Is there any possible way to take a black hole and terraform it to be a place we could actually live?
In the challenge of terraforming the Sun, we all learned that outside of buying a Dyson Spaceshell 2000 made out of a solar system’s worth of planetbutter, it’s a terrible idea.
Making a star into a habitable world, means first destroying the stellar furnace. Which isn’t good for anyone, “Hey, free energy! vs. Let’s wreck this thing and build houses!”
Doubling down on this idea, a group of brilliant Guidensians wanted to crank the absurdity knob all the way up. You wanted to know if it would be possible to terraform a black hole.
In order to terraform something, we convert it from being Britney Spears’ level of toxic into something that humans can comfortably live on. We want reasonable temperatures, breathable atmosphere, low levels of radiation, and Earthish gravity.
With temperatures inversely proportional to their mass, a solar mass black hole is about 60 billionths of a Kelvin. This is just a smidge over absolute zero. Otherwise known as “pretty damn” cold. Actively feeding black holes can be surrounded by an accretion disk of material that’s more than 10 million degrees Kelvin, which would also kill you. Make a note, fix the temperature.
There’s no atmosphere, and it’s either the empty vacuum of space, or the superheated plasma surrounding an actively feeding black hole. Can you breathe plasma? If the answer is yes, this could work for you. If not, we’ll need to fix that.
You’d be hard pressed to find a more lethal radiation source in the entire Universe.
Black holes can spin at close to the speed of light, generating massive magnetic fields. These magnetic fields whip high energy particles around them, creating lethal doses of radiation. There are high energy particle jets pouring out of some supermassive black holes, moving at nearly the speed of light. You don’t want any part of that. We’ll add that to the list.
Black holes are known for being an excellent source of vitamin gravity. Out in orbit, it’s not so bad. Replace our Sun with a black hole of the same mass, and you wouldn’t be able to tell the difference.
So, problem solved? Not quite. If you tried to walk on the surface, you’d get shredded into a one-atom juicy stream of extruded tubemanity before you got anywhere near the time traveling alien library at the caramel center.
Reduce the gravity. Got it.
Artist rendering of a supermassive black hole. Credit: NASA / JPL-Caltech.
As we learned in a previous episode on how to kill black holes, there’s nothing you can do to affect them. You couldn’t smash comets into it to give it an atmosphere, it would just turn them into more black hole. You couldn’t fire a laser to extract material and reduce the mass, it would just turn your puny laser into more black hole.
Antimatter, explosives, stars, rocks, paper, scissors…black hole beats them all.
Repeat after me. “Om, nom, nom”.
All we can do is wait for it to evaporate over incomprehensible lengths of time. There are a few snags with this strategy, such as it will remain as a black hole until the last two particles evaporate away. There’s no point where it would magically become a regular planetoid.
That’s a full list of renovations for the cast and crew of “Pimp my Black Hole”.
Let’s look at our options. You can move it, just like we can move the Earth. Throw stuff really close to a black hole, and you get it moving with gravity. You could make it spin faster by dropping stuff into it, right up until it’s rotating at the edge of the speed of light, and you can make it more massive.
With that as our set of tools, there’s no way we’re ever going to live on a black hole.
It could be possible to surround a black hole with a Dyson Sphere, like a star.
Freemon Dyson theorized that eventually, a civilization would be able to build a megastructure around its star to capture all its energy. Credit: SentientDevelopments.com
It turns out there’s a way to have a pet black hole pay dividends aside from eating all your table scraps, shameful magazines and radioactive waste. By dropping matter into a black hole that’s spinning at close to the speed of light, you can actually extract energy from it.
Imagine you had an asteroid that was formed by two large rocks. As they get closer and closer to the black hole, tidal forces tear them apart. One chunk falls into the black hole, the smaller remaining rock has less collective mass, which allows it to escape. This remaining rock steals rotational energy from the black hole, which then slows down the rotation just a little bit.
This is the Penrose Process, named after the physicist who developed the idea. Astronomers calculated you can extract 20% of pure energy from matter that you drop in.
There’s isn’t much out there that would give you better return on your investment.
Also, it’s got to have a similar satisfying feeling as dropping pebbles off a bridge and watching them disappear from existence.
Terraforming a black hole is a terrible idea that will totally get us all killed. Don’t do it.
If you have to get close to that freakish hellscape I do recommend surrounding your pet with a Dyson Sphere and then feeding it matter and enjoying the energy you get in return.
A futuristic energy hungry civilization bent on evil couldn’t hope for a better place to live.
Have you got any more questions about black holes? Give us your suggestions in the comments below.
Why is landing on a comet so difficult and what does this tell us about future missions to comets and asteroids?
Us nerds were riveted by the coverage of the ESA’s Rosetta mission and its arrival at Comet 67/P in 2014. One such nerd is Paco Juarez, friend of the show and patron. He wanted to know why is it so darned hard to land on a comet?
In 2014, the tiny Philae Lander detached from the spacecraft and slowly descended down to the surface of the comet. If everything went well, it would have gracefully touched down and then sent back a pile of information about this filthy roving snowball.
As you know, the landing didn’t go according to plan. Instead of gently touching down on 67/P, Philae bounced off the surface of the comet like a tennis ball dropped from a tower, and rose a kilometer off the surface. Then more descending, and more bouncing, finally settling down on rugged terrain, surrounded by crevices and large boulders. At that point, engineers lost contact with the lander, and so much science went undone.
If I recorded this video a few months ago, that would have been the end of the story. You know how this goes, space exploration is hard and dangerous, don’t be surprised when your missions fail and space unfeelingly smashes up your pretty little robot probes with their little gold foil 27 pieces of flair.
Rosetta
Fortunately, I’m able to report that ESA regained contact with the Philae lander on June 13, 2015, resuming its mission, and scientific operations.
But why is landing on a comet so difficult and what does this tell us about future robotic and human missions to smaller comets and asteroids? When ESA engineers designed Philae, they knew it was going to be very difficult to land on a comet like 67/P because they have a such a low gravity. And they have low gravity because they’re little.
Illustration of the Rosetta Missions Philae lander on final approach to a comet surface. (Photo: ESA)
On Earth, 6 septillion tonnes of rock and metal give you an escape velocity of 11.2 km/s. That’s how fast you need to be able to jump in order to leave the planet entirely. But the escape velocity of 67/P is only 1 m/s. You could trip off the comet and never return. Whilst small children threw rocks at you from the surface as you drifted away.
Philae was built with harpoon drills in its landing struts. The moment the lander touched the surface of the comet, those harpoons were supposed to fire, securing the lander. The surface of the comet was softer than scientists had anticipated, and the harpoons didn’t fire. Or possibly they were broken and couldn’t fire. Space is hard. Whatever the case, without being able to grab onto the surface, it used the comet as a bouncy castle.
We’re learning what it takes to land on lower mass objects like comets and asteroids. NASA’s OSIRIS-REx mission will visit Comet Bennu, and send a lander down to the surface of the asteroid. From there it’ll pick up a few samples, and return them back to Earth. It’ll be Philae, all over again.
An artist concept of the Philae lander on comet 67P/Churyumov-Gerasimenko. Credit: Astrium – E. Viktor/ESA
In the future, we’re told, humans will be visiting asteroids to study them for science and their potential for ice and minerals. You can imagine it’ll be a harrowing descent, but even just walking around on the surface will be dangerous when every step could throw an astronaut into an escape trajectory. They’ll need to learn lessons from rock climbers and Rorschach.
As we learned with Philae, landings on low mass objects is really tough. We’re going to need to get more practice and develop new techniques and technologies before we’re ready to add asteroid mining to our list of “stuff we just do, NBD”.
What are some unusual worlds you’d like humanity to visit? Put your suggestions in the comments below.
It’s a staple of scifi, and a requirement if we’re going to travel long-term in space. Will we ever develop artificial gravity?
It’s safe to say we’ve spent a significant amount of our lives consuming science fiction.
Berks, videos, movies and games.
Science fiction is great for the imagination, it’s rich in iron and calcium, and takes us to places we could never visit. It also helps us understand and predict what might happen in the future: tablet computers, cloning, telecommunication satellites, Skype, magic slidey doors, and razors with 5 blades.
These are just some of the predictions science fiction has made which have come true.
Then there are a whole bunch of predictions that have yet to happen, but still might, Fun things like the climate change apocalypse, regular robot apocalypse, the giant robot apocalypse, the alien invasion apocalypse, the apocalypse apocalypse, comet apocalypse, and the great Brawndo famine of 2506. Continue reading “Could We Make Artificial Gravity?”
The strangest feature on Iapetus is the equatorial ridge. What could possibly create a feature like this?
To paraphrase the British geneticist J.B.S Haldane, “in my suspicion, the Universe is not only stranger than we suppose, it’s stranger than we can suppose.” The context was life and evolution, but he might as well been talking about Saturn’s moons. Those teeny worlds are some of the strangest places we’ve ever seen.
Titan is a massive moon with an atmosphere thicker than Earth’s. If it wasn’t for the bone crippling cold and unbreathable atmosphere, you could wear a pair of wings and fly around in the Titanic skies.
There’s Enceladus, an icy moon that blasts water out into space through geysers at its southern pole. But the Saturnian moon that fascinates me the most has got to be Iapetus, also known as Saturn’s yin-yang moon.
Here’s a photo captured by Cassini. Check out the bizarre surface features, where half of the moon is icy white and the other is brownish red. Astronomers believe this strange coloration comes from the ice on the warmer side sublimating away, leaving this darker material beneath.
Sure that’s a bit odd, but the strangest feature on Iapetus is the equatorial ridge. This feature measures 1,300 km long and it makes the moon look like a space walnut. Because of the heavy cratering on the ridge, astronomers know that it’s ancient, nearly as old as the moon itself. At 13 kms high, it’s tall enough to keep out the most persnickety white walker or wildling mammoth & giant battalion.
What could possibly create a feature like this?
Astronomers are of a few camps. The first think it formed through convective activity early on in the moon’s history. Saturn pulls Iapetus with its tremendous gravity, and the moon undergoes massive tidal forces. This generates heat in the moon’s interior, and it might have caused it to blob out at the equator.
