Special Guests:
Dr. Sara Seager, whose research focuses on computer models of exoplanet atmospheres, interiors, and biosignatures. Her favorite projects involve the search for planets like Earth with signs of life
on them.
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.
The gravity of the Earth is a tough thing to escape, but breaking free from the gravity of the Sun is on a whole other level. But humans have achieved this amazing accomplishment, and right now there are several spacecraft leaving the Solar System and never coming back.
Special Guests:New Horizons staff Dr. Alan Stern, Principal Investigator; Alice Bowman, Mission Operations Manager; and Emily Lakdawalla from The Planetary Society
In the list of crazy hypothetical ideas, terraforming the Sun has to be one of the top 10. So just how would someone go about doing terraforming our sun, a star, if they wanted to try?
In our series on terraforming other worlds, we’ve covered Mars, Venus, the Moon and Jupiter. Even though I solved the problem of how to terraform Jupiter (you’re welcome, science), you wanted to take things to the next level and you demanded I sort out how to terraform the Sun. Seriously? The Sun. Fine… here we go.
Let’s see what we’ve got to work with here. It’s a massive ball of plasma, containing 333,000 times more mass than the Earth. It’s about 74% hydrogen and 25% helium with a few other trace elements. There’s no solid surface to stand on it, so we need to fix that.
The average temperature on the surface of the Sun is about 5,500 Celsius, while the average temperature on Earth is about 15 C. Iron boils at only 2,800 degrees, so… that’s probably too hot. We’ll need to cool it down.
The gravity on the surface of the Sun is 28 times the gravity of Earth. If you could stand on the surface of the Sun, which you can’t, you’d be crushed flat. Okay, so we’ll add reduce the gravity… check.
There’s no breathable atmosphere, there’s no solid ground, the Sun generates deadly X-rays. Oh, and don’t forget about the terrible sunburns from the ultraviolet radiation.
So, what’s the list? Hot fire unbreathable pressure cooker goo surface gravity crushing machine. Sounds impossible, or does it?
First, the gas. As we covered in a previous episode, scientists have actually considered ways that you might extract the hydrogen and helium off of a star like the Sun, known as “stellar lifting”. There are a few ways you could work this. You could zap the surface of the Sun with a powerful laser, increasing the speed of solar wind in that area, forcing the Sun to throw its mass off into space.
Another method is to set up powerful magnetic fields around the Sun’s poles, and channel its hydrogen into jets that blast out into space. I’m not sure how you actually set up those magnetic fields, but that’s not my problem.
Once you’re done with the Sun, you’ve stripped away all its hydrogen and helium gas. What are you left with? About 5,600 times the mass of the Earth in heavier elements, like oxygen, silicon, gold, etc. Great!
Except 5,600 sounds like a lot. Jupiter is only 316 times the mass of the Earth. We’re looking to reform a “planet” with more than 10 times the mass of Jupiter. And not only that, but we had to kill the Sun to make this work. You monsters.
This is a terrible idea. What else could we do? If you’re a science fiction fan, you’ve heard of a Dyson Sphere. If not, you’ve got some TNG to catch up on.
First proposed by Freeman Dyson, you cover an entire Sun in a metal ball. Instead of the measly amount of energy that falls on Earth, this would allow you to capture 100% of the energy released by the Sun: 384 yottawatts.
According to Dyson and a variety of matheletes, you could dismantle all planets in the Solar System and build a sphere at a distance of 1 Earth radii at 8 to 20 centimeters thick. That would give you a surface area 550 million times more than the Earth.
Although, building an actual rigid sphere is probably unfeasible because it would be pretty unstable and eventually collapse. It probably makes more sense to build a swarm of satellites surrounding the Sun, capturing its energy.
We did a whole video on Dyson Spheres. Check it out here.
So there you go. I just terraformed the Sun. I’m terrified about your next suggestion: how could you terraform a black hole? I guess that’ll be the next video.
Would you like to live on my imagined terraformed Sun? If not, what about a Dyson Sphere or swarm?
We know that in space, no one can hear you scream. But what would things sound like on another planet?
