Q&A 57: Is The Fermi Paradox Really a Paradox? And More...

[@cosmic_gate476]

Fraser, your videos and narration are fantastic.

[@frasercain]

Thanks a lot!

[@Ffahm]

With every new video I check the sub count and I can't believe this channel doesn't have a million subscribers. Great content as usual.

[@damnmister]

Fraser Cain I had to re-watch the question at 17:30, and realised that it stated a non-moving universe! Still I never knew gravity travelled at the speed of light, Thanks for the brilliant videos!

[@frasercain]

Thanks! That was one of the amazing discoveries made by the kilonova event last year. kzbin.info/www/bejne/e2nTimmvqM9rgtE&list=PLbJ42wpShvml6Eg22WjWAR-6QUufHFh2v

[@izurielpalanayukei5140]

At 15:58 I got a popup asking me to subtitle. Was that added by you? I can certainly help if you need it! :D

[@frasercain]

No, I didn't add it. Maybe KZbin is trying to encourage it?

[@izurielpalanayukei5140]

I think it would be incredibly beneficial for you (and your peers) to add subtitles to your videos. There's a large community across the Americas that are deaf and have to deal with KZbin's shoddy captioning. Heck, a lot of people have trouble understanding English as a second language even if they CAN hear, especially when it comes to sciences. I know Isaac Arthur uses captions but I'm not sure if he copy-pastes it or if he has to go through the pain-staking process of using youtube to add them in. Maybe he'd be a good person to ask about that. For unscripted things like podcasts or question shows, it may be best to see if there's a few people in the community who want to help out. I know there are programs that can do it but I don't really trust those.

[@izurielpalanayukei5140]

If not beneficial to you directly, then at least it would be beneficial to those who want to learn more about space and science. :)

[@frasercain]

I add the CC for the scripted episodes, but not the QA shows.

[@49walker44]

Really enjoyed the question and answer session.

[@frasercain]

I really enjoy doing them. Less work than writing a script but harder on my brain in the short term. :-)

[@Barnardrab]

Regarding your answer to the question at 10:44, wouldn't it be better to try to get Phobos to crash into Mars on purpose? I would think that this would kick up an atmosphere, which would help in terraforming the planet. Especially if you can get the moon to crash into the polar region where the carbon dioxide and water is locked up as ice.

[@frasercain]

These kinds of geoengineering challenges will always have unintended consequences. Maybe you'll make the surface of Mars inhospitable for thousands of years, and the solar wind will blast away all the water you melted.

[@gumunduringigumundsson9344]

Maybe it would be cool to do it after we have seen it all and built the infrastructure we want. I think its cooler to use them as bases to remote control the robots on the surface.. or just leave them and others in other places pristine and unspoiled for laters to enjoy and learn from. Otherwise I want EVERYONE!!! (Gary Oldman in Leon style) documenting the events of mooncrash and other awsome once in a civ chances to see and "feel" the cataclysm hehe.

[@Barnardrab]

Kind of like starting a super storm? What if we got both moons to hit the planet at the same time, but at opposite sides? That way, the impact waves could cancel each other out.

[@brainfragrances]

Thanks for naming my name suggestion first

[@frasercain]

Thanks for suggesting it.

[@WorthlessWinner]

10:00 couldn't you crash asteroids into the moon and then mine them? to avoid the burning up in the atmosphere problem

[@frasercain]

Sure, but they'd hit so hard there too.

[@desertratnt-7849]

I really enjoy Q&A. Kudos

[@frasercain]

Thanks a lot, I'm glad you're enjoying it.

[@lst1nwndrlnd]

I like the leave it in space concept. Maximize the lift investment. A company could buy stages as scrap . What are the limitations of having a raft of spent stages in orbit? Other than having to change orbits.

[@omametlekkerkontje8744]

Fermi paradox is the topic I like the most (to think about)

[@frasercain]

It's one of the most fascinating problems to think about.

[@Ktulu789]

Hi Fraser! Question here after watching 17:25 Isn't gravity quantized?

[@MrVillabolo]

As for returning rare earth metals to the surface you can shape the payload into a capsule-shaped form and coat the bottom with a ceramic finish. That would minimize the cost and complexity of returning them to Earth.

[@frasercain]

Apparently you can turn them into a spongelike structure that'll be able to slow down without burning up.

[@leopoldroos1704]

Great channel. Love your knowledge, enthusiasm, and voice. My question for future episode: Usually when we talk about black holes, we say they have an infinite density singularity. How can we be sure it is infinite and not just much smaller than a quark? Like strings taking up space but packed so much tighter than everything else.

[@Gruffas]

Question: What computer games are you playing right now? PS Don't by shy to promote your different projects across your other channels. It took me years to discover all the cool things you do outside of Astronomy Cast. Please, keep doing this forever!

[@frasercain]

I just picked up Battletech, and I've been playing a lot of Stellaris. :-) And thanks!

[@sentinelmoonfang]

I'm now having trouble remembering if it was you or Joe Scott, but I seem to recall you had a few board games kicking around in the background in one of your videos. If you like board games, I'm curious if you've tried Terraforming Mars or High Frontier. Both are fantastic hard sci-fi games I bet you'd have a ton of fun with. The former has you terraforming Mars, obviously, with some really well researched means of doing so (even the controversial way with nukes.) The later has you colonizing the solar system with a really great movement system using realistic orbits, Lagrange points and Delta-V.

