Jupiter is our solar system's biggest planet by far. It used to be twice as large: Study
A recent study found that Jupiter was once twice the size that it is now, making it big enough to swallow up 2,000 Earths.
Jupiter is already the biggest planet by far in our solar system, but new research suggests it was somehow once even larger than it is now.
Twice as large, in fact.
To put that into context, those dimensions would make the gas giant big enough to fit 2,000 Earths inside of it – if it were hollow. The shocking findings were part of a recent study in which astronomers effectively peered back in time to discover what Jupiter was like in its early years.
The astronomers behind the study – Konstantin Batygin, a professor of planetary science at the California Institute of Technology, and Fred C. Adams, a professor of physics and astronomy at the University of Michigan – didn't necessarily set out to make such an extraordinary discovery.
Rather, the researchers were set on better understanding Jupiter's early evolution and how our solar system developed its distinct structure.
"Our ultimate goal is to understand where we come from, and pinning down the early phases of planet formation is essential to solving the puzzle," Batygin said in a press release announcing the findings. "This brings us closer to understanding how not only Jupiter but the entire solar system took shape."
How big is Jupiter? What to know about gas giant
Jupiter is not only the largest in the solar system, but is so humongous that it's more than twice as massive as the other planets combined.
The gas giant is about 11 times wider than Earth alone, with a diameter around its equator of 88,846 miles.
And it's size is far from the only extreme feature that defines the fifth planet from the sun. The world is home to gigantic storms bigger than Australia, 100-mph winds pummeling its northern reaches and a rocky moon named Io orbiting it that is notoriously riddled with lava-spewing volcanoes.
According to the researchers, Jupiter's gravity, often called the "architect" of our solar system, played a critical role in shaping the orbits of other planets and sculpting the disk of gas and dust from which they formed.
Jupiter was once twice its current size, study finds
The gas giant's influential place in shaping our solar system and is what intrigued Batygin and Adams to take a closer look at Jupiter's primordial state.
According to their calculations, about 3.8 millions years after the first solid materials in our solar system formed, Jupiter was twice as large as it is now. Jupiter's magnetic field was also much more powerful at that time, about 50 times stronger than it is today.
While Io is among the most well-known of Jupiter's 95 moons, the duo instead studied two tiny moons Amalthea and Thebe to reach their conclusions.
The celestial objects are so small, they're not even among Jupiter's four famous Galilean moons, which does include Io. But Amalthea and Thebe orbit the planet even closer than Io and have slightly tilted orbits that allowed the astronomers to analyze "small orbital discrepancies" to calculate Jupiter's original size.
"It's astonishing that even after 4.5 billion years, enough clues remain to let us reconstruct Jupiter's physical state at the dawn of its existence," Adams said in a statement.
Why did Jupiter get smaller?
Astronomers estimate that Jupiter is steadily shrinking to this day by up to two centimeters a year.
This is because of a process by which the planet grows smaller as it gradually cools and its internal temperature drops, causing the planet to lose energy and consistently contract.
Research could help 'reconstruct the evolution of our solar system'
Batygin and Adam say their analysis provides a snapshot of Jupiter at a critical cosmic moment when the building materials for planet formation in our solar system disappeared, locking in its core architecture.
Their results also add context to planetary formation models developed over decades suggesting that Jupiter and other similar gas planets formed through a process called core accretion in which a rocky and icy core rapidly gathers gas.
"What we've established here is a valuable benchmark," Batygin said in a statement. "A point from which we can more confidently reconstruct the evolution of our solar system."
The findings were published Tuesday, May 20 in the journal Nature Astronomy.
Eric Lagatta is the Space Connect reporter for the Paste BN Network. Reach him at elagatta@gannett.com