Could the Death Star Destroy a Planet?

In the movie Star Wars, the Darth Vader’s Death Star destroyed a planet. Could this really happen?

You’ve watched Star Wars right? Is that still a thing? With the Starring and the Warring? Anyway, there’s this classic scene where the “Death Star” sidles up to Alderaan, and it is all like “Hey Planetoid, you lookin’ fine tonight” and then it fires up the superlaser and destroys the entire orb in a single blast. “BOOM”. Shortly followed by some collective group screaming on the interstellar forceway radio.

This is generally described as “science fiction”. And when you’re making up stories, anything you like can happen in them. George Lucas’ hunger for your childhood toy money wasn’t hampered by the pesky constraints of physics in any meaningful way.

Here at the Guide to Space, we get to take our own flights of fancy and pointlessly speculate for your amusement. That’s our job. Well, that and snark. Let’s consider what it would actually take to destroy a planet with a ‘pew pew’ style laser beam, and what kinds of energy would need to be harnessed in a fully armed and operational battle station.

Let’s go back and carefully review our “evidence”. The Death Star drifts in, charges up all its lasers into a superlaser blast focused on Alderaan. The planet then detonates and chunks fly off in every direction just like the pie eating contest in “Stand By Me”.

What we saw was every part of Alderaan given enough of a kick so that it was traveling at escape velocity from every other part of the planet. If the Death Star hadn’t delivered enough explosive energy, the planet might have fluffed up for a moment, but then the collective gravity would suck it all back in together, and then the slightly re-arranged, and likely now uninhabited planet would continue orbiting its star.

You can imagine doing this the slow way. Take each continent on Alderaan, load it up into a rocket and blast that rocket off into space as though it was on escape trajectory from the planet. Sure, you’d would need an incomprehensible number of rocket launches to get that material off the planet. But hey, midichlorians, blue finger lightning and ESP.

Fortunately, as you carted away more and more of the busted up rock, it would have less mutual gravity, and so the rocket launches would require less and less energy to get the job done. Eventually, you’d just be left with one last chunk of rock that you could just force ninja kick into the neighboring star.

Death Star beam. Credit: Lucasfilm
Death Star beam. Credit: Lucasfilm

So how much energy is that going to take? Well, there’s an “easy” calculation you can make. The energy you’d need is equal to 3 times the gravitational constant (6.673 x 10^-11) times the mass of the planet squared divided by 5 times the planet’s radius. Do this math for an Earth-sized/mass world, and let’s see that’s, two and one, carry the 5… and you get 2 x 10^36 joules. That’s a two followed by 36 zeros in joules. Is that a lot? That sounds like a lot.

Well, our own Sun puts out 3 x 10^26 joules per second. So, if you poured all the energy from the Sun into the task of tearing apart the Earth, it wouldn’t have enough energy to do it. In fact, you’d need to focus the light of the Sun for a full week to get that level of planet destruction done.

According to ancient Star Warsian dork scholars, the Death Star (SOLUS MORTIS) is powered by a hyperreactor with the output of multiple main sequence stars. So there you go, problem solved. It’s the size of a small moon, but it’s more powerful than many stars. Of course it can destroy a planet.

Exploding planet. Credit: ESO
Exploding planet. Credit: ESO

The Death Star clearly destroyed Alderaan. We watched it explode. I saw it, you saw it. We heard the screams of millions of souls cry out. It happened. But what if it wasn’t a beam thingy?

Our math is good, but clearly we’re not enlightened enough to comprehend the true wisdom hidden within the Lucasian scriptures. Perhaps the Death Star’s superlaser was just a targeting laser. Directing the placement of gigantic antimatter bomb. According to Ethan Siegel, from “Starts With a Bang,” you’d only need 1.24 trillion tonnes of antimatter.

Imagine you made a bomb out of that much antimatter iron – if that’s even a thing – you’d only need a sphere about 3 km across. If the Death Star is 150 km across or so, they could carry a bunch of these. Very carefully. Like super carefully. Okay, maybe it’d be a good idea if everyone took off their boots, and make sure they only talked with their inside voices.