A ridge that follows the equator of Saturn’s moon Iapetus gives it the appearance of a giant walnut. This image was taken by the Cassini spacecraft. Credit: NASA/JPL/SSI
A second idea is that Iapetus consumed one of Saturn’s rings, billions of years ago. The moon might have slowly wandered through the ring plane, and accreted all the ring material, like snow piling up in front of a plow.
A third is that Iapetus was smashed into by a massive asteroid billions of years ago. This impact caused the moon to fly apart, but then mutual gravity pulled it back together. The force of this recombination squeezed out material at the equator, which then solidified in place.
Alternately, it might be a walnut from a Galactus family Christmas stocking. So which is it?
It turns out that Saturn has two more moons in its system with similar equatorial ridges. Its moon Atlas is just 15 km across, but it’s dominated by an equatorial ridge. It looks like a UFO, and Pan has a similar feature.
Saturn’s relatively thin main rings are about 250,000 km (156,000 miles) in diameter. (Image: NASA/JPL-Caltech/SSI/J. Major)
Astronomers know that both of these created their ridges by pulling material out of the rings and piling it up on their surface. This is the mechanism that seems to match what’s going on with Iapetus.
One mystery, is how distantly Iapetus orbits Saturn. There’s no ring that far out, so where did it get the material to consume? Is it possible that Iapetus drifted outward, or had a ring system of its own?
You want puzzles? Iapetus is one of the strangest places in the Solar System, and it would be my candidate for a future orbiter or lander. Let’s explore it closer.
What’s your favorite bizarre object in the Solar System? Tell us in the comments below.
What would it take to destroy our moon, and eliminate the enemy of stellar astronomy for all time?
In the immortal words of Mr. Burns, “ever since the beginning of time, man has wished to destroy the Sun.” Your days are numbered, Sun.
But supervillains, being the practical folks they are, know that a more worthy goal would be to destroy the Moon, or at least deface it horribly. Nothing wrecks a beautiful night sky like that hideous pockmarked spotlight. What would it take to destroy it and eliminate the enemy of stellar astronomy for all time?
Crack out your Acme brand blueprint paper and white pencils, it’s Wile E. Coyote time.
The energy it takes to dismantle a gravitationally held object is known as its binding energy, we talked about it in a Death Star episode and inventive ways to overcome it.
For example, the binding energy of the Earth is 2.2 x 10^32 joules. It’s a lot. The binding energy of a smaller object, like our Moon is a tidy little 1.2 x 10^29 joules. It takes about 1800 times more energy to destroy the Earth than it takes to destroy the Moon.
It’s 1800 times easier. That’s downright doable, isn’t it? That’s almost 2000 times easier. Which, on the scale of easy to less easy, is definitely closer to easy.
Take the event that created the Caloris Basin on Mercury. It’s a crater, 1,500 km across. Astronomers think that a big fat asteroid, a fatsteroid(?) around 100 km in diameter crashed into Mercury billions of years ago. This event released 1.3 x 10^26 joules of energy, carving out this giant pit. It’s a thousandth of the binding energy of the Moon. We’ll need something more.
Our Sun produces 3.8 x 10^26 joules of energy every second, the equivalent of about a billion hydrogen bombs. If you directed the full power of the Sun at the Moon for 15 minutes, it’d tear apart.
That’s quite a superweapon you’ve got there, perhaps you’ll want to mount that on a space station and take it for a cruise through a galaxy far far away?
If that scene took that long, we’d have fallen asleep. It’s as if millions of voices gradually became a little hoarse from crying out for a quarter of an hour. There’s another way you could tear the Moon apart that doesn’t require an astral gate accident: gravity.
Astronomers use the Roche Limit to calculate how close an object – like a moon – can orbit another object – like a planet.
This is the point where the difference between the tidal forces on the “front” and “backside” are large enough that the object is torn apart, and if this sounds familiar you might want to look up “spaghettification”.
Spaghettification. Credit: Streeter
This is all based on the radius of the planet and the density of the planet and moon. If the Moon got close enough to the Earth, around 18,000 km, it would pull apart and be shredded into a beautiful ring.
And then the objects in the ring would enter the Earth’s atmosphere and rain down beautiful destruction for thousands of years.
Fortunately or unfortunately, depending your position in this “Die Moon, Die” discussion, the Moon is drifting away from the Earth. It’ll never be closer than it is right now, at almost 400,000 km, without a little nudge.
Phobos, the largest moon orbiting Mars is slowly approaching the planet, and astronomers think it’ll reach the Roche Limit in the next few million years.
It turns out that if we really want to destroy the Moon, we’ll need to destroy all life on Earth as well.
Now we know your new supervillain project, what’s your supervillain name? Tell us your handle in the comments below.
How long would it take for the gravitational well created by the Sun to disappear, and the Earth and the rest of the planets fly off into space?
In the very first episode of the Guide to Space, a clean shaven version of me, hunched over in my basement explained how long it takes for light to get from the Sun to the Earth. To answer that question, it takes light about 8 minutes and 20 seconds to make the trip.
