Humans are heat factories. If the average human being produces heat at a rate of 80ish watts, then 19 humans hunched together would radiate as much heat as my 1,500-watt space heater. Humans' surplus heat warms a housing project in Paris, a 13-story office building in Stockholm and the Mall of America in sub-freezing Minnesota.

A baseball stadium in the Midwest in October is, unlike a shopping mall, outdoors. But for a few hours it gathers an astounding quantity of hot mass -- roughly 7 million pounds of it, equivalent to 2,500 space heaters -- into a relatively dense seating area. If 19 people can heat the inside of a small room and several thousand can heat an office building, what might 47,325 people arranged in a ring around a baseball field do?

A baseball hit at a typical home run trajectory travels farther in warmer air, physicist Alan Nathan has shown. A change in temperature of one degree Fahrenheit affects the distance of a batted ball by about four inches, which means a half-degree would matter for two inches, a quarter of a degree for one inch -- and baseball, we all know, is a game of inches. In the biggest moments, it's often a game of even less than that.

Would 2,500 space heaters running nonstop for 3 hours, 46 minutes and 13 seconds have a collective effect on air temperature in a partially enclosed outdoor stadium by one degree Fahrenheit? "It seems plausible to me," Nathan tells us. "I can't say that I know with any authori-"

Let's stop you right there, Nathan. Plausible is enough for us. If humans' bioenergy could power the machine city in The Matrix, we believe it can power a baseball. It's an indirect power, not exactly propelling baseballs so much as freeing them to travel more easily through less dense air. And when David Freese hit a baseball to deep right field in the ninth inning of Game 6 of the 2011 World Series, we can believe that the 47,325 Cardinals fans weren't just wishing that it would carry slightly beyond the reach of Nelson Cruz, but they were actually causing it.

All hail the fan. All hail the crowd.

In a baseball stadium, spectators are strictly forbidden from breaching the border between Fans Space and Players Space. The players are allowed to reach into the Fans Space a little bit, just as the gods (or their offspring) might walk among us in the human realm. But the spectators aren't allowed into the Players Space, any more than mortals can stick an arm into heaven. If fans try to break the boundaries, it's a violation of the natural order, and there are rules against it. Reaching into the realm of the players is cause for a play's outcome to be overturned for fan interference, at a minimum. If it's extreme enough, the fan could be ejected or even put in jail.

But not all fan influence is interference. In fact, fans constantly affect play without touching any player, any equipment or any part of the field of play. Sometimes intentionally, sometimes accidentally, fans have figured out how to change outcomes without violating the rules or breaching the borders.

If you watch closely, you can see the fans' direct influence everywhere -- and we're not just talking about some emotional lift they give players with their support. Consider, for example, what might be the most memorable postseason moment of the past decade: The second-to-last play of the 2014 World Series, when Alex Gordon singled to center field and advanced to third on an error. The ball never gets close to a fan, and no fan enters the Players Space:

But the fans are there, and they force themselves into the play:

0:05: Gordon hits the ball
0:08: Ball lands safely, bounces past Gregor Blanco. Crowd erupts in predictable cheers. Gordon goes for second, digs for third.
0:13: Left fielder Juan Perez goes to pick the ball up but kicks it.
0:14: Crowd, seeing this, erupts again -- with this second eruption being unpredictable, anomalous.
0:15: This unpredictable cheer alerts Gordon to events outside his field of vision. Wondering what this unexpected ruckus could possibly be about, he lifts his head and turns to see what is happening.

In a world without fans, there's no eruption at 14 seconds. In the COVID-19 world, the fake crowd murmurs used for white noise would be replaced with the fake crowd excitement used on base hits. The cheering for the base hit would start a half-beat later than real crowd noise would, but then it would just stay at that level throughout the play. The fake crowd noisemaker doesn't do nuance. And without the second eruption, Gordon would keep his head down and charge into third, where he would expect the play to end uneventfully. Gordon would look for his third-base coach to signal whether he needs to slide into third or just stop standing up. He would find out that Perez kicked the ball only after the play was over. But with a crowd, the second roar got his attention and provided him a little intelligence about a part of the field he couldn't otherwise see or wouldn't otherwise be looking at. He changed his behavior: looking over his shoulder (and probably causing himself to slow down a little) and consequently picking up his third-base coach's stop sign only at the very last second, forcing him to stop abruptly and a little awkwardly.

