Astronomers Relegate Pluto to Dwarf Status

After a week of contentious public and private debate, a small cluster of astronomers voted to demote Pluto from its planetary status. The world wept, and we wept with you.

Newfound Fossil Is Transitional between Fish and Landlubbers

Dubbed Tiktaalik roseae, this large, predatory fish bears a number of features found in the four-limbed creatures that eventually gave rise to all amphibians, reptiles, birds and mammals. Plus, it gave our editor in chief another chance to take on creationism.

The Year of An Inconvenient Truth

The climate models were as dire as ever, despite some researchers' ongoing attempts to deny that anthropogenic climate change is even happening. Meanwhile, the effects of global warming continued to multiply, including more intense monsoon rains, the migration of America's breadbasket to Canada and the contraction of the Earth's atmosphere. (There was some good news, as well: levels of atmospheric methane, which is a powerful greenhouse gas, mysteriously stabilized.)

The Passing of Steve Irwin

An interview with the Crocodile Hunter revealed that he was more than just a showman, and possessed a deep commitment to animals, education and environmental conservation.

Grigory Perelman, Genius Who Solved Poincare Conjecture, Declines the Fields Medal

Why would anyone pass up the "Nobel Prize of mathematics" plus a $1-million bounty? Perhaps a detailed study of the man who did all of the above holds the answer.

The Fountain of Youth at the Bottom of a Wine Bottle?

Resveratrol blew up big this year as the miracle molecule in wine that could extend your life by 60 percent--if you're a yeast cell, that is. Other researchers saw it differently--Forget Resveratrol, Tannins Key to Heart Health from Wine argues that wine's beneficial effects on heart health depend more on the traditional vintner's art than on the wonder molecule resveratrol. Either way, a little knowledge about the chemistry of wine can't hurt.

Neandertal Nuclear DNA Sequenced

How closely related to humans were Neandertals? When did our ancestors diverge from theirs? What diseases might we have had in common? These questions and a thousand others could unravel as scientists retrieve more and more Neandertal nuclear DNA from the distant past--read the full account of how researchers obtained this sequence data.

Mouse Finding Violates Laws of Heredity

The discovery that RNA, like DNA, can also pass traits down through generations could have startling implications. As one researcher put it, "a particularly intriguing possibility is that such RNAs regulate other non-genetic modes of inheritance, such as metabolic or behavioral imprinting."

Cassini Captures Stunning Image of Saturn

Not to mention images of lakes of liquid methane and Earth-like dunes on Titan.

Differences Between Chimp, Human DNA Highlight Rapid Evolution of Certain Human Genes

Researchers comparing humans to our closest living relatives identified 49 areas of rapid evolution in the human genome, then plumbed just one of them, which may be linked to the rapid evolution of our brains. Months later, a different study showed that the old saw about humans and chimps sharing 98% of their DNA just isn't so--it's more like 94%.

Firm Develops Revolutionary New Method for Generating Human Embryonic Stem Cells without Harming Embryos

Unfortunately, the firm appears to have made claims that its research doesn't quite support--an event that said as much about hype surrounding new discoveries (and the way they're disseminated) as it said about stem cell research.

"Lucy's Baby"--An Extraordinary Addition to the Ancestry of Humans

Even though she predated the original Lucy by about 100,000 years, this fossilized three-year-old rocked the world of paleontology. Her discovery also gave our editors a chance to conduct an experiment in new journalism, which included soliciting reader feedback in advance of the appearance of a feature story on Lucy's baby in the pages of Scientific American. Our online coverage included a Q&A with the enterprising fossil hunter who found this 3.3-million-year-old girl, as well as a multimedia presentation of the fossils themselves.

Dozens of New Species Discovered

Perhaps you heard about the astonishing 50 new species scientists unearthed in Borneo, but what about the new monkey genus (the first in 83 years), the 52 new species of fish, shrimp and coral that showed up in a survey of the seas of New Guinea, the new piranha discovered, along with 12 other new species of fish, in Venezuela, or the Kha-Nyou, a "living fossil" that is a member of a family thought to be extinct for the past 11 million years?

