You can now check how happy the world is online on any given day.
Researchers have produced a happiness index based on expressions posted on Twitter.
The website, www.hedonometer.org, has posted the index, and it appears like a stock market chart, with highs and lows over time.
The index, which measures our happiness level from September 2008 to now, has coloured circles for each day of the week.
If you hover over a circle, you will see more details of the kinds of tweets posted that day.
Christmas Day happens to be the happiest day on the calendar judging by tweets that day.
Saturdays have a higher happiness rank than Tuesdays on Twitter.
Disasters like bombings and earthquakes are reflected in the unhappy tweets.
The Twitter Time Series collects data from the social messaging site and measures the happiness of large populations in real time.
About 50 million tweets from around the world are collected each day and the words used in those tweets rated on a scale.
Words are scored on a nine point scale of happiness: (1) sad to (9) happy.
We have also learned there was a dramatic plunge in the index on April 15, which was the day of Boston Marathon bombings.
You might think one of the happiest occasions was the day on May 2, 2011 when a U.S. tactical team shot and killed the most wanted terrorist in the world, Osama bin Laden.
However, that wasn’t the case.
The researchers explain that while words such as “celebration” appeared, the overall language of the day was driven by a negative sentiment expressed about a dangerous individual who met a very negative end.
The website explains that Hedonometer.org is based on the research team in the Computational Story Lab at the University of Vermont Complex Systems Center, and the technology of the team from The Mitre Corporation.