(CNN) -- From faraway planets to the deepest depths of the
ocean, 2012 has been an exciting year for scientific
achievements and milestones. Humans broke previously
unimaginable barriers by detecting an elusive tiny particle and
free-falling 24 miles from the edge of space. At the same time,
we said goodbye to four retired NASA space shuttles that found
new museum-type homes. Here's our list of the biggest science
achievements this year, in order of significance: 1. Curiosity
lands, performs science on Mars Every time I hear the word
"curiosity" in a sentence, I'm tempted to butt in and ask if
you're talking about the Mars rover Curiosity. She's really
there! On Mars! Right now! And people are driving it! (Forgive
me, I get excited about this.) Landing this 2-ton rover
flawlessly on the surface of Mars is our choice for the most
exciting science moment of 2012. You can see from NASA's "seven
minutes of terror" video how crazy-complicated that was -- the
landing process included a supersonic parachute and a sk