Citizen scientists discover something zooming through space
A group of citizen scientists ordinary people helping to investigate an astronomical phenomenon recently made a remarkable discovery. While analyzing images from the WISE telescope, an infrared observatory that scans the entire sky, these volunteers identified a mysterious object moving at an incredible speed. This faint point of light was speeding through space at over 1.6 million kilometers per hour relative to our solar system and other nearby stars in the galaxy.
This velocity is so extreme that experts categorize it as "hypervelocity" around 500 kilometers per second. To put that into perspective, that’s roughly the distance between Oslo and Trondheim every single second, or a complete trip around the Earth in just about 80 seconds.
But what exactly is Iit?
Astronomers at several American universities have been working to identify this mysterious object, and they’ve concluded that it’s a small star, the smallest ever measured to be moving at such an extraordinary speed. This star is traveling so fast that it could eventually escape our galaxy entirely and drift into the empty void of intergalactic space. While its speed is impressive, it’s still a far cry from the speed of light, which is around a billion kilometers per hour the ultimate speed limit in the universe.
A final farewell?
Escaping Earth’s gravity is no easy feat. The massive gravitational pull of our planet keeps us and everything else firmly planted on its surface. To break free, it takes immense energy, usually in the form of roaring rocket engines, to reach escape velocity -the speed needed to leave Earth's gravitational field. This escape velocity is enormous by our standards: about 11.2 kilometers per second, or over 40,000 kilometers per hour. Spacecraft heading to destinations like Mars need to reach these speeds to break free of Earth's grip.
But to escape a galaxy, the required speed is much greater. All the matter in a galaxy exerts a gravitational pull, meaning that to escape, an object needs to be moving at well over 500 kilometers per second precisely the speed of this newly discovered star. It’s possible that this star is on its way out of our galaxy, headed into the vast intergalactic space. How long it will remain there is impossible to predict.
A unique star among many high-speed stars
This newly discovered star stands out among other fast-moving stars. While NASA’s citizen science project has uncovered many high-speed stars, this is the only one that appears to be on its way out of the galaxy. Our galaxy, the Milky Way, is likely filled with such runaway stars. Although our solar system seems stable and reliable, countless stars and planets have been ejected from their home systems. Estimates suggest that there could be trillions of planets drifting through the cold space between stars after being flung out of their original systems.
Similar fates can happen to stars. When subjected to powerful forces, stars can reach incredible speeds. Although this newly discovered star is fast, it doesn’t set the record for star speed, some rogue stars have been clocked at more than 8 million kilometers per hour according to Space.com.
What propels these stars to such incredible speeds?
There are several possibilities, but scientists aren’t entirely sure what caused this star’s high speed and unusual trajectory. In a research paper published in the Astrophysical Journal, scientists noted that this star also has a highly unusual orbit. The star's chemical makeup suggests it’s very old and may have formed near the center of the galaxy over three billion years ago.
One theory is that the star was part of a binary system, two stars orbiting each other. If this binary system got too close to the supermassive black hole at the center of the galaxy, one star could have been captured by the black hole while the other was flung out at tremendous speed, a process known as the Hills mechanism. However, the star’s odd orbit suggests this might not be the full story. Another possibility is that one star in the binary system exploded in a supernova, with the resulting energy propelling the other star to extreme speeds. To uncover what really happened, further measurements of the star’s chemical composition are needed. A supernova would leave a distinct chemical signature, while the star's origin could offer other clues. Some researchers even speculate that the star might have come from another galaxy, though this is considered unlikely given its current trajectory.
This discovery has raised more questions than answers, and astronomers are eager to learn more about this runaway star hurtling through space. Whether it’s a cosmic orphan or the result of a stellar explosion, this star’s journey offers a fascinating glimpse into the powerful forces at work in our galaxy.