In other words, if the Sun suddenly disappeared from space itself, we’d still see it shining in the sky for over 8 minutes before the everything went dark. Martians would take about 12 minutes to notice the Sun was gone, and New Horizons which is nearly at Pluto wouldn’t see a change for over 4 hours.
Although this idea is a little mind-bending, I’m sure you’ve got your head wrapped around it. We’ve sure gone on about it here on this show. The further you look into space, the further you’re looking back in time because of the speed of light, but have you ever considered the speed of gravity?
Let’s go back to that original example and remove the Sun again. How long would it take for the gravitational well created by the Sun to disappear.
When would the Earth and the rest of the planets fly off into space without the Sun holding the whole Solar System together with its gravity? Would it happen instantly, or would it take time for the information to reach Earth?
It sounds like a simple question, but it’s actually really tough to tell. The force of gravity, compared to other forces in the Universe, is actually pretty weak. It’s practically impossible to test in the laboratory.
According to Einstein’s Theory of Relativity, distortions in spacetime caused by mass – also known as gravity – will propagate out at the speed of light. In other words, the light from the Sun and the gravity of the Sun should disappear at exactly the same time from the Earth’s perspective.
But that’s just a theory and a bunch of fancy math. Is there any way to test this out in reality? Astronomers have figured a way to deduce this indirectly by watching the interactions with massive objects in space.
In the binary system PSR 1913+16, there’s a pair of pulsars orbiting each other within just a few times bigger than the width of the Sun. As they spin around each other, the pulsars warp the spacetime themselves by releasing gravitational waves. And this release of gravitational waves causes the pulsars to slow down.
It’s amazing that astronomers can even measure this orbital decay, but the even more amazing part is that they use this process to measure the speed of gravity. When they did the calculations, astronomers determined the speed of gravity to be within 1% of the speed of light – that’s close enough.
Scientists have also used careful observations of Jupiter to get at this number. By watching how Jupiter’s gravity warps the light from a background quasar as it passes in front, they were able to determine that the speed of gravity is between 80% and 120% of the speed of light. Again, that’s close enough.
So there you go. The speed of gravity equals the speed of light. And should the Sun suddenly disappear, we’ll be glad to get all the bad news at the same time.
Gravity is a harsh mistress. Tell us a story about a time gravity was too fast for you. Put it in the comments below.
Astronomer Copernicus, or Conversations with God, by Matejko. Credit: frombork.art.pl/pl/
When it comes to understanding our place in the universe, few scientists have had more of an impact than Nicolaus Copernicus. The creator of the Copernican Model of the universe (aka. heliocentrism), his discovery that the Earth and other planets revolved the Sun triggered an intellectual revolution that would have far-reaching consequences.
In addition to playing a major part in the Scientific Revolution of the 17th and 18th centuries, his ideas changed the way people looked at the heavens, the planets, and would have a profound influence over men like Johannes Kepler, Galileo Galilei, Sir Isaac Newton and many others. In short, the “Copernican Revolution” helped to usher in the era of modern science.
Copernicus’ Early Life:
Copernicus was born on February 19th, 1473 in the city of Torun (Thorn) in the Crown of the Kingdom of Poland. The youngest of four children to a well-to-do merchant family, Copernicus and his siblings were raised in the Catholic faith and had many strong ties to the Church.
His older brother Andreas would go on to become an Augustinian canon, while his sister, Barbara, became a Benedictine nun and (in her final years) the prioress of a convent. Only his sister Katharina ever married and had children, which Copernicus looked after until the day he died. Copernicus himself never married or had any children of his own.
Nicolaus Copernicus portrait from Town Hall in Torun (Thorn), 1580. Credit: frombork.art.pl
Born in a predominately Germanic city and province, Copernicus acquired fluency in both German and Polish at a young age, and would go on to learn Greek and Italian during the course of his education. Given that it was the language of academia in his time, as well as the Catholic Church and the Polish royal court, Copernicus also became fluent in Latin, which the majority of his surviving works are written in.
Copernicus’ Education:
In 1483, Copernicus’ father (whom he was named after) died, whereupon his maternal uncle, Lucas Watzenrode the Younger, began to oversee his education and career. Given the connections he maintained with Poland’s leading intellectual figures, Watzenrode would ensure that Copernicus had great deal of exposure to some of the intellectual figures of his time.
Although little information on his early childhood is available, Copernicus’ biographers believe that his uncle sent him to St. John’ School in Torun, where he himself had been a master. Later, it is believed that he attended the Cathedral School at Wloclawek (located 60 km south-east Torun on the Vistula River), which prepared pupils for entrance to the University of Krakow – Watzenrode’s own Alma mater.
In 1491, Copernicus began his studies in the Department of Arts at the University of Krakow. However, he quickly became fascinated by astronomy, thanks to his exposure to many contemporary philosophers who taught or were associated with the Krakow School of Mathematics and Astrology, which was in its heyday at the time.
A comparison of the geocentric and heliocentric models of the universe. Credit: history.ucsb.edu
Copernicus’ studies provided him with a thorough grounding in mathematical-astronomical knowledge, as well as the philosophy and natural-science writings of Aristotle, Euclid, and various humanist writers. It was while at Krakow that Copernicus began collecting a large library on astronomy, and where he began his analysis of the logical contradictions in the two most popular systems of astronomy.