It probably didn't affect the outcome of the play. If Gordon had never turned, he'd probably have still had the stop sign, still obeyed it and still been safe at third. It would have been a little less herky-jerky, but probably the outcome would have been the same. Still, though, in the biggest moment in Kansas City Royals franchise history, when Alex Gordon had an extremely simple job -- to run forward as fast as he could until his coach told him to stop -- the fans managed to touchlessly change his course slightly.

The 2020 playoffs will be a fanless experience, and in unexpected ways it will quite possibly be decided by its fanlessness, just as so many postseason games of the past have been unexpectedly decided by their fanfulness. Not every play is like the Gordon play -- nudged by the fans but not actually toppled over. In some of the most important moments in postseason history, the fans did change history or arguably changed history or might be thought to have changed history (even if we'll never know).

The power to make demands

For example: Oct. 17, 2004. Game 4 of the American League Championship Series.

The Yankees were leading by one run in the ninth inning of a possibly clinching Game 4 against the Red Sox. Boston's Kevin Millar drew a walk in the ninth inning. Dave Roberts entered as a pinch hitter, stole second base on the first pitch and then scored on a single to tie the game. Boston won the game in extra innings, went on to come back from a 3-1 deficit to win the series -- the first time any team had ever done that -- and then won the World Series, snapping an 86-year franchise drought.

When Roberts got on first, though, there was a moment. It came after Mariano Rivera made a pickoff throw to first, then a second pickoff throw, then a third. The home crowd booed, as crowds do, impatient with the excess of pickoff attempts. Rivera could have thrown a fourth, fifth and sixth pickoff attempt over. But he stopped after three and delivered the pitch. Roberts took off and was safe by an eyelash.

Four consecutive pickoff attempts are very rare. Over the past decade, there have been only 14 instances per year, on average, of pitchers throwing four or more times in a row, about once every 180 games. But this year, without fans, that super rarity has actually changed. Pitchers have thrown four pickoff attempts in a row about four times as frequently this season.

If you believe there's a connection, it suggests that fans have the power to make demands. Of course, the pitcher knows that booing fans can't hurt him, and that he (the pitcher) is free to make a fourth pickoff attempt if the situation calls for it. But the evidence this year suggests that he is influenced by the boos, that throwing too many pickoff attempts is annoying, and he wants to avoid being annoying. Take away the fans and the social pressure to cease pickoff attempts apparently drops way down.

Take away the fans, we're saying, and Mariano Rivera might have made a fourth pickoff attempt.

If the power to make demands is one of the fans' powers, what else is there?

The power to delay

Sometimes, this delay is accomplished by violating the Players Space, as when Braves fans, protesting an umpire's call during the 2012 wild-card game, stopped play for 19 minutes by throwing trash on the field. (Or in 1934, when Tigers fans pelted Cardinals left fielder Joe Medwick with so much debris that commissioner Kenesaw Mountain Landis had Medwick ejected.)

But we're interested in influence, not interference. For instance: In 1983, the start of the eighth inning of Game 1 of the World Series was unexpectedly delayed several minutes so that the television broadcast could interview a fan who was leaving. (The fan was President Ronald Reagan.) The delay irritated the pitcher on the mound, Scott McGregor, and he later blamed it for the first-pitch home run he allowed to Garry Maddox once play resumed. That home run broke a 1-1 tie and decided the game, which the Phillies won 2-1. "There is a certain flow to the game," McGregor complained.

The crowd didn't do anything to thwart McGregor; ABC's producers did. But Reagan was interviewed because he was at the game, and he was at the game because the existence of the crowd legitimized it as an important place to be. No crowd, no president, no interview, no delay, no homer.