[@frasercain]

I think we've both got boardgames behind us, but I haven't played either. Thanks!

[@radicaledwards3449]

17:36 even with the expansion of space time?

[@frasercain]

No, I was keeping it simple. Beyond a certain point, those galaxies won't be able to beat the expansion of the Universe and the effect of dark energy.

[@Cherotal]

Hi Fraser, speaking of building a sunshade for Venus what will the best place to build one? The L1 Lagrange point, where it can cover the whole planet? But it will require some amount of fuel to hold position against the solar wind and the L1 point is not easy to reach for a service mission. Or maybe place a large amount of smaller sunshades in an orbit where a service mission easy can reach them. But on this orbit the will only block the sunlight on a small belt around the equator, i think this will cause extreme weather effects in the atmosphere between the cold and the hot areas. Thanks, Cherotal

[@frasercain]

Yeah, the best place would be the L1 Sun Venus Lagrange point or put it into orbit around Venus itself.

[@danishgagai3685]

do you think the alcubierre warp drive concept is possible for future space travel, can you explain that if such a model or technology were to be developed, how would it exactly work?

[@frasercain]

We've got an episode coming up to talk about this and the nature of spacetime. The trick is that you need to discover negative mass, which we're not sure exists.

[@rajveerchampavat6757]

Hii Can you have us a video on some concept of magnetic reconnection and Earths magnetic field?

[@frasercain]

I did a video about the Earth's field reversal a long time ago: kzbin.info/www/bejne/opScZHyGetCKjcU&index=277&list=PLbJ42wpShvml6Eg22WjWAR-6QUufHFh2v

[@DamianReloaded]

11:00 I think tidal forces are going to rip Phobos apart once it croses the Roche limit (creating a ring temporarily?) so it won't be a catastrophic collision after all.

[@frasercain]

Yeah, but that would still be a catastrophic disaster when the ring comes crashing down onto the planet.

[@DamianReloaded]

You sure? **googles** heh I see you wrote an article about this on universe today. Update it with the consequences of the collision. Homework! ^_^ (I read somewhere it's not even solid rock. It's just a bunch of "crapdite" clumped together)

[@jerry3790]

I can see it now. An asteroid the size of a mountain being landed with thousands of radial chutes.

[@frasercain]

It would be a sight to behold.

[@TheTravelingTank]

After hearing about the Galileo probe discovering water plumes on Europa 20 years before we verified it, do you think theres any other info about our universe we've already discovered but just haven't realized yet?

[@frasercain]

There must be many more out there. Tabby's Star's dimming was seen in old photographic plates from nearly a century ago.

[@DamianReloaded]

Also: If they ever make balloon rocket launching platforms they should name them after songs from Air Supply. "Here I Am", "Even the Nights are Better", "Lonely is the Night", "I can wait forever", "having you near me", "It's not too late", "Goodbye", "Come What May", "I can't Let Go", "I'll never get enough of you", "Without you", "I want to give it all", "Feel the Breeze", "News From Nowhere", "Looking Out for Something Outside", "Primitive man", "More than natural". ^_^ _The Way It's Meant To Be_

[@ArchAngelDublin]

Are you going to do a video on 2I/Borisov?

[@frasercain]

Maybe once it's made its closest flyby and its on the way out again.

[@MusikCassette]

9:17 I don't think, that the pay off of asteroid mining is bringing stuff back to earth. At best that are pennies on the side. The main pay off of Asteroid mining is that you don't have to bring the material up to orbit.

[@frasercain]

Yup, keep that stuff up in orbit. Maybe returned manufactured goods once you've made them.

[@Mosern1977]

Question popping in: Why are there more stars in the center of galaxies than in the outer regions?

[@frasercain]

It's similar to the reason why there's more mass at the center of the Solar System.

[@Mosern1977]

Fraser Cain - and that reason is?

[@JimLockwoodShow]

I have a question about black holes. At the center of a black hole is there something solid? Video I watched said the gravity smashes the black hole down to the point at which matter no longer exists. But people talk about spinning black holes. How can something that doesn’t physically exist spin

[@frasercain]

We don't know what's down inside the event horizon of a black hole, maybe it's infinitely small or some specific size. Astronomers can calculate how a black hole spins because you can actually see it interact with the accretion disk around it. www.nasa.gov/mission_pages/nustar/multimedia/pia16696.html

[@zapfanzapfan]

There is a concept proposed for landing processed metal on Earth. Make it into a very porous structure so that it slows down fast at high altitude (unlike a solid ball which would reach deep into the atmosphere before breaking and then hitting the ground at high speed) and gently falls to the ground. No need for digging it out of the ground in little pieces :-)

[@robertgraybeard3750]

Fraser Cain zapfanzapfan One of the videos by Peter Diamandis(?)/Planetary Resources Inc.(?) talked about producing something like steel wool from several tons of platinum. The net density would be quite low and the drag, even at near orbital, speed would decelerate the "gigantic glob" before much ablation occurred. And they would model its path and plan for it to drop to an uninhabited area. I propose an alternative - the space based processing facility should very carefully produce curved sheets and weld them into a several mile wide bubble with natural vacuum inside. The net density would be astronomically low and the deceleration due to atmospheric drag would be quite rapid. Furthermore, it wouldn't fall to Earth because it would float when it got down to the almost dense air of the stratosphere. It might even be the foundation for building a Cloud City - add more things and it would sink a little.

