Construction Tips from a Type 2 Engineer: Collaboration with Isaac Arthur

Type 2 Civ Tips!

By popular request, Isaac Arthur and I have teamed up again to bring you a vision of the future of human space exploration. This time, we bring you practical construction tips from a pair of Type 2 Civilization engineers.

To make this collaboration even better, we’ve teamed up with two artists, Kevin Gill and Sergio Botero. They’re going to help create some special art, just for this episode, to help show what some of these megaprojects might look like.

I’d also like to congratulate Gannon Huiting for suggesting the topic for this collaboration. We both asked our Patreon communities to brainstorm ideas, and his core idea sparked the idea for the episode. You get one of my precious metal meteorites, which I guarantee will give you a mostly worthless superpower.

We’ll tell you the story of what it took to go from our first tentative steps into space to the vast Solar System spanning civilization we have today. How did we extract energy and resources from the Moon, planets and even gas giants of the Solar System? How did we shift around and dismantle the worlds to provide the raw resources of our civilization?

Lunar Rover Concept. Credit: Sergio Botero

Humanity’s ability to colonize the Solar System was unleashed when we harvested deposits of helium 3 from the Moon. This isotope of helium is rare on Earth, but the constant solar wind from the Sun has deposited a layer across the Moon, though its regolith.

Helium 3 was the best, first energy source we got our hands on, and it changed everything. Although other kinds of fusion reactors can produce more energy with more efficiency, the advantage of helium 3 is that the fusion reaction releases no neutrons. This means you can have a fusion reactor on your starship or on your base with much less shielding.

Multi-dome base being constructed. Credit: ESA/Foster + Partners

We still use helium-3 reactors when living creatures need to be close the reactor, or the ship can’t afford to carry around heavy shielding.

The Helium 3 is found within the first 100 cm of the lunar regolith. Harvesting it started slowly, but in time, our mining machines grew larger, and we stripped this layer completely off the Moon. There are other repositories across the Solar System, in the regolith of Mercury, other moons and asteroids across the Solar System, and in the atmospheres of the giant planets. We later switched to getting our Helium 3 from Uranus and Neptune, but the Moon got everything started.

A huge lunar miner, with astronaut for scale. Credit: Sergio Botero

One of our big problems with building in space was getting raw materials. Just about every place that has the supplies we needed was at the bottom very deep gravity wells which made accessing those materials a lot harder. Asteroid and moons offered us a large supply of material that was not locked inside such deep gravity wells.

These asteroids also gave us a big initial head start on developing space-based infrastructure as they contained a great deal of precious metals that we could bring home to help fund our endeavors.

For all that, the entire Asteroid Belt contains much less material than Earth’s own Moon. The ease of mining and transport on these bodies made them a critical source of raw materials for building up the early Solar Infrastructure and many of them became homes to rotating habitats buried deep inside the asteroid, where millions of people live comfortably shielded from the hazards of space and support themselves mining the asteroid around them.

Artist’s impression of the asteroid belt. Image credit: NASA/JPL-Caltech

These asteroids and moons often contained water in the form of ice, which is vital to creating life-bearing habitats in space, as well as fuel and propellant for many early-era spaceships.

However, even if the entire Asteroid Belt was ice, instead of it being a fairly smaller percent of the mass, that would still only be the approximate mass of Earth’s Oceans. There was a plentiful supply for early efforts but not enough for major terraforming efforts on places like Mars or creating many artificial habitats.

Water is incredibly scarce in the inner Solar System, but becomes more plentiful as we make our way further out, past the Solar System’s Frost Line. Deeper out past the planets we find enough water to make whole planets out of, as hydrogen and oxygen are the first and third most abundant elements in the Universe. Also, for the most part these come in convenient iceberg-sized packages, low enough in mass to have a small gravity well and to be movable.

Mastering the Solar System required moving very large objects in space. For the less massive objects, we could put a big thruster on it, but for the largest projects, such as moving planets with atmospheres (which we’ll get to later in this article), another technique was required.

Concept for a possible gravity tractor. Credit: JPL

To move large objects around, without touching them, you need a Gravity Tractor.

Want to move an asteroid? Use the gravity of a less massive object, like a spaceship. Hold the spaceship close to the asteroid, and their gravity will put them together. Fire your rocket’s thrusters to keep the distance, and you slowly pull the asteroid in any direction you like. It takes a long time, and does require fuel, but you can use this technique to move anything anywhere in the Solar System.

Put a massive satellite into orbit around an asteroid. When the satellite is on one side of the asteroid it fires its thrusters towards the satellite. And then on the other side of its orbit, it fires its thrusters away from the satellite. The satellite will have been pushed twice in the same direction. To an outside observer that satellite has moved, though on the asteroid it will seem to have been nudged closer than put back.

Don’t forget that the satellite pulls on the asteroid with just as much force as the asteroid exerts on the satellite. Earth pulls on the Sun just as hard as it pulls on us, but it’s more massive so it doesn’t move as much. But it does move, and so by pushing on the satellite towards the primary then pushing away on the opposite side, we move the primary body.

We can also take advantage of momentum transfers from gravity to alter the course of an object by making a close flyby. You can use this gravitational slingshot to use the gravity of a planet to change the move large objects into a new trajectory.

Over time, we put gravitational tugs into orbit around every chunk of rock and ice that we wanted to move, shifting their locations to the best places in the Solar System.

Artist view of an asteroid passing Earth. Credit: ESA/P.Carril

Some places gave us raw materials. Other places would serve as our homes.

Earth is the third closest planet to the Sun and it will always be the environment we’re trying to replicate. Earth is, well, it was… home.

For all the millions of other worlds across the Solar System, we made them capable of hosting life  with a little work. Often we could make them habitable just by increasing the amount of energy they received from the Sun.

Creating artificial gravity by spinning a habitat or breathable air by doming it over did us no good if there wasn’t enough light to melt ice into water or let plants grow.