Obviously, Star Wars is a story, so anything, ANYTHING can happen. The future is unknown, and we might discover all kinds of weirdo physics and harness them into all kinds of powerful weapons. I’m only suggesting, that a space station capable of deploying a week’s worth of solar energy in a single second might be a stretch. And maybe, George, if you just done a little back of the napkin math, we wouldn’t be talking about this right now. Also, maybe no Ewoks. I’m just saying.

Where do you stand on the feasibility of imaginary space station weaponry? How big a planet can your imagination destroy?

How Do We Know Dark Energy Exists?

We have no idea what it dark energy is, so how are we pretty sure it exists?

I’ve talked about how astronomers know that dark matter exists. Even though they can’t see it, they detect it through the effect its gravity has on light. Dark matter accounts for 27% of the Universe, dark energy accounts for 68% of the Universe. And again, astronomers really have no idea what what it is, only that they’re pretty sure it does exist. 95% of the nature of the Universe is a complete and total mystery. We just have no idea what this stuff is.

So this time around, lets focus on dark energy. Back in the late 90s, astronomers wanted to calculate once and for all if the Universe was open or closed. In other words, they wanted to calculate the rate of expansion of the Universe now and then compare this rate to its expansion in the past. In order to answer this question, they searched the skies for a special type of supernova known as a Type 1a.

While most supernovae are just massive stars, Type 1a are white dwarf stars that exist in a binary system. The white dwarf siphons material off of its binary partner, and when it reaches 1.6 times the mass of the Sun, it explodes. The trick is that these always explode with roughly the same amount of energy. So if you measure the brightness of a Type 1a supernova, you know roughly how far away it is.

Astronomers assumed the expansion was slowing down. But the question was, how fast was it slowing down? Would it slow to a halt and maybe even reverse direction? So, what did they discover?

In the immortal words of Isaac Asimov, “the most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka’, but ‘That’s Funny’” Instead of finding that the expansion of the Universe was slowing down, they discovered that it’s speeding up. That’s like trying to calculate how quickly apples fall from trees and finding that they actually fly off into the sky, faster and faster.

Since this amazing, Nobel prize winning discovery, astronomers have used several other methods to verify this mind-bending reality of the Universe. NASA’s Wilkinson Microwave Anisotropy Probe studied the Cosmic Microwave Background Radiation of the Universe for 7 years, and put the amount of dark energy at 72.8% of the Universe. ESA’s Planck spacecraft performed an even more careful analysis and pegged that number at 68.3% of the Universe.

Einstein Lecturing
Einstein Lecturing. (Ferdinand Schmutzer, Public Domain)

Astronomers know that dark energy exists. There are multiple lines of evidence. But as with dark matter, they have absolutely no clue what it is. Einstein described an idea he called the cosmological constant. It was a way to explain a static Universe that really should be expanding or contracting. Once astronomers figured out the Universe was actually expanding, he threw the idea out.

Hey, not so fast there “Einstein”. Maybe just one of the features of space itself is that it pushes stuff away. And the more space there is, the more outward pressure you get. Perhaps from virtual particles popping in and out of existence in the vacuum of space.

Another possibility is a phenomenon called Quintessence, a negative energy field that pervades the entire Universe. Yes, that sounds totally woo-woo, thanks Universe, Deepak Chopra crazy talk, but it might explain the repulsive force that makes up most of the Universe. And there are other theories, which are even more exotic. But mostly likely it’s something that physicists haven’t even thought of yet.

So, how do we know dark energy exists? Distant supernovae are a lot further away from each other than they should be if the expansion of the Universe was slowing down. Nobody has any idea what it is, it’s a mystery, and there’s nothing wrong with a mystery. In fact, for me, it’s one of the most exciting ideas in space and astronomy.

What do you think dark energy is?

How are Energy and Matter the Same?

As Einstein showed us, light and matter and just aspects of the same thing. Matter is just frozen light. And light is matter on the move. How does one become the other?