[@twirlipofthemists3201]

Those are cool ideas. I'm still fond of making robot reentry gliders out of asteroid stuff and flying refined materials and finished goods down to airstrips.

[@frasercain]

That's an awesome idea, so there you go. Make platinum steel wool. :-)

[@robertgraybeard3750]

Fraser Cain I misspoke - didn't remember it correctly. The video is kzbin.info/www/bejne/mofdg2Ohr9CfiKc "We Solve for X: Peter Diamandis and Eric Anderson on space exploration" a 30 minute video, and to the general public I recommend watching the entire video. BTW it was 100 kilograms "platinum foam", a tenth of a ton, a fluffy two meter ball - so much drag for a modest amount of inertia, easily decelerate before melting and will get down to the surface with a 60 mph terminal velocity. The graphic is at 27:47

[@Mosern1977]

Question 2 popping in. Waves move at different speed in different mediums. Is there possibly a medium which light could move faster than C? And why is C about 300.000km/s and not some other value, like 100.000km/s or 650.000km/s.

[@frasercain]

We don't know why it's the speed it is, that's just one of the fundamental constants of the Universe. No, the speed of light in a vacuum is the fastest it can actually go.

[@cyber3tesla83]

should we explore neptunes moons.

[@frasercain]

We should, especially Triton.

[@rafaxerife]

Hey, Fraser! Thanks for your work, I've learned so much from you!(And I really appreciate using the metric system!) What if there are whole structures, planets and life that are made with a different kind of matter than us, like dark matter? Wouldnt it be awesome? Also, could you do an episode about the effects of low gravity in human body? Yeah, I'm a a Venus sympathizer :)

[@frasercain]

Thanks! From what we can tell, the structure of the Universe is the same everywhere. We don't live in a special place. Regarding gravity, did you see this? kzbin.info/www/bejne/iXnJhpWEh7RgaaM&list=PLbJ42wpShvml6Eg22WjWAR-6QUufHFh2v

[@pgantioch43]

Questions: 1. Why not build a robotic method to service the James Webb Space Telescope? It seems like a lot of money to spend to just abandon it when the fuel runs out, or if something else malfunctions. Robotics are constantly advancing, so why not try? 2. Presumably when their rockets are launched, balloon-assisted systems would shoot up into the sky once the mass of the rocket isn't holding it down. So the helium is just lost to space? Helium is a finite resource, & personally I don't think we should waste it. For that matter, why is it still used for hobby purposes? >:-( 3. Have you done a vid on possible life in the Venusian clouds? There's a silicon derivative that would protect theoretical life there from sulfuric acid, & the spectrum of reflected light is consistent with it. Thanks Fraser!!

[@slysynthetic]

The answer to your answer about the Fermi Paradox is the Modified Zoo Hypothesis. I still have yet to see a space communicator cover this (peer reviewed) concept on youtube.

[@frasercain]

I think that some variation on the Zoo Hypothesis is a reasonable explanation to the Fermi Paradox, but it needs to be respected by every civilization in the Milky Way. We can't get societies here on Earth to agree on a single set of rules.

[@slysynthetic]

That's why I said Modified Zoo Hypothesis. Think about the start of the universe: no life as we know it is possible. Later on stars and planets form, but not stars like we know them today - life, still pretty much impossible. But, slowly the heavier elements form, and life becomes ever so fleetingly possible. There had to be a first. Let's take an example of the first in the Milky Way: How long before the first technological civilization and second technological civilization? It might easily be many millions of years! Plenty of time for that civ to watch every other civ in the galaxy, or even nearby galaxies get started. What rules might they have established? What legacy might they leave?

[@IlicSorrentino]

Great as always... I think the Drone mission on Titan will win the race... and I have to admit I prefer it.

[@frasercain]

Oh, I totally agree with you. :-)

[@turnerroll9431]

Hi Fraser! When scientists reference a galaxy's location, are they describing where the galaxy appears to be? Or is the location a prediction of where the galaxy will be in X billion years based upon its current velocity vector, gravitational interactions, and how far in the past the light was emitted by the galaxy. Thanks!

[@frasercain]

They're referencing its current position in the night sky.

[@chump4978]

Hey Fraser. I have got a question. Since we are traveling very fast through space (earth rotation, Earth speed when moving oround the Sun, rotation of the Milky Way...), does this mean we are younger than we would be if we 'd just existed, stationary for example somewhere between Milky Way and Andromeda. Another question: How old is a photon since it travels at the speed of light? Tnx in advance and sorry for my broken English

[@frasercain]

It's all relative. So, we might have experienced more time than someone who's moving faster than us, but less time compared to someone moving slower than us.

