In April, astronomers discovered the first Earth-size planet within a star’s habitable zone, the region where liquid water can exist. This artist’s concept shows the planet, dubbed Kepler-186f, which is 1.1 times the size of Earth. The ultimate goal is to find another planet just like Earth, and this one—although more like a cousin than a twin—is close.

In June, astronomers revealed that this newly discovered star is a white dwarf so cold (for a star---it’s still almost 3,000 degrees) that its carbon atoms have crystallized into a diamond and it hardly shines at all. It also orbits a pulsar (on the left in the illustration), a spinning star as dense as an atomic nucleus.

This illustration depicts MY Camelopardalis, a system of two young stars orbiting each other so closely that they’re touching. They will eventually merge into a single star 60 times heavier than the sun. Astronomers think that most extremely massive stars form in this fashion. The finding, published in December, could be the first known example of such a scenario.

This illustration shows comet Siding Spring zipping by Mars in October. The comet ventured within 87,000 miles of Mars, the closest anyone has ever seen a comet get to a planet without crashing. The comet’s trail of debris fell onto the Martian atmosphere, generating a meteor shower. The meteors created ions in the atmosphere, which were detected by several spacecraft in orbit around the red planet.

Over the summer, astronomers were eager to watch a mysterious glob of gas called G2 get gobbled up by the supermassive black hole at the galaxy’s center. But then the glob, the orange object in this illustration, escaped digestion. To explain its surprising survival, astronomers have proposed that it’s actually a star. Others disagree, and still say it’s gas.

Rings aren’t just for planets like Saturn anymore. In March, astronomers announced that an asteroid-like object called a centaur has a ring system, seen in this artist’s concept. The 154-mile-wide object, named Chariklo, orbits between Saturn and Uranus. Its rings are dense and full of water ice, making them relatively bright, like a miniature version of Saturn’s.

Almost all big galaxies are believed to have a supermassive black hole at the center, as in this galaxy, NGC 1275. But this summer, astronomers described another galaxy that seemed to have three black holes. Further observations have cast some doubt on the triplet, however, suggesting two of the black holes are just one.

In January, the Herschel space observatory discovered watery plumes spewing from Ceres, the largest object in the asteroid belt. Seen in this artist’s concept, Ceres is big and round, making it a dwarf planet like Pluto. Scientists think jets of water vapor sprout when Ceres nears the sun---perhaps due to sublimation of surface ice. Ceres is thought to be rock, covered in ice so thick it would account for more fresh water than there is on Earth.

In March, astronomers announced they found what’s likely a dwarf planet with the most distant orbit known, ranging between 7 billion miles and 42 billion miles from the sun. The object’s official name is 2012 VP113, but it has been dubbed “VP” or “Biden,” in honor of the vice president. The only other object with a similar known orbit is Sedna, discovered more than 10 years ago.

The ALMA telescope in Chile snapped this baby picture of a planetary system. A star forms from a collapsing cloud of gas and dust, which flattens as it spins. Dust particles eventually stick together to form planets, which can carve out rings and gaps in the disk. This image, released in November, is the most detailed yet of an infant system, revealing the structure that previously had only been depicted in artist concept drawings.

For the first time, astronomers saw an asteroid in the midst of falling apart into as many as 10 pieces. The Hubble space telescope captured these images of the asteroid P/2013 R3 as it crumbled away over the course of several months from October 2013 to January 2014. The four largest pieces are up to one-eighth of a mile wide.

In September, scientists announced they found a black hole that appears too big for its galaxy, an ultra-compact dwarf galaxy called M60-UCD1. The black hole, depicted in this artist’s concept, weighs 21 million times the mass of the sun, more than five times the black hole in the Milky Way. But its host galaxy is a mere one-six-hundredth of the Milky Way’s diameter.

And, of course, there’s comet 67P/Churyumov-Gerasimenko. The discoveries are just beginning, but scientists are expecting a lot of exciting finds from the Philae lander and the Rosetta spacecraft now following the comet toward the sun. So stay tuned in 2015.