Humans have been exploring space for decades, and there is still so much we don't understand. There remain unexplained events and anomalies that astronomers have not been able to solve. Check out seven of the weirdest unsolved mysteries that continue to stump leading experts.

In 2018, researchers described the discovery of the only known repeating fast radio burst (FRB). The flashes of radio waves lasted a split second and had seemingly no physical origin — leading many astronomers to speculate if it was a sign of extraterrestrial life. Further research determined that the waves had a very high level of polarization, meaning they passed through an incredibly strong magnetic field, so the evidence points to the FRB coming from a neutron star or a black hole. Still pretty cool.

Photography: NASA

For a decade, astronomers studied a giant star located in a dwarf galaxy 75 million light-years away, and then suddenly one day it disappeared. Scientists aren’t exactly sure what happened, but the two likely scenarios are that it either had a massive outburst or it quietly turned into a black hole.

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In 2006 and 2014, a NASA-funded experiment stumbled across very unusual, almost impossible, events. Scientists detected extremely high-energetic fundamental particles, called neutrinos, that seemed to have traveled through the earth. The first hypothesis? That scientists had discovered evidence of a parallel universe that mirrors our own. While this would have been incredible, the more likely scenario is the discovery of a new particle.

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How many planets are in our solar system? Many would argue eight, but scientists think there might be a ninth undiscovered planet they’ve dubbed Planet 9. The orbital trajectories of Uranus and Neptune (the two furthest planets) have some peculiarities, meaning there is likely a massive gravitational body — like a ninth planet.

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When a star reaches the end of its life it runs out of fuel and collapses under the weight of its own gravity. Larger stars leave behind black holes, while smaller stars create what are known as neutron stars – the very dense, dead core of a star. In 2019, astronomers discovered an object that fell into neither of these categories. To this day, no one knows if it’s the heaviest known neutron star or the lightest known black hole.

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In 1977, students The Ohio State University received a 72-second-long signal from a distant star system, 120 light-years from Earth. The guy who received it wrote, “Wow!” next to the original printout of the signal. To this day it is still known as the “Wow! Signal” and has yet to be explained.

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It's pretty common knowledge that the Earth rotates. In fact, you’re moving about 1000 miles per hour right now. But did you know that something 150 million light-years away is pulling our entire galaxy towards it at a rate of 1,342,162 miles per hour? For context, if Earth moved that fast around the sun, our years would only be 18 days long. This gravitational anomaly is pulling our galaxy and millions and millions of stars toward it, and it’s called The Great Attractor.

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Scientists are not quite able to identify this mysterious force because the view is blocked by an area of our own galaxy called the “Zone of Avoidance,” which is basically the space equivalent of the dump. So what is it? The most widely accepted explanation is that it’s a galactic cluster known as the Shapley Supercluster, but there are other, more unlikely theories, ranging from a supermassive black hole to aliens.

Photography: NASA