Top stories of 2015: Pluto, gene editing, a new hominid and more

It probably comes as no surprise that the New Horizons mission to Pluto takes the top spot in Science News’ list of 2015’s most important stories.

Since New Horizons awoke last December, we’ve devoted more than two dozen stories in the magazine and on the website — upwards of 10,000 words — to this first-ever visit. No other science news this year garnered so many headlines.

But it’s not headlines alone that won this story, or the others, a spot on our list. What’s important is how they launched our thinking in a new direction. The outer solar system is no longer seen as a vast area of indistinguishable specks, but instead as a new frontier. Advances in gene editing made us reconsider how far we’ll go to rid our bodies of disease. A newly proposed species, Homo naledi, challenged our vision of the earliest members of our genus.

No one yet knows how H. naledi will rewrite our history, but one thing is certain: Like New Horizons, we have reoriented. We’ll start 2016 on a new trajectory, with many new questions to ask. — Elizabeth Quill

Here’s the complete list of this year’s top 25 science stories: