“On the bubble.” You’re probably familiar with the phrase. In sports broadcasting, an athlete who is on the bubble is one on the verge of being cut from a qualifying round of competition.

But why a “bubble” exactly?

Is the phrase an allusion to the fleeting and fragile fate of said athlete? Is it a representation of one’s hopes and dreams about to be burst? Does it have some other archaic meaning altogether?

According to phrases.uk.org, the obscure phrase can be traced back to a May 1970 report in The Lima New on Indy car racing:

“The most popular theory relates to the Indy 500 and suggests that if a driver were about to qualify and then someone did a better time and pushed him down the rankings into the non-qualifiers then dreams of qualification would be dashed and his bubble would be burst.”

It’s worth noting that the qualify event for the Indy 500 is known as “Bubble Day.”

Others theories suggest that enigmatic “bubble” may be a reference to bubbles in spirit levels, the bubbling of a saucepan as the water is on the verge of boiling, or to the bubble in a level, in which case to be on the bubble means straight, true, level, or balanced.

While we may never know from where exactly the curious phrase originated, we will have a definitive answer to whose bubbles will be burst in the $100,000 Longines FEI World Cup Qualifier, presented by Golden Ocala Golf & Equestrian Club, at Live Oak International come Sunday March 12.

As the final leg of the North American League (NAL) East series, it’s the last chance for US, Canadian and Mexican riders to qualify for the World Cup Jumping Final in Omaha, Nebraska. Read our detailed report on the current rankings to find out who’s in, who’s out and who’s on the bubble!

Whose bubble will burst on Sunday? Whose dreams will be realized? Tune in to FEI TV or follow our live results blog on March 12 at 1:30EST to find out!