Astrophysicist Neil deGrasse Tyson decided to spend part of Christmas Day riling up Christians. 
 
 The "Cosmos" host cracked wise about the biggest holiday of the year in a series of tweets. 
 
 "On this day long ago, a child was born who, by age 30, would transform the world," Tyson wrote Thursday. "Happy Birthday Isaac Newton b. Dec 25, 1642." 
 
 Considering there are more than two billion Christians worldwide, some were not pleased with his joke, though it has been retweeted more than 56,000 times. 
 
 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 
 
 QUESTION: ThIs year, what do all the world's Muslims and Jews call December 25th? ANSWER: Thursday — Neil deGrasse Tyson (@neiltyson) December 25, 2014 
 
 "Hi @neiltyson, trolling Christians on Dec 25 is so EDGY. Please let me know when you troll Muslims on Ramadan. Merry Christmas!," wrote one Twitter user. 
 
 "Looking fwd to witty jabs during the spiritual days of Islam, Buddhism, Judaism etc. Or is it reserved for the easiest target?" wrote another. 
 
 Some also took issue with Tyson's grasp of history, claiming that Isaac Newton was actually born on January 4, 1643. However, some countries used different calendars during that era, and Newton's birthdate is open for debate. Many have questioned the birthdate of Jesus Christ as well. 
 
 Tyson's ribbing of Christmas didn't stop there. He also tweeted, "Merry Christmas to all. A Pagan holiday (BC) becomes a Religious holiday (AD). Which then becomes a Shopping holiday (USA)." 
 
 The cosmologist also used social media to poke fun at last year's blockbuster film "Gravity," saying the film overlooked some laws of physics. ||||| (CNN) -- It's a number that even astrophysicist Neil deGrasse Tyson is having a hard time wrapping his brilliant mind around. 
 
 His Christmas Day tweet commemorating the birthday of Isaac Newton was retweeted more than 69,000 times as of this writing, making it the most popular of his Twitter career so far -- and, arguably, his most controversial. 
 
 "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," the StarTalk host tweeted. 
 
 He followed it up with a nod to the commercialization of Christmas: "Merry Christmas to all. A Pagan holiday (BC) becomes a Religious holiday (AD). Which then becomes a Shopping holiday (USA)." By then, he was on a roll. Earlier in the day, he tweeted, "QUESTION: This year, what do all the world's Muslims and Jews call December 25th? ANSWER: Thursday." 
 
 His comments drew criticism and name-calling from various corners of the internet. "Overly reductive, deliberately cynical and unnecessarily provocative," one person said on Twitter. 
 
 Another accused him of "trolling Christmas today to show you how smart he is." 
 
 Tyson's response to the controversy? "Imagine a world in which we are all enlightened by objective truths rather than offended by them." 
 
 Later Friday, Tyson pondered "My Most Retweeted Tweet" in a Facebook post. He did not defend or disavow his comments. Instead, in true scientific form, he attempted to quantify their popularity compared to previous tweets. 
 
 "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," he wrote. "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." 
 
 According to his calculations, his average retweet rate falls between 2,500 and 3,500. "Fun" tweets can reach 10,000 while "boring tweets barely break 1,000." The Newton Christmas Day tweet had surpassed 62,000 retweets by the time he posted his Facebook note on Friday. By Saturday evening, it had reached more than 69,000. 
 
 "I wonder if you are as astonished by this fact as I am," he wrote. 
 
 For example, he directly referenced Jesus in previous tweets that did not spread nearly as far. By way of example, he offered the following, which earned more than 13,000 retweets: "Some claim the USA is a Christian nation, compelling me to wonder which assault rifle Jesus would choose: the AR-15 or AK-47." 
 
 He also addressed criticism that according to the calendar in use during Newton's time, his birthday would fall on January 4, 1643. 
 
 "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." 
 
 Tyson closed his note with holiday wishes and a warning that he'll be tweeting about Earth's perihelion in the New Year. 
 
 "Just a head's up in case people want to avert their eyes over that one."
– Neil deGrasse Tyson's Christmas musings might not have made it to the cosmos, but the Twitterverse is buzzing with them: As CNN reports, Tyson on Thursday tweeted out birthday greetings to a babe who went on to rock planet Earth. Except not that babe."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," he tweeted in a post that as of this writing has been retweeted almost 74,000 times. CNN notes that Tyson was on something of a Christmas roll, also tweeting, "QUESTION: ThIs year, what do all the world's Muslims and Jews call December 25th? ANSWER: Thursday" as well as, "Merry Christmas to all. A Pagan holiday (BC) becomes a Religious holiday (AD). Which then becomes a Shopping holiday (USA)." The tweets went over with a thud among many Christians, reports the New York Daily News, which notes that of the "more than two billion Christians worldwide, some were not pleased with his joke." Per CNN, reaction ranged from accusing Tyson of being "Overly reductive, deliberately cynical and unnecessarily provocative," to "trolling Christmas today to show you how smart he is." Counters Tyson via a Facebook post: "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."