The Earthiest planets in the universe (that we know of)

Last week, Rob told you how scientists announced that they'd found two Earth-like planets orbiting the star Kepler-62. One of those, Kepler-62e, now ranks as the most Earth-like exoplanet we've ever found. Of course, all of this is relative.

What I like about this chart is that it kind of shows you how "Earth-like" doesn't really mean, "Man, that is totally exactly like Earth." Instead, you should translate it more as, "Welp, this is about the closest to Earth that we've found so far." Even Kepler-62e, as you can see, is much larger than the Earth and Mars. And size matters when it comes to actual habitability. As does density — and we don't know what Kepler-62e is made of yet. It's also worth noting that #2 on this list, the infamous Gleise 581g, is really a planet candidate, rather than a planet. We aren't actually certain it exists, just yet.

Popular Science has a neat little breakdown explaining what life might be like on Kepler-62e, if we could go there. But it's worth keeping the context in mind on these Earth-like planets. Don't pack your bags just yet.

Fraud, failure, and FUBAR in science

Here's an issue we don't talk about enough. Every year, peer-reviewed research journals publish hundreds of thousands of scientific papers. But every year, several hundred of those are retracted — essentially, unpublished. There's a number of reasons retraction happens. Sometimes, the researchers (or another group of scientists) will notice honest mistakes. Sometimes, other people will prove that the paper's results were totally wrong. And sometimes, scientists misbehave, plagiarizing their own work, plagiarizing others, or engaging in outright fraud. Officially, fraud only accounts for a small proportion of all retractions. But the number of annual retractions is growing, fast. And there's good reason to think that fraud plays a bigger role in science then we like to think. In fact, a study published a couple of weeks ago found that there was misconduct happening in 3/4ths of all retracted papers. Meanwhile, previous research has shown that, while only about .02% of all papers are retracted, 1-2% of scientists admit to having invented, fudged, or manipulated data at least once in their careers.

The trouble is that dealing with this isn't as simple as uncovering a shadowy conspiracy or two. That's not really the kind of misconduct we're talking about here.

Read the rest

New monkey isn't so much "new" as "newly documented in a scientific journal"

When somebody says that a new species has been discovered, it's easy to get the impression that this is an animal nobody has ever seen before. But that's usually not exactly what scientists mean.

Take the lesula (or Cercopithecus lomamiensis), an African monkey whose "discovery" is making headlines this week. While it does seem to be true that this particular species hasn't been previously named and documented in the scientific literature, the scientists who wrote about the lesula were not the first people to encounter one. What's more, lesula do not represent a species totally removed from animals we already knew about. Here's Mongabay's Jeremy Hance:

"There are monkeys out there between the three rivers that no one recognizes. They are not in our field guides," Terese Hart wrote tantalizingly in a blog post in 2008. "We've sent photos to the most renown of African Primatologists. Result: a lot of raised eyebrows. And the more we find out the higher our eyebrows go."

One of these monkeys was the lesula (Cercopithecus lomamiensis). John Hart first came across the new species in June 2007 when he and a field team were shown a captive baby lesula, kept as a pet by the local school director's daughter in the remote village of Opala. The next step was locating the species in the wild.

...the lesula is apart of the Cercopithecini family, which are commonly referred to as guenons. It's most similar to the owl-faced monkey (Cercopithecus hamlyni), which is also found in the region. But the lesula sports a lighter coat and has unique calls. Genetic testing, furthermore, proves the species are distinct from each other and have likely been separated for a few million years, probably by impassable rivers.

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Autism is more than a parasite deficiency

The New York Times Sunday Review had an article this week linking autism with the hygiene hypothesis. Written by Moises Velasquez-Manoff, the piece is part of the Times' opinion coverage, not reported news. It was also one of those sort of stories that comes across as highly persuasive ... until you start looking at the details. About halfway through reading it yesterday, it occurred to me that Velasquez-Manoff was making a lot of big statements—"perhaps 1/3 of autism, and very likely more, looks like a type of inflammatory disease", for example—without citing the sources to back those statements up.

That's easy to do when you're writing a relatively short article summarizing the contents of a much bigger book, as Velasquez-Manoff seems to be doing here. But the problems go deeper than that, according to biologist and science writer Emily Willingham. In a must-read blog post, she goes through the NYT piece and points out many flaws in argument and detail. The main problem, though, is a pretty simple one: Moises Velasquez-Manoff presents what seems to be a largely speculative hypothesis as sure-fire truth. To make that case as persuasive as it is, he leaves out lots of evidence that doesn't match up with his thesis.

