Step 1: Have multiple Earths and tell no one where any of them are, esecially each other.

are you telling me Hollywood lied to me about saving the planet on a few months notice with improvised rockets, Bruce Willis and rock and roll??

A giant gun that fires supernova neutralizing shields is something I never even imagined, and is metal AF.

Dale Skran. You know that feeling when you are listening to Issac and he mentions the name of a guy you knew back in College. And you say to yourself I knew a Dale Skran that said he was going to do great things involving outer space. And then you find a KZfaq video where they interview Dale Skran, and yes, I would recognize that voice anywhere. Dale, congratulations on making your dream come true. Michigan State University 1979

Here's how we defend Earth: we pour the planet's GDP into building a huge fusion-powered space fleet for a hundred years and then watch in horror as a tiny metallic droplet destroys the whole thing within a minute.

Dude over these years, I've forgotten your speech quirks. I hear your voice and I hear the voices of all the futurists ever, speaking wisdom through you. I love your voice, and I wouldn't have it any other way my friend.

I love how Issac brings the outlandish into a donwn to earth perspective of what could happen.

🎶To save our Mother Earth from any alien attack🎵 🎶From vicious giant insects who have once again come back🎵 🎶We'll unleash all our forces, we won't cut them any slack🎵 🎶The EDF deploys🎵

Man, not insect, will rule this galaxy now and always!

"Hey, aliens! You have reached Earth...or have you?" *The cardboard Earth flops over while the real Earth is a galaxy away*

Knowing is half the battle. The other half is usually violence. Yo Joe! :D

All you need are.... Trillions of Helldivers...

"Mr. President, we have good news and bad news. The good news, the asteroid has been destroyed, New York City is saved." "What's the bad news?" "We shattered it into a shotgun blast, half of everything in low Earth orbit's about to be shredded, and we don't have insurance."

18:12 "One Loonie with some skill..." made me think of Heinlein 😄

Just imagine the emergency meeting pending news of an incoming singularity. Head of State: How do we stop it? Bearer of Bad News: We don't.

My life for Super Earth!

I can't believe I've been watching Isaac Arthur for almost 10 years! How time flies!!!

We can't even defend Earth from our corrupt governments, they'll destroy it. I absolutely LOVE your videos. They are the BEST!

Some think outer space is empty. I say it’s not empty enough.

Only a few seconds in and now im imagining a fanfiction of how would future-Earth defend themselves in the Star Wars galaxy. More specifically, it would be interesting to see how would Earth interact with the galaxy at large. *EDIT* Something like: - How it was discovered. Ex: Future-Earth being isolated from the rest of galaxy until recently, which opens up a lot of interesting plot and world building opportunities. - How future-Earth's technology would be different from rest of galaxy. Ex: Undeveloped in other areas but advanced in others. Such as, lacking of any form of anti-gravity and shield technology or inferior power generation technology due to lack of access and knowledge to more exotic material such as Tibanna gas or Hyperspace fuel. But more advanced and knowledgeable in computers, AI, nanotechnology, metamaterial creation, and advanced Transhumanist practices (I.e CP 2077 or above cybernetics, advanced biological implants and alterations, and mind augmentation). - And most relevant, how would future-Earth would defend themselves from attack. From littering the space near Earth with heavily armed and armored O'Neill cylinders whose presence alone would make usage of hyperspace jumps naturally dangerous in their area, pusher satellites with lasers or mass beams intended for pushing space craft being used as improvised weapon platforms to fight off invading armadas, to Earth retaliating with Hyperspace RKVs later on if escalation reaches galactic DEFCON 1 levels. Another great opportunity for world building on how future-Earth's technology differed from general Star Wars technology as a result of eons of galactic isolation. We would end up as a suped up version of Umbara in this case, possessing revolutionary technology despite being confined to our solar system. Sorry y'all, got a bit excited with my comment.

If it's any consolation, Isaac, your voice is what first drew me into watching your channel in the first place. Believe it or not, it's part of what makes your channel a joy to watch. The only other example I can think of, although he doesn't speak with an impediment, is David Attenborough. The content of his documentaries is pretty standard and anyone with a good voice could do the job, but Attenborough's voice makes it all the more enjoyable to watch.

