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TONIGHT: President Obama on MythBusters

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Tonight at 9pm ET/PT: The MythBusters tackle, once and for all, the "Archimedes Solar Ray" myth! Set your DVRs for the Discovery Channel.

Way back in 2004, the MythBusters first tried out the "Archimedes Solar Ray" myth. The myth essentially was (quoting an excellent writeup at The Annotated MythBusters):

Myth: At the seige of Syracuse in 212 BC (during the Second Punic Wars), Archimedes built his 'burning mirrors,' which was an arrangement of mirrors that was capable of focusing a ray of sunshine on approaching ships and setting them aflame.

In 2004, they failed to replicate this effect and called the myth busted. Viewers cried foul, and a group from MIT claimed they had in fact created an array of mirrors that set a boat on fire. So the next year, the MythBusters encouraged various viewers to come on the show and do it themselves -- including the MIT class. Well, as The Annotated MythBusters says, this second series of attempts also failed. (I urge you to read the writeup of this second attempt, as it really is an in-depth essay on the topic.)

But still, the myth would not die. People really, really wanted to see a boat set on fire using mirrors. After all, those MIT folks claimed to have done it! So now, President Obama himself has set the MythBusters on a mission to investigate the myth one last time. Here's a sneak peak:

Obama's involvement is part of his administration's STEM (Science, Technology, Engineering, and Math) awareness initiative. The idea, in brief, is to get STEM careers noticed by students, so they'll consider them when choosing career paths. As someone who actually has a STEM career (when I'm not writing, I'm a software engineer), I think this is awesome. And who better to show off practical applications of science, technology, engineering, and math than Adam and Jamie?

The big question, though, is whether this myth is busted or not! I have seen the episode, but I am sworn to secrecy about it. I can tell you this, though: the MythBusters rallied a huge number of students in order to make the ultimate solar ray, vastly ramping up all previous efforts. Watching Jamie in his solar-proof suit on the trireme, being blasted by mirror reflections, is pretty intense. Watching all those kids directly engaged in a large-scale science experiment is also totally awesome.

After the jump, some more promo shots from the episode. Jamie plays the attacking General Marcellus and Adam plays the Syracusian general urging his defending army to keep the mirrors focused.

MythBusters with students
Part of the Syracusian defending army.

Adam and Jamie with the Trireme
Adam and Jamie with the trireme.

Mirrors aiming at the trireme
The army's assault begins....

Tune in tonight to learn how it all turns out.

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Live Smarter
Researchers Say You’re Exercising More Than You Think
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They say a journey of a thousand miles starts with a single step. If the thought of a thousand-mile journey makes you tired, we've got some great news for you: You've probably already completed one.* A new study published in the journal Health Psychology [PDF] finds that people underestimate the amount of exercise they're getting—and that this underestimation could be harmful.

Psychologists at Stanford University pulled data on 61,141 American adults from two huge studies conducted in the 1990s and the early 2000s: the National Health Interview Survey and the National Health and Nutrition Examination Survey. Participants answered questionnaires about their lifestyles, health, and exercise habits, and some wore accelerometers to track their movement. Everybody was asked one key question: "Would you say that you are physically more active, less active, or about as active as other persons your age?"

The researchers then tapped into the National Death Index through 2011 to find out which of the participants were still alive 10 to 20 years later.

Combining these three studies yielded two interesting facts. First, that many participants believed themselves to be less active than they actually were. Second, and more surprisingly, they found that people who rated themselves as "less active" were more likely to die—even when their actual activity rates told a different story. The reverse was also true: People who overestimated their exercise had lower mortality rates.

There are many reasons this could be the case. Depression and other mental illnesses can certainly influence both our self-perception and our overall health. The researchers attempted to control for this variable by checking participants' stress levels and asking if they'd seen a mental health professional in the last year. But not everybody who needs help can get it, and many people could have slipped through the cracks.

Paper authors Octavia Zahrt and Alia Crum have a different hypothesis. They say our beliefs about exercise could actually affect our risk of death. "Placebo effects are very robust in medicine," Crum said in a statement. "It is only logical to expect that they would play a role in shaping the benefits of behavioral health as well."

The data suggest that our ideas about exercise and exercise itself are two very different things. If all your friends are marathoners and mountain climbers, you might feel like a sloth—even if you regularly spend your lunch hour in yoga class.

Crum and Zahrt say we could all benefit from relaxing our definition of "exercise."

"Many people think that the only healthy physical activity is vigorous exercise in a gym or on a track," Zahrt told Mental Floss in an email. "They underestimate the importance of just walking to the store, taking the stairs, cleaning the house, or carrying the kids."
 
*The average American takes about 5000 steps per day, or roughly 2.5 miles. At that pace, it would take just a little over a year to walk 1000 miles.

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Medicine
Scientists Are Working on a Way to Treat Eye Floaters With Lasers
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Even people with 20/20 eyesight should be familiar with this scenario: You're enjoying a clear view when a faint doodle shape drifts into your peripheral vision like an organism under a microscope. Floaters affect almost everyone, but there's currently no medically accepted, non-invasive way to treat them. Two doctors with Ophthalmic Consultants of Boston are working to change that. As IFLScience reports, the team believes that lasers may be the solution to bothersome eye squiggles.

As Chirag Shah and Jeffrey Heier write in their study in the journal JAMA Ophthalmology, lasers can be used to safely combat the underlying causes of floaters. Also known as muscae volitantes, Latin for “hovering flies,” the condition comes from physical debris leaking into your eyeball. The front of your eyes is filled with a liquid called vitreous humor, and when drops of that gelatinous substance break off from the whole, the bits cast shadows on your retinas that look like gray blobs. Because floaters literally float inside your eyes, trying to focus on one is almost impossible.

These spots aren't typically a problem for young people, but as you get older your vitreous humor becomes more watery, which increases the chance of it slipping out and clouding your vision. Retinal detachment and retinal tears are also rare but serious causes of symptomatic floaters.

Shah and Heier tested a new method of pinpointing and eliminating floaters with a YAG laser (a type of laser often used in cataract surgery) on 36 patients. An additional 16 test subjects were treated with a sham laser as a placebo. They found that 54 percent of the treated participants saw their floaters decrease over six months, compared to just 9 percent of the control group. So far, the procedure appears be safe and free of side effects, but researchers noted that more follow-up time is needed to determine if those results are long-term.

At the moment, people with symptomatic floaters can choose between surgery or living with the ailment for the rest of their lives. YAG laser treatment may one day offer a safe and easy alternative, but the researchers say they will need to expand the size of future studies before the treatment is ready to go public.

[h/t IFLScience]

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