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Does sunscreen actually prevent skin cancer?

It does successfully prevent sunburn, but what about the evidence for sunscreen protecting you from skin cancer later in life?

The answer: Nobody is really sure. Last year, I wrote a short piece for BoingBoing that looked at this a little bit. The key point: Cancer takes a long time to happen and we haven't been using sunscreen long enough to have much evidence about it.

But, at Discover's The Crux blog, Emily Elert expands on some of the other problems in play. One of the key things—and something that will hopefully be fixed by this time next year—there's nothing on the sunblock you buy to tell you how protective it is against skin cancer. SPF is all about the burn. So even if some sunscreens do protect against cancer, you don't have a good way to know whether or not you're using one of them.

First of all, the way sunscreen’s effectiveness is measured—its SPF rating—basically only describes its ability to block UVB rays. That’s because UVB is the main cause of sunburn, and a sunscreen’s SPF stands for how long you can stay in the sun without getting a sunburn (a lotion that allows you to spend 40 minutes in the sun rather than the usual 20 before burning, for example, has an SPF of 2).

UVA rays can cause cancer but not sunburn, so they don’t factor into the SPF calculation. That means that if you slather on a high SPF sunscreen that only protects against UVB, you’d still absorb lots of UVA radiation, potentially increasing your long-term cancer risk.

Soon it will be easier to tell which sunscreens include ingredients that block or absorb UVA as well as UVB. According to FDA regulations passed last year, products that pass a “Critical Wavelength” test—meaning that they block wavelengths across the ultraviolet spectrum—will carry the label “Broad Spectrum” alongside the SPF, while sunscreens that don’t pass the test will be forbidden from claiming they have such capabilities. However, those regulations don’t go into effect until December, so for this summer, you’re still stuck with SPF. And, by the way, you probably need to apply twice as much sunscreen as you think to actually get an SPF as strong as that marked on the bottle: manufacturers test their products’ SPF with the assumption that you will slather on obscene amounts. This discrepancy could be contributing to the fact that the NIH, when looking the connection between sunscreen use and skin cancer in large populations, doesn’t see clear evidence that sunscreen is effective in reducing the risk of skin cancer. (It’s worth pointing out, too, that there is a clear genetic component in some skin cancers, so just avoiding sun or using sunscreen regularly are not the only factors that determine whether someone gets it.)

Read the rest of the story at The Crux

Image: Beer, cigarettes and sun block: Roskilde Festival 2009 essentials., a Creative Commons Attribution (2.0) image from wouterkiel's photostream

What do Christian fundamentalists have against set theory?

I've mentioned here before that I went to fundamentalist Christian schools from grade 8 through grade 11. I learned high school biology from a Bob Jones University textbook, watched videos of Ken Ham talking about cryptozoology as extra credit assignments, and my mental database of American history probably includes way more information about great revival movements than yours does. In my experience, when the schools I went to followed actual facts, they did a good job in education. Small class sizes, lots of hands-on, lots of writing, and lots of time spent teaching to learn rather than teaching to a standardized test. But when they decided that the facts were ungodly, things went to crazytown pretty damn quick.

All of this is to say that I usually take a fairly blasé attitude towards the "OMG LOOK WHAT THE FUNDIES TEACH KIDS" sort of expose that pops up occasionally on the Internet. It's hard to be shocked by stuff that you long ago forgot isn't general public knowledge. You say A Beka and Bob Jones University Press are still freaked about Communism, take big detours into slavery/KKK apologetics, and claim the Depression was mostly just propaganda? Yeah, they'll do that. Oh, the Life Science textbook says humans and dinosaurs totally hung out and remains weirdly obsessed with bombardier beetles? What else is new?

Well, for me, this is new:

"Unlike the "modern math" theorists, who believe that mathematics is a creation of man and thus arbitrary and relative, A Beka Book teaches that the laws of mathematics are a creation of God and thus absolute....A Beka Book provides attractive, legible, and workable traditional mathematics texts that are not burdened with modern theories such as set theory." — ABeka.com

Wait? What?

Read the rest

TV, video games, or Internet: Which activity makes teenagers fat?