[@horizonbrave1533]

Fraser: Would putting a "Light shield" around Venus really work? Wouldn't the space around Venus and the shield still be very hot from the proximity of the sun? And despite the light not hitting Venus, the space around it would still keep it very hot? Also, sort of related... if we could set up a series of really large space mirrors that would adjust themselves to keep the light from the sun angled to hit the outer planets, could this be used to (slowly) warm up planets? So if we could set up a series of mirrors, that would "channel" the light from the sun and beam it onto a planet, could that be used to warm it up?

[@frasercain]

The shield would heat up, but you could radiate the heat away.

[@alexseioo610]

One resolution of the Fermi paradox gets consistently overlooked or dismissed. Here is my hypothesis (some parts of it i seen mentioned to some extent). Let's assume biogenesis is a common event. Billions of planets with some form of life in our galaxy alone. Evolution almost certainly takes place almost everywhere (even on worlds with absolutely stable uniform environments). Then intelligent life with a culture develops, let's say this is common too, happened millions of times in our galaxy already. Where are they? We are right now in the information age and it’s not a coincidence that we are at the same time a global species and at the beginning of space exploration/expansion. Computers, global communication, spacefaring nations are direct results of our scientific and therefore technological progress. Our culture, specifically scientific knowledge but also overall information grows exponentially. Also our population grows. But we don’t. We are basically the same as 100.000 years ago, maybe slightly less hair and a little higher. But the brain is still the same old homo sapiens brain. You might be guessing where I’m going with this. Not quite that. Futurists, sci-fi authors, transhumanists imagine genetic modifications, artificial intelligence, transcendence of the human intelligence into a smarter life form. And then the imagination breaks down. How can we imagine what a super intelligence is like? And worse than that: we have no idea what the evolution of intelligence, the third step of life (after biological and cultural), would look like. I’m sure our current metric for measuring progress will fail here miserably. We are in the scary unimaginable territory beyond exponential growth of knowledge. Because not only the means (technology, scientific methods, societal institutions) to acquire new knowledge are proportional to the ever growing knowledge, but the rate at which new knowledge can be found also scales up in some unknown (to us) way with intelligence. It’s a mind-boggling iterative explosion of intelligence (instead of colonization explosion in the “great filter” concept), knowledge and technology rise at rates beyond exponential or factorial. Like David Deutsch pointed out (TED talk, 2007), knowledge is the most precious ressource in the universe. A sufficiently advanced civilization has no need to expand. Or rather an insanely fast developing civilization would outgrow the detection window of a “lesser” civilization almost immediately, maybe faster than the development and implementation of self-replicating probes would take. In the sense that their technology and presence would be unrecognizable to us or that they would be physically beyond our detection capabilities (other dimensions, “outside” the visible universe etc.). We can also only hope to detect life which has not achieved the intelligence explosion yet. The interesting implication is, that we are right now entering this new phase of our evolution.

[@frasercain]

We would expect to see them utilizing the resources of the Universe. Power from stars, matter to build structures. Obviously there can be laws of physics we don't understand, and then who knows what happens?

[@klausgartenstiel4586]

my guess is that when life takes root outside of inner solar systems, it becomes something vastly different, completely independent of anything we consider crucial. including planets, and even stars.

[@frasercain]

The problem is that we only have this single planet to give us examples of life. We need to find it anywhere else to know how it works and how it could be different from world to world.

[@klausgartenstiel4586]

Fraser Cain bigger telescopes will hopefully one day allow us to spot life, maybe even alien civilisations, on other planets. but my guess is that these civilisations will only be type 1. because they are the ancestors of a type 3 civilisation that is already all around us, and that, for some reason, doesn't care about star systems. well... that is, at this point, my personal solution to the fermi paradox. we'll see ;>

[@frasercain]

Sounds good. :-)

[@freedomfighter2463]

I enjoy hearing about the concept of Self Replicating Robots. The Universe is almost infinite. Having Robots just jumping from Solar System to Solar System is just something really amazing and cool. I probably will have a hard time explaining it to coworkers and parents haha

[@nathancolgan4296]

Hi Fraser, is there a theoretical maximum limit to the size of a black hole?

[@DarinKollins]

Is matching velocities of existing orbital platforms more difficult than finding a re-entry window that allows the cargo to survive?

[@Jameson1776]

Unrelated topic what are your thoughts on the Expanse? I see syfy has cancelled it .Have you watched it yet?

[@frasercain]

I'm really sad about the Expanse, and I hope someone else picks it up like Amazon...

[@Jameson1776]

Fraser Cain yes one of the best Sci-fi shows I’ve seen in a while

[@DagarCoH]

Yet another follow-up to the Fermi Paradox: How likely is it for us with our present and near-future technology to even detect any signal that strongly hints towards other intelligence, assuming that they do not go out of their way to contact us? And in which ways could we detect them? To my knowledge (I think it was mentioned in a video of Isaac Arthur) we could not even conclude intelligence from a radio bubble like our own if it came from Proxima Centauri right now. What else is there? markers of industrialization in the atmospheres of expolanets and light blocked by dyson swarms is what comes to my mind.

