Welcome to 2020: The year of the rat — as of January 25 — according to the Chinese Zodiac. In that context, the rat is a symbol of shrewd intelligence and vitality.

Vitality will — of course — be on full display the world over this summer at the Olympics. 2020 brings the Summer Games in Tokyo, from July 24-August 9. New events this year include surfing, karate, and 3-on-3 basketball. The famed Olympics theme music you’ll likely be hearing ad infintum come July was composed by John Williams, an adopted Bay Stater — given his New England-born parents and his long-time association with the Boston Pops. He wrote the piece, titled "Olympic Fanfare and Theme," for the 1984 Summer Games in Los Angeles.

And speaking of Bay Staters and the Olympics, the very first Olympic medal winner, in the very first event, at the very first modern Olympics in Athens in 1896 was a Massachusetts man. James Brendan Connolly — the son of Irish immigrants who was born and raised in Southie — won the hop skip and jump. That's still a medal event today, under the name the triple jump.

And as long as we’re talking about jumping, I should note that 2020 is a leap year, which means February gets a little extra love and all those people born on February 29 finally get another official birthday. As for auspicious leap days in Massachusetts history, how about February 29, 1692?

It was on that day that the first three arrest warrants were issued in Salem, kicking off an ignominious, year-long, community-wide hysteria remembered today as the Salem Witch Trials.

We add a leap day to the calendar every four years because the earth’s revolution around the sun actually takes more like 365 and a quarter days. So, every four years we need to add a day. Otherwise, slowly overtime, we’d get all out of whack. If we stopped doing the leap year thing today, by the year 3020 it would be winter in June and summer in January.

And there’s more. Adding a whole day every four years is slightly too much, as the earth’s yearly trip around the sun is technically more like 365.2425 days. To counteract this, three leap days need to be skipped every 400 years. So, when do we do that? Every time a year is divisible by 100 but not by 400. The next leap year that we will leap over is 2100.

If you think all this remarkable precision is thanks to modern technology, think again. Hipparchus — the same fella who brought you trigonometry — apparently worked this all out in the 2nd century B.C.

But it’s another quadrennial event that is poised to dominate the news in 2020. In November — for the 59th time in American history — citizens will go to the polls and cast their vote in a U.S. presidential election.

It’s now been 36 years since Massachusetts voters favored a republican presidential candidate and all signs point to that blue streak continuing in 2020. Massachusetts' 11 electoral votes are actually about the same number we had in the country’s very first presidential election, when we had 10. The difference is that in 1788, those 10 votes were nearly 15 percent of the entire electoral vote (69). Today, our 11 constitute just about two percent of the total (538).

This year’s election marks the 100th anniversary of the 1920 election, which was historic on a number of fronts. For starters, it was the first election following the ratification of the 19th Amendment — which meant women across the country were able to vote for the first time. And on election night, Nov. 2, 1920, the results were broadcast live by radio station KDKA in Pittsburgh. It is disputed by some, but most consider this to be the first ever commercial radio broadcast.

Some other big anniversaries — specifically of the births of now dead luminaries — are in the docket in 2020. They including composer Ludwig van Beethoven’s 250th, nurse and social reformer Florence Nightingale’s 200th, Russian revolutionary Vladimir Lennon’s 150th, and James Doohan’s 100th — ya know, Scottie from Star Trek.

Around here the biggest anniversary will likely be the 400th of the Mayflower’s voyage from England to the New World. Events galore are planned throughout the year here, in England, and in the Netherlands. On board that renowned ship in 1620 were 102 passengers — fewer than half which were so-called Pilgrims by the way — about 30 crew members, at least two dogs and, more likely than not, plenty of rats.