We've all seen the ridiculous moon-orbiting blasts and never-ending barrage of home runs. On Sunday, the Nationals tied a record with four consecutive home runs. On Monday, the Diamondbacks and Phillies set a record by combining for 13 home runs. On Tuesday, the Braves hit four home runs in one inning. Jerad Eickhoff allowed five home runs on Monday, and Chris Archer did it on Tuesday.

Entering Wednesday's games, 25 players had already hit 17 home runs, putting them on a 40-homer pace. The single-season record for players with 40 home runs is 17 in 1996. As recently as 2014, only one player -- Nelson Cruz -- hit 40 home runs.

Needless to say, MLB is once again set to shatter the record for total home runs. There were 6,105 home runs in 2017. We're on pace for 6,566 in 2019 -- nearly 1,000 more home runs than there were in 2018. It's not just the quantity but also the apparent cheapness of many of the home runs, seemingly lazy fly balls that land in the bleachers. As Buster Olney said on his podcast the other day, "How many times have we heard announcers say, 'I can't believe that one went out'?"

Compared with last season, runs per game are up 0.27, and home runs are up 0.20 per game. Yes, hitters are going for launch angle and all-or-nothing swings while accepting even more strikeouts, but something is clearly up with the ball. The juiced ball of 2017 has returned with rockets attached this time.

Now it's time for a little history lesson. This kind of dramatic season-to-season increase in offense has occurred at various times throughout major league history, with increases traced directly to changes (intentional or not) to the ball. Let's look at some of those seasons and see what happened.

1911: Introducing cork

Runs per game: up 0.68

Home runs per game: up .07

For decades, the National League (and later the American) used a ball produced by the A.G. Spalding Company, founded by White Sox pitcher Albert Spalding in 1876 to manufacture a standard ball for the new professional league. Prior to that, balls were of inconsistent standards and quality. (The American League ball bore a "Reach" label, but Spalding was the actual manufacturer.)

That ball included a rubber core, but during the 1910 World Series, a cork-centered ball was used -- yes, imagine changing the ball that had been used all season for the World Series -- and the cork-centered ball became the new standard. Even though it was still the dead ball era, the increase in runs per game remains the largest year-to-year increase in any season since 1900.

The overall major league batting average increased from .249 to .266. In 1910, 15 players hit .300 across the two leagues, and only three (Ty Cobb, Nap Lajoie and Sherry Magee) slugged above .470. In 1911, 30 players hit .300 and 13 slugged above .470.

Leading the way was Cobb, who hit .419 after hitting .382 the season before. He followed with a .409 mark in 1912. He went from 35 doubles and 13 triples to 47 doubles and 24 triples. Shoeless Joe Jackson, in his first full season in the majors, hit .408. Sam Crawford, Cobb's Hall of Fame Tigers teammate, was a 31-year-old veteran with a .305 career average. He hit .378.

The offensive gains proved short-lived, however. Runs per game went from 4.51 in 1911 and 4.53 in 1912 all the way down to 3.56 by 1916. According to John McMurray of SABR's dead ball era committee in a 2011 New York Times article, a pitcher named Russ Ford started scuffing the ball, which soon became a widespread tactic. Add various forms of the spitball, and offense fell back to low levels.

1930: The year the National League hit .303

Runs per game: up 0.36

Home runs per game: up .08

The so-called "lively ball" era began in 1920 (runs increased from 3.88 to 4.36 from 1919 to 1920), though the initial increase wasn't so much the result of a different ball. There were two other reasons: (A) banning the spitball; (B) using new balls throughout the game rather than dirty, scuffed-up ones. Babe Ruth began slugging home runs, and the new style of power hitting quickly took over.

The most notorious high-offense season in major league history saw an average of 5.55 runs per game, the highest of the live ball era. Next highest: 5.19 in 1929 and 5.14 in 2000. The National League averaged 5.68 runs per game and hit a collective .303. The New York Giants hit .319 as a team, and the Phillies allowed 7.69 runs per game with a 6.71 ERA.

Some of the individual highlights:

-- Hack Wilson hit 56 home runs with a record 191 RBIs.

-- Bill Terry of the Giants hit .401.

-- Chuck Klein hit .386 with 107 extra-base hits and 170 RBIs.