Albert Einstein’s most famous equation says that energy and matter are two sides of the same coin.
But what does that really mean? And how are equations famous? I like to believe equations can be famous in the way a work of art, or a philosophy can be famous. People can have awareness of the thing, and yet never have interacted with it. They can understand that it is important, and yet not understand why it’s so significant. Which is a little too bad, as this is really a lovely mind bending idea.

The origin of E=mc2 lies in special relativity. Light has the same speed no matter what frame of reference you are in. No matter where you are, or how fast you’re going. If you were standing still at the side of the road, and observed a car traveling at ¾ light speed, you would see the light from their headlights traveling away from them at ¼ the speed of light.

But the driver of the car would still see that the light moving ahead of them at the speed of light. This is only possible if their time appears to slow down relative to you, and you and the people in the car can no longer agree on how long a second would take to pass.

Einstein's famous equation. Image via Pixabay.
Einstein’s famous equation. Image via Pixabay.

So the light appears to be moving away from them more slowly, but as they experience things more slowly it all evens out. This also affects their apparent mass. If they step on the gas, they will speed up more slowly than you would expect. It’s as if the car has more mass than you expect. So relativity requires that the faster an object moves, the more mass it appears to have. This means that somehow part of the energy of the car’s motion appears to transform into mass. Hence the origin of Einstein’s equation. How does that happen? We don’t really know. We only know that it does.

The same effect occurs with quantum particles, and not just with light. A neutron, for example, can decay into a proton, electron and anti-neutrino. The mass of these three particles is less than the mass of a neutron, so they each get some energy as well. So energy and matter are really the same thing. Completely interchangeable. And finally, Although energy and mass are related through special relativity, mass and space are related through general relativity. You can define any mass by a distance known as its Schwarzschild radius, which is the radius of a black hole of that mass. So in a way, energy, matter, space and time are all aspects of the same thing.

What do you think? Like E=mc2, what’s the most famous idea you can think of in physics?

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Mr. Fusion? Compact Fusion Reactor Will be Available in 5 Years Says Lockheed-Martin

The Farnsworth Fusor; Pons and Fleishmann. It seems the trail to fusion energy has long gone cold — stone cold, that is, and not cold as in cold fusion. Despite the promise of fusion providing a sustainable and safe energy source, fusion reactors are not a dime a dozen and they won’t be replacing coal fired power plants any time soon. Or will they? Lockheed-Martin Skunk Works announced a prototype compact fusion reactor that could be ready within five years. This revelation has raised eyebrows and sparked moments of enthusiasm.

But, let’s considers this story and where it all fits in both the history and future.

For every Skunk Works project that has made the runway such as the Stealth Fighter or SR-71 Blackbird, there are untold others that never see the light of day. This adds to the surprise and mystery of Lockheed-Martin’s willingness to release images and a detailed narrative describing a compact fusion reactor project. The impact that such a device would have on humanity can be imagined … and at the same time one imagines how much is unimaginable.

Lockheed-Martin engineers in the Skunkworks prepare a vessel, one component of an apparatus that they announced will lead to nuclear fusion in a truck-sized reactor within 5 years. An international effort is underway in Europe to create the worlds first practical tokamak fusion reactor, a much larger and costlier design that has never achieved the long sought "breakeven" point. (Photo Credit: Lockheed-Martin)
Lockheed-Martin engineers in the Skunkworks prepare a vessel, one component of an apparatus that they announced will lead to nuclear fusion in a truck-sized reactor within 5 years. An international effort is underway in Europe to create the world’s first practical tokamak fusion reactor, a much larger and costlier design that has never achieved the long sought “breakeven” point. (Photo Credit: Lockheed-Martin)

The program manager of the Skunk Works’ compact fusion reactor experiment is Tom Maguire. Maguire and his team places emphasis on the turn-around time for modifying and testing the compact fusion device. With the confidence they are expressing in their design and the ability to quickly build, test and modify, they are claiming only five years will be needed to reach a prototype.

What exactly the prototype represents was left unexplained, however. Maguire continues by saying that in 10 years, the device will be seen in military applications and in 20 years it will be delivered to the world as a replacement for the dirty energy sources that are in use today. Military apps at 10 years means that the device will be too expensive initially for civilian operations but such military use would improve performance and lower costs which could lead to the 20 year milestone moment if all goes as planned.