The farther you get from the Sun, the less light you get, but we bounce light that would have been lost, concentrating it to let life flourish. The Sun gives off over a billion times the light that actually reaches Earth, so there’s no shortage in quantity, just concentration.

This was the first sunset observed in color by Curiosity on Mars. Credit: NASA/JPL-Caltech/MSSS/Texas A&M Univ.

To double the light reaching a planet like Mars, you would need a mirror surface area of twice the size of Mars. But not twice the mass of Mars. For every square meter of land on Earth, there’s about 10 billion kilograms of mass under our feet. A mirror on Earth wouldn’t weigh much more than a kilogram a square meter, but in space we can go far thinner. Any one of millions of small asteroids in the solar system contains enough material to make a planetary surface’s worth of mirrors.

Lenses or parabolic reflectors let us move light in from far more densely concentrated locations closer to the Sun. Reflecting light also allows us to remove harmful or less useful invisible wavelengths like ultraviolet or x-rays.

This allowed us to make almost any place warm and bright enough. We took distant moons and asteroids far from the Sun, and gave them a collar of thin mirrors bouncing light into a parabolic dish. By bouncing this light into rotating habitats safely buried inside the asteroid, we created warm, lush garden worlds in environments so cold that air itself would condense into a liquid.

Artist’s concept of a Venus cloud city — a possible future outcome of the High Altitude Venus Operational Concept (HAVOC) plan. Credit: Advanced Concepts Lab/NASA Langley Research Center

For most of the Solar System we wanted to warm planets up. But for Venus and Mercury, we needed to cool them down. We did this by placing shades between them and the Sun to reflect away some of the light hitting them.

The easiest way to do this was to position an opaque material between the planet and the Sun, at the L1 Lagrange point. At this point the gravitational pull of the planet counteracts the pull of the Sun allowing a large thin solar shade to remain in position with minimal energy. This way the planet is cooled.

A solar shade above Venus. Credit: Kevin Gill

But we did better than merely cool, we shaped the light to our needs. With a collection of many small shades, we avoided putting a visible dark spot on the Sun. Sunlight comes in many frequencies, from radio to x-rays; some were more valuable to us than others. Plants mostly use red and blue light, while green light doesn’t help with photosynthesis. So blocked a decent amount of green light, some blue, and no red, and cooled the planet without harming plant life and without really altering how the light looked to our eyes.

We engineered the perfect material for our shades which was mostly transparent to the wavelengths of light we wanted and mostly reflective or absorptive to the ones we didn’t.

Ultraviolet is a good example. We wanted some to get to our planet, as it does help as a sterilizing agent to biological processes and it helps make ozone, but we wanted to cut most of that out. Even better, about half of the light coming from the Sun is in infrared, which we can’t see and which plants don’t use.

We blocked most of that and seriously lowered temperatures on Venus and Mercury.

We set up shades to block the light from reaching our planets. And we did the same with dangerous radiation streaming from the Sun. We set up a concentrated magnetic shield at the Mars-Sun L1 Lagrange point, which catches and redirects high energy particles. This protects a world from the Sun, but it doesn’t prevent harmful cosmic rays, which can come from any part of the sky.

Our own planet Earth has a robust magnetosphere, and it’s the main reason we have air to breath and don’t absorb dangerous radiation from the Sun and space.

Places like Mars don’t. For this purpose, we created artificial magnetospheres. We considered trying to get Mars’ core spinning fast and hot so that rapid spinning molten ferromagnetic materials would generate a protective magnetosphere.

But that was too much effort. We didn’t actually care what generated the magnetic field, we just wanted the magnetic field. In the end we deployed a constellation of electromagnetic satellites around every world exposed to space. These satellites could do double duty, harvesting solar radiation and generating an artificial magnetosphere.

Mars used to have a natural magnetic field, but restarting it wasn’t worth it. Credit: NASA/JPL/GSFC

Cosmic rays and radioactive particles from the Sun were captured and redirected safely away from the world, allowing us to roam freely on the surface.

Once we had made acquired the resources of every world in the Solar System, we began our next great engineering effort. To move and dismantle the worlds themselves. To create the optimal configuration that gave us the most living space and the most usable energy. We began the construction of our Dyson swarm.

Moving planets is almost impossible. But not completely impossible. How do you get all that energy to move a world without melting it? The orbital energy of Earth around the Sun is approximately 30 million, trillion, trillion joules. That’s equal to all the energy the Sun puts out over a few months.

Of course, the Sun is slowly warming up, and while estimates vary, it’s generally accepted that in about a billion years it will have warmed up enough that Earth would be uninhabitable. Moving the Earth was inevitable.

To move the Earth outward to counteract the increased solar luminosity, we needed to add orbital energy. A lot of energy.

Earlier, we discussed using gravity tractors and gravitational slingshots to slowly and steadily move objects around the Solar System. This technique works at the largest scales too.

A gravity tractor could slowly and steadily move an entire planet if you had enough time and fuel. Because we already had mastery of all the asteroids in the Solar System, we put them into orbits that swept past worlds.

Credit: NASA/JPL-Caltech

Each gravitational slingshot gave or stole orbital momentum from the world, pushing it closer or farther from the Sun.

We also used orbital mirrors to bounce sunlight from the Sun. With enough of them, deflecting their light in the same general directional while maintaining an orbit around the planet, we could move worlds without touching them or heating them up from the light beams.

With enough satellites to keep the net gravitational force on the planet homogenous, we didn’t have to worry about tidal heating, allowing us to move a planet far faster.

In the future, we’ll use a king-size version of this to move the entire Solar System, using the star as the power source, called a Shkadov Thruster. We will push the Sun and every star we control into a constellation that matches our needs. But that’s a problem our Type III civilization engineers will have to worry about.

Like a cosmic lava lamp, a large section of Pluto’s icy surface in Sputnik Planum is being constantly renewed by a process called convection that replaces older surface ices with fresher material. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.