These models – Aristotle’s theory of homocentric spheres, and Ptolemy’s mechanism of eccentrics and epicycles – were both geocentric in nature. Consistent with classical astronomy and physics, they espoused that the Earth was at the center of the universe, and that the Sun, the Moon, the other planets, and the stars all revolved around it.
Before earning a degree, Copernicus left Krakow (ca. 1495) to travel to the court of his uncle Watzenrode in Warmia, a province in northern Poland. Having been elevated to the position of Prince-Bishop of Warmia in 1489, his uncle sought to place Copernicus in the Warmia canonry. However, Copernicus’ installation was delayed, which prompted his uncle to send him and his brother to study in Italy to further their ecclesiastic careers.
In 1497, Copernicus arrived in Bologna and began studying at the Bologna University of Jurists’. While there, he studied canon law, but devoted himself primarily to the study of the humanities and astronomy. It was also while at Bologna that he met the famous astronomer Domenico Maria Novara da Ferrara and became his disciple and assistant.
An illustration of the Ptolemaic geocentric system by Portuguese cosmographer and cartographer Bartolomeu Velho, 1568. Credit: bnf.fr
Over time, Copernicus’ began to feel a growing sense of doubt towards the Aristotelian and Ptolemaic models of the universe. These included the problematic explanations arising from the inconsistent motion of the planets (i.e. retrograde motion, equants, deferents and epicycles), and the fact that Mars and Jupiter appeared to be larger in the night sky at certain times than at others.
Hoping to resolve this, Copernicus used his time at the university to study Greek and Latin authors (i.e. Pythagoras, Cicero, Pliny the Elder, Plutarch, Heraclides and Plato) as well as the fragments of historic information the university had on ancient astronomical, cosmological and calendar systems – which included other (predominantly Greek and Arab) heliocentric theories.
In 1501, Copernicus moved to Padua, ostensibly to study medicine as part of his ecclesiastical career. Just as he had done at Bologna, Copernicus carried out his appointed studies, but remained committed to his own astronomical research. Between 1501 and 1503, he continued to study ancient Greek texts; and it is believed that it was at this time that his ideas for a new system of astronomy – whereby the Earth itself moved – finally crystallized.
The Copernican Model (aka. Heliocentrism):
In 1503, having finally earned his doctorate in canon law, Copernicus returned to Warmia where he would spend the remaining 40 years of his life. By 1514, he began making his Commentariolus (“Little Commentary”) available for his friends to read. This forty-page manuscript described his ideas about the heliocentric hypothesis, which was based on seven general principles.
These seven principles stated that: Celestial bodies do not all revolve around a single point; the center of Earth is the center of the lunar sphere—the orbit of the moon around Earth; all the spheres rotate around the Sun, which is near the center of the Universe; the distance between Earth and the Sun is an insignificant fraction of the distance from Earth and Sun to the stars, so parallax is not observed in the stars; the stars are immovable – their apparent daily motion is caused by the daily rotation of Earth; Earth is moved in a sphere around the Sun, causing the apparent annual migration of the Sun; Earth has more than one motion; and Earth’s orbital motion around the Sun causes the seeming reverse in direction of the motions of the planets.
Andreas Cellarius’s illustration of the Copernican system, from the Harmonia Macrocosmica (1708). Credit: Public Domain
Thereafter he continued gathering data for a more detailed work, and by 1532, he had come close to completing the manuscript of his magnum opus – De revolutionibus orbium coelestium(On the Revolutions of the Heavenly Spheres). In it, he advanced his seven major arguments, but in more detailed form and with detailed computations to back them up.
However, due to fears that the publication of his theories would lead to condemnation from the church (as well as, perhaps, worries that his theory presented some scientific flaws) he withheld his research until a year before he died. It was only in 1542, when he was near death, that he sent his treatise to Nuremberg to be published.
Copernicus’ Death:
Towards the end of 1542, Copernicus suffered from a brain hemorrhage or stroke which left him paralyzed. On May 24th, 1543, he died at the age of 70 and was reportedly buried in the Frombork Cathedral in Frombork, Poland. It is said that on the day of his death, May 24th 1543 at the age of 70, he was presented with an advance copy of his book, which he smiled upon before passing away.
In 2005, an archaeological team conducted a scan of the floor of Frombork Cathedral, declaring that they had found Copernicus’ remains. Afterwards, a forensic expert from the Polish Police Central Forensic Laboratory used the unearthed skull to reconstruct a face that closely resembled Copernicus’ features. The expert also determined that the skull belonged to a man who had died around age 70 – Copernicus’ age at the time of his death.
These findings were backed up in 2008 when a comparative DNA analysis was made from both the remains and two hairs found in a book Copernicus was known to have owned (Calendarium Romanum Magnum, by Johannes Stoeffler). The DNA results were a match, proving that Copernicus’ body had indeed been found.
