Top Stories 2015

No. 1 New Horizons at Pluto

3 January 2016 Keith Cooper

The long-awaited fly-by of Pluto by the New Horizons spacecraft, on 14 July 2015, was an event 85 years in the making, following Pluto’s discovery by Clyde Tombaugh in 1930. Since then, Pluto has gone from planet to dwarf planet, but despite protestations from the New Horizons team, its reclassification never really changed the mission or the importance of what it would find at Pluto.

Top Stories 2015

No. 2 Water on Mars

3 January 2016 Keith Cooper

Liquid water existing on the surface of Mars, in the here and now, has been the holy grail of Martian exploration for some time, but in October 2015 NASA announced that the orbiting Mars Reconnaissance Orbiter (MRO) had turned water-diviner to find compelling evidence that water is bursting out onto the red surface and trickling down the slopes of crater walls and hillsides.

Top Stories 2015

No. 3 Dark matter is ‘sticky’

3 January 2016 Keith Cooper

For years, dark matter seemed to do nothing. It had mass and therefore could influence space gravitationally, but there was no evidence of it interacting with anything else in the Universe in any other way, which made it incredibly frustrating to study. Then, in 2015, a breakthrough occurred.

Top Stories 2015

No. 4 A planet like Earth?

2 January 2016 Keith Cooper

There was great media excitement in July when it was announced that the Kepler Space Telescope had discovered the most Earth-like planet yet, but appearances can be deceiving.

Top Stories 2015

No. 5 The great galaxy shutdown

2 January 2016 Keith Cooper

Stars are not forming in the same great numbers that they did billions of years ago and several advances in 2015 have shed light on why this downturn took place.

Top Stories 2015

No. 6 Our first up close look at Ceres

2 January 2016 Keith Cooper

In spring 2015 NASA’s Dawn mission, coming off the back of exploring the asteroid Vesta, entered into orbit around the dwarf planet Ceres and immediately found a puzzle for the space probe to unpick.

Top Stories 2015

No. 9 Rosetta rides with its comet

1 January 2016 Keith Cooper

While 2014 was the year the Rosetta spacecraft celebrated making it into orbit around a comet, 2015 was the year it got down to some serious hard work. Its comet, with the tongue-twisting name 67P/Churyumov–Gerasimenko, made its closest approach (186 million kilometres) to the Sun, a period known as perihelion when the comet would be expected to be at its most active. Rosetta was there to witness this.

Top Stories 2015

No. 10 Solving the lithium mystery

1 January 2016 Keith Cooper

At number 10 in our top stories of the year: one of the most perplexing problems of modern cosmology and astrophysics was solved. For decades scientists had puzzled over where all the lithium in stars had disappeared to. Fortunately for the Big Bang model, Italian scientists at the International School for Advanced Studies in Trieste discovered that it was the stars that were to blame.