We always needed ice. For water, for fuel and for air. And the outer Solar System had all the ice we could ever need. We brought comets and other icy bodies in from the outer Solar System to bring water to the planets we’re terraforming – Mars, Venus, and the large moons of the Solar System.

Pushing ice is a tricky process, but the comet itself is the source of fuel, either liquid hydrogen and oxygen as the propellants or using the hydrogen for a fusion torch drive. However we have an alternative trick we can use.

We just talked about using energy beams, focused sunlight, lasers, or microwave beams to push objects outward from the sun. You can also move inward by reflecting the beam off at an angle, removing orbital momentum. This lowers their orbit into the Solar System.

Credit: NASA/Denise Watt

By setting up energy collectors on comets, we could beam power out them, and use that energy to melt atoms into gas and accelerate them away with a magnetic field, just like an ion drive. This let us take high-strength lasers and microwave beams powered from the inner Solar System and use it to tractor comets inward. The propellant melted off the comets could carry away far more momentum than the energy beam added, though at the cost of losing some of your mass in the process.

One by one we identified the icy bodies in the Kuiper Belt and Oort Cloud, installed an ice engine, and pulled them inward, to the places we needed that water the most.

The day to day energy for our civilization comes from the Sun. Solar collectors power the machines, computers and systems that make day-to-day life spanning the Solar System possible.

Just as the ancient Earth civilizations used hydrocarbons as a store of fuel, we depend on hydrogen. We use it for our rocket fuel, to manufacture drinking water, and most importantly, for our fusion reactors. We always need more hydrogen.

Illustration Credit:© David A. Hardy/, Project Daedalus

Fortunately, the Solar System has provided us with vast repositories of hydrogen: the giant planets, Jupiter, Saturn, Uranus and Neptune all made up of at least 80% hydrogen. But harvesting the planets for their hydrogen isn’t without its challenges.

For starters, the gravity on the surface of Jupiter is nearly 25 m/s2, which is nearly three times the surface gravity of Earth. On top of that, Jupiter’s magnetosphere produces intense radiation fields through its entire system. You can’t spend much time near Jupiter without receiving a lethal radiation dose.

Gas Giant Harvesting Concept. Credit: Sergio Botero

We deploy huge robotic scoopers to swoop down into Jupiter’s gravity well, skim across the upper cloud tops, funneling in as much hydrogen as they can. On board compressors liquefy the hydrogen, or refine it into the more energy dense metallic hydrogen. The fuel is then distributed across the Solar System through the interplanetary transport network.

For Uranus and Neptune, where the gravity well is less extreme, we have permanent mining stations which float in the cloud tops, harvesting raw materials for return back to space. These factories are a huge improvement over the more expensive scoop ships. Smaller cargo ships ferry the deuterium, helium-3 and hydrogen up to orbit, for an energy hungry Solar System.

Gas Giant Harvesting Concept. Credit: Gas Giant Harvesting Concept. Credit: Sergio Botero

In order to construct our Dyson Swarm, we will eventually need to dismantle almost all the planets and moons in the Solar System to provide the raw materials to house countless people.

This process has begun, and we we have a number of options. For some worlds, we plan to just keep mining and refining them with robotic factories until they are gone, but this can be quite time consuming and often we would rather do our refining and manufacturing elsewhere.

Instead, we have set up very large mass drivers running around the object to launch material directly towards its desired destination. To avoid building up angular momentum inside the shrinking mass of the planetoid, we run these giant cannons in both directions. This prevents it spinning so fast that it tears itself apart. There’s very little gravity holding these objects together after all.

For the smaller objects that’s actually just fine. When we want to disassemble a smaller asteroid or moon into rock and dirt for the inside of a cylinder habitat, we construct a cylindrical shell around the asteroid, and spray material from the asteroid onto the cylinder, giving it some spin and artificial gravity to hold the material up, or rather down to its surface. We spin the asteroid faster and faster until it flies apart, transferring its material and its angular momentum to the cylinder.

Credit: NASA.

With larger asteroids we send a series of cylinders past them in a chain, painting their interiors with the material we will turn into dirt later on, until we run out of asteroid.

For full blown minor planets and moons, which are much more massive but still fairly low in gravity and lacking an atmosphere, we pump matter up tubes to high above the planetoid to fill freighters, get compacted into cannon balls to be launched elsewhere, or simply pumped into rotating habitats being built nearby.

Mercury is already half consumed. In a few more generations, it will be a distant memory.

Perhaps our greatest accomplishment is the work underway at Jupiter and Saturn. We are now in the process of dismantling these worlds to harvest their resources.

Jupiter and Io. Image Credit: NASA/JPL
Jupiter and Io. Image Credit: NASA/JPL

The largest machines humanity has ever built, fusion candles, have been deployed into the atmospheres of Jupiter and Saturn. These enormous machines scoop up raw hydrogen from Jupiter to run their fusion reactors. One side of the fusion candle fires downward, keeping the machine aloft. The other end blasts out into space, spewing material that can be harvested from orbit.

Not only that, but these candles provide thrust, pushing Jupiter and Saturn slowly but steadily into safer, more useful orbits for our civilization. As we use up the hydrogen, their mass will decrease. Uranus and Neptune will follow slowly, from farther out in the Solar System.

Eventually, eons into the future, we will have dismantled them down to their cores. There is more than a dozen times the mass of the Earth in rock and metal down at the core of Jupiter. More raw materials than any other place in the Solar System.

Credit: Kevin Gill

The long awaited construction of our fully operational Dyson swarm will finally begin. We’ll miss the presence of Jupiter and Saturn in the Solar System, and remember them fondly, but humanity needs room to stretch its legs.

Of course, as huge as the gas giants are compared to Earth, the Sun is far bigger, and contains not just hydrogen and helium but thousands of planets worth of heavier elements, which are spread around the sun, not just concentrated deep down.

Trying to scoop matter off a star is much harder than out of gas giant, though conveniently, we can take advantage of all that energy the Sun is giving off to power our extraction.