The crowd causes smaller, non-presidential delays all the time. Earlier this year, the Rays' Brandon Lowe tied a game with a solo home run in the bottom of the ninth inning. He rounded the bases in an empty dome, celebrated briefly with his teammates, returned to the dugout and play resumed. The first post-homer pitch came 54 seconds after Lowe had made contact. By contrast, when Alex Gordon homered to tie a game in the bottom of the ninth inning of a 2015 World Series game, he rounded the bases, celebrated with his teammates, returned to the dugout -- and then the fans kept cheering. The next batter stepped out, the pitcher stepped off and it ultimately took 1 minute and 11 seconds between pitches. Without throwing a single water bottle, fans froze baseball time for 17 seconds.

The power to introduce uncertainty

In the 2018 ALCS, Jose Altuve hit a fly ball over the wall in right field. Mookie Betts made a leap for it and had his glove in position to attempt the catch, but his glove collided with the hands of fans sitting in the outfield seats in Houston. An umpire called it fan interference. A video review, failing to find a camera angle that was conclusive -- indeed, finding that camera angle to have been serendipitously blocked -- let that call stand. Instead of a game-tying home run, it was an out.

Fans have the right to impede a fielder's attempt to catch a ball so long as they don't cross the border between Fans Space and Players Space. The home crowd can, in effect, defend its space, and it can become an occasional accomplice of the home team's defense. A home crowd that doesn't thwart at least one catch by the visitors each a season probably isn't doing a good job of influencing. (A home fan that does the opposite gets a 30 for 30 film made about him.) On its face, this play is an example of near fan influence by the four men attempting to catch the ball at the railing.

But what's more interesting about this play is the uncertainty the fans' mere presence introduced to the play. Because the Fans Space and the Players Space abut each other, it can be nearly impossible to distinguish between legal fan actions and illegal ones. Human eyes and video technology couldn't see whether the fans had crossed the line on the Betts play, which led to a situation that was ambiguous on multiple levels. We didn't know whether the fans' actions were legal, and we didn't know whether the fans actions mattered:

• Perhaps Betts would not have caught the ball at all, even if there had been no fans. But the fans -- through no illegal action, but merely their existence -- confused the umpires' perception and caused them to turn it into an out instead.

• Perhaps Betts would not have caught the ball at all, even if there had been no fans. But perhaps the fans -- through an illegal act of reaching over the barrier -- turned the play into an out. In this case, Betts would have failed first, but the fans overwrote his failure with their own.

• Perhaps Betts would have caught the ball had there been no fans, but he had to enter the Fans Space to do it -- and the fans, through legal and appropriate means, were able to make the catch too hard for him. But because the fans had to be present to (legally) thwart Betts, and their presence confused the umpires' perceptions, Betts ended up getting credit for a catch he couldn't actually make.

• Perhaps Betts would have caught the ball had there been no fans, or had there been fans defending their realm legally, but perhaps the fans did violate the barrier between players and fans and interfered with him. In this case, the correct call was made -- but nobody will ever know, because of the layers of ambiguity. Instead of a single great catch in a single postseason game, the uncertainty will cause the play to survive as an all-time moment of what mighta been that will be written about for roughly 500 years.

It's sort of tautological, but the only reason there is ever controversy over fan interference calls is that there's a fan interference rule, and there's only a fan interference rule because there are fans. Umpire judgment is fallible and changes outcomes, and fans make umpire judgment necessary, so fans change outcomes.

The power to normalize umpire behavior

The plate umpire's response to crowd pressure has long been one of the leading explanations for home-field advantage. The 2011 book "Scorecasting" concluded that the plate umpire is responsible for most of the home team's edge, while The Hardball Times' John Walsh found that it explains about a third of that advantage.

According to pitch data kept by ESPN Stats & Information, that home-field favoritism has held up in recent years. On taken pitches deemed "likely be called strikes," umpires from 2017 to 2019 called 88.6% strikes when the home team was batting and 89% strikes when the home team was pitching. On pitches "likely to be called balls," the gap was similar: 5.4% called strikes on home hitters and 5.7% called strikes on visiting hitters. That's about one pitch switched in the home team's favor every three games.

But this year, without fans, there's no difference, according to ESPN Stats & Info's categories. Home hitters are slightly more likely to have a strike called on pitches out of the zone (5.8% to 5.7%) and slightly less likely to have a strike called on pitches in the zone (89.4% to 89.5%) -- two tiny differences that basically cancel each other out.