I talk a lot about the importance of context in understanding science. The results of one, single research paper do not tell you everything you need to know on a given subject. Instead, you have to look at how those results fit into the big picture. How do they compare to the results of other studies on the same subject? Have the results been independently verified? How do the specific experiments being done influence what you can and cannot say about the results? What questions aren't answered by the study, and what new questions does it bring up?

You should be thinking about that every time you see anybody talk about the results of a single, new study. Without context, you get situations like this one, described by Travis Saunders on the Obesity Panacea blog:

Earlier this year my friend and colleague Valerie Carson published an interesting paper examining the health impact of various types of sedentary behaviour in a sample of 2500 children and adolescents. They created a clustered risk score (CRS) which took into account a child’s waist circumference, blood pressure, cholesterol, and inflammation, and then examined whether it was associated with 3 different measures of sedentary behaviour – accelerometry (an objective measure of movement), self-reported TV watching, and self-reported computer use.

Here is what they found (emphasis mine): For types of sedentary behavior, high TV use, but not high computer use, was a predictor of high CRS after adjustment for MVPA and other confounders. Here is what the Daily Mail had to say: Watching TV most damaging pastime for inactive children, increasing risk of heart disease.

Last month, our group in Ottawa published another paper (led by Dr Gary Goldfield) looking at different types of sedentary behaviour and heart disease risk factors in a cohort of overweight and obese teens (in contrast, the earlier study was on a sample of nationally representative youth). Interestingly, we found that neither TV time nor computer time was associated with increased risk in this group - in our dataset it was video games that were by far the most important sedentary behaviour.

Why is this a problem? Put yourself in the shoes of someone who just read the Daily Mail article, and who now believes that TV viewing is the single most damaging sedentary behaviour for kids to engage in. What reaction are you going to have when you read a similar article about our new study, suggesting that TV viewing and computer use aren’t important at all, but that video games are actually “the most damaging activity an inactive child can indulge in”?

As the source of this problem, Saunders rightly calls out journalists for pushing every individual study as a "GROUNDBREAKING NEW FINDING". It is, unfortunately, rare to find TV and newspaper coverage that treats new studies in context, rather than as the final word. But to that, I'd add university PR people. The sad truth is, with newspaper layoffs, many of the people writing about science aren't specialists. They cover city council one day, school board the next, and a new research finding after that. The press releases they get (and I know, because I get those press releases, too) push GROUNDBREAKING NEW FINDINGS not research that fits into a larger context. It's the journalists job to know better. But it's also the university's job to not manipulate journalists.

Potentially habitable exoplanet: The fine print

Kepler-22b is a newly confirmed exoplanet, orbiting a Sun-like star 600 light years away from Earth. The exoplanet sits in the "habitable zone"—a range of orbits around a star that are, based on what we know about life on Earth, most likely to provide the right conditions for life to happen.

That is pretty damn cool. But it does not mean there must be life on Kepler-22b. As Phil Plait explains on the Bad Astronomy blog, there's a lot we don't know about this exoplanet yet, and "within the habitable zone" is not a guarantee of habitability. Case in point: Our solar system. Earth is within the Sun's habitable zone. But so are Mars and Venus, and you may have noticed that they are not especially teeming with life.

Kepler detects planets when they transit their star, passing directly in front of the star, blocking its light a little bit. The bigger the planet, the more light it blocks. The astronomers going over the data determined that Kepler-22b is about 2.4 times bigger than the Earth. The problem is, that and its distance from its star are all we know. We don’t know if it’s a rocky world, a gaseous one, or what. It may not even have an atmosphere!

Another good post to read on this subject is Matthew Francis' explanation of "habitability" on the Galileo's Pendulum blog. Even the statement, "Kepler 22-b is within the habitable zone," comes along with a lot of assumptions that may or may not turn out to be true.

The following factors are needed to calculate whether a planet is in the habitable zone: The temperature of the host star: the hotter the star, the more it emits light of all wavelengths ... The size of the host star: a large star emits more light from its surface simply because there is more surface area ... The albedo of the planet: how much light gets reflected back into space ... Hand in hand with albedo comes the composition of the planet’s atmosphere—if it has one.

When we say Kepler-22b is in the habitable zone, we're assuming that it has the same atmospheric composition and albedo as Earth. We don't know that. And it's a big leap, bearing in mind (again) that there's not even another planet in our own solar system that shares those characteristics.

