There are always discoveries in space exploration. What we know about space today is leaps and bounds beyond what you might have learned in school. The space facts of your youth may no longer be accurate or could be a small part of a bigger story. New research has completely upended several of the most basic ideas: for example, the existence of nine planets is not a given (RIP Pluto), and Saturn's rings aren't as unique as previously believed.
Some modern finds inspire hope among astronomers, while other discoveries can prove confusing and raise more questions than answers. Here are the highlights in the exciting and ever-changing frontier that is space.
Scientists have searched for proof of liquid water - the foundation for carbon-based life - on Mars for decades. In 2017, NASA researchers found evidence of tsunami activity on Mars from roughly three billion years ago, indicating the red planet may have had oceans at one time. Researchers speculate an asteroid had plummeted into a sea, causing the tsunami and shaping the planet's topography. Scientists believe the asteroid's impact created Lomonosov crater in the northern plains of Mars.
Researchers have long speculated water once flowed on the Martian surface, and - at one point, according to NASA - "several large aquifers catastrophically ruptured," flooding the northern plains. They could find no shoreline, however, until a topographic map revealed ridge-like indents below the surface. These grooves suggest two tsunami waves formed Mars's distinct patterns. In 2017, scientists released evidence of a large lava waterfall on the planet, which they nicknamed the "Niagara Falls of Mars." It likely circled a crater in the planet's Tharsis volcanic province.
In 2009, NASA revealed scientists found water molecules on the moon. Scientists discovered the water by using a cutting-edge spectrometer, which measures the light reflected off the moon's surface. The tool, NASA's Moon Mineralogy Mapper, can assess infrared wavelengths, which scientists deemed consistent with water molecules' absorption patterns - a breakthrough confirmed by three separate spacecraft.
When scientists reevaluated "water-bearing volcanic glass" with more satellite data in 2017, they theorized there was once - and may still be - a large amount of water deep below the surface. Researchers analyzed the glass beads collected during the Apollo 15 and 17 missions in the '70s. The study indicated water and the volcanic eruptions that produced the water-bearing glass were widespread across the moon. Future visitors to the moon could extract the water instead of having to bring their own.
Known as the Methuselah star, HD 140283 became the oldest-known star in the universe in 2007. Once estimated to be 16 billion years old - and placing its origin before the Big Bang - the Methuselah star, according to scientists, may be closer to 14 billion years old.
Astronomers have long known that planets can have rings, but in 2014, they realized asteroids could, too. First discovered near Saturn in 1997, Chariklo has an estimated diameter of about 155 miles. In 2013, scientists observed the asteroid traveling in front of a star, which illuminated its features. What they found surprised them - Chariklo had two rings: the more massive inner ring is four miles wide, while the outer one is about half that size.
Chariklo is the first non-planetary body known to have rings. Researchers believe Chariklo may have at least one moon as well.