Supersonic Man

June 21, 2018

hydrogen economy? how about methane instead?

Filed under: Hobbyism and Nerdry,science!,the future! — Supersonic Man @ 4:52 pm

Ever since the seventies, there’s been an idea floating around that someday, in order to replace fossil fuels, we’d start using hydrogen as our main chemical fuel.  We’d have hydrogen tanks instead of gasoline tanks, and hydrogen pipelines instead of natural gas pipes.  The hydrogen would be produced from water with either renewable or nuclear energy sources, and then whenever we needed a chemical fuel, we’d use hydrogen.  And wherever we needed a portable source of electric power, we’d use hydrogen fuel cells.  Our cars might be fuel cell powered, for instance.

Since then, fuel cell cars have advanced pretty well, and building a fleet of electric cars which get their power from hydrogen fuel cells looks fairly doable.  There are even some demo filling stations which allow you to fill up a fuel cell car with hydrogen, if you have one of the test vehicles.

So that part is doable, though nobody’s sure if there’ll be any need for it.  Cars might do just as well by simply using batteries, and plugging in to charge, as many people do today.  Making a new network for delivering hydrogen to cars might be an unnecessary expense.

But what about all the other things we use fossil fuel for, besides transportation?  What about heating our houses, and fueling our stoves and ovens?  Could we, for instance, substitute hydrogen for natural gas?

I think the answer is that we could, but maybe we shouldn’t, because there’s a better idea.  An approach which lets us keep using the natural gas infrastructure that we already have.  Switching to hydrogen would entail replacing most of it, because a pipe or a valve that safely contains natural gas can easily fail at containing hydrogen.  Since it is the lightest of all gases, one of its properties is that it can find its way through leaks which, to any ordinary gas, aren’t leaks at all.  Every piece of every pipe, and every valve in every appliance, would have to be either carefully tested, or replaced.  Also, the pipes would either have to be expanded for a larger volume, or operated at higher pressure.

We can avoid all that with one simple step: taking the hydrogen we produce and converting it into methane.  Natural gas is 95% methane, and if we make it artificially, it could be used as a direct replacement for gas.  And the way we’d do that is with a process called the Sabatier reaction.  In this process, hydrogen is combined with carbon dioxide by means of a metallic catalyst.  The oxygen is stripped off of the carbon atoms and hydrogen takes its place.  The result is methane, plus leftover oxygen.

The best part is where we get the carbon dioxide: out of the atmosphere.  At first, we could take it directly from the smokestacks of industries which still burn fossil fuel.  (Steelmaking, for instance, might have a hard time using anything but coal.)  Later, as the scale increases, we could just separate it out of regular air.  This makes your home’s existing stove and furnace and water heater carbon neutral.  And even your car, because existing piston engines can be modified to run on methane, which might help ease the transition to the time when we all go electric.

With some further chemical processes we could probably convert the methane into longer chain hydrocarbons, producing oils and so on — substitutes for things like butane or kerosene or diesel or gear oil… or even gasoline for classic car enthusiasts.

Between battery cars and methane conversion, maybe there wouldn’t be all that big a market for straight pure hydrogen.  It would definitely have some uses, but I don’t think all that big a part of our energy supply would be used in hydrogen form.  We might, however, use hydrogen to store solar energy from midday for use at night.  Such hydrogen might be produced directly by vats of algae, then fed to stationary fuel cells as the sun sets.

If a big methane convertor works, we should of course encourage its use.  We’ll have tax credits for making carbon-neutral methane, and penalties for fossil fuels.  The rival approach of getting gas by fracking might even be banned outright, because of its harmful side effects.  This assumes, of course, that at some point we overcome the reactionary political forces who want to prop up the oil and coal industries, and would let all the profitable advances in renewables be done overseas.

One cool thing is that methane making machines are being developed right now, as part of the space program.  Not NASA’s space program, but SpaceX’s private program.  They’re building it for future Martian explorers and colonists, so they’ll be able to make their own rocket fuel for flights back to Earth.  Who knows, maybe at some point they’ll use the machine to fuel rockets here as well  so they can say they have carbon neutral satellite launchers.  Both of the major reusable rocket companies say methane is the fuel they want to use… and there’s no denying that a lot of older rockets are terrible polluters.