[@frasercain]

There are many ways that aliens could let us know they're out there. They could set up satellites that blocked the light in obvious ways. Or send robotic probes to leave artifacts in the Solar System.

[@DagarCoH]

Ah, yes, but that is not what I meant, exactly. I meant what chance we actually have to find a civilization that does not go out of their way to make their existence obvious, just from what they might "naturally" do. I.e. they build something like Dyson Swarms, but for the energy they can get, not for blocking light so that we can see them. As a guide line what about a civilization as advanced as ourselves. In which distance could we detect them?

[@macbuff81]

The properties of moon dust, regolith, sound very similar to those of asbestos. Sharp very small and persistent particles that cause scarring in the lung tissue once inhaled

[@frasercain]

Yup, that stuff is bad news.

[@twirlipofthemists3201]

My lava tube comment got famous! I am honored. I agree they might geologically (lunalogically?) interesting, and a good, short term, low-budget camp site. It's the idea of building permanent cities in them that I can't understand.

[@frasercain]

Doing anything on the Moon is going to be really hard, so if there are any short cuts, we should take them.

[@eivindmn]

Something I was thinking about: Why do we say that the universe is old? I mean, of course nearly 14 billion years is old compared to any timespan that humans can comprehend, but don't we define if something is young or old in relation to the total lifespan? We know that there will probably be trillions of years with stars and galaxies in the universe, not to mention the time it will take to reach the heat death (presuming that is the most likely scenario, though), with over a googol years of radiating black holes. Because of this, shouldn't we instead say that the universe is in its very early stage, and has barely begun? Who knows what will happen to the universe when we start thinking in these timespans ...

[@frasercain]

Everything's relative. And in the deep time future, when the Universe is septillions of years old, I'm sure they'll look back fondly at mere billions of years.

[@eivindmn]

Fraser Cain And to continue this thought experiment (which I thought was kind of mind blowing): If the universe dies with the heat death in about a googol years (I read somewhere that it is more close to 10^103 years, which is a thousand times greater, but let’s make it simple here, though), and the stars run out of gas in about a hundred trillion years (hey Wikipedia!), the amount of time there is light in the universe, compared to the time it’s just darkness, is so minuscule that it’s barely noticeable. If you compressed the total timescale down to one year, the period with light wouldn’t even be registered as a Planck time unit - far from it. If my math is correct, you would need the universe to be around 10^21 years to have stars shine for just one Planck. All in all we absolutely are nothing ...

[@charjl96]

SLS - Suborbital Launch System. Creative, I know.

[@frasercain]

Oh great, then we won't know which one you're talking about. :-)

[@charjl96]

Haha! oh right, I guess that won't work.

[@vivekanandbiet]

I always have a question. Imagine if i anchor a rope on moon face which is facing earth. And the let it reach till the earth. Just few metres to earth surface. Then can i 1) pull moon to earth. 2) can i hang a object to it and deliver the object to other end of earth as earth is spinning on its axis and expecting rope to be at stangnent with respect to moon. 3) what will happen if i anchor the same rope to earth also. Will moon move faster with Axis of earth. Thanks waiting for your view.

[@frasercain]

You're describing a space elevator. Here's a video we did about them: kzbin.info/www/bejne/gHjXonVrgLKGZ6s&index=349&list=PLbJ42wpShvml6Eg22WjWAR-6QUufHFh2v

[@blow-sky-high]

could gravity be an effect caused by the pressure of the space displaced by the mass pushing back on the mass ?

[@blow-sky-high]

the closer to the mass the more the pressure we experience as gravity

[@frasercain]

Gravity seems to just be the effect that mass has on spacetime.

[@gilde915]

i saw the report bout the new mars mission with a helo drone....why dont they use not a Kind some airship with solar Panels on the upper side which had not that many problem with the thinner atmosphere?

[@massimookissed1023]

Gil DE , a Mars 'air'ship would need to be less dense than Mars' atmosphere, which is tenuous at best, similar to Earth's at 100,000' or higher.

[@gilde915]

true....but we have alot experience with those sorts high altitude balloons and airships which might work better in these kinda atmospheres then ultra fast rotors as used in the drone

[@frasercain]

The Mars helicopter is going to be solar powered, so that's halfway there. But NASA has been considering balloons on Mars. They'd heat up during the day, go airborne, and then cool down and flop onto the surface at night: mars.nasa.gov/programmissions/missions/missiontypes/balloons/

[@calmterror]

Hey Fraser what is the difference between an asteroid belt and asteroid field?

[@HeyHeyHarmonicaLuke]

If gravity moves at the speed of light, is it a bit wrong to say that we feel gravity from everything in the universe? We'd feel gravity from everything in the observable universe, or something like that accounting for the horizon problem.

[@frasercain]

That's right, you experience gravity from everything in the observable Universe.

[@polkaking1978]

Please explain how you move around in space

[@Hovado_Lesni]

Hello Fraser. Do you have any recommendations what would be the best app to track rocket launchs? I use "SpaceXnow" which is great but its spacex only

[@HebaruSan]

There's also nothing to prevent us from building colonies under the sea, yet we don't see that either. Undersea colony paradox!