-- Freddie Lindstrom of the Giants hit .379 and became one of the worst Hall of Fame selections ever on the strength of that season.

-- Brooklyn's Babe Herman hit .393 with 35 home runs.

-- Cubs pitcher Guy Bush finished with a 6.20 ERA. He still went 15-10.

That was just in the National League.

What happened? The manufacturer insisted that nothing had changed. "There has been absolutely no change in the major league baseball in the past five years," Spalding president Julian Curtis said that June. "There isn't even a change in the yarn. If we bought our yarn, there might be, but we don't. We have our own yarn mills, and there has been no change in the manufacture or quality; no change in the wrapping; no change in the covers; no change in the rubber or cork."

Giants manager John McGraw suggested the owners needed to fix the ball. "It has taken the confidence out of the pitchers and is so lively the fielders cannot handle it," he said. He also proposed moving the pitching distance two feet closer to home plate. Cubs president Bill Veeck offered that the fans liked all the hitting. "It's the punch that has made baseball over in the last 10 years," he said.

In the end, it was too much offense, even for the owners. The National League changed the ball for 1931, adding a slightly thicker cover and raising the seam. Offense fell from 5.68 runs per game to 4.48, the league average declined from .303 to .277, and home runs dropped from 892 to 493. The American League, however, apparently didn't change its ball, and runs per game remained above 5.0, including 5.67 in 1936 -- just shy of the National League's mark in 1930.

1977: Welcome aboard, Rawlings

Runs per game: up 0.48

Home runs per game: up 0.29

A New York Times story from 1975 detailed the end of Spalding's reign as MLB's baseball manufacturer. With its contract set to expire after the 1976 season, the company reportedly asked for a 5% price increase per ball for 1975 and another 5% for 1976. According to the article, Spalding sold about 250,000 balls per year to MLB at a cost of $2 apiece. A 5% increase to $2.10 per ball would have increased MLB's annual cost to $525,000.

Spalding had produced every baseball ever used in major league baseball, but it was kicked to the curb over an additional $25,000. "The reason is price," said Lee MacPhail, president of the American League. "We're sorry we're ending such a long and proud relationship. But we've been able to work something out with another manufacturer."

That manufacturer became Rawlings in 1977. Before it took over, however, offense nose-dived in 1976 to 3.99 runs per game. Only four players across the majors hit 30 home runs, and only 22 hit even 20. With Rawlings presumably manufacturing a higher quality ball in 1977 (plus new expansion teams in Seattle and Toronto slightly diluting the pitching), 19 players hit 30-plus home runs, and 56 hit at least 20. Among the big hitters:

-- George Foster of the Reds slugged 52 home runs, the first 50-homer slugger since Willie Mays in 1965.

-- Rod Carew hit .388 and slugged .570, the only full season he slugged .500 in his career.

-- The Dodgers had four players hit 30-plus home runs (Steve Garvey, Reggie Smith, Dusty Baker, Davey Lopes), the first time four teammates had done that (11 teams have done it since, all since 1995).

The 4.47 runs per game in 1977 were not topped until something strange happened in 1987.

1987: The rabbit ball

Runs per game: up 0.31

Home runs per game: up 0.15

The first sentence in Frank Deford's column in the July 27 edition of Sports Illustrated asked the question on everyone's mind: "If the baseball is juiced up, who's responsible?" Deford dismissed any conspiracy to change the ball -- something would have leaked if that were the case, he surmised -- and attempted rational explanations for the home run explosion that season. Batters were stronger, a generation of pitchers was on the defensive due to growing up facing aluminum bats and throwing too many breaking balls, and the best athletes had chosen hitting as their trade.

Or this: "The last incredible generation of pitchers -- Gibson, Marichal, Koosman, Seaver, Palmer, Sutton, Hunter, John, Jenkins, Carlton, Tiant, the Perrys and the Niekros -- was the product of that postwar time when traditional philosophy still prevailed: discipline and dedication, the Protestant ethic and the commitment to the long haul." Pitchers weren't tough enough. Or something. George Will went with the aluminum bat theory and increased weight training. Pirates GM Syd Thrift said pitchers were being rushed to the majors. Braves catcher Ozzie Virgil said the bats were better.

