There are seven continents on Earth — or so we learned in school. But these designations are more complex than they seem, and different scientists have different views on how continents should be grouped.

How many continents are there?
The seven continents are Africa, Antarctica, Asia, Europe, North America, Oceania and South America, but some experts argue that there could be less. There's a "question as to what exactly defines each continent," said BBC Science Focus. 

While the U.S. teaches that there are seven continents, Europe teaches that there are only six, with North and South America counting as one consolidated America. Some combine Europe and Asia into Eurasia since the two are connected by land. Another model denotes Africa, Asia and Europe as one continent, Afro-Eurasia, because the "landmass is completely traversable by land and not broken up by any water," said IFL Science. 

A continent is "typically defined as being a large continuous mass of land, loosely correlating with the positions of the tectonic plates," said Science Focus. One recent study published in the journal Gondwana Research argued, controversially, that North America and Europe are one continent because "North America and Eurasian tectonic plates have not yet actually broken apart," said Jordan Phethean, the lead author of the study, to Earth.com. The evidence comes down to Iceland and the Greenland-Iceland-Faroe Ridge, which, according to recent findings, "contains geological fragments from both European and North American tectonic plates," said Earth.com, suggesting the regions are interconnected parts of a larger whole. 

What makes a continent?
Continents are difficult to define because the Earth is often changing. Originally, Earth contained one landmass known as Pangea, which eventually broke apart into separate masses.

"Plate tectonics and the Pangea supercontinent suggest that continents move and break up over periods of time due to convection from the decay of radioactive elements in the mantle," said Science Focus. The current continents are also not the ones that always existed. For example, scientists only recently mapped the completely submerged microcontinent of Zealandia.

Celebrities getting involved with politics is nothing new, but recent data has revealed that the rich and famous have a more palpable impact on elections than expected. This revelation comes as celebrities on both sides of the political spectrum are working to endorse causes and candidates ahead of the 2024 election.

The study, published by Harvard University's Ash Center for Democratic Governance and Innovation, analyzed the ways in which celebrity participation leads to more civic engagement in the U.S. 

What role do celebrities play in political discourse?
While "some polling shows that people claim they aren't influenced by celebrity voices when it comes to politics, more rigorous evidence indicates that these voices are incredibly powerful," the Harvard study said. This is notably prevalent in efforts to increase voter registration, as "nonprofits report higher rates of online voter registration or poll worker sign-ups when a celebrity promotes these calls to action."

There have been "numerous examples of measurably impactful celebrity civic activations," said the study. In 2018, Taylor Swift shared a "single Instagram Story asking her then-112 million followers to register to vote at vote.org." The organization reported "adding 65,000 new registrants on the site in 24 hours. In 72 hours, they had added 250,000 new registrants." Similarly, Ariana Grande "promoted voter registration by setting up booths at her concerts on the American leg in 2019" and "signed up more than 33,000 voters."

The study also "explored celebrity campaigns across mediums including television, documentaries, merchandising and public service announcements," said CNN. It "looked at data from celebrity initiatives in the 2018, 2020 and 2022 election cycles." 

The bigger picture
Young voters have "relatively low levels of trust in a lot of leaders and institutions, including traditional news media, but celebrities are often a rare exception," Ashley Spillane, a civic engagement and political expert and the author of the study, said to ABC News. Voting "should be the trendy, cool thing to do," and the study shows there's "evidence that when people feel this way about voting, they participate."