When humans finally set foot on Mars, they’re going to be curious about everything around them.
What’s under that rock? What does it feel like to jump in the lower Martian gravity. What does Martian regolith taste like? What’s the bitcoin to red rock exchange rate?
As long as they perform their activities in the safety of a pressurized habitation module or exosuit, everything should be fine. But what does Mars sound like?
I urge all future Martian travelers, no matter how badly you want to know the answer to this question: don’t take your helmet off. With only 1% the atmospheric pressure of Earth, you’d empty your lungs with a final scream in a brief and foolish moment, then suffocate horribly with a mouthful of dust on the surface of the Red Planet.
But… actually, even the screaming would sound a little different. How different? Let me show you. First you just need to take your helmet off for a just a little sec, just an itsy bitsy second. Here, I’ll hold it for you. Oh, come on, just take your helmet off. All the cool kids are doing it.
What about Venus? Or Titan? What would everything sound like on an alien world?
We evolved to exist on Earth, and so it’s perfectly safe for us to listen to sounds in the air. No space suit needed. Unless you didn’t evolve on Earth, in which case I offer to serve as emissary to our all new alien overlords.
You know sounds travel when waves of energy propagate through a medium, like air or water. The molecules bump into each other and pass along the energy until they strike something that won’t move, like your ear drum. Then your brain turns bouncing into sounds.
The speed of the waves depends on what the medium is made of and how dense it is. For example, sound travels at about 340 meters/second in dry air, at sea level at room temperature. Sound moves much more quickly through liquid. In water it’s nearly 1,500 m/s. It’s even faster through a solid – iron is up past 5,100 m/s. Our brain perceives a different sound depending on the intensity of the waves and how quickly they bounce off our ears.
Artist’s impression of the surface of Venus. Credit: ESA/AOES
Other worlds have media that sound waves can travel through, and with your eardrum exposed to the atmosphere you should theoretically hear sounds on other worlds. Catastrophic biological failures from using your eardrums outside of documented pressure tolerances notwithstanding.
Professor Tim Leighton and a team of researchers from the University of Southampton have simulated what we would hear standing on the surface of other worlds, like Mars, Venus or even Saturn’s Moon Titan.
On Venus, the pitch of your voice would become deeper, because vocal cords would vibrate much more slowly in the thicker Venusian atmosphere. But sounds would travel more quickly through the soupy atmosphere. According to Dr. Leighton, humans would sound like bass Smurfs. Mars would sound a little bit higher, and Titan would sound totally alien.
Dr. Leighton actually simulated the same sound on different worlds. Here’s the sound of thunder on Earth.
Here’s what it would sound like on Venus.
And here’s what it would sound like on Mars.
Here’s what a probe splashing into water on Earth would sound like.
And here’s what it would sound like splashing into a hydrocarbon lake on Titan.
You might be amazed to learn that we still haven’t actually recorded sounds on another world, right up until someone points out that putting a microphone on another planet hasn’t been that big a priority for any space mission.
A fish-eye view of Titan’s surface from the European Space Agency’s Huygens lander in January 2005. Credit: ESA/NASA/JPL/University of Arizona
Especially when we could analyze soil samples, but hey fart sounds played and then recorded in the Venusian atmosphere could prove incredibly valuable to the future of internet soundboards.
The Planetary Society has been working to get a microphone included on a mission. They actually included a microphone on the Mars Polar Lander mission that failed in 1999. Another French mission was going to have a microphone, but it was cancelled. There are no microphones on either Spirit or Opportunity, and the Curiosity Rover doesn’t have one either despite its totally bumping stereo.
Here’s is the only thing we’ve got. When NASA’s Phoenix Lander reached the Red Planet in 2008, it had a microphone on board to capture sounds. It recorded audio as it entered the atmosphere, but operators turned the instrument off before it reached the surface because they were worried it would interfere with the landing.
Meh. I’m going to need you to do better NASA. I want an actual microphone recording winds on the surface of Mars. I hope it’s something Dethklok puts on their next album, they could afford that kind of expense.