[@HavardStreAndresen]

Good one! Why do we assume that a civilization would feel the need to colonize the galaxy. Personally I don't want to travel through space. I am happiest at home, tending to my plants and mosses.

[@panzrok8701]

Håvard Støre Andresen: Every empire or organization would do it to gain more power. HebaruSan: The earth isnt fully populated yet. Thats why.

[@HavardStreAndresen]

Maybe they have other values. Not saying it is so, but I am entertaining the possibility.

[@MultiGoban]

The paradox remains. Give the size of the Galaxy, there surely must be ONE civilization to colonize it. Out of many million or whatever the number.

[@HebaruSan]

Given the number of countries on Earth, there surely must be ONE willing to build undersea colonies!

[@donaldgrant9067]

In your opinion is anti gravity possible.

[@frasercain]

There doesn't seem to be anything that can generate anti-gravity today, but who knows what we'll discover in the future?

[@donaldgrant9067]

Thank you.

[@0016JB]

Fraser: I was just reading an article about the James Webb telescope and it talked about some of the recent problems they have experienced. Things like a transducer that was incorrectly powered, and an incorrect solvent was run through the propulsion system, and a catalyst bed heater that was accidentally overstressed, etc. My question is "is anyone being held accountable for these human errors. Is anyone losing their job because of them or do we keep on going forward with the same error prone people running the show as always ?"

[@sandrisvirsis9440]

Could there by star that splitts heavy atoms uranium star?

[@frasercain]

Uranium would naturally split itself over time. Maybe I don't understand the question?

[@tauceti8060]

Fraser Cain I think he was was wondering can stars use nuclear fission to produce energy rather than fusion.

[@Chemson1989]

Hi Fraser, it sounds crazy, I believe changing asteroids orbits toward Earth and aim for specific area is a greater threat than nukes, a threat we will face eventually. Unlike nukes has M.A.D. to maintain balance, once a company or nation has the ability to control asteroids' paths...idk it sounds like faction but it feels real.

[@CyrilleParis]

Is it possible that panspermia can work both ways? In that case, one can imagine an object coming from Earth, crashing on Mars, thriving there and be either now extinct or not yet discovered (for ex. microbes in the soil)? Then, if we discover it, how will we be ale to say if it is genuiely life from Mars or some recent contamination from our space age?

[@frasercain]

That's definitely an idea. Astronomers think it might go from Mars to Earth because Mars has the lower gravity. So it's easier for material to escape from Mars.

[@BrienMalone]

Question: When we are told a star, say Alpha Centauri, is 4.3 light years away, does that mean it _was_ 4.3 light years away 4.3 years ago? If so, doesn’t that make 3d rotating maps of the universe rather pointless? The moment you shift your perspective any significant distance, the map is instantly incorrect because the map was created with earth time as its starting point.

[@frasercain]

Yes, but they don't move that quickly. Remember that plate tectonics are moving the continents apart, so does that mean that maps are inaccurate?

[@MrVillabolo]

You can make up for that by measuring the velocity and direction the star is going at and using that to predict where it's going to be umpteen years later.

[@Jens.Krabbe]

Getting stuff back to earth should be fairly easy with the BFR.

[@frasercain]

Definitely. Come on BFR... launch already!

[@sandrisvirsis9440]

And is there water inside venus mantle just like earth?

[@frasercain]

There's no evidence of water on Venus, in fact, it looks like its plate tectonics stopped because the mantle is so dry.

[@sandrisvirsis9440]

Thanks i was thinkink would there by water in the mantle since both planets formed similary

[@R.Instro]

Just to add to Fraser's answer, the terrain on Venus shows slopes that are MUCH steeper than we see on the hills & mountains of Earth, despite similar levels of surface gravity. It just so happens that minerals & rock that have had all of the water cooked out are capable of supporting much steeper slopes than hydrated minerals can, so Venus' terrain itself seems to be further evidence of the lack of water on/in Venus.

[@Hero323]

Hey Fraser, instead of creating a new launch vehicle, could NASA just restart the shuttle program and use the cargo bay to house a lunar lander or a habitat for the lunar surface?

[@frasercain]

They had good reasons for shutting down the space shuttle program, it was never as safe as they wanted it to be. Remember that 14 astronauts died in two catastrophes over the program. The whole purpose of the Orion and the new crewed exploration program is to make it much safer.

[@pyroslavx7922]

For baloon assisted launch i suggest NAMBY - Not Above My Back Yard You better check those engines before you drop the bomb :-) And accelerometers should be marked with big UP and DOWN engravings. Just in case. Nobody reads the pdf datasheet it came with anyway.

[@frasercain]

Nice one. :-)

[@DrNappers]

How feasible would it be to attach a bunch of ion thrusters to an asteroid and use the asteroid itself as fuel for the drives to deflect or capture it for mining?

[@PeterArnold1969]

Another great Q&A, Fraser. Just one piece of friendly advice, though. Slow down a little, if you can. Sometimes you speak so fast that I have to read the tweets carefully so I can get the question. This episode was very interesting, though.

[@frasercain]

Thanks Peter, I'll see what I can do.

[@PeterArnold1969]

Fraser Cain No worries. Other than that, I learn a lot from your Q&A sessions.

