We love our solar system, but there are many unknowns about it that we’d like to elucidate. Fortunately, 2015 has been a good year, as we’ve found out plenty more about our 4.6 billion years old system.
More than the fact that it consists of eight planets and five known dwarf planets, our solar system might have hosted a long-lost ninth planet. Here are some of the other exciting discoveries scientists made about our solar system in 2015.
Dwarf planet Pluto has blue skies and red ice
Remember the amazing photo NASA released of Pluto this July? Ever since the New Horizons spacecraft blazed by 7,750 miles of Pluto, we have been seeing more and more of the dwarf planet.
The distant world is largely unknown to us, but so far we’ve learned that it has light-blue skies and red patches of water ice. It also features large mountains and craters on its surface, and some ice-spewing volcanoes.
Mars’s history and future is slightly less mysterious
According to a NASA press conference in November, Mars was once surprisingly Earth-like, housing massive lakes and rushing streams. However, the power of solar wind most likely stripped away the Mars’ atmosphere, causing its water to disappear.
Even though the Red Planet’s past sounds a lot like Earth’s, its future looks more like Saturn’s. You might just get your rings, Mars; only 20 million to 40 million years to go.
Once upon a time, nine planets lived together
According to an August discovery, our solar system might have hosted another mysterious world, which was alike to the four “giant” planets of Uranus, Jupiter, Neptune, and Saturn. A possible collision with Jupiter might have ejected the long-lost planet straight out of our solar system.
The most distant object in our solar system was spotted
Astronomers announced in November the surprising presence of a dwarf planet – roughly half the size of Pluto – spacing out some 9.5 billion miles from the sun. The planetoid, dubbed V774104, is thus the most distant object in the solar system we’ve are aware of so far.
One of Saturn’s moons features a global, sprawling ocean
It is long since scientists suspected there’s water hiding under the icy crust that covers Saturn’s moon Enceladus, and their suspicion was confirmed in September by NASA researchers. Not only it exists, but it’s incredibly large, believed to expand across the entire surface of the moon.
There’s more than meets the human “eye”
The edge of our solar system might be populated by two unknown planets, both larger than Earth, according to a team of Spanish and British astronomers.
Image Source: NASA