 (27 decimal).
Binary Times
People have also been tweeting about binary times. There are binary times every day, but they’ll seem more significant on binary days. There are 12, not including seconds and duplicates for AM/PM: 1:00, 1:01, 1:10, 1:11, 10:00, 10:01, 10:10, 10:11, 11:00, 11:01, 11:10, 11:11. (I’ll leave it as an exercise to compute these as decimal values.)
Now having thrown time into the mix, we can consider some new palindromes. For example, 1/1/10 (mm/dd/yy) at 1:11 AM is 1110111. Have a toast for me!



December 20th, 2009 at 4:44 pm
You do love binary more than I do. Wait, can one love something more than someone else? Love is love. Computer programmer have gotten away from the machine thanks to the modern programming environments… they collect our garbage, they utilize memory on our behalf and save us from ourselves, they hold our hand… I suppose that’s okay, but I still have a soft spot for reading a 6502 machine code book and writing programs in hex, counting jump offsets by hand.
December 20th, 2009 at 9:24 pm
I still look upon “peek” and “poke” fondly.
January 1st, 2010 at 4:44 am
I am a Pastor preparing my sermon for Sunday Service, your blog really helped me, looks like tis Binary thing may attract more attention than you may imagine…
January 3rd, 2010 at 6:46 pm
Love It! Thanks!!! I am going to use this for a math lesson in 6th grade.
January 4th, 2010 at 4:54 am
@Hugh: Thanks. I’d be interested in how you incorporated “binary” into your sermon.
@Lenore: Thanks. Let me know how it turns out. I’ve been wondering what the best grade is in which to introduce binary.
January 10th, 2010 at 6:25 am
this is so cool, thanks for laying it out…my b-day is today 01/10/10 and I’m turning 26 so thanks again for the info!
January 10th, 2010 at 9:39 am
@serene: Your 27th birthday — 1/10/11 — will also “match”: 11011 = 27 (and 11011 is also palindromic as I noted above).
January 11th, 2010 at 8:21 am
[...] Binary Dates in 2010 and 2011 (Exploring [...]
January 11th, 2010 at 8:34 am
Yesterday, 1/10/10, my stats report says this article was viewed 101 times:
You gotta love it!