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Hank talks about space shuttle Discovery's retirement, a private space "taxi cab" service, a breakthrough with man-made DNA, and the similarities between religion and pornography in your brain.

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SEGMENT 1 IMAGES: (credit SpaceX/Roger Gilbertson) [public domain]




god spot:


Hello.  This week we've got a lot to cover including an historic space launch, a breakthrough in man-made DNA, and what religion and pornography have in common.  So let's get to it.

[SciShow intro]



It's the end of an era at NASA but also the start of a new one.  Last week, NASA sent Discovery, the first of its three retired space shuttles, to its final destination at the National Air and Space Museum.  And in the next week or two a huge step will be taken in the replacement of the space shuttle program.

Early in May the private space flight company SpaceX is expected to launch its new cargo vehicle, The Dragon, from Cape Canaveral to rendezvous with the International Space Station.  If successful, The Dragon will be the first private space craft to berth with the ISS and offload cargo.

Launch was originally scheduled for this coming Monday but earlier this week SpaceX founder Elon Musk tweeted that he wanted to spend more time testing the code that The Dragon will use to dock with the ISS.  This is how we disseminate information now, apparently.  Lift off is now tentatively scheduled for May 7th.

And it's smart to be conscious, SpaceX already has a $1.6 billion contract with NASA to fly 12 missions to the ISS, but a lot is riding on how this first one goes.  In addition to this launching and getting into orbit successfully, SpaceX will also have to prove that its unmanned space craft can perform some tricky maneuvers before actually docking, essentially taking one long lap around the ISS at about 27,000 km/hr.  If all goes well Dragon will dock on day four of the mission, unloading 500 kg of equipment and some nonessential supplies.  So don't worry, it's not like the six astronauts aboard the ISS are in danger of running out of water or oxygen or anything if the the test fails.

The plan is for The Dragon to stay docked for 18 days in which point it will return to Earth with 660 kg of cargo which is notable, because that's more weight than the Russian Soyuz Soviet's capsules can carry.

SpaceX isn't the only company that's developing a taxi cargo service for NASA, but it's the first to demonstrate that it can launch a vehicle into space and return it safely to Earth which it did in December of 2010.  The company is also working on a prototype 7-person crew cabin for The Dragon that could be ready for testing within a year or two.

I'd totally volunteer to be one of Dragon's first passengers but, you know, the airsickness.



Next, big news in the field of synthetic biology, a field that we talked about a few weeks ago.  This week, SynBio saw its biggest advance yet with news that synthetic alternatives to DNA and RNA can not only replicate but also adapt over time.

These man-made alternatives, called xenonucleic acids or XNAs, have been around for a few years.  The ones that we're talking about have the same genetic code as DNA with the bases A, G, T, and C but the sugars that make up the backbones are different and they actually make XNAs structurally stronger than DNA.

The first breakthrough came last week when an international team of chemists said that they created enzymes that replicate XNA molecules just like the enzymes that replicate DNA.  The team put these polymerase enzymes to work, copying DNA into XNA and then used them to copy the XNAs back over and over.

This kind of replication is exactly with DNA in your cells right now, but it's never been with anything other than DNA or RNA in, like, the history of the world.

In another possibly even cooler experiment, the scientists tested whether XNAs could adapt under pressure.  In this case they wanted to see if random sequences of an XNA molecule could evolve to bond to two specific target proteins.  They used their new enzymes to produce batches of XNA segments and then selected the one that found their targets successfully.  Those segments were then replicated by the new enzymes and the new copies were put to the same task.  After eight generations, the resulting XNA sequences had essentially been bred to bind perfectly with the proteins, much like we breed animals and plants.

This research means that life doesn't necessarily depend on two molecules, DNA and RNA.  There could be all kinds of other, maybe simpler, maybe better ways of storing and sharing genetic information in the universe.  So when we find extra-terrestrial life, and we will, the code it'll carry in its alien blood could look a lot like XNA.



Finally, new discoveries about two things that make your brain turn off, religion and porn.

Let's start out with the porn, 'cause that's the kind of day I'm having.  The Journal of Sexual Medicine reports this week that when women watch porn they stop using their visual cortex, the part of the brain that's responsible not just for observing but also processing what's observed.

Now I don't know if you've seen porn, but there's not a whole lot there to process.  Anyway, 12 women were given PET scans of their brains while they watched three videos.  The first was a totally unsexy nature documentary, the second showed some kind of R-rated action and the third was what some team of Dutch physicians called "high intensity erotic film."

Only when the women watched the porn did the blood flow to their visual cortex drop dramatically.  The research is believed that this is because the blood is redirected to regions in the brain involved in sexual arousal, and also because porn, and I quote, "does not require precise scanning."  Like I said, not a lot to actually process there.

The researchers noted though that the visual cortex is also the region of the brain associated with anxiety, which might suggest that sexual arousal can quiet anxious behavior.  Sex, good.  Anxiety, bad.

As for religion, let me be the one to tell you, you don't have a God spot.  That's the term some researchers have been using to describe a hypothetical region supposedly associated with spirituality.  But research at the University of Missouri has confirmed earlier studies that say that no such spot exists.  Instead, spirituality is just something that your whole brain does together.

Still, some regions of the brain contribute to this more than others.  Lead scientist Brick Johnstone (what an amazing name!).  Anyway, he studied 20 people with severe injuries to the right parietal lobe, that's the area just above your right ear that's responsible for things like spatial relationships and self awareness.  He found that subjects with the most severe injuries there felt the most associated with and closest to a higher power.

This kind of makes sense because the whole right side of your brain tends to be dedicated to you when for looking out for yourself.  And a lot of research has found that monks and nuns and the like, tend to use that self-centered part of their brains a lot less.  Main thing is, there's no structural part of your brain that's responsible for religion and spirituality.

Thanks for watching this episode of SciShow News.  If you want more news and other science stuff and to be a smarter person, you can go to and subscribe.  If you have questions for suggestions for us, you can reach us on Facebook or Twitter or of course the comments below.  See you next time.