One of Kepler's most exciting discoveries was a rocky world similar in size to Earth orbiting a Sun-like star. Photo / AP
Exploration of the solar system over the past year has produced exciting finds, writes Alan Duffy.
This was a golden year for planetary exploration, thanks to all of the Nasa and European Space Agency missions that were planned and implemented decades ago. Here are the top 10 space events that I've been most excited about this year.
1 Pluto Flyby by New Horizons
Organic material staining the surface orange, kilometres high water-ice mountains plunging into freshly resurfaced nitrogen-ice sheets and a collapsing atmosphere all made this dwarf planet astoundingly exciting and well worth the almost decade-long journey to reach.
The announcement that Mars has flowing water on its barren surface was of huge importance as (at least on Earth), where there's flowing water, there's life. It meant we need to reassess the conditions under which water can exist and hence the possibilities for life. The red planet made the list because of the incredible discovery by Nasa's Maven spacecraft that the Sun was responsible for stripping the Martian atmosphere away, turning a water-rich world nearly four billion years ago into inhospitable desert today.
3 Philae called home (and more Rosetta discoveries)
The idea that there's a spacecraft sitting on a comet still astounds me. That #WakeUpPhile came true (briefly) this year is a great reason to feature Rosetta and explore the scientific discoveries from the comet, such as how the iconic tail forms from comet ice.
Nasa's Kepler spacecraft continued to search for exoplanets around stars in our Milky Way, even after the failure of critical gyroscope stabilisers, bringing the total to 1030 confirmed worlds (with thousands more candidates to be followed up). One of the most exciting discoveries was of a rocky world similar in size to Earth orbiting a Sun-like star, Earth's "cousin". A rocky world orbiting in the "goldilocks zone" suitable for liquid water to exist was a huge step forward in our ultimate search for Earth 2.0 and finding life beyond Earth.
5 Breakthrough Listen to hunt for ET
An incredible US$100 million initiative funded by Russian billionaire Yuri Milner to use two of the world's largest radio telescopes including Australia's Parkes (aka The Dish) to search the closest million stars and 100 nearest galaxies for alien signals. Breakthrough Listen will also use the optical Lick observatory in the chance that aliens have upgraded from radio/TV signals to laser-based communications. In the decade-long search astronomers will upgrade the telescopes to the benefit of astronomy worldwide, and learn incredible things about the stars of our Milky Way.
6 The Martian
Rarely does a film convey the science so well that it could be considered an educational resource, but The Martian managed it. Exceptionally detailed consideration of the physics of orbital dynamics, life support systems, astro-biology and some poignant moments of the cost of space exploration to astronauts as much as their families left behind.
7 Super blood moon
One of the most observed events of the celestial year, the lunar eclipse was also, in some circles, reported as being the harbinger of the apocalypse. This was because during a lunar eclipse the moon turns blood red as sunlight travelling through our atmosphere scatters on to the moon. Only longer, red, wavelengths of light make it through the atmosphere which is why the sun low on the horizon appears red. The result is that the "blood" is being illuminated by all the sunrises and sunsets of Earth. This eclipse occurred when the moon was at its closest point to Earth (known as a perigee or "super" moon). We won't see a similar super lunar eclipse until 2033.
8 Dawn exploration of Ceres
Nasa's Dawn mission to Ceres, a dwarf planet and largest body in the asteroid belt, was overshadowed by the flashier, high speed flyby of Pluto by the New Horizons mission. Yet as Dawn drifted towards Ceres, it spotted a huge surprise. Ceres had bizarre bright regions shining out from an asphalt-dark world. These were so unexpected that Nasa even created an online poll so everyone could make a guess.
• Alan Duffy is a research fellow at the Swinburne University of Technology.