I swear, I'm not a fun-hater. Kepler-22b is awesome. Just keep it in context and know that there's still a lot we don't know about this thing.

Size comparison of Kepler-22b via Galileo's Pendulum.

Can cows sense magnetism? The debate continues

In 2008, some scientists proposed that cows can sense magnetism and actually line up in fields along Earth's magnetic lines. It's the sort of paper that everybody in the media wants to talk about for, roughly, two weeks ... and then never mention again.

But that's not how science works. One research paper does not an unquestionable fact make. Luckily Discover's Discoblog has been kind enough to update us on the current state of magnetic cow research. Shorter version: This issue is far from settled, with a second research team attempting to poke holes in the original study. Nevertheless, outside researchers say, the original findings still look strong. There is evidence that herds of cows stand along magnetic lines, and fail to stand along those lines in the presence of magnetic-field distorting high-voltage power lines. Whether this is absolutely the case and, if so, why, remains a bit of a mystery. Needs moar research.

... an analysis of Google Earth images by another team finds no such lining up. In a back-and-forth over the last year in scientific journals, the first team reanalyzed the second’s data and said that half of the images were useless, since they were near high-voltage power lines or contained hay bales or sheep instead of cows. Plus, the first team points out that the second team looked at single cows within herds instead of herds as a whole, and it’s pretty clear at this point that animals in herds and flocks aren’t operating as independent entities. The second team retorts that their images were too okay to use, and the first team may have been looking at the wrong pictures.

Image: Cows, a Creative Commons Attribution (2.0) image from 35463710@N06's photostream

Science helps old mice age gracefully

There was some interesting research out of the Mayo Clinic announced this week. The study focused on a new method to combat aging, though not, significantly, one that could extend life. Instead of living forever, Darren Baker and colleagues would just like to help people enjoy the time they do have—by reducing the physical downsides of aging, such as lost muscle and stiff joints.

Their method centers around something called senescent cells, normal cells that have basically shut down all growth, but continue to release chemicals into the body. Some scientists have suspected this process of cellular senescence contributes to the negative physical effects of aging and Baker's team was able to provide some big support for that theory. They killed senescent cells in the bodies of fast-aging mice. Those mice went on to age more gracefully, delaying the physical breakdown of their bodies. Ed Yong explains:

Baker exploited the fact that many senescent cells rely on a protein called p16-Ink4a. He created a genetic circuit that reacts to the presence of p16-Ink4a by manufacturing an executioner: a protein called caspase-8 that kills its host cell. Caspase-8 is like a pair of scissors – it comes in two halves that only work when they unite. Baker could link the two halves together using a specific drug. By sneaking the drug into a mouse’s food, he activated the executioners, which only killed off the cells that have lots of p16-Ink4a. Only the senescent ones get the chop.

Baker tested out this system in a special strain of genetically engineered mice that age very quickly. It worked. The senescent cells disappeared, and that substantially delayed the onset of muscle loss, cataracts, and fat loss. Typically, around half of these mice show signs of muscle loss by five months of age. Without their senescent cells, only a quarter of them showed the same signs at ten months. Their muscle fibres were larger, and they ran further on treadmills. Even old mice, whose bodies had started to decline, showed improvements.

It really should go without saying that there's a big jump between getting something to work in mice and getting it to work in people. So do not expect your doctor to be able to kill off your senescent cells anytime soon, if ever. There's also potential risks to this therapy and a lot we don't yet know about it. Will this work as well in mice that age at a normal rate? Will killing senescent cells allow us to delay or eliminate other signs of aging, or just muscle loss and cataracts? If you kill of senescent cells, will damaged cells continue to grow, producing cancer?

When you're thinking about a study like this, it's probably best to treat it as an interesting discovery about the way mammal biology might work, rather than something that has any immediate practical medical applications for humans. From that perspective, this is pretty cool science.

Bonus fun: Read Ed Yong's write-up of the study. Then read this version written by a reporter at the New York Times. Then think about how much you would have misunderstood about this study if you'd only read the New York Times story.

Thanks Doug!

Image: The Apple Mouse, a Creative Commons Attribution Share-Alike (2.0) image from moparx's photostream

How big are solar flares, really?

Mmmmmmm, delicious context. When the news says "massive," this is what they mean.

Thanks to Scott Stevenson for making this and sending it my way!