Their system uses magnetic confinement, the same basic principle behind the tokamak toroidal plasma confinement system that has received the greatest attention and government funding for over 50 years.

The ITER Tokamak Fusion Reactor is expected to begin operational testing in 2020 and begin producing deuterium-tritium fusion reactions in 2027. (Credits: ITER, Illus. T.Reyes)
The ITER Tokamak Fusion Reactor is expected to begin operational testing in 2020 and begin producing deuterium-tritium fusion reactions in 2027. (Credits: ITER, Illus. T.Reyes)

The International Thermonuclear Experimental Reactor (ITER) is currently under construction in Europe under the assumption that it will be the first net energy producing fusion generator ever. It is funded by the European Union, India, Japan, People’s Republic of China, Russia, South Korea and the United States. But there are cost over-runs and its price has gone from $5 billion to $50 billion.

ITER is scheduled to begin initial testing in 2019 about the time Lockheed-Martin’s compact fusion reactor prototype is expected. If Lockheed-Martin succeeds in their quest, they will effectively have skunked ITER and laid to waste a $50 billion international effort at likely 1/1000th the cost.

There are a few reasons Lockheed-Martin has gone out on a limb. Consider the potential. One ton of Uranium used in Fission reactors has as much energy as 1,500 tons of coal. But fission reactors produce radioactive waste and are a finite resource without breeder reactors, themselves a nuclear proliferation risk. Fusion produces 3 to 4 times more energy per reaction than fission. Additionally, the fuel — isotopes of hydrogen — is available from sea water — which is nearly limitless — and the byproducts are far less radioactive than with fission. Fusion generators once developed could provide our energy needs for millions of years.

More pragmatically, corporations promote their R&D. They are in a constant state of competition. They present a profile that ranges from the practical to the cutting edge to instill confidence in their Washington coffers. Furthermore, their competitors have high profile individuals and projects. A fusion project demonstrates that Lockheed-Martin is doing more than creating better mouse-traps.

To date, no nuclear fusion reactor has achieved breakeven. This is when the fusion device outputs as much energy as is input to operate it. Magnetic confinement such as the various tokamak designs, Lawrence Livermore’s laser-based inertial confinement method, and even the simple Philo Farnsworth Fusor can all claim to be generating energy from fusion reactions. They are just all spending more energy than their devices output.

An example of a homemade Fusor. Originally invented in the 1960s by the inventor of the television, Philo Farnsworth. (Credit: Wikipedia, W.Jack)
An example of a homemade Fusor. Originally invented in the 1960s by the inventor of the television, Philo Farnsworth. (Credit: Wikipedia, W.Jack)

The fusor, invented in the 1960s by Farnsworth and Hirsh, is a electrostatic plasma confinement system. It uses electric fields to confine and accelerate ions through a central point at which some ions will collide with sufficient energy to fuse. Although the voltage needed is readily achieved by amateurs – about 4000 volts – not uncommon in household devices, no fusor has reached breakeven and theoretically never will. The challenge to reaching breakeven involves not just energy/temperature but also plasma densities. Replicating conditions that exist in the core of stars in a controllable way is not easy. Nevertheless, there is a robust community of “fusioneers” around the world and linked by the internet.

Mr Fusion, the compact fusion reactor that drove the 21st Century version of the DeLorian in Back to the Future. The movie trilogy grossed $1 billion at the box office. Mr Fusion could apparently function off of any water bearing material. (Credit: Universal Pictures)
Mr Fusion, the compact fusion reactor that drove the 21st Century version of the DeLorean in Back to the Future. The movie trilogy grossed $1 billion at the box office. Mr Fusion could apparently function off of any water bearing material. (Credit: Universal Pictures)

It remains to be seen who, what and when a viable fusion reactor will be demonstrated. With Lockheed-Martin’s latest announcement, once again, fusion energy is “just around the corner.” But many skeptics remain who will quickly state that commercial fusion energy remains 50 years in the future. So long as Maguire’s team meets milestones with expected performance improvements, their work will go on. The potential of fusion energy remains too great to dismiss categorically.