Of course, some other rockets will keep on using hydrogen, which when practical is still the cleanest option.

Advertisements

June 3, 2018

Trends in rocketry

Filed under: Hobbyism and Nerdry,science! — Supersonic Man @ 11:07 am

I’ve been taking an interest in the space industry and orbital rockets — a field which is evolving very rapidly nowadays.  So far this year we’ve seen the debut orbital flights of the Electron, the Falcon Heavy and Falcon 9 Block 5, and seen a new record set for the smallest rocket to put up a working satellite.  In the remaining months, we’re expecting the maiden flights of the LauncherOne, the Kuaizhou 11, the Vector R, and the Starliner and Dragon 2 crew capsules.  We just might see one of those capsules take live astronauts to the Space Station by the end of the year.  And the next couple of years will have plenty of action too, with several lunar landers being sent up by different countries, and more new vehicles making their debut: the SLS, the Vulcan, the New Glenn, the Dream Chaser, and more.

With so much short-term activity, it may be hard to spot the longer term trends, but I think I can lay out a few here: (more…)

May 10, 2018

if the solar system fit in a stadium…

Filed under: Hobbyism and Nerdry,science! — Supersonic Man @ 12:00 pm

(I wrote a post about this a few years ago somewhere else, but now I can’t find it, so I am redoing it here, and expanding it.)

How big is the Solar System?

Let’s start by assuming that we have some general idea of how big the Earth is.  If we fly from coast to coast in the United States, we’ve gone one eighth of the way around it.  A long day of driving in a car, say 500 miles, goes about one fiftieth of the way around.  So the Earth is very large compared to your local town or neighborhood, but it’s of a scale that can be grasped and managed with common means of travel, such as cars and planes.  Even preagricultural people sometimes traveled and traded over distances of a thousand miles or more, and that’s not tiny compared to the size of the Earth.

The Moon is a good deal smaller than the Earth, but quite far away from it.  It takes well over one second for a beam of light to travel from the Moon to the Earth.  The distance to the Moon is enough to wrap around the Earth nine or ten times (the Moon’s distance varies over that range during each month).  It’s the sort of distance that a junky old car might accumulate on its odometer after twenty or thirty years of driving — over a quarter million miles when the moon is furthest out.  People are capable of traveling such distances over many years, or in just a few days with our most powerful rockets.

To appreciate the scale of the rest of the solar system in comparison to this, let’s imagine a scale model, sized to fit into a big football stadium.  The scale of this model will be 1/100,000,000,000 of life size.

Let’s look at how each part of the solar system would appear at this scale.  The Sun, which hangs over the middle of the fifty yard line, is a bit over half an inch across — about 14 millimeters, to be more exact.  It’s the size of an olive.  Mercury, the innermost planet, has an eccentric elliptical orbit around it which is eighteen inches (46 cm) from the sun at its closest, and twenty-seven and a half inches (70 cm) at its furthest.  The planet itself is a practically invisible speck, only one five hundredth of an inch across, or a twentieth of a millimeter.  Venus, the second planet, circles our olive-sized sun at a distance of about three and a half feet (108 cm), so its orbit crosses the 49 yard line on each side. The size of the planet is about 1/200 inch, or an eighth of a millimeter, a speck which is probably big enough to see if you get close enough.

The Earth’s orbit is found at a distance of a bit under five feet (150 cm) from the sun.  And the orbit of the Moon makes a little circle around the Earth.  The distance from the Moon to the Earth, which in real life is up to a quarter million miles, and is the farthest distance that any human being has ever voyaged, is only about 5/32 of an inch, or 3.9 mm, in this scale model.  The entire circle traveled by the Moon around the Earth is barely half as big across as the Sun is.  It would fit inside a pea.  The distance to the Sun is almost four hundred times as large.  The diameter of the Earth itself in this model is about 1/200 of an inch, the same as Venus, and likewise would be a barely visible speck.  The Moon, being smaller than Mercury, would be very difficult to see.

