Sketchy Fact #86: Space is hard to get to

90% of the mass of a typical rocket is fuel. Less than 1% is astronauts.

Dig a Little Deeper: A natural history of male nipples

You may recall that last October we took a tour around the human body to tally up the spare parts. During that discussion we broached the subject of male nipples, but perhaps we didn’t give them their full due. The truth is, when you dig a little deeper, these useless chest nubs are a good jumping off point to learn about everything from embryology to hormones to evolution. With that in mind let’s take a clothing optional journey into the natural history of these intriguing appendages.

  

  
As the Bloodhound Gang taught us all so many moons ago “You and me baby ain’t nothing but mammals…” and that is the short answer for why we all still have nipples. Part of what has made our order of the animal kingdom so successful is the fact that all of our mothers for millions of years have been able to produce milk for us. Without going into too much detail – because what milk is made of could be an article onto itself – milk is a mixture of water, fat and other chemicals found in a woman’s body. It provides a readily available food source for babies and gives their immune systems a boost as antibodies are passed down through a substance called colostrum.

When a human embryo begins to form there is a specific order in which different processes take place. Around week 4 the development of sexual systems begins, but curiously the system that takes shape is not gender differentiated. It is not until week 8 that the male Y chromosome kicks into gear and starts producing testosterone, which initiates the development of male parts and blocks the development of female ones.

The thing about nipples is that the basic structures are past the point of no return at that point. In the end, the milk-producing systems of the body fully form in both men and women, but men usually lack the hormonal trigger to lactate. Milk is produced in cavities in breast tissue called alveoli which are lined with milk producing cells, men’s alveoli are just ridiculously under-worked.

Interestingly, there are certain circumstances under which some men can produce milk. That isn’t really news to male dayak fruit bats, who routinely do so, but it is pretty uncommon in the human world. Milk production is triggered by a hormone called prolactin, which is usually lacking in men’s bodies. However, when something happens to throw off hormone production like starvation followed by access to food (as has been seen in POWs), or liver cirrhosis the pituitary gland can go haywire and flood the body with prolactin.

A not-so-fun fact that derives from the fact that both men and women have the necessary hardware to produce milk is that both men and women can get breast cancer. Cases of male breast cancer are rare, accounting for less than 1% of all cases, but they do happen. Risk factors for male breast cancer are age (older is worse), alcohol abuse, radiation exposure, family history and an inherited genetic condition called Klinefelter Syndrome where lower levels of androgens (male hormones) and higher levels of estrogen are produced in the body.

Not all male mammals are burdened as humans are with nipples. Male mice, horses and platypuses are born with the creepily smooth chests all men who have been purple-nurpled dream of. The problem with our nipples though, is that they aren’t that costly to produce in terms of the raw materials your body needs. That is why millions of years of evolution have failed to select against male nipples. We would need to produce a whole new protein during embryonic development (PTHrP in mice) to stop the process. The upshot is that men are stuck with nipples for at least another few million generations.

Sketchy Fact #85: Figure Apes

Chimps are more than twice as strong as humans despite being about the same size because their brains have less precise control over their muscles. Their brains are designed to use all their muscles at once whereas humans are built to be precise.

Ice Fishing in Space: Two new oceans discovered in our solar system

During the last week of August in 1835 readers of the New York Sun were treated to one of the great scientific discoveries of all time. A series of articles reported that British astronomer Sir John Herschel had developed a ridiculous new telescope that had given him glimpses of planets in other solar systems, close views of comets and – just to put a nice bow on things – he had discovered life on the moon. Of course, this all turned out to be a hoax (John Herschel had no part in it), but it got people thinking about life on the worlds that orbit other worlds and we call moons. Now, in the second week of March 2015, a couple major discoveries could reignite that curiosity.

On March 11th and 12th two teams of scientists reported in the journal Nature and in a NASA teleconference respectively that they had serious reason to believe that they had discovered two brand new oceans right here in our own solar system. The first on Enceladus, an icy moon orbiting Saturn, and the second on Ganymede, the largest moon in our solar system (it’s almost the size of Mars) which orbits Jupiter. Along with Europa, another Jovian (Jupiter-orbiting) satellite, these icy encrusted water worlds are the best candidates we’ve so far discovered for alien life.

Europa has long been a hot topic at astronomical dinner parties. Back in the 70’s when Pioneer spacecraft 11 and 12 flew by Jupiter they took the first pictures Europa’s surface and shocked the world when they revealed long dark channels on an otherwise smooth icy surface along with a stunning lack of craters. A lack of craters is interesting because it suggests that some force exists on the moon that can erase surface features. The Earth doesn’t have many craters because they erode. Our moon has lots, because not a lot happens up there.

