Object heading toward Earth is mysteriously accelerating as scientist claims it is a long-lost spacecraft

A mysterious object once believed to be a simple space rock passing Earth is accelerating, and scientists cannot explain why.

A new study by researchers at the Georgia Institute of Technology has determined that 1998 KY26, a suspected near-Earth asteroid, is speeding up in a way that the gravity of the sun and planets cannot account for.

Simply put, the alleged space rock has something else powering it as it moves around our solar system.

Near-Earth objects are rocky space bodies that orbit the sun and sometimes come relatively close to Earth. This object is roughly 36 feet in length, about the size of a school bus, and spins once every 5.35 minutes – extremely fast for a space rock.

Although it is about 189million miles from Earth right now, its current course is taking it within 32million miles of our planet in 2028. The European Space Agency said the object's orbit will take it even closer in 2039, coming within 10million miles.

While 1998 KY26 is widely believed to be a relatively tiny rock, its unexplainable increase in speed has led one scientist to claim the mystery object is actually a long-lost spacecraft that disappeared four decades ago.

Harvard Professor Avi Loeb has theorized the object is really Phobos 1, a spacecraft launched by the former Soviet Union in 1988.

It was lost and vanished just months after its journey to Mars began, but Loeb believes 1998 KY26's size and mysterious movements could be proof astronomers have finally located the missing craft.

An artist's rendition of the near-Earth object 1998 KY26 with Japan's Hayabusa2 probe landing on it. The probe will attempt to intercept the object in 2031

In 2023, scientists first discovered that 1998 KY26 was moving faster than normal after looking at telescope data collected over the previous 25 years.

Those long-term measurements showed a small, steady extra push that slowly nudged the object's path differently than scientists had predicted based solely on the impact of gravity on an average space rock.

Now, the new study by aerospace engineers Korbin Hansen and Masatoshi Hirabayashi has concluded that this mysterious uptick in speed is not the result of a natural phenomenon taking place inside 1998 KY26.

Specifically, Hansen and Hirabayashi said it is not possible that the acceleration is being caused by ice on its surface or buried deep inside melting off and blasting out into space like a jet engine.

According to the latest findings in the journal Icarus, 1998 KY26 is too warm to carry water ice through the vacuum of space.

Even the coldest spots average around -53°F to -78°F or warmer over the course of its orbit around the sun. Ice needs to stay much colder, roughly staying below -198°F for it to last a long time in space.

'We determined that 1998 KY26 is likely a dehydrated asteroid,' the researchers wrote in their report, released this month.

However, the team's findings have therefore ruled out the 'dark comet' theory, which suggested that hidden ice inside the asteroid was slowly turning into gas and giving it a gentle push, even though no visible tail or dust cloud could be seen.

A model of the Phobos 1 spacecraft, the Soviet probe which was lost on route to Mars in 1988. Professor Avi Loeb has theorized that 1998 KY26 is Phobos 1

That has left Loeb's theory that the mysterious object is not a 36-foot rock orbiting the sun after all. 

Loeb and co-authors Adam Hibberd and Adam Crowl released their own study on arXiv which argued that the object’s size, unusually high shininess, rapid spin and orbit are consistent with a man-made spacecraft.

Loeb, a respected physicist and the Frank B Baird Jr Professor of Science at Harvard, explained that the object's acceleration would come from the sun's energy pushing on Phobos 1's shiny metal surfaces and solar panels – creating a condition known as 'solar radiation pressure.'

They also found that a simple 3D model of Phobos 1 matched several of the 1998 KY26’s brightness changes seen by telescopes from Earth, called light curves.

'The similarity of the orbit of 1998 KY26 to the orbit of the lost Phobos 1 spacecraft suggests that the two objects are the same,' Loeb declared in a statement.

A Japanese space probe is set to intercept the object in 2031, when the spacecraft Hayabusa2 will use its remaining fuel to become the first Earth spacecraft to make contact with and study a space object that small.

Hayabusa2 previously visited the asteroid Ryugu, collected samples from its surface and returned those samples to Earth in 2020. 

'Our prediction is that instead of an iceberg, Hayabusa 2’s cameras will reveal the label "Made in the U.S.S.R."' the professor added.