The Sun loses mass via the solar wind, mass ejections and simply by emitting energy (Credit: NASA)

The material on the Sun is also ionized, so it reacts strongly to magnetic forces, and the Sun generates a massively powerful magnetic field too. In fact, our Sun ejects about a billion kilograms of matter a second as solar wind. We have a few ways to increase this flow and harvest it.

The first is called Thermal Driven Outflow. We hover mirrors over the surface, reflecting and concentrating light down on spots on the Sun’s surface to heat it up and increase the mass being ejected. This kicks up an eruption much like a solar flare, feeding more solar wind.


We then place a large ring of satellites around the Sun’s equator, connected to each other by a stream of ionized particles generating a huge current, themselves running that stream off solar power. This ring creates a powerful magnetic field pushing outward toward the Sun’s poles, and sending the super-heated matter in that direction.

Hovering over the poles further out, we have a giant ring sucking up sunlight and generating a huge toroidal magnetic field. All the matter we stir up on the sun and off the poles is sucked through that and slowed down for collection. It’s a lot like the VASIMR Drive, using a magnetic nozzle, so that nothing has to touch the ultra hot plasma. Giant Plasma Thrusters essentially acting as the pump to gather the matter, it stays in place using the momentum it’s stealing from the particles it is slowing down, again it’s a giant plasma thruster.

We will eventually build far more of these rings around the Sun, spaced up and down from the equator, and intermittently shut off the power beam holding them aloft. As all the satellites in that ring drop, building up speed, we switch the power for the beam back on and their plummet stops and they push back up to their original position. We do this with all the rings, in sequence, pushing much larger waves of matter toward the poles than the Thermal Driven Outflow method provides, and we call this option the Huff-n-Puff Method.

A montage of planets and other objects in the solar system. Credit: NASA/JPL

And there you have it, our tips and techniques to harvest all the resources from the Solar System. To push and pull worlds, to heat them up, cool them down and use their raw materials to house humanity’s growing, ever expanding population.

As we nearly achieve our Type II civilization status, and control all the energy from our Sun and all the resources of the Solar System, we set our sights on a new goal: doing the same thing for the entire Milky Way Galaxy.

Perhaps in a few million years, we’ll create another guide for you, to help you make this transition as efficiently as possible.

Good luck!

What Was Cosmic Inflation? The Quest to Understand the Earliest Universe

Cosmic Inflation?

The Big Bang. The discovery that the Universe has been expanding for billions of years is one of the biggest revelations in the history of science. In a single moment, the entire Universe popped into existence, and has been expanding ever since.

We know this because of multiple lines of evidence: the cosmic microwave background radiation, the ratio of elements in the Universe, etc. But the most compelling one is just the simple fact that everything is expanding away from everything else. Which means, that if you run the clock backwards, the Universe was once an extremely hot dense region

A billion years after the big bang, hydrogen atoms were mysteriously torn apart into a soup of ions. Credit: NASA/ESA/A. Felid (STScI)).

Let’s go backwards in time, billions of years. The closer you get to the Big Bang, the closer everything was, and the hotter it was. When you reach about 380,000 years after the Big Bang, the entire Universe was so hot that all matter was ionized, with atomic nuclei and electrons buzzing around each other.

Keep going backwards, and the entire Universe was the temperature and density of a star, which fused together the primordial helium and other elements that we see to this day.

Continue to the beginning of time, and there was a point where everything was so hot that atoms themselves couldn’t hold together, breaking into their constituent protons and neutrons. Further back still and even atoms break apart into quarks. And before that, it’s just a big question mark. An infinitely dense Universe cosmologists called the singularity.

When you look out into the Universe in all directions, you see the cosmic microwave background radiation. That’s that point when the Universe cooled down so that light could travel freely through space.

And the temperature of this radiation is almost exactly the same in all directions that you look. There are tiny tiny variations, detectable only by the most sensitive instruments.

Cosmic microwave background seen by Planck. Credit: ESA

When two things are the same temperature, like a spoon in your coffee, it means that those two things have had an opportunity to interact. The coffee transferred heat to the spoon, and now their temperatures have equalized.

When we see this in opposite sides of the Universe, that means that at some point, in the ancient past, those two regions were touching. That spot where the light left 13.8 billion years ago on your left, was once directly touching that spot on your right that also emitted its light 13.8 billion years ago.

This is a great theory, but there’s a problem: The Universe never had time for those opposite regions to touch. For the Universe to have the uniform temperature we see today, it would have needed to spend enough time mixing together. But it didn’t have enough time, in fact, the Universe didn’t have any time to exchange temperature.

Imagine you dipped that spoon into the coffee and then pulled it out moments later before the heat could transfer, and yet the coffee and spoon are exactly the same temperature. What’s going on?

Alan H. Guth
Alan H. Guth. Credit: Betsy Devine (CC BY-SA 3.0)

To address this problem, the cosmologist Alan Guth proposed the idea of cosmic inflation in 1980. That moments after the Big Bang, the entire Universe expanded dramatically.

And by “moments”, I mean that the inflationary period started when the Universe was only 10^-36 seconds old, and ended when the Universe was 10^-32 seconds old.

And by “expanded dramatically”, I mean that it got 10^26 times larger. That’s a 1 followed by 26 zeroes.

Before inflation, the observable Universe was smaller than an atom. After inflation, it was about 0.88 millimeters. Today, those regions have been stretched 93 billion light-years apart.

This concept of inflation was further developed by cosmologists Andrei Linde, Paul Steinhardt, Andy Albrecht and others.

Inflation resolved some of the shortcomings of the Big Bang Theory.

The first is known as the flatness problem. The most sensitive satellites we have today measure the Universe as flat. Not like a piece-of-paper-flat, but flat in the sense that parallel lines will remain parallel forever as they travel through the Universe. Under the original Big Bang cosmology, you would expect the curvature of the Universe to grow with time.

The horizon problem in Big Bang cosmology. How is it that distant parts of the universe possess such similar physical properties? Credit: Addison Wesley.