Copernicus’ 2010 grave in Frombork Cathedral, acknowledging him as a church canon and the father of heliocentricism. Credit: Wikipedia/Holger Weinandt
On May 22nd, 2010, Copernicus was given a second funeral in a Mass led by Józef Kowalczyk, the former papal nuncio to Poland and newly named Primate of Poland. Copernicus’ remains were reburied in the same spot in Frombork Cathedral, and a black granite tombstone (shown above) now identifies him as the founder of the heliocentric theory and also a church canon. The tombstone bears a representation of Copernicus’ model of the solar system – a golden sun encircled by six of the planets.
Copernicus’ Legacy:
Despite his fears about his arguments producing scorn and controversy, the publication of his theories resulted in only mild condemnation from religious authorities. Over time, many religious scholars tried to argue against his model, using a combination of Biblical canon, Aristotelian philosophy, Ptolemaic astronomy, and then-accepted notions of physics to discredit the idea that the Earth itself would be capable of motion.
However, within a few generation’s time, Copernicus’ theory became more widespread and accepted, and gained many influential defenders in the meantime. These included Galileo Galilei (1564-1642), who’s investigations of the heavens using the telescope allowed him to resolve what were seen at the time as flaws in the heliocentric model.
These included the relative changes in the appearances of Mars and Jupiter when they are in opposition vs. conjunction to the Earth. Whereas they appear larger to the naked eye than Copernicus’ model suggested they should, Galileo proved that this is an illusion caused by the behavior of light at a distance, and can be resolved with a telescope.
1973 Federal Republic of Germany 5-mark silver coin commemorating 500th anniversary of Copernicus’ birth. Credit: Wikipedia/Berlin-George
Through the use of the telescope, Galileo also discovered moons orbiting Jupiter, Sunspots, and the imperfections on the Moon’s surface, all of which helped to undermine the notion that the planets were perfect orbs, rather than planets similar to Earth. While Galileo’s advocacy of Copernicus’ theories resulted in his house arrest, others soon followed.
German mathematician and astronomer Johannes Kepler (1571-1630) also helped to refine the heliocentric model with his introduction of elliptical orbits. Prior to this, the heliocentric model still made use of circular orbits, which did not explain why planets orbited the Sun at different speeds at different times. By showing how the planet’s sped up while at certain points in their orbits, and slowed down in others, Kepler resolved this.
In addition, Copernicus’ theory about the Earth being capable of motion would go on to inspire a rethinking of the entire field of physics. Whereas previous ideas of motion depended on an outside force to instigate and maintain it (i.e. wind pushing a sail) Copernicus’ theories helped to inspire the concepts of gravity and inertia. These ideas would be articulated by Sir Isaac Newton, who’s Principia formed the basis of modern physics and astronomy.
Today, Copernicus is honored (along with Johannes Kepler) by the liturgical calendar of the Episcopal Church (USA) with a feast day on May 23rd. In 2009, the discoverers of chemical element 112 (which had previously been named ununbium) proposed that the International Union of Pure and Applied Chemistry rename it copernicum (Cn) – which they did in 2011.
Mosaic image of the Copernicus Crater on the Moon, taken by the Lunar Reconnaissance Orbiter, . Credit: NASA/LRO
In 1973, on the 500th anniversary of his birthday, the Federal Republic of Germany (aka. West Germany) issued a 5 Mark silver coin (shown above) that bore Copernicus’ name and a representation of the heliocentric universe on one side.
In August of 1972, the Copernicus– an Orbiting Astronomical Observatory created by NASA and the UK’s Science Research Council – was launched to conduct space-based observations. Originally designated OAO-3, the satellite was renamed in 1973 in time for the 500th anniversary of Copernicus’ birth. Operating until February of 1981, Copernicus proved to be the most successful of the OAO missions, providing extensive X-ray and ultraviolet information on stars and discovering several long-period pulsars.
Two craters, one located on the Moon, the other on Mars, are named in Copernicus’ honor. The European Commission and the European Space Agency (ESA) is currently conducting the Copernicus Program. Formerly known as Global Monitoring for Environment and Security (GMES), this program aims at achieving an autonomous, multi-level operational Earth observatory.
On February 19th, 2013, the world celebrated the 540th anniversary of Copernicus’ birthday. Even now, almost five and a half centuries later, he is considered one of the greatest astronomers and scientific minds that ever lived. In addition to revolutionizing the fields of physics, astronomy, and our very concept of the laws of motion, the tradition of modern science itself owes a great debt to this noble scholar who placed the truth above all else.
We hear that black holes absorb all the light that falls into them. And yet, we hear of black holes shining so brightly we can see them halfway across the Universe. What’s going on? Which is it?
I remember back to a classic episode of the Guide to Space, where I provided an extremely fascinating and concise explanation for what a quasar is. Don’t recall that episode? Well, it was super. Just super. Alright slackers, let’s recap.
Quasars are the brightest objects in the Universe, visible across billions of light years. Likely blanching life from everything in the path of the radiation beam from its lighthouse of death. They occur when a supermassive black hole is actively feeding on material, pouring out a mountain of radiation. Black holes, of course, are regions of space with such intense gravity where nothing, not even light itself, can escape.
But wait, not so fast “recap” Fraser Cain. I call shenanigans. If black holes absorb all the radiation that falls into them, how can they be bright?
