The Mega Millions jackpot hit a billion dollars on Friday.

Friday's jackpot for the multistate Mega Millions lottery has reached a record $1 billion, but the odds of winning are very long -- about one in 302.5 million.

To put that in perspective, Chris O'Byrne, a Management Information Systems expert at San Diego State University, told TheStreet that there's about a one-in-10 million chance you could walk down the street and have an airplane part fall on you. "So, you're 30 times more likely to get get hit by an airplane piece," he said.

O'Byrne said one sure way of winning would be to buy every possible number combination. The problem: "It would cost you approximately $605 million," given that tickers cost $2 apiece.

Then, of course, there's the taxes you'd have to pay on the winnings and the chance someone else might score a winning ticket, too.

Mega Millions will draw winning numbers for the lottery at 11 p.m. ET on Friday, with tickets for sale up until 10:45 p.m. ET in the District of Columbia, the U.S. Virgin Islands and 44 states. (Only Alaska, Alabama, Hawaii, Mississippi, Nevada and Utah don't participate.)

For the record, as bad as O'Byrne knows the odds of winning are, he said he'll buy a ticket. He said the $2 price is worth the "dream" of winning that it will give him for the hours ahead of the drawing.

(This article has been updated.)