The second is the horizon problem. And this is the problem I mentioned above, that two regions of the Universe shouldn’t have been able to see each other and interact long enough to be the same temperature.

The third is the monopole problem. According to the original Big Bang theory, there should be a vast number of heavy, stable “monopoles”, or a magnetic particle with only a single pole. Inflation diluted the number of monopoles in the Universe so don’t detect them today.

Although the cosmic microwave background radiation appears mostly even across the sky, there could still be evidence of that inflationary period baked into it.

The Big Bang and primordial gravitational waves. Credit:

In order to do this, astronomers have been focusing on searching for primordial gravitational waves. These are different from the gravitational waves generated through the collision of massive objects. Primordial gravitational waves are the echoes from that inflationary period which should be theoretically detectable through the polarization, or orientation, of light in the cosmic microwave background radiation.

A collaboration of scientists used an instrument known as the Background Imaging of Cosmic Extragalactic Polarization (or BICEP2) to search for this polarization, and in 2014, they announced that maybe, just maybe, they had detected it, proving the theory of cosmic inflation was correct.

Unfortunately, another team working with the space-based Planck telescope posted evidence that the fluctuations they saw could be fully explained by intervening dust in the Milky Way.

Planck’s view of its nine frequencies. Credit: ESA and the Planck Collaboration

The problem is that BICEP2 and Planck are designed to search for different frequencies. In order to really get to the bottom of this question, more searches need to be done, scanning a series of overlapping frequencies. And that’s in the works now.

BICEP2 and Planck and the newly developed South Pole Telescope as well as some observatories in Chile are all scanning the skies at different frequencies at the same time. Distortion from various types of foreground objects, like dust or radiation should be brighter or dimmer in the different frequencies, while the light from the cosmic microwave background radiation should remain constant throughout.

There are more telescopes, searching more wavelengths of light, searching more of the sky. We could know the answer to this question with more certainty shortly.

One of the most interesting implications of cosmic inflation, if proven, is that our Universe is actually just one in a vast multiverse. While the Universe was undergoing that dramatic expansion, it could have created bubbles of spacetime that spawned other universes, with different laws of physics.

Multiverse Theory
Artist concept of the multiverse. Credit: Florida State University

In fact, the father of inflation, Alan Guth, said, “It’s hard to build models of inflation that don’t lead to a multiverse.”

And so, if inflation does eventually get confirmed, then we’ll have a whole multiverse to search for in the cosmic microwave background radiation.

The Big Bang was one of the greatest theories in the history of science. Although it did have a few problems, cosmic inflation was developed to address them. Although there have been a few false starts, astronomers are now performing a sensitive enough search that they might find evidence of this amazing inflationary period. And then it’ll be Nobel Prizes all around.

Quasar Light Confirms Consistency Of Electromagnetism Over 8 Billion Years

Back in November, a team of researchers from the Swinburne University of Technology and the University of Cambridge published some very interesting findings about a galaxy located about 8 billion light years away. Using the La Silla Observatory’s Very Large Telescope (VLT), they examined the light coming from the supermassive black hole (SMBH) at its center.

In so doing, they were able to determine that the electromagnetic energy coming from this distant galaxy was the same as what we observe here in the Milky Way. This showed that a fundamental force of the Universe (electromagnetism) is constant over time. And on Monday, Dec. 4th, the ESO followed-up on this historic find by releasing the color spectrum readings of this distant galaxy – known as HE 0940-1050.

To recap, most large galaxies in the Universe have SMBHs at their center. These huge black holes are known for consuming the matter that orbits all around them, expelling tremendous amounts of radio, microwave, infrared, optical, ultra-violet (UV), X-ray and gamma ray energy in the process. Because of this, they are some of the brightest objects in the known Universe, and are visible even from billions of light years away.

 Artist’s interpretation of ULAS J1120+0641, a very distant quasar. Credit: ESO/M. Kornmesser

Artist’s interpretation of ULAS J1120+0641, a very distant quasar.
Credit: ESO/M. Kornmesser

But because of their distance, the energy which they emit has to pass through the intergalactic medium, where it comes into contact with incredible amount of matter. While most of this consists of hydrogen and helium, there are trace amounts of other elements as well. These absorb much of the light that travels between distant galaxies and us, and the absorption lines this creates can tell us of lot about the kinds of elements that are out there.

At the same time, studying the absorption lines produced by light passing through space can tell us how much light was removed from the original quasar spectrum. Using the Ultraviolet and Visual Echelle Spectrograph (UVES) instrument aboard the VLT, the Swinburne and Cambridge team were able to do just that, thus sneaking a peak at the “fingerprints of the early Universe“.

What they found was that the energy coming from HE 0940-1050 was very similar to that observed in the Milky Way galaxy. Basically, they obtained proof that electromagnetic energy is consistent over time, something which was previously a mystery to scientists. As they state in their study, which was published in the Monthly Notices of the Royal Astronomical Society:

“The Standard Model of particle physics is incomplete because it cannot explain the values of fundamental constants, or predict their dependence on parameters such as time and space. Therefore, without a theory that is able to properly explain these numbers, their constancy can only be probed by measuring them in different places, times and conditions. Furthermore, many theories which attempt to unify gravity with the other three forces of nature invoke fundamental constants that are varying.
A laser beam launched from VLT´s 8.2-metre Yepun telescope crosses the majestic southern sky and creates an artificial star at 90 km altitude in the high Earth´s mesosphere. The Laser Guide Star (LGS) is part of the VLT´s Adaptive Optics system and it is used as reference to correct images from the blurring effect of the atmosphere. The picture field is crossed by an impressive Milky Way, our own galaxy seen perfectly edge-on. The most prominent objects on the Milky Way are: Sirius, the brightest star in the sky, visible at the top and the Carina nebula, seen as a bright patch besides the telescope. From the right edge of the picture to the left, the following objects are aligned: the Small Magellanic Cloud (with the globular cluster 47 Tucanae on its right), the Large Magellanic Cloud and Canopus, the second brightest star in the sky.
A laser beam launched from the Very Large Telescope (VLT) at the ESO’s La Silla Observatory in Chile. Credit: ESO

Since it is 8 billion light years away, and its strong intervening metal-absorption-line system, probing the electromagnetic spectrum being put out by HE 0940-1050 central quasar – not to mention the ability to correct for all the light that was absorbed by the intervening intergalactic medium – provided a unique opportunity to precisely measure how this fundamental force can vary over a very long period of time.