You, Fraser Cain of days of yore, cannot have it both ways. It’s either a vortex of total destruction gobbling all the matter and light that fall into them OR alternately light can escape, which still sounds good. I mean, it could be WHERE NO STUFF CAN ESCAPE, except light.
If you’ll admit that you of the past was wrong, we’ll put you in the temporal cone of shame and move on with the episode. Right? Right? Wrong.
Let’s review. Black holes are freaky complicated beasts, with many layers. And I don’t mean that in some abstract Choprian “many connections on many different levels”. They’re a gobstopper from a Sam Neill Event Horizon style hellscape. Let’s take a look at the anatomy of a black hole, and everything should fall into place, including the terror.
At the very heart of the black hole is the singularity. This is the region of compressed matter that used to be a star, or in the case of a supermassive black hole, millions or billions of times the mass of a star. Astronomers have no idea what the singularity looks like or behaves, because our understanding of physics completely breaks down, along with the rest of our brains.
Illustration of Cygnus X-1, another stellar-mass black hole located 6070 ly away. (NASA/CXC/M.Weiss)
It’s possible that the singularity is a sphere of exotic matter, or maybe it’s constantly compressing down into an infinitely small size. It could also be a pork pie. We’ll never know, because nothing goes fast enough to escape from a black hole, not even light.
Maybe you’d need to be going 10 times the speed of light to escape. Or maybe a trillion times the speed of light. Which makes it easy; as far as we can tell, nothing can go faster than the speed of light, and so nothing is escaping.
As you get further from the singularity, the force of gravity decreases. Initially, it’ll still requires that you go faster than light. You’ll finally reach a very specific point where the escape velocity is exactly the speed of light. This is the event horizon, and it’s a different distance from the singularity with every black hole. That’s the line. Within the event horizon, the light is doomed, outside the event horizon, it can escape. This is the hard candy shell surrounding the chocolately unimaginable nightmare of physics.
So when see bright black holes, like a quasar, we’re not actually seeing light coming from inside the black hole itself or reflected of its surface. What we’re seeing is the material that’s piling up just outside the event horizon. For all its voracious hunger, a black hole’s gravitational eyes are much bigger than its stomach, and it can only feed so quickly. Excess stuff piles up around the black hole’s face and forms a vast disk of material, just like me at a Pizza Hut’s $5 all you can eat buffet. This pizza heats up until it’s like the core of a star, and starts blasting out radiation into space.
A WFPC2 image of a spiral-shaped disk of hot gas in the core of active galaxy M87. HST measurements show the disk is rotating so rapidly it contains a massive black hole at its hub.
Everything I’ve said is for non-spinning black holes, by the way. Physicists will always make this point with great emphasis. Stay your angry comments astrophysicists, for I have said the magic stone-cutter appeasement code-word, “Non-rotating”.
Of course, black holes do rotate, and can rotate at nearly the speed of light. And this rotation changes the nature of the black hole’s event horizon in ways that make difficult math even harder. All this spinning generates powerful magnetic fields around the black hole, which focuses jets of material that blast out for hundreds of thousands of light-years. When we see these bright quasars, we’re staring right at these jets with our delicate little eyeballs.
So how can we see light coming from black holes when black holes absorb all light? It’s not coming from black holes. It’s coming from the super-heated region of junk all around the black hole. And still, anything that falls through the event horizon, whether it be light, junk, you, me or Grumpy Cat it will never been seen again.
What’s your favorite sci-fi black hole? Tell us in the comments below.
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Fritz Zwicky. Image Source: Fritz Zwicky Stiftung website
Dark matter can’t be seen or detected by any of our instruments, so how do we know it really exists?
Imagine the Universe was a pie, and you were going to slice it up into tasty portions corresponding to what proportions are what. The largest portion of the pie, 68% would go to dark energy, that mysterious force accelerating the expansion of the Universe. 27% would go to dark matter, the mysterious matter that surrounds galaxies and only interacts through gravity. A mere 5% of this pie would go to regular normal matter, the stuff that stars, planets, gas, dust, and humans are made out of.
Dark matter has been given this name because it doesn’t seem to interact with regular matter in any way. It doesn’t collide with it, or absorb energy from it. We can’t see it or detect it with any of our instruments. We only know it’s there because we can see the effect of its gravity.
Now, you might be saying, if we don’t know what this thing is, and we can’t detect it. How do we know it’s actually there? Isn’t it probably not there, like dragons? How do we know dark matter actually exists, when we have no idea what it actually is?
Oh, it’s there. In fact, pretty much all we know is that it does exist. Dark matter was first theorized back in the 1930s by Fritz Zwicky to account for the movement of galaxy clusters, but the modern calculations were made by Vera Rubin in the 1960s and 70s. She calculated that galaxies were spinning more quickly than they should. So quickly that they should tear themselves apart like a merry-go-round ejecting children.
Rubin imagined that every galaxy was stuck inside a vast halo of dark matter that supplied the gravity to hold the galaxy together. But there was no way to actually detect this stuff, so astronomers proposed other models. Maybe gravity doesn’t work the way we think it does at vast distances.