It turns out, that if you travel to an alien world, not only would the sights be different, but the sounds would be alien too. Of course, you’d never know because you’re be too chicken to take your helmet off and take in the sounds through the superheated carbon dioxide or methane atmosphere.
What sounds would you like to hear on an alien world? Tell us in the comments below.
We’ve only had blurry images of Pluto up until New Horizons. So what did we learn when we got up close and personal with Pluto and its moons?
Clyde Tombaugh first discovered Pluto in 1930. He saw only see a single speck of light moving slowly in front of the background stars as he flipped photographic plates back and forth. Sadly, this was the best anyone could do for decades. Even the mighty Hubble, the most sensitive instrument ever focused on Pluto, could only resolve a few grainy pixels.
It’s because Pluto is really really far away: 7.5 billion kilometers. Just the light alone from there takes over 4 hours to reach us. In order to get any more information, humanity needed to reach out and send a spacecraft to Pluto, and photograph it, up close and personal.
In 1989, Alan Stern and a group of planetary scientists began working on a mission. Their work culminated in NASA’s New Horizons spacecraft, launched in 2006, beginning a 9 and a half year journey. And unless you’ve been living in a lunar lava tube, you know that New Horizons finally reached its destination in mid July 2015, passing a narrow 12,472 kilometers above the surface.
For the very first time in human history, we saw a member of the Kuiper Belt right up in it’s business. And now I retire these old low quality images Pluto! Begone artist’s illustrations!
From here on out, we’re all about sick high def photos of the surface and its moons. I for one am going to revel in them for a while.
So fashion shoots aside, what did we actually learn about Pluto? The primary mission was to map the geography of Pluto and its biggest moon, Charon. It would study the surface chemistry of these icy worlds, and measure their atmospheres, if they even exist at all.
The mission had a few other objectives, and of course, planetary scientists knew that the spacecraft would just surprise us with stuff we never expected. Kuiper Belt objects like Pluto and Charon are ancient; geologists expected them to be pockmarked with craters, large and small.
Views of Pluto during New Horizons’ approach. Credit: NASA/Damian Peach
Surprisingly, New Horizons showed relatively smooth surfaces on both worlds. Pluto has a Texas-sized region newly named Sputnik Planum, where exotic ices flow like glaciers. Frozen nitrogen, carbon dioxide and methane ices act just like the ones we have here on Earth. We can see from the relative lack of craters that this process is still happening.
Pluto has mountains. Mountains! Close ups show a young range with peaks as high as 11,000 feet, or 3,500 meters. Here’s the crazy part. Those exotic chemicals that act like snow and ice? They’re not hard enough to make mountain peaks like this.
At extreme cold temperatures, water ice becomes as hard as rock. These mountains are made of ice, and they’re very young, probably less than 100 million years old. There could be plate tectonics on Pluto, but with ice, not rock. My mind is blown.
Pluto’s moon Charon has a huge chasm longer and deeper than the Grand Canyon in Arizona and although scientists hoped to see an atmosphere, the reality was beyond anyone’s expectations.
Backlit by the sun, Pluto’s atmosphere rings its silhouette like a luminous halo in this image taken by NASA’s New Horizons spacecraft around midnight EDT on July 15. This global portrait of the atmosphere was captured when the spacecraft was about 1.25 million miles (2 million kilometers) from Pluto and shows structures as small as 12 miles across. The image, delivered to Earth on July 23, is displayed with north at the top of the frame. Credits: NASA/JHUAPL/SwRI
New Horizons detected a thin nitrogen atmosphere at Pluto. It could be snowing nitrogen on Pluto right now. There could be faint winds, since there are regions on Pluto that look like they might have undergone weathering.
Take a look at this photograph as New Horizons zipped away. You can see the atmosphere clearly surrounding the dwarf planet, interacting with the solar wind and creating a tail that stretches away from the Sun.
Here’s my favorite thing we learned. Pluto is about 80 km larger than previous estimates, which makes it the largest Kuiper Belt Object found so far. Even bigger than Eris, which is still a little more massive. So maybe it’s time to revisit that Pluto planethood debate again. I’m just messing with you. No good will ever come from having that debate. It will only end in tears.