Of course, umpires miss calls all the time, and it's hard to know which one every three games to credit to the home crowd. Was it the home crowd that kept Rich Garcia from ringing up Tino Martinez in Game 1 of the 1998 World Series -- the pitch that "turned" the 1998 World Series, just before Martinez hit a two-strike grand slam to break a seventh-inning tie? Or was it just a bad call? We'll never know.

But it's fair to say that home-influenced calls are sprinkled throughout postseason history. It's also fair to say that a game like Livan Hernandez's 15-strikeout performance in the 1997 National League Championship Series probably wouldn't happen on the road. As umpire Eric Gregg expanded the strike zone farther and farther outside, rewarding Hernandez with called strike after called strike, one assumes the home crowd's approval had to play some role in preventing Gregg from correcting himself. Ultimately, we shape our reality around the reality that other people are living. There were 52,000 people in the ballpark that night, and all but about 30 of them -- the Braves' players and coaches -- were telling Gregg that, yes, that's what a strike is. To Gregg, that zone must've seemed more and more true as the game went on.

The power of noise

The most direct influence the crowd has is the noise it makes. This shows up in unexpected ways, which the crowd itself is often not aware of. We'll never know exactly how much the sign-stealing Astros were stealing signs during the 2017 postseason, for instance, but some players said (after they were caught) that they had quit their trash can-banging scheme in the postseason because the noisier crowds made it too difficult for batters to hear the bangs. There's ambiguity about whether that's fully true, but there's some evidence that the Astros' fans, with the influence of their lungs, actually caused the home team to play with some integrity.

Less speculatively, take Game 5 of the 2011 World Series. Cardinals manager Tony La Russa called the bullpen to get two pitchers -- lefty Marc Rzepczynski and closer Jason Motte -- warm. But the crowd was so loud that La Russa was misheard, and only Rzepczynski got up. When La Russa saw the problem, he called back -- and was misheard again. Lance Lynn, who wasn't supposed to be available unless it was an emergency, got up instead of Motte. Without a right-hander warm, Rzepczynski ended up having to face Mike Napoli with the bases loaded. Napoli doubled, breaking a 2-2 tie and winning the game for Texas.

"That phone in a loud ballpark, it's not an unusual problem," La Russa said after the game. He was underselling the magnitude of what had happened: In the middle of a World Series game, the Rangers' fans got to choose the Cardinals' pitcher.

It's thanks to that Napoli double that, one game later, the Rangers were in a position to clinch the World Series in the ninth inning. They had David Freese down to his final strike with two outs, when Freese hit a fly ball to deep right field and the Cardinals' 43,000 fans roared with hope.

As an outfielder gets close to the wall, he often gets guidance from teammates nearest him: "Room, room, room" when he has room; "wall" when he is nearing the wall. This is necessary, because, as Doug Glanville wrote for ESPN, "the warning track is useless," and perhaps worse than useless: good only for scaring and distracting fielders.

This season, in silent stadiums, we've been able to sometimes hear the outfielders talk to each other, guide and prepare and protect each other. "Wall, wall, wall, wall," Jason Heyward tells Ian Happ as Happ chases a ball in the gap. "WALL!" Brandon Nimmo (probably) warns as Jeff McNeil reaches out and prepares to smash into it.

But when Freese flied to right field, there was nothing for Cruz to listen out for. The 43,000 fans made him all alone: His center fielder was on another auditory continent, his five senses cut down to four. Cruz moved back, and he had room -- but there was nobody capable of telling him he had room. For all he knew, he was about to smash into a wall, with nobody to yell, "Wall!" He retreated tentatively, unbalanced, confused -- without conviction.

And to make matters worse, the air around him might have been slightly warmer than usual. The ball sailed just beyond him.

Democracy is not a spectator sport, the saying goes. Or life isn't. Or religion isn't. Or health isn't. But all of those things, at times, can make us feel like spectators. One lesson of baseball is that even spectating isn't a spectator sport. Even spectators can make matter move.