Overfishing Could Take Seafood off the Menu by 2048

It's hard to imagine a world without seafood, but regional fishing stocks have collapsed before, so what's to stop global fishing stocks from doing the same?

Martian Gullies Show Traces of Flowing Water within the Past Decade

It's long been known that water flowed across the surface of Mars in the past, but scientists were shocked to discover that liquid water exists on Mars today. Whether or not that means life has ever existed on Mars is still up for debate--but if Mars's oceans were as acidic as scientists currently believe, all signs point to no.

Radiation-Fueled Microbe Has Thrived Deep Underground for Past 20 Million Years

As if that weren't enough, extremophiles were also discovered in an ultraheated environment as acidic as vinegar, caught in the act of repairing chromosomes after massive doses of radiation, and found use as models of extraterrestrial life for NASA.

Existence of Dark Matter Proved

There's been more than a little debate about whether or not dark matter actually exists, but the collision of two clusters--known as the Bullet cluster--revealed the existence of the mythical stuff via a measure of its gravitational lensing.

Six Volunteers in Serious Condition after Receiving a Trial Antibody from Pharmaceutical Company TeGenero

The attempt to test a "superantibody" on human volunteers highlighted the pitfalls of human testing, even after extensive animal tests.

Fewer Breast Cancers Linked to Less Hormone Therapy

In a late-breaking end-of-year development, it appears that eliminating hormone therapy has led to a 7 percent drop in the rate of breast cancer, after decades of increases. Researchers debated for years whether hormone therapy would have a measurable effect on rates of breast cancer--if this finding holds, we can consider that debate settled.

Invisibility Cloak Proposed and Unveiled

Mere months after making headlines for proposing a technologically feasible way of rendering objects invisible, a research team demonstrated a rudimentary example of an invisibility cloak. Harry Potter's invisibility cloak it ain't--this one is constructed from metamaterials, and only works in the microwave range of the electromagnetic spectrum.

Wireless Energy Transfer May Power Devices at a Distance

Scientists are perfecting a new method for transmitting electrical energy from a base station using a technique that resembles a wireless Internet connection. Alas, it's still only theory and has yet to be demonstrated.

Element 118 Discovered Again--for the First Time

Element 118 is an elusive beast; it had to be dropped from the periodic table in 2002 on account of its not existing, but now it's back, and this time for good. (Also worth checking out: How do scientists detect new elements, such as element-118, if they only last milliseconds before disintegrating?)

Tiny Chip Converts Paraplegic's Thought into Action

Someday we'll all be controlling computers with mere thought; until then this nascent technology is the sole domain of people who have lost the use of their limbs.

Cervical Cancer Vaccine Approved

A vaccine for a disease that strikes more than 10,000 women every year, indiscriminately killing more than a third of them? If only it weren't now mired in a debate about whether or not such a vaccine will encourage promiscuity in the young.

First Teleportation Between Light and Matter

At long last researchers have teleported the information stored in a beam of light into a cloud of atoms, which is about as close to getting beamed up by Scotty as we're likely to come in the foreseeable future.

Unique Marvel of Ancient Greek Technology Gives Up New Secrets

Unmatched in complexity for 1,000 years, the device counted down the months until eclipses and might once have shown the positions of the planets.

Crossing Wild and Conventional Wheat Boosts Protein, Avoids Genetic Modification

And there probably isn't a difference, nutritionally, between organic and conventional wheat. Rice got a boost, too--New Gene Allows Rice to Survive Submersion.

Ritualized Submission and Pseudocopulation Reduce Aggression Among Male Crayfish

In a finding sadly neglected by the mainstream press, two researchers at Georgia State University discovered that, just like in mammals, dominance in crayfish can be reinforced through same-sex copulation. As the editors of Science put it, this is "an intriguing example of the convergent evolution of social behavior."