Mars circles seven and a half feet out (2.3 meters), and is about 1/400 inch or 1/16 of a millimeter across — a dust speck.  The asteroid belt spreads in a hollow disk around the sun, with the bulk of it starting about ten feet out, and then it thins out at a distance of around eighteen feet (3 to 5.5 meters).  None of the individual asteroids are big enough to see.

Jupiter, the largest planet, sits a little over 25 feet (7.8 meters) out from the Sun.  Its orbit crosses past the 42 yard line on each side of midfield.  The planet itself is plenty big enough to be more than a speck: it’s 1.4 millimeters in diameter, or somewhat under one sixteenth of an inch — the diameter of the head of a pin.  If the Sun is an olive, Jupiter might be a large poppyseed, or a small millet grain.  It has a number of moons, the four large ones being Io, Europa, Ganymede, and Callisto.  The orbit of Io sits about 5/32 inch (4 mm) from Jupiter, and the orbit of Callisto is about 3/4 inch (18 mm) out.

Saturn is 46 feet (14 meters) from the sun.  Its orbit crosses the 35 yard line.  It’s smaller than Jupiter, but if you include its rings, it looks bigger.  You might model it with a small flat sesame seed.  Its major moon Titan sits half an inch (12 mm) out from the planet.  Uranus is much further out, 98 feet (30 meters) from the Sun, so it nearly reaches the 17 yard line, and on the sides it spills over the out-of-bounds line into the sidelines.  Its diameter is half a millimeter, so you might represent it with a grain of fine sand.

In this model, the orbit of Neptune, the most remote true planet, has a span that just about reaches the one yard line, but can’t quite reach the goal lines, orbiting 148 feet (45 meters) from the sun.  Its size is about the same as sand-grain Uranus.

From this you can see that the Solar System is very empty.  Besides the olive-sized sun, everything else on the field is just some specks which, all added together, wouldn’t amount to a grain of wheat.

Now the Sun and all the planets pretty much fit onto the playing field, but that’s not the whole Solar System.  Beyond all the planets are a number of icy bodies, large and small.  They constitute a sort of second asteroid belt.  It’s called the Kuyper belt.  Pluto is one of these icy bodies, and it isn’t even the biggest one.  As far as we presently know, it’s the second biggest.

In our scale model, the Kuyper belt fills the rest of the stadium, beyond the playing field.  Pluto is down in a good low seat right near the sidelines, and some of the others are way up in the cheap seats, hundreds of feet from the field.

The light of the Sun doesn’t reach up there very well.  It casts a good bright illumination in midfield, but the goalposts are pretty dim, and in the top row of the seats you can’t see much when you look away from the sun.  If I have this figured correctly, at this scale, it puts out about five thousand watts of light.  But don’t compare that to a 5000 watt lightbulb — your ordinary traditional bulb puts out mostly heat, so the 100 watt lamp in your living room is only emitting about ten watts of actual light, and if you use a modern bulb such as a compact fluorescent, it will say “100 watts” on the box while only actually using about 25 watts.  The Sun puts out at least three quarters of its energy as visible light.  Think of it more as a 5000 watt welder’s arc than a 5000 watt lamp.

One thing this idea of an arc lamp in a football stadium fails to convey is how slow the light is.  You have to remember that the light from our tiny Sun takes minutes to reach Earth just five feet away, hours to reach Neptune, and most of a day to reach the upper seats.  If there were a snail crawling around on the grass, it might well be moving at several times the speed of light.  And the fastest rockets never approach even a thousandth of that speed.  (The fastest moving objects we’ve ever launched into space, or will launch soon, are solar probes that drop inside the orbit of Mercury.  That inward fall can give them a speed dozens of times faster than, say, the Apollo moon rocket.)