But in the last few years, astronomers have gotten better and better at detecting dark matter, purely though the effect of its gravity on the path that light takes as it crosses the Universe. As light travels through a region of dark matter, its path gets distorted by gravity. Instead of taking a straight line, the light is bent back and forth depending on how much dark matter is passes through.
And here’s the amazing part. Astronomers can then map out regions of dark matter in the sky just by looking at the distortions in the light, and then working backwards to figure out how much intervening dark matter would need to be there to cause it.
Large Hadron Collider. Credit: NY Times
These techniques have become so sophisticated that astronomers have discovered unusual situations where galaxies and their dark matter have gotten stripped away from each other. Or dark matter galaxies which don’t have enough gas to form stars. They’re just giant blobs of dark matter. Astronomers even use dark matter as gravitational lenses to study more distant objects. They have no idea what dark matter is, but they can still use it as a telescope.
They’ve never captured a dark matter particle, and haven’t studied them in the lab. One of the Large Hadron Collider’s next tasks will be to try and generate particles that match the characteristics of dark matter as we understand it. Even if the LHC doesn’t actually create dark matter, it will help narrow down the current theories, hopefully helping physicists focus in on the true nature of this mystery.
This is how science works. Someone notices something unusual, and then people propose theories to explain it. The theory that best matches reality is considered correct. We live in a modern world, where so many scientific theories have already been proven for hundreds of years: germs, gravity, evolution, etc. But with dark matter, you’re alive at a time when this is a mystery. And if we’re lucky, we’ll see it solved within our lifetime. Or maybe there’s no dark matter after all, and we’re about to learn something totally new about our Universe. Science, it’s all up to you.
What do you think dark matter is? Tell us in the comments below.
If you’ve read your share of sci-fi, and I know you have, you’ve read stories about another Earth-sized planet orbiting on the other side of the Solar System, blocked by the Sun. Could it really be there?
No. Nooooo. No. Just no.
This is a delightful staple in science fiction. There’s a mysterious world that orbits the Sun exactly the same distance as Earth, but it’s directly across the Solar System from us; always hidden by the Sun. Little do we realize they know we’re here, and right now they’re marshalling their attack fleet to invade our planet. We need to invade counter-Earth before they attack us and steal our water, eat all our cheese or kidnap our beloved Nigella Lawson and Alton Brown to rule as their culinary queen and king of Other-Earth.
Well, could this happen? Could there be another planet in a stable orbit, hiding behind the Sun? The answer, as you probably suspect, is NO. No. Nooooo. Just no.
Well, that’s not completely true. If some powerful and mysterious flying spaghetti being magically created another planet and threw it into orbit, it would briefly be hidden from our view because of the Sun. But we don’t exist in a Solar System with just the Sun and the Earth. There are those other planets orbiting the Sun as well. As the Earth orbits the Sun, it’s subtly influenced by those other planets, speeding up or slowing down in its orbit.
So, while we’re being pulled a little forwards in our orbit by Jupiter, that other planet would be on the opposite side of the Sun. And so, we’d speed up a little and catch sight of it around the Sun. Over the years, these various motions would escalate, and that other planet would be seen more and more in the sky as we catch up to it in orbit.
Eventually, our orbits would intersect, and there’d be an encounter. If we were lucky, the planets would miss each other, and be kicked into new, safer, more stable orbits around the Sun. And if we were unlucky, they’d collide with each other, forming a new super-sized Earth, killing everything on both planets, obviously.
Diagram of the five Lagrange points associated with the sun-Earth system, showing DSCOVR orbiting the L-1 point. Image is not to scale. Credit: NASA/WMAP Science Team
What if there was originally two half-Earths and they collided and that’s how we got current Earth! Or 4 quarter Earths, each with their own population? And then BAM. One big Earth. Or maybe 64 64th Earths all transforming and converging to form VOLTREARTH.
Now, I’m now going to make things worse, and feed your imagination a little with some actual science. There are a few places where objects can share a stable orbit. These locations are known as Lagrange points, regions where the gravity of two objects create a stable location for a third object. The best of these are known as the L4 and L5 Lagrangian points. L4 is about 60-degrees ahead of a planet in its orbit, and L5 is about 60-degrees behind a planet in its orbit.
A small enough body, relative to the planet, could hang out in a stable location for billions of years. Jupiter has a collection of Trojan asteroids at its L4 and L5 points of its orbit, always holding at a stable distance from the planet. Which means, if you had a massive enough gas giant, you could have a less massive terrestrial world in a stable orbit 60-degrees away from the planet.
Grumpy Cat has the correct answer. Credit: grumpycat.com
Well, it was a pretty clever idea. Unfortunately, the forces of gravity conspire to make this hidden planet idea completely impossible. Most importantly, when someone tells you there’s a hidden planet on the other side of the Sun, just remember these words:
No.
Nooooo.
No.
Go ahead and name your favorite sci-fi stories that have used this trope. Tell us in the comments below.
Thanks for watching! Never miss an episode by clicking subscribe. Our Patreon community is the reason these shows happen. We’d like to thank Gary Golden and the rest of the members who support us in making great space and astronomy content. Members get advance access to episodes, extras, contests, and other shenanigans with Jay, myself and the rest of the team.
