Professional astronomers are responsible for 13 billion years' worth of discoveries about our universe, but the cosmos is a big place, and at-home stargazers have been staring at the sky with a keen eye for a long time, too. These examples of weird and wonderful planetary phenomena—with an asteroid and comet in there too for good measure—were all first spotted by amateur astronomers, and prove that you don't have to be a pro to make some stellar discoveries.
1. A PLUME ON MARS
When amateur astronomers discovered a plume-like cloud on Mars, scientists were at a loss for an explanation. Mars has clouds, of course, but to form at such a height was unheard of on Mars or Earth. Scientists later correlated the phenomenon with a coronal mass ejection from the Sun. Studies continue, but the plume and its solar cause might help unlock the mystery of the vanished Martian atmosphere.
2. A PLANET WITH FOUR SUNS
Tatooine has nothing on planet PH1, which has four suns (of sorts). The planet, discovered by amateurs, orbits two stars. Eighty billion miles away, those two stars are, in turn, orbited by two more stars.
3. A GEOMETRIC STORM ON NEPTUNE
While processing Voyager 2 images of Neptune, amateur astronomer Rolf Wahl Olsen discovered what appears to be a hexagon-shaped storm. More work needs to be done to confirm the phenomenon (perhaps in conjunction with some future mission there), but such a storm would not be without precedent: Jet streams near Saturn's north pole form a hexagon as well.
4. AMMONIA BLIZZARDS ON SATURN
In 2010, amateur scientists worked with the Cassini spacecraft team to go storm chasing on Saturn. As the spacecraft's Radio and Plasma Wave Science (RPWS) instrument picked up evidence of possible storms, the information would be relayed to amateur astronomers, who would study Saturn for visual evidence. Discoveries would then be relayed back to the Cassini team for possible imaging and further study. (Yes, the ammonia-ice blizzards of Saturn could be seen by home stargazers here on Earth.)
5. THE FASTEST SUPER-FAST ROTATOR IN THE SOLAR SYSTEM
In 2008, Richard Miles, a British amateur astronomer, discovered the then-fastest-spinning object in the solar system. Asteroid 2008HJ completes one rotation every 42.7 seconds, and falls under a class of celestial objects called "super-fast rotators," for obvious reasons. Dwarf planet Haumea is now considered the solar system's fastest spinner.
6. A VANISHING STRIPE ON JUPITER
Photos of Jupiter taken by amateur astronomers in 2010 revealed the disappearance of one of its famous red stripes. Jupiter's mystifying weather means that its bands sometimes fade and its great red spot changes in size.
7. WHITE SPOTS ON SATURN
In 1933, actor and amateur astronomer Will Hay discovered a "white spot" on Saturn. It wasn't the first instance of such a spot being observed, but Hay's study was perhaps the most famous. The spots were once thought to be signs of collisions by foreign bodies, but are now thought to be related to the planet's turbulent weather (see #4).
8. ICE VOLCANOES ON A COMET
Cryovolcanoes are just what they sound like: volcanoes that erupt ice as opposed to lava. They are well-known features of such moons as Enceladus (one of Saturn's satellites), and in 2015, were spotted by amateurs on Comet 29P/Schwassmann-Wachmann.
9. SPACE WEATHERING ON THE MOON
In 1953, an amateur astronomer named Leon Stuart witnessed what appeared to be an explosion on the Moon. He took a picture of it, and in the process became "the first and only human in history to witness and document the impact of an asteroid-sized body impacting the Moon's scarred exterior," according to NASA. Fifty years later, planetary scientists proved Stuart's discovery to be a legitimate instance of space weathering.
10. A MYSTERIOUS COMET CIRCLING THE SUN
In 1779, amateur astronomer William Herschel, using a telescope of his own design, discovered what he first thought was an oddly behaving star and later thought was a comet. As it turned out, Herschel had inadvertently built one of the most powerful telescopes in the world, and his comet was, in fact, the first new planet to be discovered since antiquity: Uranus.