There’s more stuff beyond the Kuyper belt, also consisting mainly of icy bodies.  But I don’t really count this as part of the solar system.  This is where long period comets come from (short comets, such as Halley’s, come from the Kuyper belt).  This zone is called the Oort Cloud.  It’s found out in the stadium’s parking lot, and some thin parts of it probably extend out into the surrounding city, perhaps miles from the stadium.  While the Kuyper belt is similar to the asteroid belt in that it mainly lies in the same plane as the orbits of the planets and rotates in the same direction that they do, the Oort cloud is spread in all directions, and appears to have no net orbital direction shared in common among the various objects.  For all we know this spread of icy bodies may extend throughout the space between the stars, and not constitute a part of our own solar system at all, except to the extent that the Sun’s gravity causes a thickening in nearby parts of it.

Speaking of other stars, how far away is the nearest other solar system?  It would be about 250 miles away at this scale… about the distance you might find between your hometown football stadium and that of a rival team in the next state.  For instance, the distance between Cleveland and Cincinnati, or Green Bay and Minneapolis, or Chicago and Detroit.

As an afterthought…  What if we changed scales in the opposite direction?  What if we magnified everything so that a football stadium engulfed the solar system?  How big would individual atoms be then?

As big as a house, it turns out — unbound hydrogen atoms would be around twelve meters across, carbon atoms about seventeen meters…  Counterintuitively, heavy metals aren’t much bigger than light elements: uranium is just a bit bigger than carbon, and gold is actually smaller.  The stronger the positive charge of the nucleus, the more densely the electrons pull in around it, so the overall size has remarkably little variation.

Green light would have a wavelength of fifty kilometers.  One of your intestinal bacteria would stretch from Columbus to Pittsburgh.  A red blood cell would sprawl over several midwestern states.  If you have a good thick head of hair, your individual hairs might be as big around as the Earth.  A flea would reach halfway to the Moon.  And if you stood on the Sun, your head might reach past the orbit of Earth.

August 25, 2017

ten percent of our brains

Filed under: Hobbyism and Nerdry,science!,thoughtful handwaving — Supersonic Man @ 9:40 am

If it were really true that we use only ten percent of our brains, then being granted the ability to use all one hundred percent wouldn’t really make a dramatic difference. It would be like comparing a desktop computer from 2017 with one from about 2005. Sure, the new one is better, but definitely not as much better as you’d hope it would be. They still both do basically the same things, and they’re both still probably hampered by running Windows.

I think there’s some metaphorical truth to the idea for a lot of people, though, because if they don’t get a good strong educational start, the majority of people don’t really have any chance of developing the intellectual side of their innate capabilities. I’m pretty convinced that most of the differences we see between people in “intelligence” have nothing to do with one person being born with a better brain than another. If you’re going to develop into a brainiac, you need to start very early and you need support for it, and most people around the world simply never get that opportunity. It’s only when drawing comparisons between people who have had those advantages, and are already part of a privileged minority, that you can even start looking at innate differences in talent.

August 17, 2016

will there ever be a material to replace steel?

Filed under: science!,the future!,thoughtful handwaving — Supersonic Man @ 12:14 pm

This post has been promoted to my website, here.

 

June 21, 2016

light

Filed under: science! — Supersonic Man @ 10:58 am

This post has been promoted to my website, here.

June 16, 2016

is there only spacetime? (part 1)

Filed under: science!,thoughtful handwaving — Supersonic Man @ 6:33 am

In a recent post, I mentioned in passing that “the close relationship between energy, gravity, and inertia is still a mystery, despite apparent confirmation of the Higgs boson.”  But wow, I may have just stumbled on an outsider theory that can resolve that whole mystery, and more.  It’s from a laser specialist and entrepreneur named John A. Macken, and his work can be found at onlyspacetime.com.

Where Macken begins is with the idea that “mass” is just energy confined to a particular frame of reference.  This sounds like it might be just an obvious truism based on special relativity, but once one looks at the details, it covers more ground than you might think.

His start on this came, naturally enough, when thinking about lasers.  The light inside a laser has energy, which means it has an equivalent mass, which means it has inertia.  Now inertia seems very mysterious as a property for particles, but for light, he realized, there’s nothing mysterious about it. (more…)

Create a free website or blog at WordPress.com.