The year in science by Alan Boyle - Top 10 scientific Breakthroughs in 2009

J.H. Matternes / Science via AFP - Getty Images

Click for video: An artist's conception shows how Ardipithecus ramidus, or "Ardi," might have looked during life 4.4 million years ago. Click on the image to watch an "NBC Nightly News" video about Ardi from October.

Is she our oldest known ancestor, or just another cousin on the primate family tree? The scientific debate over the 4.4 million-year-old fossil now known as Ardi is continuing, two months after her skeleton was unveiled. However the debate turns out, Ardi is shining "bright new light on an obscure time in our past" and rates as the top scientific breakthrough of the year, the journal Science proclaims today.
Science's annual breakthrough roundup serves as a status report for the research world - and its top-10 list includes discoveries that have gotten plenty of play in the past year (such as NASA's moon crash) as well as discoveries that are just on the verge of bearing fruit (such as the effort to boost longevity). Here's a recap of the journal's review of 2009 - and preview of 2010.
Top breakthrough: It took 15 years for researchers to reconstruct the skeleton of Ardipithecus ramidus, an apparent human ancestor unearthed in Ethiopia in 1994. The results were surprising: Ardi's image didn't look like a cross between an African ape and early hominids such as Australopithecus afarensis (represented by another famous skeleton, nicknamed Lucy). Rather, her skeleton was structured for upright walking as well as climbing, with long, curving fingers suited for grasping tree branches.
The message was that apes as well as humans have changed significantly since Ardi's heyday to adapt to their particular evolutionary niches. Anyone who still thinks that "humans evolved from apes" will have to shift their paradigm.
Some researchers question whether Ardi was actually able to walk upright. Others question whether being able to walk upright should continue to be a requirement for admittance to the club of human ancestors, also known as hominins. But the important thing is that scientists have been given "a Rosetta stone" to help answer the questions surrounding our ancient family tree, according to Science's Ann Gibbons.
"In the year of the bicentennial of Darwin's birth, it seems fitting that researchers finally broke through the 4-million-year barrier to understanding our origins," she writes. "Models for our earliest ancestors can now be informed by plenty of fresh data and at least one body of hard evidence."
The other nine: Science doesn't rank the other items in its list of top 10 breakthroughs - but here they are, as they were listed in the journal.

Pulsars in the gamma-ray sky: NASA's Fermi Gamma-ray Space Telescope reveals a new wave of pulsars.
How plants get a rush: Scientists are learning how ABA receptors help plants get through stressful times.
Mock monopoles spotted: An elusive phenomenon, involving materials that have only a north or a south magnetic pole, is created in the lab using special materials. Magnetic monopoles have figured in the debate over the Large Hadron Collider's safety as well as in episodes of "The Big Bang Theory."
The stuff of longevity: Drugs such as rapamycin are being targeted for animal studies that eventually could lead to life extension for humans.
Our icy moon revealed: NASA's Lunar Crater Observation and Sensing Satellite crashes into the moon to find fresh evidence of water ice.
The return of gene therapy: Gene therapy has suffered setbacks over the past 20 years, but this year researchers reported success in treating maladies such as X-linked adrenoleukodystrophy, Leber's congenital amaurosis and "bubble boy" disease.
Graphene takes off: Single-atom-thick sheets of carbon atoms are the hot new thing in materials science, potentially opening the way for graphene transistors that can outdo silicon.
Hubble reborn: The Hubble Space Telescope gets its final scheduled upgrade from shuttle astronauts and emerges working better than ever.
First X-ray laser shines: SLAC's Linac Coherent Light Source was fired up for the first time in April, beginning a series of experiments that will use X-rays to probe structures on the atomic scale. Check this item to look back at my tour of SLAC while the LCLS was under construction.

Virus of the year: H1N1 (a.k.a. swine flu), naturally.
Breakdown of the year: The economic downturn's effect on academic research (which was highlighted last year as well).
Trends to watch in 2010: Reprogrammed cells, also known as IPS cells. ... The Alpha Magnetic Spectrometer, which was revived by NASA at Congress' insistence. ... Exome studies, which could reveal genetic causes of hereditary diseases. ... Biochemical cancer treatment, using glycolysis disruption. ... NASA's rethinking of human spaceflight.
... And by the way: Climate change studies came in for shout-outs from Science, which noted the Copenhagen proceedings as well as increased attention for ocean acidification. The race for the Higgs boson was also noted, with runs at Fermilab's Tevatron now extended through 2011 and the Large Hadron Collider restarted at last.
Does this cover everything that was significant in the world of science during 2009? I doubt it. You're probably thinking, "I can't believe they didn't mention [fill in the blank]," right?