Without FTL communication, there is no way to defend a planet. You have to keep moving.

For alien invasion: How about hiding underground in vaults/bunkers and trying to wage a (hopefully) successful guerilla war against the invaders? Basically a scenario like in Oblivion (2013) or Falling Skies would be the best option for us.

LOVE YOU ISAAC! Sfia is the goat of youtube channels!

Anyone else immediately get the old "Defenders of the Earth" cartoon theme song stuck in their head? Just me? OK. Lol

Ooooh boy

🎉🎉 oh yeah !!! Time for a drink and a snack 😋

William Shatner spoke so movingly of the immense sadness he felt, looking back at Earth from orbit, seeing how vulnerable our only home was. Even when we have settled all the way out to the Kuyper Belt, Earth will still be the most densely populated location in the System, and including our orbiting settlements and factories, Earth will be the biggest industrial center. It will likely be a thousand years or more before there are more humans off Earth than on it. Plus, of course, even in ten thousand years, a hundred thousand years, a hundred million years, Earth will still be the Ship of Stone upon which the First Humans sailed.

Nice timing, we have a 3 metre rock passing {we hope) tomorrow

Military veteran? Advised Space Force? Isaac is truly one of our greatest Americans

I was in civil air patrol as a kid,,airforce auxiliary...basic stuff but interesting,,,then life happed ...I remember the book called Horizons Unlimited my first history of flight and more ,,it stuck with me ,,lots of family and friends in government and military ⚔ so I have grown up with a lot of respect for our country and yall who sacrifice so much,,,I had a car accident at an erly age in my twentys that has prevented me from being eligible for many things...but I am always trying my best with what I have an I am just greatful for every day I exist...that being said,,thank you for your service ,, and sharing your thoughts and insights science and science fiction has been a great way for me to cope with current events and my own personal experiences lol especially when I had my kid's long story,,,😊😂,,anyway best wishes for you and your family and much appreciated keep up the great work!! Aloha's stay safe out there!!!

We must not have a Mine Shaft Gap!

A space battleship named Thunderchild is all we need.😌

Informative look at a topic that much sci-fi is written around but never seriously examined. Great work, as always Isaac.

I discovered your content a few months ago and I listen to it often while working (or falling asleep, since your voice is very soothing). It shocked me when you mentioned the place I work (as the sponsor). I had JUST suggested to the team today to check out your channel, since there's a couple scifi worldbuilding fans I work with! Glad someone here was ahead of the curve! And thanks for all your videos - they're really well done!

Simple, make the moon into a massive weapons platform

Thank you to mention that confidence. Was totally unaware that such a cool thing existed

Yay! Got my drink and snack

I missed this one when you released it, so it’s a nice find for this afternoon while exercise!

Once again.. great stuff!🤘🤘🤘

Isaac you worry about your voice too much. You make good vids and at this point it just sounds iconic. 👍

Great topic.

Firstly, we as a populace, need to exude sincere peace and love. We need to openly embrace benevolence.. this has MANY positive consequences. One big one being, it ensure that any malevolence displayed towards us, would be met with what I like to call, _Honourable Resistance_ ... which embues a fierceness like no other. Our morals and integrity should preceed us at all times.

LOVE your show!!

Id be shocked if we didn't squabble our time away regardless,alas.

Always very good. Dare I say; the primary difficulty 'we' have with any threat is the wiring of our 'monkey minds': A threat is only 'real' if it is right in front of us, and even then we have only two hard-wired options: "Fight" or "Hide". Any threat that isn't both immediate and amenable to 'fighting' is something we will usually 'hide from', physically or psychologically. As a result there are a great many threats we virtually never deal with until it's too late!

We have laser welders. Lasers that can melt steel. How about an orbital mega laser to cause ablation or better yet, spalling off the surface of the rock and cause a mild thrust.

Negan was ahead of his time. One of the reasons The Saviors were so successful was that they were very decentralized. With many colonies and outposts spread out.

if an asteroid destroys my home and i somehow survive, i demand a share of it's mineral value.

I'm so glad the nice intro music is back. Thanks for your content Isaac, excellent wind down listening in bed!