Source: Lockheed-Martin Products Page, Compact Fusion

A Fun Way of Understanding E=mc2

Many people fail to realize just how much energy there is locked up in matter. The nucleus of any atom is an oven of intense radiation, and when you open the oven door, that energy spills out; oftentimes violently. However, there is something even more intrinsic to this aspect of matter that escaped scientists for years.

It wasn’t until the brilliance of Albert Einstein that we were able to fully grasp this correlation between mass and energy. Enter E=mc2. This seemingly simple algebraic formula represents the correlation of energy to matter (energy equivalence of any given amount of mass). Many have heard of it, but not very many understand what it implies. Many people are unaware of just how much energy is contained within matter. So, for the next few minutes, I will attempt to convey to you the magnitude of your own personal potential energy equivalence.

First, we must break down this equation. What do each of the letters mean? What are their values? Let’s break it down from left to right:

Albert Einstein's Inventions
Albert Einstein. Image credit: Library of Congress

E represents the energy, which we measure in Joules. Joules is an SI measurement for energy and is measured as kilograms x meters squared per seconds squared [kg x m2/s2]. All this essentially means is that a Joule of energy is equal to the force used to move a specific object 1 meter in the same direction as the force.

m represents the mass of the specified object. For this equation, we measure mass in Kilograms (or 1000 grams).

c represents the speed of light. In a vacuum, light moves at 186,282 miles per second. However in science we utilize the SI (International System of Units), therefore we use measurements of meters and kilometers as opposed to feet and miles. So whenever we do our calculations for light, we use 3.00 × 108m/s, or rather 300,000,000 meters per second.

So essentially what the equation is saying is that for a specific amount of mass (in kilograms), if you multiply it by the speed of light squared (3.00×108)2, you get its energy equivalence (Joules). So, what does this mean? How can I relate to this, and how much energy is in matter? Well, here comes the fun part. We are about to conduct an experiment.

This isn’t one that we need fancy equipment for, nor is it one that we need a large laboratory for. All we need is simple math and our imagination. Now before I go on, I would like to point out that I am utilizing this equation in its most basic form. There are many more complex derivatives of this equation that are used for many different applications. It is also worth mentioning that when two atoms fuse (such as Hydrogen fusing into Helium in the core of our star) only about 0.7% of the mass is converted into total energy. For our purposes we needn’t worry about this, as I am simply illustrating the incredible amounts of energy that constitutes your equivalence in mass, not illustrating the fusion of all of your mass turning into energy.

Let’s begin by collecting the data so that we can input it into our equation. I weigh roughly 190 pounds. Again, as we use SI units in science, we need to convert this over from pounds to grams. Here is how we do this:

1 Josh = 190lbs
1 lbs = 453.6g
So 190lbs × 453.6g/1 lbs = 86,184g
So 1 Josh = 86,184g

Since our measurement for E is in Joules, and Joule units of measurement are kilograms x meters squared per seconds squared, I need to convert my mass in grams to my mass in kilograms. We do that this way:

86,184g × 1kg/1000g = 86.18kg.

So 1 Josh = 86.18kg.
Now that I’m in the right unit of measure for mass, we can plug the values into the equation and see just what we get:
E=mc2
E= (86.18kg)(3.00 × 108m/s)2
E= 7.76 × 1018 J

That looks like this: 7,760,000,000,000,000,000 or roughly 7.8 septillion Joules of energy.

Artistic rendition of energy released in an explosion. Via Pixabay.
Artistic rendition of energy released in an explosion. Via Pixabay.

This is an incredibly large amount of energy. However, it still seems very vague. What does that number mean? How much energy is that really? Well, let’s continue this experiment and find something that we can measure this against, to help put this amount of energy into perspective for us.