When the Galileo mission returned to Jupiter in the 90’s, photos revealed that Europa’s surface channels appeared to be the result of the cracking that was later filled in by some flowing material (warmer ice or liquid water). Analysis of Jupiter’s magnetic field around Europa also provided evidence that some conductive material (probably salt water) exists beneath the ice.

If you’re wondering how moons so far out in the solar system could have liquid water beneath thick, sun-blocking ice, the answer is a process called tidal heating. See, as moons orbit planets the gravity of their hosts stretches them every which way, producing heat. If you’ve ever played squash or messed around with modeling clay you’ve seen similar forced at work. As a material gets stretched (be it clay, rubber or moon) it generates heat and becomes more elastic. On the scale of moons the heating can be kind of nuts. The ocean on Saturn’s moon Enceladus is thought to be as hot as 90 degrees Celsius (200 F)!

That heat is actually what led to its discovery. Back in 2005 the spacecraft Cassini saw massive plumes of water vapor shooting out of the moon’s south pole. Analysis of particles found in the vapor revealed silicon, which on Earth is generally created around hot ocean vents. That means that Enceladus is geologically active, and that is thought to be a prerequisite for life.

The ocean on Ganymede (back in the Jupiter system) is equally interesting but less likely to be home to any freaky fish-type things. That is because the liquid water probably doesn’t touch a rocky surface like on Enceladus. If you were to start digging on Ganymede you would burrow through 100 miles of ice before hitting water. When you sunk to the bottom of the ocean you would find yourself on more ice beneath which lies the rocky mantle and finally the moon’s iron core. The only reason we know there is water down there is because the auroras around the moon’s magnetic poles (caused by its iron core, just like Earth) are more stable than they would be if there was no water.

To sum things up, it has been a pretty crazy week in space exploration. It seems that will our focus on all the planets outside the solar system that may harbour life, we might have missed some supremely weird ice-fishing opportunities closer to home.

Sketchy Fact #84: Humming Along

Edit: Even the best of us miss obvious math errors occasionally...

80 wing flaps per second x 60 seconds in a minute = 4,800 flaps per minute

The wings are faster by a mile, but we stand by the original implication that hummingbird biology is cool.

... Our bad.

Please note that Geoff is an engineer. This fact explains why spaceships explode.

Hummingbirds can flap their wings up to 80 times per second, but that's nothing compared to their hearts which can beat at up to 1260 beats per minute!

Feel the Burn: What does exercise actually do to your body?

Ask any doctor what the top five things are that you can do to protect your health and they are likely to rhyme off a bunch of stuff you already knew. Eat healthy, unprocessed foods. Sleep at least 7 hours a night. Avoid stress. But few things are as likely to appear on virtually every list as exercise. From the time we are in grade school right up until our teachers give us the boot at prom we are encouraged to participate in physical education and exercise. But why? What does exercise actually do to your body that is so great anyway?

Everyone hates their first day of exercise, and for good reason. Day one is really hard. That is because our bodies have a tendency to do the bare minimum in terms of upkeep. If the hardest thing you do all day is climb 5 steps in front of the building you work at before hopping in the elevator, that is what your body will prepare you for. When you take a body that is used to a sedentary lifestyle and force it to exercise, you shock the system. That is why it is so important to do your research before taking on anything too strenuous. If you think you might have a heart condition or some other underlying problem, you might even want to talk to a doctor.

The great thing about exercise, however, is that it begins to change your body very quickly. Within the first few weeks (if you stick with it) your body will begin to adapt at the cellular level. Each of your body’s cells contains mitochondria which break down carbohydrates and fats and turn them into energy. Regular exercise spurs your body on to pack as many mitochondria into cells as it can. That means the food you eat is more likely to turn into energy than to be stored as fat.

In addition to a mitochondrial population boost, your entire circulatory system becomes more beefy. When you exercise, and especially when you’re starting out, your muscles are basically screaming for oxygen and your body is doing whatever it can to get it there. Oxygen travels in our blood, so one way to carry more oxygen to the muscles that need it is to make more blood. According to BodyBuilding.com, exercise can add an extra half litre of blood to your body. The heart itself also gets stronger as it is called on to pump more blood quicker. Over time the heart will even increase in size to allow each pump to carry the maximum amount of blood.

Finally, in terms of blood, your body adapts to exercise by improving the highway along which it is carried. As you exercise regularly your blood vessels become better at constricting and relaxing. They become more elastic and let blood flow through them more smoothly. Over time your body even builds more of the tiny vessels called capillaries that supply muscles directly. This, along with a stronger heart, is one of the main ways exercise adds years to your life. The idea is that by forcing your heart to work hard in short bursts, it won’t have to work as hard on average over your whole life. Trained people generally have slower resting heart rates and don’t develop heart disease as often as untrained people.

