The largest lottery jackpot in the history of the universe may be upon us. Tonight's Mega Millions draw has been boosted to an astonishing $636 million, the second largest prize ever in the U.S., and is threatening to go higher.

Georgia lottery officials confirmed tonight's jackpot total with CNNThe draw Tuesday night is second only to a Mega Millions draw last March that split a $656 million jackpot between three lucky winners. Last Friday's, huge $400 million jackpot went unclaimed, which we predicted, and sales since have juiced the prize well into the stratosphere. With a few more hours to go before sales are cut off, the final total may burst through the record.

No one has claimed the Mega Millions jackpot since October 1, and a rules change on October 22 made your already slim odds of winning even, well, slimmer. Under the new rules, gamblers choose five numbers between 1 and 75, instead of 1 and 46 under the old rules. Mega Millions added more prizes, so the odds of you winning something went up, but the odds of winning the jackpot shifted from 1-in-176 million under the old rules to an even more outrageous 1-in-259 million. The change was made to produce bigger jackpots and fewer winners, but lottery officials probably did not foresee their plans working so well, so quickly.

But once Friday's jackpot went unclaimed, Mega Millions knew they'd flirt with the ceiling. "I think we'll be very close to the record, and maybe even surpass it," Mega Millions' lead director Paula Otto told the Associated Press earlier this week. At the time Otto estimated roughly 75 percent of the number possibilities will be in play for Tuesday night's draw. If somehow the winning combination is not among, the prize for Friday's drawing will likely surpass $1 billion for the first time ever. 

Here's an existing top ten list for U.S. lotteries, via CBS News

1. $656.0 million, Mega Millions, March 30, 2012 (3 tickets from Kansas, Illinois and Maryland)

2. $590.5 million, Powerball, May 18, 2013 (1 ticket from Florida)

3. $587.5 million, Powerball, Nov. 28, 2012 (2 tickets from Arizona and Missouri)

4. Estimated $586 million, Mega Millions, (next drawing scheduled Tuesday, Dec. 17; jackpot could grow)

5. $448.4 million, Powerball, Aug. 7, 2013 (3 tickets from Minnesota and New Jersey)

6. $399.4 million, Powerball, Sept. 18, 2013 (1 ticket from South Carolina)

7. $390.0 million, Mega Millions, March 6, 2007 (2 tickets from Georgia and New Jersey)

8. $380.0 million, Mega Millions, Jan. 4, 2011 (2 tickets from Idaho and Washington)

9. $365.0 million, Powerball, Feb. 18, 2006 (1 ticket from Nebraska)

10. $363.0 million, The Big Game(asterisk), May 9, 2000 (2 tickets from Illinois and Michigan)