First, let’s convert our energy into an equivalent measurement. Something we can relate to. How does TNT sound? First, we must identify a common unit of measurement for TNT. The kiloton. Now we find out just how many kilotons of TNT are in 1 Joule. After doing a little searching I found a conversion ratio that will let us do just this:

1 Joule = 2.39 × 10-13 kilotons of explosives. Meaning that 1 Joule of energy is equal to .000000000000239 kilotons of TNT. That is a very small number. A better way to understand this relationship is to flip that ratio around to see how many Joules of energy is in 1 kiloton of TNT. 1 kiloton of TNT = 4.18×1012 Joules or rather 4,184,000,000,000 Joules.

Now that we have our conversion ratio, let’s do the math.

1 Josh (E) = 7.76 x 1018 J
7.76 x 1018 J x 1 kT TNT/ 4.18 x 1012 J = 1,856,459 kilotons of TNT.

Thus, concluding our little mind experiment we find that just one human being is roughly the equivalence of 1.86 MILLION kilotons of TNT worth of energy. Let’s now put that into perspective, just to illuminate the massive amount of power that this equivalence really is.

The bomb that destroyed Nagasaki in Japan during World War II was devastating. It leveled a city in seconds and brought the War in the Pacific to a close. That bomb was approximately 21 kilotons of explosives. So that means that I, 1 human being, have 88,403 times more explosive energy in me than a bomb that destroyed an entire city… and that goes for every human being.

So when you hear someone tell you that you’ve got real potential, just reply that they have no idea….

Hydrogen Bomb Blast. Image via Pixabay.
Hydrogen Bomb Blast. Image via Pixabay.

Could We Harvest Energy From a Star?

Our civilization will need more power in the future. Count on it. The ways we use power today: for lighting, transportation, food distribution and even entertainment would have sounded hilarious and far fetched to our ancestors.

As our technology improves, our demand for power will increase. I have no idea what we’ll use it for, but I guarantee we’ll want it. Perhaps we’ll clean up the oceans, reverse global warming, turn iron into gold, or any number of activities that take massive amounts of energy. Fossil fuels won’t deliver, and they come with some undesirable side effects. Nuclear fuels will only provide so much power until they run out.

We need the ultimate in energy resources. We’ll want to harness the entire power of our star. The Soviet astronomer Nikolai Kardashev predicted that a future civilization might eventually harness the power of an entire planet. He called this a Type I civilization. A Type II would harness the entire energy output of a star. And a Type III civilization would utilize the power of their entire galaxy. So let’s consider a Type II civilization.

What would it actually take to harness 100% of the energy from a star? We’d need to construct a Dyson Sphere or Cloud and collect all the solar energy that emanates from it. But could we do better? Could we extract material directly from a star?

You bet, it’s the future!

This is an idea known as “stellar lifting”. Stealing hydrogen fuel from the Sun and using it for our futuristic energy needs. In fact, the Sun’s already doing it… poorly. Stars generate powerful magnetic fields. They twist and turn across the surface of the star, and eject hydrogen into space. But it’s just a trickle of material. To truly harness the power of the Sun, we need to get at that store of hydrogen, and speed up the extraction process.

There are a few techniques that might work. You can use lasers to heat up portions of the surface, and increase the volume of the solar wind. You could use powerful magnetic fields to carry plasma away from the Sun’s poles into space.Which ever way it happens, once we’ve got all that hydrogen. How do we use it to get energy? We could combine it with oxygen and release energy via combustion, or we could use it in our space reactors and generate power from fusion.

Plasma on the surface of the Sun. Image credit: Hinode
Plasma on the surface of the Sun. Image credit: Hinode

But the most efficient way is to feed it to a black hole and extract its angular momentum. A highly advanced civilization could siphon material directly from a star and send it onto the ergosphere of a rapidly spinning pet black hole.

Here’s Dr. Mark Morris, a Professor of Astronomy at UCLA. He’ll explain:
“There is this region, called the ergosphere between the event horizon and another boundary, outside. The ergosphere is a very interesting region outside the event horizon in which a variety of interesting effects can occur. For example, if we had a black hole at our disposal, we could extract energy from spinning black holes by throwing things into the ergosphere and grabbing whatever comes out at even higher speeds.”