[@GrimReaper1123]

Thank you for your videos. Been watching them before bed every night. I had a dream the other night where the sun had an issue and ended up expanding and consuming the earth. Was unnerving and amazingly fascinating at the same time. Terrified and awe inspired. Question: I think you said something about parts of the universe, expanding faster than the speed of light? How can that be if things can't go that fast? Can you cover that so I can understand better? Thanks and keep it up!

[@frasercain]

Thanks a lot, here's a video for you: kzbin.info/www/bejne/rKS3Y5Vjmbdsq6s&list=PLbJ42wpShvml6Eg22WjWAR-6QUufHFh2v&index=141

[@GrimReaper1123]

Fraser Cain Awesome. Thank you.

[@joshbeaulieu7408]

Hey Fraser, you are on good terms with a number of physicists, right? I am wondering if energy production through moderation of neutrons emitted during acoustic cavitation in deuterated acetone is possible. It has been shown that we can trigger d-d fusion in deuterated acetone by placing it in a glass flask, using a piezoelectric driver ring to agitate it, and firing a pulsed neutron generator into it to induce cavitation. That causes a fusion reaction and sonoluminescence upon cavity implosion. ORNL had a setup, but I can't find if it was actually producing energy, or not. Any way to find out, because this seems fascinating?

[@frasercain]

Do you have a link for the setup?

[@joshbeaulieu7408]

Fraser Cain - science.sciencemag.org/content/295/5561/1868/

[@joshbeaulieu7408]

Fraser Cain - www.newenergytimes.com/v2/library/2002/2002-TAL-EvidenceForNuclearEmissions.shtml

[@gonzotown9438]

I suppose the first galactic empire could have been big on stealth and that they suppress other galactic empires from spreading. They may just quietly take down other burgeoning empire's automated vessels, without those other alien empires even knowing what went wrong. If we start sending automated missions to other stars and those missions keep vanishing, then we can get suspicious this is true, but we wouldn't be able to do much about it.

[@panzrok8701]

And why didnt they just colonize all planets in the whole galaxy millions of years ago?

[@gonzotown9438]

Maybe they did colonize all of the planets, but they're so good at hiding themselves we can't tell.

[@frasercain]

This is the idea of Berserker probes. Automated spacecraft who travel from system to system searching for future rivals to destroy.

[@gonzotown9438]

It's a similar idea to Berserker probes, but more pacifistic. Instead of destroying the rivals, they just keep them contained and oblivious. Almost every race would send automated probes first, before ever going themselves, and if all of the probes go missing, most races will be too afraid to venture out further. It makes a lot of sense if you are dealing with aliens who focused a lot more on being stealthy than humans. Consider advanced chameleons or octopi and how the direction of their technological growth might differ from our own.

[@brobrah4595]

I love to know your thoughts on the electric universe theory.

[@frasercain]

No thoughts, but check this out: briankoberlein.com/2014/02/25/testing-electric-universe/

[@brobrah4595]

Thanks for the link! That's why I love all the different theory's about the universe. So much we still don't know and what we think we know changes with time.

[@zzzztj]

I've got a question! Heavy Elements are made in the sun (or stars) right? So how do they get to the planets? Are we constantly being bombarded by moles of gold and iron? And if so couldn't we just put a big collector in space and wait? Wouldn't that mean that the entire universe has these elements all dispersed over from billions of years of ejections from billions of stars? how does that happen?

[@frasercain]

Astronomers think that the heavier elements came from supernovae and colliding neutron stars. They would have seeded the stellar nebulae, places where stars like our Sun formed. So they were right here at the beginning of the Solar System.

[@PhysicsPolice]

If you tented over the moon and filled that tent with water, air, plants, etc. how long would it take the resulting weathering process to detoxify the jagged fine-grained Lunar regolith?

[@frasercain]

Hah, good question. I guess we'll need to find out. I say just vacuum the stuff up and turn it into building material.

[@remidickinson2498]

Hi Fraser, quantum physics say that something can be in two places at the same time. How is that possible? And if so, how has that theory been proved?

[@twirlipofthemists3201]

How to reenter asteroidal ore: build reentry gliders out of asteroidal materials. Land them on airstrips.

[@frasercain]

That would be awesome. Gliders made of platinum.

[@solanumtinkr8280]

It is an assumption that there is anyone else in the galaxy to colonise this galaxy. Or that we would recognise anything that was adapted to be able to live here (as in not ET running around with ray rungs), say put into the oceans as it would likely be adapted using what works here already.

[@frasercain]

In theory alien life would still depend on energy inputs, need to radiate its heat, move, etc. So we'd probably recognize it if we saw it.

[@zrebbesh]

I think we need to revisit the actual design and software for self-replicating probes. With recent advances in AI, 3d printing, and ondemand manufacturing, I think we can probably really do that right now.

[@drdemon1]

Great channel. big fan. What are your thoughts about quantum entanglement? Do you think any usable communication system can be built using this? If so will it be possible to watch live TV on Mars using that system?

[@violetskydiver7684]

Do you think the UK should revive it's rocket program, perhaps with a modernised black arrow? Or should they just continue to launch payloads on foreign rockets?