On top of that, the spectral information they obtained happened to be of the highest quality ever observed from a quasar. As they further indicated in their study:

“The largest systematic error in all (but one) previous similar measurements, including the large samples, was long-range distortions in the wavelength calibration. These would add a ?2 ppm systematic error to our measurement and up to ?10 ppm to other measurements using Mg and Fe transitions.”

However, the team corrected for this by comparing the UVES spectra to well-calibrated spectra obtained  from the High Accuracy Radial velocity Planet Searcher (HARPS) –  which is also located at the at the La Silla Observatory. By combining these readings, they were left with a residual systematic uncertainty of just 0.59 ppm, the lowest margin of error from any spectrographic survey to date.

High Accuracy Radial velocity Planet Searcher at the ESO La Silla 3.6m telescope. Credit: ESO
High Accuracy Radial velocity Planet Searcher at the ESO La Silla 3.6m telescope. Credit: ESO

This is exciting news, and for more reasons that one. On the one hand, precise measurements of distant galaxies allow us to test some of the most tricky aspects of our current cosmological models. On the other, determining that electromagnetism behaves in a consistent way over time is a major find, largely because it is responsible for such much of what goes on in our daily lives.

But perhaps most importantly of all, understanding how a fundamental force like electromagnetism behaves across time and space is intrinsic to finding out how it – as well as weak and strong nuclear force – unifies with gravity. This too has been a preoccupation of scientists, who are still at a loss when it comes to explaining how the laws governing particles interactions (i.e. quantum theory) unify with explanations of how gravity works (i.e general relativity).

By finding measurements of how these forces operate that are not varying could help in creating a working Grand Unifying Theory (GUT). One step closer to truly understanding how the Universe works!

Further Reading: ESO

What Are Virtual Particles?

Sometimes I figure out the weak spot in my articles based on the emails and comments they receive.

One popular article we did was all about Stephen Hawking’s realization that black holes must evaporate over vast periods of time. We talked about the mechanism, and mentioned how there are these virtual particles that pop in and out of existence.

Normally these particles self annihilate, but at the edge of a black hole’s event horizon, one particle falls in, while another is free to wander the cosmos. Since you can’t create particles from nothing, the black hole needs to sacrifice a little bit of itself to buy this newly formed particle’s freedom.

But my short article wasn’t enough to clarify exactly what virtual particles are. Clearly, you all wanted more information. What are they? How are they detected? What does this mean for black holes?

In situations like this, when I know the actual Physics Police are watching, I like to call in a ringer. Once again, I’m going to go back and talk to my good friend, and actual working astrophysicist, Dr. Paul Matt Sutter. He has written papers on subjects like the Bayesian Analysis of Cosmic Dawn and MHD Simulations of Magnetic Outflows. He really knows his stuff.

Fraser Cain:
Hey Paul, first question: What are virtual particles?

Paul Matt Sutter:
Alright. No pressure, Fraser. Okay, okay.

To get the concept of virtual particles you actually have to take a step back and think about the field, especially the electromagnetic field. In our current view of how the universe works all of space and time is filled up with this kind of background field. And this field can wibble and wabble around, and sometimes these wibbles and wabbles are like waves that propagate forward, and we call these waves photons or electromagnetic radiation, but sometimes it can just sit there and you know bloop bloop bloop, just you know pop fizzle in and out, or up and down, and kind of boil a little all on its own.

In fact all the time space is kind of wibbling/wabbling around this field even in a vacuum. A vacuum isn’t the absence of everything. The vacuum is just where this field is in its lowest energy state. But even though it’s in that lowest energy state, even though maybe on average there is nothing there. There’s nothing stopping it from just bloop bloop bloop you know bubbling around.

 Credit: NASA, ESA, Q.D. Wang (University of Massachusetts, Amherst), and S. Stolovy (Caltech)

Credit: NASA, ESA, Q.D. Wang (University of Massachusetts, Amherst), and S. Stolovy (Caltech)

So actually the vacuum is kind of boiling with these fields. In particular the electromagnetic field which is what we are talking about right now.

And we know that photons, that light, can turn into particle, anti-particle pairs. It can turn into say an electron and a positron. It can just do this. It can happen to normal photons, and it can happen to these kind of temporary wibbly wobbly photons.

So sometimes a photon or sometimes the electromagnetic field can propagate from one place to another, and we call it a photon. And that photon can split off into a positron and an electron, and other times it can just wibble wobble kind of in place and then wibble wobble POP POP. It pops into a positron and an electron and then they crash into each other or whatever, and they just simmer back down. So, wibble wobble, pop pop, fizz fizz is kind of what’s going on in the vacuum all they time, and that’s the name we give these virtual particles are just the normal kind of background fuzz or background static to the vacuum.

Okay. So how do we see evidence for virtual particles?

Yeah, great question. We know that the vacuum has an energy associated with it. We know that these virtual particles are always fizzing in and out of existence for a few reasons.

One is the transition of the electron in different states of the atom. If you excite the atom the electron pops up to a higher energy state. There is kind of no reason for that electron to pop back down to a lower energy state. It’s already there. It’s actually a stable state. There is no reason for it to leave unless there is little wibble wobbles in the electromagnetic field and it can giggle around that electron and knock it out of that higher energy state and send it crashing down into a lower state

Another thing is called the Lamb Shift, and this is when the wibbly wobbly electromagnetic field or the virtual particles interact again with electrons in say a hydrogen atom. It can gently nudge them around, and this shift effects some states of the electron and not other states. And there are actually states that you would say have the exact same say energy properties, they are just kind of identical, but because the Lamb Shift, because of this wibbly wobbly electromagnetic field interacts with one of those states and not the other, it actually subtly changes the energy levels of those states even though you’d expect them to be completely the same.