OK ... except the 1988 season saw one of the biggest drops in offense in the game's history. Runs per game fell from 4.72 to 4.14, not just below 1987 figures but well below 1986 or 1985 or 1984. There were 3,813 home runs in 1986 (which was a record for total home runs, though not quite the highest per-game average), then 4,458 in 1987, then 3,180 in 1988. The MLB-wide batting average went from .258 to .263 to .254.

It was the ball. That was the prevailing theory from those in the game. Tigers manager Sparky Anderson referred to the "nitroglycerin ball." Astros pitcher Mike Scott said the balls were going farther. Reds manager Pete Rose said the ball was definitely livelier.

Indeed, some individual numbers were eye-popping. A's rookie Mark McGwire hit 49 home runs. So did Andre Dawson. Twenty-eight players hit 30-plus home runs, compared with 13 in 1986. Singles- and doubles-hitting Wade Boggs, who hit 22 home runs the previous three seasons, hit 24; he never hit more than 11 the rest of his career. Tony Gwynn hit .370, Boggs hit .363, and Paul Molitor hit .353 and had a 39-game hitting streak. Larry Sheets hit .316 with 31 home runs for the Orioles. (He finished at .266 and 94 in his career.)

Four of the six highest individual home run seasons in the 1980s came in 1987. Eight of the top 14 OPS seasons in the decade came in 1987. As Matthew Pouliot pointed out in an article several years ago, perhaps no player benefited from the 1987 rabbit ball more than Dawson. He won MVP honors for a last-place Cubs team on the strength of those 49 home runs and a league-leading 137 RBIs. His second-highest home run total in his career: 32. Without that 49-homer season and MVP award, he might not have made the Hall of Fame.

Then, just like that, the ball was dead. In 1987, only four starting pitchers had a sub-3.00 ERA. In 1988, 20 pitchers achieved that mark. The sport entered a five-year span with a relative lull in offense.

1993: Juiced players or juiced ball?

Runs per game: up 0.48

Home runs per game: up 0.17

After the lull came the explosion. In a two-year span, runs per game went from 4.12 to 4.60 to 4.92. Home runs per game increased from 0.72 to 0.89 to 1.03. Yes, the Rockies joined the National League in 1993, helping to create more offense, but that alone hardly explains a half-run per game increase. Indeed, the American League -- without games in Colorado -- went from 4.32 runs to 4.71 to 5.23. No doubt, PED use was starting to spread across the sport, but the PED theory assumes the unlikelihood that everyone started using all at once.

So it was the ball. Something changed in the 1992-93 offseason. The full impact was felt more intensely over two seasons, but some of the individual increases in 1993 were dramatic:

-- In 1992, 10 players hit 30 home runs, and two hit more than 35: Juan Gonzalez (43) and Mark McGwire (42). In 1993, 22 players hit 30 home runs, and 10 hit more than 35.

-- Seven players in 1993 posted an OPS above 1.000. Over five seasons from 1988 to 1992, only five players topped 1.000.

-- Barry Bonds slugged .677 in 1993, the highest figure since Mickey Mantle in 1961.

-- Andres Galarraga hit .370 (in Colorado), and John Olerud hit .363 with 54 doubles for the Blue Jays.

-- Ken Griffey Jr. went from 27 home runs to 45.

In 1994, things went completely nuts:

-- When the strike hit in August, Matt Williams (43), Griffey (40), Jeff Bagwell (39) and Frank Thomas (38) were trying to chase down Roger Maris' record of 61 home runs.

-- Three players -- Bagwell (.750), Thomas (.729) and Albert Belle (.714) -- slugged over .700, which had been accomplished just three times since World War II (Ted Williams, Mantle and Stan Musial). Bagwell's .750 mark was higher than anybody's since Babe Ruth and Lou Gehrig in 1927.

-- Tony Gwynn hit .394.

And so on. So what happened? One suggestion is that it was around this time that Rawlings switched from hand manufacture of the core to machine manufacture, which resulted in more tightly wound cores. The offensive gains were only partially realized in 1993 due to some leftover balls from 1992 still existing in the pipeline.

The owners certainly realized what was happening. The fans loved the long ball. Attendance increased from 26,529 fans per game in 1992 to 30,964 in 1993 to 31,256 in 1994.

There's your history lesson. It's a reminder that a baseball is a lot more complex object than it might appear.