Monday April 21, 2014

Top 10 science stories of 2013: one to five


Top stories lists are actually surprisingly difficult. After choosing my Top 10, out of curiosity, I checked to see how they stacked up against what the scientific publications are saying.

Perhaps not surprisingly, there is not much consensus out there. Unlike last year, which saw the discovery of the Higgs Boson, there was not a real stand out story that virtually everyone could point to.

Of course, we all bring some personal or national bias to these things. Virtually every Canadian list, for example, put Chris Hadfield's stint as commander of the International Space Station right up there, while it didn't even register on most international lists.

There's also a matter of criteria. If I were to rank the stories based on some kind of objective criteria, I would likely come up with quite different conclusions.

That's not how this works, however. As with last year's columns for the Christmas and New Year's editions, I am going with the stories that most intrigued me.

1. In the beginning

With each passing year, our understanding of evolution increases, but the nagging question remains: how did it all get started in the first place?

My biggest obstacle to including this item on my list was whether I could sufficiently dumb it down so I could understand it myself.

At a basic level, the complex enzymes that modern cells use in replicating nucleic acids (including DNA and RNA) would not have existed in the "primordial soup."

For decades, scientists have been batting around the idea that simple chemical processes could have driven non-enzymatic replication of primitive nucleic acids.

Much experimental progress has been made in this regard. What you need to make synthetic primitive protocells are magnesium ions (Mg2+) to drive the assembly of RNA molecules and some kind of protective membrane such as the kind of fatty acids that would have abundant at the dawn of life on Earth and naturally form themselves in cell-like vesicles when concentrated in water.

Unfortunately, the presence of Mg2+, necessary as the RNA catalyst also breaks down the fatty acid membrane, a longstanding problem in the origin of cellular life.

This year a team at Massachusetts General Hospital solved that problem by adding chelators (chemicals that bind to metal ions), one of which was citrate (a derivative of citric acid) to the solution. They found citrate worked best, but, of course, citrate would likely not have been present in sufficient quantities in the early Earth.

That does not mean, however, that there was not some sort of similar chemical to do the job.

As a model, this research gets us one step closer to answering that most human of questions: Where did we come from?"

That is why it is my number one.

2. Chris Hadfield, superstar

In the late 1960s and early 1970s, what kid did not want to be an astronaut? Of course, the odds against it were astronomical, especially for a kid from Milton, Ontario, a Canadian in a field dominated by Americans and Russians.

But Hadfield did just that, becoming initially a fighter pilot in the Canadian forces, then one of four Canadians chosen for the space program out of 5,330 applicants. He has made three space flights culminating in 2013 when he became the first Canadian to command the International Space Station.

The numerous awards and accolades he has accumulated during his 35 years as a pilot and astronaut speak for themselves, but none of that is why this story makes my Top 2.

The vast majority of scientists work in relative anonymity, but science also needs its superstars, the Carl Sagans, Neil Degrasse-Tysons and Bill Nyes, who are not only legitimate scientists in their own right, but serve to popularize science.

The flight of Commander Hadfield brought a profile to space exploration it hasn't enjoyed since Neil Armstrong took the giant leap for mankind in 1969.

3. Customized livers

Speaking of giant leaps, regenerative medicine took one this year when Japanese scientists created functional human livers in mice using pluripotent (adult) stem cells.

For years researchers have been able to culture human tissue in petri dishes, but fully-functioning, 3D organs genetically matched to a recipient to avoid immune system rejection is the Holy Grail of this burgeoning field.

The team of researchers found that by combining liver precurser cells with two other human cell lines important to embryonic liver development they could grow a structure they termed a "liver bud." They transplanted these buds into mice with disabled immune systems in the hope that the proto-organs would attach to the animal's blood system and continue to mature. They did, and they produced proteins typically made by human livers and metabolized human medications that mice livers cannot handle.

The next giant leap, of course, is to find out if it works in people.

4. To Pluto and beyond

In 1977, NASA launched the Voyager 1 probe, its three-year mission to study the planetary systems of Jupiter and Saturn.

Anything beyond that would be a bonus. Remarkably, after completing its primary mission Voyager 1 has continued to operate and in September became the first human-made object to leave the solar system.

In fact, the space agency estimates the probe entered interstellar space in August 2012, but only confirmed the fact in September when scientists were able to listen to vibrations in the interstellar plasma caused by a massive solar wave in April. By calculating the plasma's density, which is different than within the solar system, it became official that Voyager had left the neighbourhood.

It is simply amazing that we are still able to communicate with a spacecraft that is now more than 19 billion kilometres away from the Sun.

5. CO2 Blues

We didn't learn anything in 2013 we didn't know when it comes to climate change. We know it is happening and we know that our own activities are the major factor, but we did hit a symbolic milestone when, in May, levels of carbon dioxide in the atmosphere reached 400 parts per million.

In September, the Intergovernmental Panel on Climate Change (IPCC) confirmed human influence is the cause, with 95 per cent certainty, of global warming.

What put this story on my list is the sad fact that, despite all the evidence and the potential implications for humanity, there are still those, particularly in positions of power, who deny it and use the so-called "uncertainty" as an excuse for inaction.

My Top 10 list continues next week with numbers 6 through 10.



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