And another piece of evidence is in photon photon scattering usually two photons just, phweeet, fly by each other. They are electrically neutral, so they have no reason to interact, but sometimes the photons can wibble wobble into say electron/positron pairs, and that electron/positron pair can interact with the other photons. So sometimes they bounce off each other. It’s super rare because you have to wait for the wibble wobble to happen at just the right time, but it can happen.

Credit: NASA/Dana Berry/SkyWorks Digital
Credit: NASA/Dana Berry/SkyWorks Digital

So how do they interact with black holes?

Alright, this is the heart of the matter. What do all of these virtual particles or wibbly wobbly electromagnetic fields have to do with black holes, and specifically Hawking radiation? But check this out. Hawkings original formulation of this idea that black holes can radiate and lose mass actually has nothing to do with virtual particles. Or it doesn’t speak directly about virtual particle pairs, and in fact no other formulations or more modern conceptions of this process talk about virtual particle pairs.

Instead, they talk more about the field itself and specifically what’s happening to the field before the black hole is there, what’s happening to it as the black hole forms, and then what happens to the field after it’s formed. And it kind of asks a question: What happens to these wibbly wobbly bits of the field, these like transient kind of boiling nature of the vacuum of the electromagnetic field? What happens to it as that black hole is forming?

Well what happens is that some of the wibbly wobbly bits just get caught near the black hole, near the event horizon as it is forming, and they spend a long time there, and eventually they do escape. So it takes awhile, but when they escape because of the intense curvature there, the intense curvature of space-time, they can get boosted or promoted. So instead of being temporarily wibbly wobbly’s, in the field they get boosted to become “real” particles or “real” photons. So it’s really like an interaction of the formation of the black hole itself with the wibbly wobbly background field, that eventually escapes because it’s not quite trapped by the black hole.

Eventually it escapes and gets turned into real particles, and you can calculate like what happens with say the expected number of particles near the event horizon of the black hole. The answer is the negative number, which means the black hole is losing mass and spitting out particles.

Now this popular conception of virtual particle pairs popping into existence and one getting caught inside the event horizon. That’s is not exactly tied to the mathematics of Hawking radiation but it’s not exactly wrong either. Remember the wibbly wobbly’s in the electromagnetic field are related to these pairs of particles and anti-particles that are constantly popping in and out of existence. They kind of go hand in hand. So by talking about wibbly wobbly’s in the field you’re also kind of talking about the production of virtual particles. And it’s not exactly the math, but you know close enough.

An artist's conception of a supermassive black hole's jets. Image Credit: NASA / Dana Berry / SkyWorks Digital
An artist’s conception of a supermassive black hole’s jets. Image Credit: NASA / Dana Berry / SkyWorks Digital

Okay, and finally, Paul. I need you to just randomly blow the minds of the viewers. Something about virtual particles that is just amazing!

Alright. So you want to bend people’s minds? All right. I was saving this for the last. Something juicy, just for you, Fraser.

Check this out, it’s one other big piece of evidence we have for the existence of these background fluctuations and the existence of virtual particles, and that’s something we call the Casimir Effect, or Casimir Force.

You take two neutral metal plates, and what happens is this field that permeates all of space-time is inside the plates and it’s outside the plates. Inside the plates, you can only have certain wavelengths of modes. Almost like the inside of a trumpet can only have certain modes that make sound. The ends of the wavelengths must connect to the plates, because that’s what metal plates do to electromagnetic fields.

Outside the plates you can have any wavelength you want. It doesn’t matter.

So it means outside the plates you have an infinite number of possible wavelengths of modes. Every kind of possible kind of fluctuation, wibble wabble in the electromagnetic field is there, but inside the plates it’s only certain wavelengths that can fit inside the plates.

Now, outside there’s an infinite number of modes. Inside, there is still an infinite number of modes, just slightly fewer infinite number of modes. And you can take the infinity on the outside, and subtract the infinite infinity on the inside, and actually get a finite number, and what you end up with is a pressure or a force that brings the plates together. And we have actually measured this. This is a real thing, and yes, I am not kidding around, you can take infinity minus a different infinity, and get a finite number. It’s possible. One example is the Euler Mascheroni Constant. I dare you to look it up!

So there you go, now I hope you understand what these virtual particles are, how they’re detected, and how they contribute to the evaporation of a black hole.

And if you haven’t already, make sure you click here and go to his channel. You’ll find dozens of videos answering equally mind-bending questions. In fact, send your questions and he might just make a video and answer them.

If You Could See in Radio These Are the Crazy Shapes You’d See in the Sky

Even though it’s said that the average human eye can discern from seven to ten million different values and hues of colors, in reality our eyes are sensitive to only a very small section of the entire electromagnetic spectrum, corresponding to wavelengths in the range of 400 to 700 nanometers. Above and below those ranges lie enormously diverse segments of the EM spectrum, from minuscule yet powerful gamma rays to incredibly long, low-frequency radio waves.

Astronomers observe the Universe in all wavelengths because many objects and phenomena can only be detected in EM ranges other than visible light (which itself can easily be blocked by clouds of dense gas and dust.) But if we could see in radio waves the same way we do in visible light waves – that is with longer wavelengths being perceived as “red” and shorter wavelengths seen as “violet,” with all the blues, greens, and yellows in between – our world would look quite different… especially the night sky, which would be filled with fantastic shapes like those seen above!

View of the VLA in New Mexico. Image courtesy of NRAO/AUI.
View of the VLA in New Mexico. Image courtesy of NRAO/AUI.