Interestingly, the data connection between Earth and New Horizons is tenuous. Possibly the worst internet since AOL. It can only transmit back about 1kb of data per second, which means that we’ll need to wait about 16 months for the photographs and data to be sent home during the first few days of the flyby.
As an extra bonus, this isn’t the last we’re going to hear from New Horizons. Because it’s so far away, as the spacecraft can only trickle data back to Earth. It’s going to take almost 2 years for all the images and measurements it gathered during its flyby to get back to Earth for scientists to study. Expect many more discoveries and announcements over the coming years, and more videos from us.
Now that Pluto has finally been explored, where do you think we should go next in the Solar System? Tell us in the comments below.
Just how dangerous are the terrifying dust storms that swarm Mars?
Brave explorers trek across the red dunes of Mars when a dangerous dust storm blows in. In moments, our astronauts are blasted by gale force winds and driving sand, reducing visibility to zero. The brave heroes stumble desperately through the driving onslaught, searching in vain for shelter from the catastrophic conditions. One is blown into a ravine, or right to the edge of the cliff, requiring a dramatic rescue and likely a terrible terrible sacrifice and important parting words showing the true mettle of our heroes.
“Tell my Asuka… printed body pillow… I loved her…”
Will they make it? Why the heck would anyone land on that dusty irradiated death trap? Actually, a better question might be “Why do writers lean so hard on this trope?”. I’m looking at you Andy Weir.
Martian dust storms don’t just come from the fevered imagination of the same sci-fi writer who gave us a lush Venusian jungle, Saturnalian lava flats and Moon floor cheese. These dust storms are all too real and they drive at serious windspeeds.
NASA’s Viking landers clocked them at 100 km/h during dust storm season. Which is a thing on Mars. The landers sheltered enough from the big storms that they probably didn’t experience the greatest winds they’re capable of.
Scientists have seen evidence that sand is shifted around on the surface of Mars, and the regolith requires high wind speeds to pick it up and shove it around. Dust devils spin up across the surface, and rotate at hurricane speeds.
When the wind is above 65 km/h, it’s fast enough to pick up dust particles and carry them into the atmosphere encasing the planet in a huge, swirling, shroud. Freaked out yet? Is this dangerous? It sure sounds dangerous.
Apologies to all the fearmongering sci-fi writers, but actually, it’s not that dangerous. Here’s why.
First off, you’re not on Mars. It’s a book. Second, it’s a totally different experience on Earth. Here when you feel the wind blasting you in the face, or watch it dismantle a house during a tornado, it’s the momentum of the air particles hammering into it.
An illustration of a dust storm on Mars. Credit: Brian Grimm and Nilton Renno
That momentum comes from air particle density and their velocity. Sadly, the density of the atmosphere on Mars is a delicate 1% of what we’re used to. It’s got the velocity, but it just doesn’t have the density.
It’s the difference between getting hit by a garden hose and a firehose with the same nozzle speed. One would gets you soaked, the other can push you down the street and give you bruises.
To feel a slight breeze on Mars similar to Earth, you multiply the wind speed by 10. So, if the wind was going about 15 km/h here, you’d need to be hit by winds going about 150 km/h there to have the same experience.
It’s not impossible for winds to go that fast on Mars, but that’s still not enough wind to fly a kite. To get it off the ground your mission buddy holds the kite, and you run around in the dumb Martian sand like a try-hard ass.
It would fly for a second and then crash down. You’d wonder why you even brought a kite to Mars in the first place because it’s NEVER windy enough.
Boo hoo. Your Mars kite doesn’t work. Good news! You’re on Mars!
Bad news. It was a one way trip. Good news! A wizard has made you immortal!
Bad news. The wizard has brought to life the entire fictional cast of the Twilight series and they’re also there and immortal. Have fun brooding with your new dorky friends, FOR ETERNITY.