This is known as the Penrose process, first identified by Roger Penrose in 1969. It’s theoretically possible to retrieve 29% of the energy in a rotating black hole. Unfortunately, you also slow it down. Eventually the black hole stops spinning, and you can’t get any more energy out of it. But then it might also be possible to extract energy from Hawking radiation; the slow evaporation of black holes over eons. Of course, it’s tricky business.

Combining observations done with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. The black hole blows a huge bubble of hot gas, 1,000 light-years across or twice as large and tens of times more powerful than the other such microquasars. The stellar black hole belongs to a binary system as pictured in this artist's impression.  Credit: ESO/L. Calçada
Artist’s impression of a Star feeding a black hole. Credit: ESO/L. Calçada

Dr. Morris continues, “There’s no inherent limitation except for the various problems working in the vicinity of a massive black hole. One can’t be anywhere near a black hole that’s actively accreting matter because the high flux of energetic particles and gamma rays. So it’s a hostile environment near most realistic black holes, so let me just say that it won’t be any time soon as far as our civilization is concerned. But maybe Type III civilizations so far beyond us that it exceeds our imagination won’t have any problem.”

A Type 3 civilization would be so advanced, with such a demand for energy, they could be extracting the material from all the stars in the galaxy and feeding it directly to black holes to harvest energy. Feeding black holes to other black holes to spin them back up again.

It’s an incomprehensible feat of galactic engineering. And yet, it’s one potential outcome of our voracious demand for energy.

The Secret of the Stars

“Say, do you like mystery stories? Well we have one for you. The concept: relativity.

Well look at that, it’s a new video from John D. Boswell — aka melodysheep — which goes into autotuned detail about one of the standard principles of astrophysics, Einstein’s theory of general relativity.

Featuring clips from Michio Kaku, Brian Cox, Neil deGrasse Tyson, Brian Greene and Lisa Randall, I’d say E=mc(awesome).

John has been entertaining science fans with his Symphony of Science mixes since 2009, when his first video in the series — “A Glorious Dawn” featuring Carl Sagan — was released. Now John’s videos are eagerly anticipated by fans (like me) who follow him on YouTube and on Twitter as @musicalscience.

E = mc2… that is the engine that lights up the stars.”

(What does Einstein’s famous mass-energy equivalence equation mean? For a brief and basic explanation, check out the American Museum of Natural History’s page here.)

Podcast: Energy

Our entire civilization depends on energy: getting it, converting it, burning it, and conserving it. But how do physicists think about energy? How do they measure and quantify it. And what is energy’s special relationship with mass?

Click here to download the episode.

Or subscribe to: astronomycast.com/podcast.xml with your podcatching software.

“Energy” on the Astronomy Cast website.

And the podcast is also available as a video, as Fraser and Pamela now record Astronomy Cast as part of a Google+ Hangout:
Continue reading “Podcast: Energy”

A Balanced Budget on Titan

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It’s been said many times that the most Earthlike world in our solar system is not a planet at all, but rather Saturn’s moon Titan. At first it may not seem obvious why; being only a bit larger than the planet Mercury and coated in a thick opaque atmosphere containing methane and hydrocarbons, Titan sure doesn’t look like our home planet. But once it’s realized that this is the only moon known to even have a substantial atmosphere, and that atmosphere creates a hydrologic cycle on its surface that mimics Earth’s – complete with weather, rain, and gully-carving streams that feed liquid methane into enormous lakes – the similarities become more evident. Which, of course, is precisely why Titan continues to hold such fascination for scientists.

Now, researchers have identified yet another similarity between Saturn’s hazy moon and our own planet: Titan’s energy budget is in equilibrium, making it much more like Earth than the gas giant it orbits.

A team of researchers led by Liming Li of the Department of Earth and Atmospheric Sciences at the University of Houston in Texas has completed the first-ever investigation of the energy balance of Titan, using data acquired by telescopes and the Cassini spacecraft from 2004 to 2010.

Energy balance (or “budget”) refers to the radiation a planet or moon receives from the Sun versus what it puts out. Saturn, Jupiter and Neptune emit more energy than they receive, which indicates an internal energy source. Earth radiates about the same amount as it receives, so it is said to be in equilibrium… similar to what is now shown to be the case for Titan.