Exercise also damages your body in a way that ends up working to your benefit. Each hard workout produces small tears in your muscles. As your body works to rebuild the gaps between the tears your muscles get bigger. The result is that there are more fibers that are better able to contract and relax, meaning they can produce more force, making you stronger.

Finally, one of the biggest benefits of exercise is also one of the least expected: it makes your brain work gooder! Believe it or not, studies have shown that exercise encourages your brain to build connections between neurons and can even stimulate the growth of new brain cells, something that was long thought to be impossible in adults. Regular aerobic exercise has been linked to increased brain volume in areas like the hippocampus, which is responsible for memory. The upshot is that if you go for a run today, you’re more likely to remember where your keys are on your 90^th birthday.

Ultimately exercise does a lot beyond what we’ve had time to cover here. If there is a miracle method to achieve better health, feel better, look better, and live longer it is working up a sweat. As much as we all want to believe we can get ripped and live forever by taking a pill or buying one of those belt things that electrocutes your abs, the only way to get there is by putting in the work.

Skecthy Fact #83: Computing the Universe

The world's fastest supercomputer, China's Tianhe-2 can run 100,000 times more calculations each second than there are stars in our Milky Way galaxy. That works out to 300 trillion calculations in less time than it took you to read this sentence.

Colour Confusion: What’s the deal with that damn dress?

Welcome to another week of Sketchy Science. We should all be thankful that we can still take these few minutes out of our day to enjoy a slice of knowledge, because there were moments last week when the future of our civilization was in serious doubt. In addition to losing our interstellar voice of reason and logic through the passing of Leonard Nimoy, our society was on the verge of collapse as millions of people argued over the colour of a

dress. Thankfully, science prevailed as we learned once and for all that the dubious garment was in fact blue and black. But how could so many people see the same image so differently? The answer lies in the way our brain interpret colour.

Wired offered a great and much more timely explanation of the mechanism at work than this one, but they don’t have our flare for comics, so what follows is largely based on their explanation with a Sketchy Science twist. The heart of the problem lies in the fact that what we all take as reality is just an interpretation based on our five senses. The three dimensional wonderland we all navigate through in our waking lives is the result of electrical impulses zipping through our brains that make a picture we can use. Some philosophers have even suggested that it is possible that each of us is nothing more than a brain in a vat in the lab of a mad scientists who has us hooked up to strategically placed wires. The really interesting part about that Matrix-eqsue theory is that there is literally nothing anyone can do to prove it wrong.

But back to the dress. Assuming for a minute that we are in fact living breathing, non-wired-up beings and that the image we all saw this week was in fact real, there is a simple (albeit super interesting) explanation for the confusion. The truth is, that what we think of as colour is just our brains’ interpretation of light reflecting off different objects. A universe without light, as anyone who has ever gone spelunking can tell you, is a universe without colour. When you see an object as, for example, red, that object is just absorbing all the wavelengths of light except for red which it reflects back into your eyes. As we all know from elementary school science, normal white light is actually made up of different wavelengths that our brains see as red, orange, yellow, green, blue, indigo and violet. Interestingly, some people debate whether indigo is actually a colour of the rainbow, but that is another article.

The thing about our brains is that they aren’t always operating in a world of perfect lighting conditions. At twilight, for example there is less light for objects to reflect but our brains still have to see our car is red, lest we commit an accidental felony at the supermarket. To do this, the area of your brain that interprets colour factors in the context in which it is seeing an object. Though this works in most situations, it is possible for mistakes to occur. The internet is loaded with examples of optical illusions where two identically coloured shapes are presented against different coloured backgrounds and the effect is that they look like two totally different shades.

That is basically what is happening with this dress. You look at the image and your brain has to decide whether to discount the blue end or the gold end of what is called the “chromatic bias of the daylight axis.” Basically, it needs to decide whether it is seeing a blue dress in good lighting conditions or a white dress in poor lighting. If you see the dress as white and gold, your brain is discounting the blue end of the light spectrum. If you see the dress as blue and black, your brain is (correctly) discounting the gold in the visible light. To make things even more confusing, your brain can change its mind as so many people (myself included) found out when they loaded an image of a white and gold dress that gradually turned blue and black.

So as it turns out if you suspected the work of a crafty troll when you first saw the dress, you were spot on. However, rather than sitting in a dark basement in the anywhereville, USA the trickster was inside your own head. Yet another reason to question everything.