What I’m saying is you could stand on the red planet restaurant patio and laugh at anything the weather system could throw at you. That is unless, you’re solar powered.
Opportunity Rover. Credit: NASA
Mars gets regular dust storms. From time to time, they can get truly global. In 2001, a storm picked up enough dust to shroud the entire planet in a red haze. Temperatures went up as dust helped trap heat in the atmosphere. This storm lasted for 3 months before temperatures cooled, and the dust settled back down again.
During a storm in 2007, dust blocked 99% of the light reaching the solar panels of the Opportunity rover. This severely decreased the energy it had to power its instruments, and most importantly, the heaters. Ultimately, it was possible that the cold could kill the rover, if the dust hadn’t subsided quickly enough.
If you happen to see a movie or read a book about an astronaut on Mars dealing with a dangerous dust storm, don’t worry. They’ll be fine, the wind won’t shred them to pieces. Instead, focus on unbreathably thin atmosphere, the bone chilling cold, or the constant deadly radiation.
That and where’s their food come from again? Well, now you know dust storms aren’t a big issue. Want to travel to Mars? Tell us in the comments below.
If you haven’t checked it out yet, go read “The Martian”. Jay and I loved the pants off it and we can’t wait to see the film version.
Rogue stars are moving so quickly they’re leaving the Milky Way, and never coming back. How in the Universe could this happen?
Stars are built with the lightest elements in the Universe, hydrogen and helium, but they contain an incomprehensible amount of mass. Our Sun is made of 2 x 10^30 kgs of stuff. That’s a 2 followed by 30 zeros. That’s 330,000 times more stuff than the Earth.
You would think it’d be a bit of challenge to throw around something that massive, but there are events in the Universe which are so catastrophic, they can kick a star so hard in the pills that it hits galactic escape velocity.
Rogue, or hypervelocity stars are moving so quickly they’re leaving the Milky Way, and never coming back. They’ve got a one-way ticket to galactic voidsville. The velocity needed depends on the location, you’d need to be traveling close to 500 kilometers per second. That’s more than twice the speed the Solar System is going as it orbits the centre of the Milky Way.
There are a few ways you can generate enough kick to fire a star right out of the park. They tend to be some of the most extreme events and locations in the Universe. Like Supernovae, and their big brothers, gamma ray bursts.
Supernovae occur when a massive star runs out of hydrogen, keeps fusing up the periodic table of elements until it reaches iron. Because iron doesn’t allow it to generate any energy, the star’s gravity collapses it. In a fraction of a second, the star detonates, and anything nearby is incinerated. But what if you happen to be in a binary orbit with a star that suddenly vaporizes in a supernova explosion?
That companion star is flung outward with tremendous velocity, like it was fired from a sling, clocking up to 1,200 km/s. That’s enough velocity to escape the pull of the Milky Way. Huzzah! Onward, to adventure! Ahh, crap… please do not be pointed at the Earth?
This artist’s impression shows the dust and gas around the double star system GG Tauri-A.
Another way to blast a star out of the Milky Way is by flying it too close to Kevin, the supermassive black hole at the heart of the galaxy.
And for the bonus round, astronomers recently discovered stars rocketing away from the galactic core as fast as 900 km/s. It’s believed that these travelers were actually part of a binary system. Their partner was consumed by the Milky Way’s supermassive black hole, and the other is whipped out of the galaxy in a gravitational jai halai scoop.
Interestingly, the most common way to get flung out of your galaxy occurs in a galactic collision. Check out this animation of two galaxies banging together. See the spray of stars flung out in long tidal tails? Billions of stars will get ejected when the Milky Way hammers noodle first into Andromeda.
A recent study suggests half the stars in the Universe are rogue stars, with no galaxies of their own. Either kicked out of their host galaxy, or possibly formed from a cloud of hydrogen gas, flying out in the void. They are also particularly dangerous to Carol Danvers.
Considering the enormous mass of a star, it’s pretty amazing that there are events so catastrophic they can kick entire stars right out of our own galaxy.
What do you think life would be like orbiting a hypervelocity star? Tell us your thoughts in the comments below.