This video got me thinking about implausibility, which is Michael Bay's Armageddon. To summarize: after they first spot the asteriod, a bunch of people get together to discuss how they will stop it. General Keith David is like let's shoot nukes at it and blow it up. To which Dr. Jason Isaacs is like "nah, that would work. Can't deliver enough energy to destroy it." Then I thought, "But it's enough to knock the rock of course or maybe even slow it down enough to be captured by the moon." Then you sent the drillers up to mine the asteriod.

Wouldn't a big "Dart" style impactor, that is just enough to tweak an asteroid's orbit so that it just misses us, be better than blasting it with a big bomb?

I’m kind of surprised that I didn’t hear about your military experience before, but I just wanted to say thank you for your service. :)

Ok but how do we defend Super Earth?

What would it cost to build an AU-radius spherical telescope by sprinkling cubesats with cameras/antennas, using solar panels as make-shift solar sails for maneuvering, on a constellation of close-to-polar orbit around the Sun, Startlink/GPS style, using mesh networking so they don't have to be strong enough to reach Earth, just the nearest cubsesat in the constellation, and relay their data till reaching Earth? And what kind of data could we expect to get from something like that? If the cubesats were launched at the same rate as Starlink have been launched on average, how long until we could get the full sphere?

I so hoped you'd mention the Vogons, and you did 🙂👍

I had a buddy who was trying to write Sci-Fi, his idea for ubiquitous space travel, had the ships enter into a zone controlled by the orbital defenses, if you did not allow this and strayed out of very specific space lanes, said orbital defenses would vaporize you, no warnings no second chances. He described it as "if all traffic violations were punished by sudden and instant death."

For what it's worth, the way you sound is just the way you sound. I sound like i sound. No one but you is bothered by it. We're all here because we enjoy listening to you.

I'm so grateful that you, an intelligent, open minded, and experienced person with grounded expectations, are on KZfaq making videos like this. You make so many topics more accessible to the average person in ways few others can - all my friends and family constantly make poorly educated comments about space time, because they're innocently ignorant to many laws of physics, let alone countless other topics and subjects that can be referenced or relied upon to explain or theorize things in our known universe. You take topics that the vast majority of individuals see only in shitty, pulpy clickbait headlines like "Physicists say we're actually in a simulation!" "Scientists say AI will cause our extinction!" "A giant Superearth is sending signals to earth!" And so on and so forth. You reliably lay out the known facts, explain what that *means* for the world as we know it, and also helpful illustrate how the world would be under different circumstances where the implications of a clickbait headline were true. What if we were in a simulation? What if AI has a desire to cause our extinction? What if we picked up radio signals from another planet? What would life on a planet of that nature look like? The amount of times I have to explain to friends why "aliens hiding among us" isn't as simple as Men in Black masquerades, or why "aliens come to earth just for water" is a giant plot hole, not a reasonable explanation... I can always rely on your videos to explain the gaps in logic that I'm incapable of crossing, and I get to feel the joy of people learning new things. Born too late to discover the laws of physics and biology, born too soon to explore the stars on foot, but born just in time to experience new SFIA content every week!

... Does Arthur know something about an imminent alien invasion that we don't?

So about the different star explosion concepts: Would the Sun's helioshpere lessen the blow of such a blast? Would those blasts be able to cause asteroids to gas off and change there orbits?

Mk1 eyeball! SPACE GAVIN!

Niven and Pournelle back in the 1970's wrote "Lucifer's Hammer" which is the story of us getting hit shotgun shell like by a broken up comet. I suspect that is a bigger threat than a single big rock. Keep showing water strikes and those would be far more damaging than a land strike.

Defend Europe ... I mean Earth :)

The best defense is an offense. Scatter mankind to the four corners of the galaxy.

I know this is off topic, but I would love to know your thoughts on the three-body problem specifically the TV show and what you would do to defend Earth against the alien threat or perhaps solutions you might offer to the aliens so that they don't see Earth as the only option they have

Form some strange reason, I thought Shatner was dead. Glad to know he is still serving the sci-fi comunity well.

Regarding the question of using nukes against asteroids, did anyone ever model what the impact of weeks or months or years of cosmic radiation/solar radiation can do to the nukes? There was that idea to blow neutron bombs in space to disable ICBMS warheads. Will space nukes have to be shielded too?

