The amazing accomplishments of the European Space Agency's Rosetta mission are my two top astronomy stories for 2014. The others are in no particular order.

Rosetta and Comet Churyumov-Gerasimenko
Rosetta had traveled for a decade and clocked up over 6 billion kilometers (4 billion miles) before the historic August rendezvous with Comet C-G. She will continue to orbit the comet and study it as it heads into the inner Solar System.

Philae and the comet
It was the turn of Rosetta's lander Philae to get our attention in November. After a few bounces, Philae landed on the comet, and collected and returned the required data until the battery gave out. Unfortunately, she hadn't landed on the target, but in a place shaded from the Sun. Unless the shady spot gets some sunlight in 2015, the battery can't recharge.

First lunar eclipses of a new tetrad
There was much ado about the tetrad of blood moons. This sounds apocalyptic, but it's just a series of four total lunar eclipses. Two of them occurred in 2014, and there are two more in 2015. A totally eclipsed Moon does have a reddish color, but it's nothing sinister. Some sunlight gets to it indirectly via the Earth's upper atmosphere. The bluer colors are scattered by air molecules, but the redder ones get through. Eclipse tetrads aren't even phenomenally rare. We had one in 2003-4. I wonder how many people noticed.

MOM on Mars
India's Mars Orbiter Mission (MOM) reached Mars in September. It's also known as Mangalyaan, Hindi for “Mars craft”. The Indian Space Research Organisation (ISRO) is justly proud of getting its orbiter to Mars on the first attempt. The mission also has the distinction of being very economical, having cost less than the film Gravity. ISRO will be pooling findings with NASA whose Mars Atmosphere and Volatile EvolutioN (MAVEN) craft arrived shortly before Mangalyaan. MAVEN is trying to answer the question of how Mars became a desert.

Comet Siding Spring
In 2013 a comet was discovered at Siding Spring Observatory in Australia. Astronomers realized that in October 2014 it would make a close pass of Mars. There were already 3 orbiters and 2 rovers there, and MAVEN and MOM would arrive not long before the comet did. Not all of them got good pictures, but altogether there is a data set showing the effects on the Martian atmosphere of the comet's close passage.

Curiosity finds organic chemicals
Curiosity drilled into a rock that contained organic chemicals, i.e., chemicals containing carbon, and which are the building blocks of Earth life. The rover also measured a spike in the methane level – methane is itself an organic chemical. The molecules in the rocks could be native or could be from meteorites. Either way, the researchers were quite excited. As for the methane, although it can be produced by living organisms, it's also produced by geological processes.

Kepler reborn
In May 2013 the Kepler mission seemed to be over. The space telescope's job was detecting dips in starlight that occurred when exoplanets passed in front of their stars. It was a valuable asset, finding new stars and detecting hundreds of planets, including some Earth-sized ones. But for the precision pointing required, it needed three stabilizers. Having only two, it was crippled. But in February 2014 some very smart people devised an innovative way to stabilize Kepler using the radiation pressure of sunlight as the third stabilizer. In May, NASA approved a new mission called K2. One new planet has been discovered and there is a data set awaiting analysis.

Discovery of the first Earth-size planet in the habitable zone
At last! In 2014 we saw the discovery of an Earth-size exoplanet in its star's habitable zone. This is the area around a star in which liquid surface water might exist. The discovery came from observations made in the original Kepler mission. The planet is Kepler-186f, one of five planets known to orbit red dwarf star Kepler-186.

An ocean on Enceladus
Ever since Cassini saw geysers on Saturn's moon Enceladus in 2005, scientists have strongly suspected that the moon has an ocean under its icy crust. But how to find out? You can't just go and drill a hole through tens of kilometers of ice. But gravitational strength is related to mass, so a research team made a gravity map of Enceladus by measuring the moon's gravitational effect on Cassini. The best explanation of the results is that there is an ocean of liquid water in the southern hemisphere under the icy surface.

Laniakea supercluster
The Solar System is located about two-thirds of the way from the center of our galaxy, the Milky Way. Our Galaxy is a member of the Local Group of galaxies. Galaxies don't seem to come on their own, but are in clusters held together by gravity. But gravity affects the clusters as well, bringing them together as superclusters. The Milky Way, according to a breathtaking study, is on the edge of a supercluster which has been named Laniakea. That's Hawaiian for “immense heaven”. And immense scarcely describes it. It's 500 million light years across, contains 100,000 galaxies and the mass of a hundred quadrillion suns. Wow!