Blue hazes hover high above thicker orange clouds over Titan's south pole (NASA/JPL/SSI)

The energy absorption and reflection rates of a planet’s – or moon’s! – atmosphere are important clues to the state of its climate and weather. Different balances of energy or changes in those balances can indicate climate change – global cooling or global warming, for instance.

Of course, this doesn’t mean Titan is a balmy world. At nearly 300 degrees below zero (F) it has an environment that even the most extreme Earth-based life would find inhospitable. Although Titan’s atmosphere is ten times thicker than Earth’s its composition is very different, permitting easy passage of infrared radiation (a.k.a. “heat”) and thus exhibits an “anti-greenhouse” effect, unlike Earth or, on the opposite end of the scale, Venus.

Still, some stable process is in place on Saturn’s moon that allows for distribution of solar energy across its surface, within its atmosphere and back out into space. With results due in from Cassini from a flyby on Jan. 2, perhaps there will soon be even more clues as to what that may be.

Read more about Earth’s changing energy budget here.

The team’s report was published in the AGU’s Geophysical Research Letters on December 15, 2011. Li, L., et al. (2011), The global energy balance of Titan, Geophys. Res. Lett., 38, L23201, doi:10.1029/2011GL050053.

First Law of Thermodynamics

First Law of Thermodynamics

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Ever wonder how heat really works? Well, not too long ago, scientists, looking to make their steam engines more efficient, sought to do just that. Their efforts to understand the interrelationship between energy conversion, heat and mechanical work (and subsequently the larger variables of temperature, volume and pressure) came to be known as thermodynamics, taken from the Greek word “thermo” (meaning “heat”) and “dynamis” (meaning force). Like most fields of scientific study, thermodynamics is governed by a series of laws that were realized thanks to ongoing observations and experiments. The first law of thermodynamics, arguably the most important, is an expression of the principle of conservation of energy.

Consistent with this principle, the first law expresses that energy can be transformed (i.e. changed from one form to another), but cannot be created or destroyed. It is usually formulated by stating that the change in the internal energy (ie. the total energy) contained within a system is equal to the amount of heat supplied to that system, minus the amount of work performed by the system on its surroundings. Work and heat are due to processes which add or subtract energy, while internal energy is a particular form of energy associated with the system – a property of the system, whereas work done and heat supplied are not. A significant result of this distinction is that a given internal energy change can be achieved by many combinations of heat and work.

This law was first expressed by Rudolf Clausius in 1850 when he said: “There is a state function E, called ‘energy’, whose differential equals the work exchanged with the surroundings during an adiabatic process.” However, it was Germain Hess (via Hess’s Law), and later by Julius Robert von Mayer who first formulated the law, however informally. It can be expressed through the simple equation E2 – E1 = Q – W, whereas E represents the change in internal energy, Q represents the heat transfer, and W, the work done. Another common expression of this law, found in science textbooks, is ?U=Q+W, where ? represents change and U, heat.

An important concept in thermodynamics is the “thermodynamic system”, a precisely defined region of the universe under study. Everything in the universe except the system is known as the surroundings, and is separated from the system by a boundary which may be notional or real, but which by convention delimits a finite volume. Exchanges of work, heat, or matter between the system and the surroundings take place across this boundary. Thermodynamics deals only with the large scale response of a system which we can observe and measure in experiments (such as steam engines, for which the study was first developed).

We have written many articles about the First Law of Thermodynamics for Universe Today. Here’s an article about entropy, and here’s an article about Hooke’s Law.

If you’d like more info on the First Law of Thermodynamics, check out NASA’s Glenn Research Center, and here’s a link to Hyperphysics.

We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.

Sources:
http://en.wikipedia.org/wiki/First_law_of_thermodynamics
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/firlaw.html
http://en.wikipedia.org/wiki/Internal_energy
http://www.grc.nasa.gov/WWW/K-12/airplane/thermo1.html
http://en.wikipedia.org/wiki/Thermodynamics
http://en.wikipedia.org/wiki/Laws_of_thermodynamics