Could something with an atmosphere ablate material in a way that would affect the overall motion of the body (like when moving an asteroid or space junk, or as a propulsion system)? Say focus a steady light on a pole versus at the equator? Or at a single point, like say Kingston Jamaica..? or Alert, Canada? How does that work with a rotating body? Is Mercury ablating material from its sunny-side? Could Io experience ablation from Jupiter's influence? Any insight is greatly appreciated. Sorry if they're silly questions. Thank you for the MANY hours of awesomeness. One of my favorite channels for years.

How about an episode on the ultimate brute force weapon, creating another Big Bang as a Doomsday weapon?

Love to see how you suggest we defend against a Volgon construction fleet..... their space bullsdozer isn't military weapon 😆😆😆😆😁🤣😂🙃

You didn’t cover a comet, like the Tunguska event? Maybe a comet coming out of the Ort cloud or swinging around the sun.

Have you ever considered taking the "upcoming schedule" segment off your videos once they get pretty old? Is that practical to do?

Isaac Arthur for Space President, so he can build giant space lasers!

Thank you for your service! (in both the traditional and the meme sense)

the indomitable human spirit 💫

Fun topic

what sort of useful metals does mercury have beneath its iron rich crust? after we use the iron to make Statites (spell check still does not recognize you word) do we get a big heap of heavy elements, and if we do, is it enough to make us Kardashev 2

That’s a Starship Troopers frigate at the start!

Ok, i used to tune in every week but i haven't listened to an episode in art least five years. I'm going to do it this time.

Doesn't an explosion fall off as an inverse cube? Is the super nova an inverse square for some reason?

If we developed warp drive it may save us from the big bang. Several sidewarp craft will be able to detect the big bang long before it could cripple our way of life and VIP crowds.

Immedietly thought of the cole protocol with this video

Random question for you Isaac :is the type of flight superman or thor makes in movies possible on known (or foreseeable) under known/possible physics of our universe ?!?

3 body problem is awesome

Best defense earth, IMHO, is to move beyond the technological and dive deep into consciousness

Is there a step 2 to warfare, or is it all just step 1?

We need to provide protection for our neighbors on Earth and having a hard time doing it. Someone coming to Earth from another world would have us before lunch.

A rogue planet at 10,000 AU will get 100 millionth of sunlight, not 10 millionth

If invasion is our problem, hopefully we don't have to count on O'Neill and the chair.

4:36 great photo looks like you were able to loose some weight too! well done!

12:00: “Spread blast“ - Wait, wait, wait, _what_ blast in a vacuum? The mass of the nuclear warhead is all there is to turn into the gas, and, unlike the air blast in the atmosphere, just dissipates into near-vacuum at hundreds of meters. A flash that would melt an asteroid or at the least preheat it so it breaks up easier is non-directed, thus requires too much radiative energy from a nuclear explosion. A better option is a long nuclear-powered "gun" device, accelerating a mass to a high kinetic energy by evaporating solid filling, stored in the tube, all at once by the flash, possessing a compromise speed of sound to exert the pressure on the projectile-as high as possible to accelerate the kinetic projectile but not high enough to "notice" that the "lock" end of the tube itself has already evaporated and gone, is a better option.

The 0th rule of warfare is the list is sorted on the basis of what point needs to be made, aka who needs chewing out

EDF!

It took me very much too long to realise that the first rule of warfare is a running gag. omg

I, for one, would like to know more.

Brutal

I prefer infrastructure that would benefit society today and be useful for incoming objects. Inexpensive foil mirrors in heliostatic orbit can be used to reflect a percent of sunlight away from ocean in front of a hurricane weakening the power of the storm. Reflect away light from ski slopes, glaciers, the poles, etc. Reflect light onto a city at night, onto a farm or solar array. The mirrors can all be rotated to heat one side of an incoming object, hundreds of them would heat one side very effectively. Solar arrays that can transmit their energy via laser can also cut it up, or heat one side to ablate, but can be active in power generation and other applications until needed for planetary defense.

If we discover that Earth is going to collide with a rogue planet, we will just have to build space arks to transport as many people as possible to Bronson Beta.

in case of asteroid impact: call bruce willis in case of alien attack: call will smith and jeff goldblum