Amateur astronomers have discovered an unknown object that is moving so fast that it will inevitably leave our galaxy. Scientists are now puzzling over what this object is and why it has such a desire to abandon our stellar home. The article was published in the journal Astrophysical Journal Letters. In a series of photographs, a tiny point occupied a different position each time. It was evident that something was moving at a colossal speed. And it turned out to be true—1.6 million kilometers per hour, or 440 kilometers per second. This number might not seem astonishing, given that the term "cosmic speeds" suggests that everything in space moves very fast. But believe me, that's incredibly fast. All objects in our galaxy rotate around its center, and the speed of this rotation is determined only by the distance from the center. For example, the Sun moves at a speed of 220 kilometers per second, dragging Earth and all the planets with it. That's fast, but this object is moving at twice that speed. Calculations have shown that at such a speed, the object will not be held within the galaxy and will inevitably leave it. This is already an outstanding scientific discovery: we now understand that the space between galaxies is not empty; it contains "rogue" objects. The object is small and most closely resembles a brown dwarf. A brown dwarf is a substellar object that is too small to sustain full-fledged nuclear reactions. Some reactions may occur within it, but they don't reach the design output, so the celestial body barely glows. Right now, you can observe an almost brown dwarf with the naked eye. It's the planet Jupiter, which rises above the northeastern horizon around half past midnight. Jupiter is the largest planet in the Solar System, and its mass is such that there may be very weak nuclear reactions occurring within it. Add a bit more mass to it, and you'd get a brown dwarf. Brown dwarfs occupy an intermediate position between stars and giant planets. Studies have shown that the object contains almost no iron or other metals. This suggests that the mysterious wanderer is very old and may belong to the first generation of stars in our galaxy. The fact is that the modern chemical diversity—whether it's gold, iron, or uranium—did not appear all at once. It is the product of nuclear reactions in the cores of stars, and over several generations. From generation to generation, the chemical composition of the universe becomes more complex, with new elements emerging. Old stars are chemically poor, which is what we see in our runaway object. How it hasn't burned out yet remains a mystery. Scientists still have no idea what accelerated it so much. The classical explanations are being considered. For example, it might have flown past a black hole, narrowly avoiding being swallowed, but executing a gravitational maneuver instead. Or perhaps it was part of a binary system, and when its partner exploded as a supernova, this object was ejected. But these are still just speculations. The celestial body was found by amateurs, but not through their own telescope. The NEOWISE telescope, which constantly photographs the sky in infrared light (and thus sees very cold objects, like our runaway), was used. There are a lot of images, and about 15 years ago, NASA invited amateurs to review them and report anything they noticed. This time, Martin Kabatnik from Germany and his colleagues got lucky. The work is truly grueling, unpaid, so he deserves recognition.