Jupiter-sized objects in Orion Nebula captured by James Webb Telescope

The new entities have been called Jupiter Mass Binary Objects, or JuMBOs

Scientists at the European Space Agency (ESA) have used the National Aeronautics and Space Administration's (Nasa) James Webb Space Telescope to make an astonishing discovery: free-floating objects the size of Jupiter, the largest planet in our solar system, in the Orion Nebula, the nearest star-forming region to Earth.

The discovery has upended our understanding of how stars and planets are formed. Previously, scientists believed that nebulae, which give birth to stars within large clouds of gas and dust, were not capable of spontaneously creating planet-sized objects. The new findings, however, suggest otherwise.

Even more perplexing is the fact that these objects form in pairs rather than individually.

"There's something wrong with either our understanding of planet formation, star formation — or both," said Samuel Pearson, an ESA scientist who worked on the research, in an interview with The New York Times. "They shouldn't exist," he added.

The newly discovered entities have been named Jupiter Mass Binary Objects, or JuMBOs. They are not large enough to be stars and are not technically considered planets because they do not orbit a star.

"Most of us don't have time to get wrapped up in this debate about what is a planet and what isn't a planet," Professor Mark McCaughrean, a senior adviser for science and exploration at the ESA, told The Guardian.

According to a research paper co-authored by McCaughrean, which has not yet been peer-reviewed, JuMBOs are approximately a million years old. This makes them relatively young when compared to the rest of the universe.

The surface temperatures of JuMBOs are around 1,000 degrees Celsius, the research indicates. Unlike planets, which are able to maintain steady temperatures due to the energy they receive from their host stars, JuMBOs cool down rapidly and eventually freeze. Composed mainly of gas, they are unlikely to support life.

How JuMBOs Came Into Being

Scientists have proposed several hypotheses to explain the formation of JuMBOs. The first is that they were created in areas of the nebula too sparse to form proper stars. Another possibility is that they were initially formed as planets intended to orbit stars but were then "ejected" for unknown reasons.

"The ejection hypothesis is the favoured one at the moment," McCaughrean told the BBC. "We know single planets can get kicked out of star systems, but how do you eject pairs of these objects together? At the moment, we don't have an answer. It's one for the theoreticians," he added.

Other scientists have described the paired phenomenon as unprecedented.

"My reactions ranged from 'Whaaat?!' to 'Are you sure?' to 'That's just so weird,' to 'How could binaries be ejected together?'" astronomer Heidi Hammel, who was not part of the research team, told the BBC.

No current scientific models predict pairs of planet-sized objects being ejected from a nebula. However, Hammel added that perhaps there simply hasn't been a telescope powerful enough to spot them before.