Some of our top stories of 2017 are pretty unsettling

(Credit: Getty Images)

On the cusp of the new year, we’re revisiting the five stories from 2017 that most sparked our readers’ curiosity—as well as a few that resurfaced from deep in the archives.

Enjoy these hits and have a wonderful 2018!


1. Something big is warping the outer solar system

planet 9
(Credit: Heather Roper/LPL)

“According to our calculations, something as massive as Mars would be needed to cause the warp that we measured.” Whoa.


2. Brand new snake species found in Tennessee sinkhole

snake skeleton
(Credit: Rob and Stephanie Levy/Flickr)

Say hello to the new species.


3. Are you ‘old’ yet? The cut-off has shifted

(Credit: Getty Images)

Traditional population projections categorize “old age” as a simple cutoff at 65. That doesn’t work anymore.


4. Defects explain why Roman concrete was so tough

(Credit: <<>>/Flickr)

“Our study provides the first report on how to leverage seemingly weak attributes—the defects—in cement and turn them to highly desired properties, high strength and toughness.” Find out more.


5. Did this other human species overlap with our ancestors?

homo naledi skull
Credit: John Hawks/U. Wisconsin)

“We can no longer assume that we know which species made tools, or even assume that it was modern humans that were the innovators of some of these critical technological and behavioral breakthroughs in the archaeological record of Africa.” Check out the fossils.


From 2014: Spiders infest Guam after native birds disappear

spiders in web
(Credit: Isaac Chellman)

“There isn’t any other place in the world that has lost all of its insect-eating birds.”


From 2014: How US Civil War rebels got away with treason

robert e lee
(Credit: Wikimedia Commons)

What exactly were the boundaries of loyalty and disloyalty?


From 2016: The periodic table is finally complete

finish line on black
(Credit: Getty Images)

The seventh row is all filled in.