On Christmas, astrophysicist Neil deGrasse Tyson tweeted this:

On this day long ago, a child was born who, by age 30, would transform the world. Happy Birthday Isaac Newton b. Dec 25, 1642 — Neil deGrasse Tyson (@neiltyson) December 25, 2014

The message racked up thousands of retweets and made it his most popular, and seemingly most controversial, tweet yet.

Some thought his sentiment was anti-Christian. Many agreed he was trolling (with a twinkle in his eye).

Santa knows Physics: Of all colors, Red Light penetrates fog best. That's why Benny the Blue-nosed reindeer never got the gig — Neil deGrasse Tyson (@neiltyson) December 25, 2014

The day after Christmas, Tyson turned to Facebook to flesh out an explanation for his Isaac Newton tweet, which quickly became his most retweeted ever.

Below is his full note, which he posted here:

Well. It's official. Far and away my most re-tweeted tweet appeared Christmas day. Here are the 125 characters (my usual length) in their entirety:

"On this day long ago, a child was born who, by age 30, would transform the world. Happy Birthday Isaac Newton b. Dec 25, 1642"

Everybody knows that Christians celebrate the birth of Jesus on December 25th. I think fewer people know that Isaac Newton shares the same birthday. Christmas day in England - 1642. And perhaps even fewer people know that before he turned 30, Newton had discovered the laws of motion, the universal law of gravitation, and invented integral and differential calculus. All of which served as the mechanistic foundation for the industrial revolution of the 18th and 19th centuries that would forever transform the world.

My sense in this case is that the high rate of re-tweeting, is not to share my enthusiasm of this fact, but is driven by accusations that the tweet is somehow anti-Christian. If a person actually wanted to express anti-Christian sentiment, my guess is that alerting people of Isaac Newton's birthday would appear nowhere on the list.

Some even called for me to delete the tweet. But instead, earlier today, I tweeted this:

"Imagine a world in which we are all enlightened by objective truths rather than offended by them."

A few facts: My average re-tweet rate falls between 2,500 and 3,500. My fun tweets can go somewhat higher - up to 10,000. My boring tweets barely break 1,000. The Newton Christmas day tweet, as of this writing - a day after posting -- is rising through 62,000 re-tweets.

I wonder if you are as astonished by this fact as I am. For example, I've made direct reference to Jesus in previous tweets that have not come close to this number. How about:

"Some claim the USA is a Christian nation, compelling me to wonder which assault rifle Jesus would choose: the AR-15 or AK-47."

Posted September 7, 2014, that one garnered 13,000 re-tweets. So I can honestly say that I don't understand the breadth and depth of reaction to the Newton tweet, relative to all my other tweets over the years.

In any case, I'm happy to see that many people liked my "Santa knows Physics" tweet from Christmas day:

"Santa knows Physics: Of all colors, Red Light penetrates fog best. That's why Benny the Blue-nosed reindeer never got the gig"

I worked hard on that one, which has received 13,000 re-tweets in a day -- a factor of 4-5 times my average.

One last bit of historical fact. All of England was celebrating Christmas the day Newton was born. But the Gregorian Calendar (an awesomely accurate reckoning of Earth's annual time), introduced in 1584 by Pope Gregory, was not yet adopted in Great Britain. To do so required removing ten days from the calendar -- excess time that had accumulated over the previous 16 centuries from the mildly flawed Julian Calendar, introduced by Julius Caesar in 46 BC. These remnants of the turbulent schism between the Anglican and Catholic churches meant that Catholic Christendom was celebrating Christmas ten days earlier than anybody was in England.

If you wanted to reckon Newton's birthday on today's Gregorian Calendar, we would place his birth on January 4, 1643.

Happy Holidays to you all. And a humble thanks for your continued interest in what I have to say about life, the universe, and everything. But most importantly, enjoy a Happy New Year. A few days after, I'll be tweeting about Earth's perihelion. Just a head's up in case people want to avert their eyes over that one.

I am, and always will be, a servant of your cosmic curiosity.

-Neil deGrasse Tyson, New York City

p.s. For those who are Facebook-friendly but Twitter-averse, my tweets stream, almost in real time, to this Facebook page:

https://www.facebook.com/TysonsTweets