Created from observations made at the Very Large Array in New Mexico, the image above shows a cluster of over 500 colliding galaxies located 800 million light-years away called Abell 2256. An intriguing target of study across the entire electromagnetic spectrum, here Abell 2256 (A2256 for short) has had its radio emissions mapped to the corresponding colors our eyes can see.

Within an area about the same width as the full Moon a space battle between magical cosmic creatures seems to be taking place! (In reality A2256 spans about 4 million light-years.)

See a visible-light image of A2256 by amateur astronomer Rick Johnson here.

The VLA radio observations will help researchers determine what’s happening within A2256, where multiple groups of galaxy clusters are interacting.

“The image reveals details of the interactions between the two merging clusters and suggests that previously unexpected physical processes are at work in such encounters,” said Frazer Owen of the National Radio Astronomy Observatory (NRAO).

Radio image of the night sky. (Credit: Max Planck Institute for Radio Astronomy, generated by Glyn Haslam.)
Radio image of the night sky. (Credit: Max Planck Institute for Radio Astronomy, generated by Glyn Haslam.)

Learn more about NRAO and radio astronomy here, and you can get an idea of what our view of the Milky Way would look like in radio wavelengths on the Square Kilometer Array’s website.

Source: NRAO

Radio Waves

Radio waves are electromagnetic waves, or electromagnetic radiation, with wavelengths of about a centimeter or longer (the boundary is rather fuzzy; microwaves and terahertz radiation are sometimes considered to be radio waves; these have wavelengths as short as a tenth of a millimeter or so). In other words, radio waves are electromagnetic radiation at the lowest energy end of the electromagnetic spectrum.

Radio waves were predicted two decades or so before they were generated and detected; in fact, the historical story is one of the great triumphs of modern science.

Many years – centuries even – of work on electrical and magnetic phenomena, by many scientists, culminated in the work of James Clerk Maxwell. In 1865 he published a set of equations which describe everything known about electricity and magnetism (electromagnetism) up till that time (the next major advance was the work of Planck and Einstein – among others – some four decades or so later, involving the discovery of photons, or quantized electromagnetic radiation). Maxwell’s equations, as they are now called, predicted that there should be a kind of wave of interacting electrical and magnetic fields, which is self-propagating, and which travels at the speed of light.

In 1887, Heinrich Hertz created radio waves in his lab, and detected them after they’d travelled a short distance … exactly as Maxwell had predicted! It wasn’t long before practical applications of this discovery were developed, leading to satellite TV, cell phones, GPS, radar, wireless home networks, and much, much, more.

For Universe Today readers, the discovery of radio waves lead to radio astronomy. Interestingly, theory again preceded observation … several scientists – Planck among them – predicted that the Sun should emit radio waves (be a source of radio waves), but the Sun’s radio emission was not detected until 1942 (by Hey, in England), nearly a decade after celestial radio waves were detected and studied, by Jansky (and Reber, among others).

Here are some other webpages, or websites, with more on radio waves: Radio Waves (NASA), How Radio Waves Are Produced (National Radio Astronomy Observatory), and Radio Waves & Electromagnetic Fields (an interactive simulation from the University of Colorado).

Universe Today stories on radio waves? Sure! Device Makes Radio Waves Travel Faster Than Light, Magnetar Crackles with Radio Waves, and All-Sky Radio Image in 60 Seconds, No Moving Parts. And that’s just a sample.

Astronomy Cast episodes covering radio waves? Sure! Radio Astronomy, and Across the Electromagnetic Spectrum are two particularly good ones.


Light Spectrum

Light spectrum can mean the visible spectrum, the range of wavelengths of electromagnetic radiation which our eyes are sensitive to … or it can mean a plot (or chart or graph) of the intensity of light vs its wavelength (or, sometimes, its frequency). More possible ambiguity: ‘light’ … which can refer to what we see, or to the part of the electromagnetic spectrum that optical telescopes (especially the ones down here on the ground) work in (and sometimes, just occasionally, it means the whole of the electromagnetic spectrum, or any electromagnetic radiation). Good news: the context makes it clear!

The realization that visible light is made up of colors is most often attributed to Isaac Newton (though a strong case can be made that it was known well before him), who used a prism to create a spectrum (rainbow of colors) from a beam of white light, and another to recombine them back into white light. And what’s it called when you spread light into a spectrum, for the purpose of studying it (in astronomy, chemistry, …)? Spectroscopy. And is there a different word if it’s infrared, ultraviolet, x-rays, … which are spread into a spectrum (rather than visible light)? Nope, it’s still spectroscopy.

Visible light ranges from about 380 nanometers (nm) to about 750 nm (or, as is still common in astronomy, ~3800 angstroms (Å) to ~7500 Å); the window in the Earth’s atmosphere which allows us to do astronomy from down here on its surface (and lets the light of the Sun through, so we can see!) is a bit wider than the visible spectrum; it goes from about 300 nm to about 1100 nm (or 1.1 µ).

To an astronomer, a light spectrum has two main components, the continuum and the lines (sometimes bands as well). The lines are discrete wavelengths (well, they do have some ‘width’, hence ‘narrow lines’ and ‘broad lines’), either emission or absorption, and correspond to a particular atomic transition (an electron jumps between one allowed energy level in an atom, or ion, and another; bands are the same thing, except for molecules … and the allowed states are either vibrational or rotational). And the continuum? Well, it’s the part that isn’t lines! It varies smoothly, and generally slowly, across the spectrum.

Spectroscopy – analysis of the light spectrum – is one of the most powerful tools astronomers use to work out what’s going on, and what it’s like, way out there where the light from the sky originates. Do you know why? If not, then these two NASA webpages will help! Visible Light Waves , and Electromagnetic Spectrum.

It’s such a broad topic, light spectrum, no wonder Universe Today has so many articles on it! For example, Amateur Spectroscopy, Atmosphere of an Extrasolar Planet Measured, and Oops, the Universe is Beige.

Astronomy Cast has several good episodes on the spectrum of light; here’s two to get you started Energy Levels and Spectra, and Detectors.