[@frasercain]

In theory they're working on their SSTO Skylon strategy. But they just don't have a big enough launch market, I guess.

[@violetskydiver7684]

Fraser Cain as a brit myself I'm always very sad that the government canceled our rocket program as the UK would probably be technology on par with the USA.

[@twirlipofthemists3201]

Rockets are privatized now. Focus on science missions.

[@clydecessna737]

When rockets take off from Earth, they basically want to go as fast as possible, as soon as possible. Altitude is important only in that we want to get the vehicle in the low drag higher atmosphere as soon as possible to allow higher speed. We notice though that rockets do go down range immediately. How is this trade-off between altitude and speed worked out optimally? I have a sense it has something to do with not being able to accelerate faster than a structural limit of the vehicle and the capacity of the engines. Can you illuminate?

[@frasercain]

You're exactly right, it's a balance between getting out of the thicker atmosphere and accelerating to the higher orbital velocity. And rockets have to decrease their thrust at certain parts of the atmosphere to minimize the atmospheric pressure on the vehicle. You can hear them talking about these forces during SpaceX launch broadcasts.

[@Johann63769]

Is there liquid carbon dioxyde on mars? I mean if it is a gas or a solid (snow) shoult not it bea liquid to?

[@frasercain]

It's really hard to get liquid carbon dioxide, especially in low pressure. It goes from solid directly to gas. In fact, it does that here on Earth too.

[@NoGodsUnderStars]

Fraser, I understand the theory of panspermia and we can definitely apply the concept when studying the life we'll find on other planets in the future. But, considering life formed on Earth almost as quickly as it could have (800 million years after the Earth/Moon system formed?) what are the chances that Mars could have done that even FASTER? (Ignoring travel time of the lucky asteroid that held the surrogate organisms).

[@frasercain]

Mars is smaller and farther from the Sun so it would have cooled off sooner. Also, it has less surface gravity, so it's more likely that organisms could have escaped from its surface.

[@williambays3534]

I have see and read many stories about life coming to earth from a another planet like Mars or comet and as someone asked in this V'log Venus. Now since Earth is so accommodating to life isn't far more likely that it happened the other way around and any life found on Mars, comets or Venus most likely came from Earth?

[@frasercain]

Well, in theory, since the gravity on Mars is lower, it's much easier for life to get blasted off Mars and travel to Earth. That's the only reason people think it might have started on Mars.

[@RandoomDude]

They say all life is connected, but now some people are saying Octupi might have come from space, is that basically just ignoring that?

[@eduardokurt]

I got a mith busting question about something i've read iin a comic book: If i theres a stick measuring few atoms of diameter and..... lets say a light year of lenght. if we push it here the other end will move immediately or one year later? could be used as FTL communicaton?

[@MultiFortunatus]

Do you think space colonies should be prepared to be their own countries or be new parts of existing earth nations?

[@xstalchild]

What about rocketoons???

[@SarevokRegor]

*Question* : JWST has decreased its time from now from 10 years in 1997 to 2 years in 2018. As this means that the JWST decreased its estimated time to arrival by average of 0.36 years per year ( derived by dividing estimated time till completion decrease 8 by the 22 years of real time) . This means that the time frame for JW to hit zero is 2 / .36 , or 5.5 years if it matches its historical decrease rate in estimated arrival time. Hence my question is, are you excited for when the JWST launches in 2024 ?

[@frasercain]

I like that estimate. It sounds pretty realistic...

[@mostevil1082]

You're my favourite space tuber, but I'm not sold on your orbital mechanics there. Lagrange points are easy to get to... but only if you don't mind taking the ITN slow road. Manned missions definitely won't want to take that long. An efficient (or faster) Hohmann Transfer has too much energy and doesn't naturally want to stop at the L points. Aero capture into an orbital station may well be easier to achieve with a low energy mid course adjustment to set up a capture into the correct inclination.

[@frasercain]

You can drift slowly using the ITN, but you can also use your engines to make those journeys more quickly too.

[@mostevil1082]

Thanks for replying! Interesting do you have a source? Everything I've read says otherwise. As I understand it any burn to shorten the time will adjust your trajectory towards that of a Hohmann transfer, only it's worse because you lose out on those Oberth effect gains from burning low (fast) in the gravity well. It might combine okay with ion engines where you trade efficient burns for huge Isp's. Then you have the bigger issue that your atmospheric craft (the hard part) has a lot more work to do to get to your station. From the (confusing) information I can find L1/L5 need an extra ~4km/s on top of the ~10km/s to LEO. That's going to decimate your launch payload. And that 4km/s is roughly what you need to Hohmann transfer to Mars! It either really doesn't work, or all of the Δv maps I've found are wrong.

[@NathanaelDuke]

Re: the Fermi Paradox and panspermia, how cool would it be if we found out someday that life on earth was the seed for life in the Milky Way galaxy sent by another civilization in another galaxy, and Earth was only chosen because it’s near the galaxy edge, it was new at the time, and about right conditions for that civilization to test the life experiment in an otherwise uninhabited young galaxy?

[@Norman92151]

QUESTION: Fraser do we know what concentrations of precious metals are present in asteroids and in which ones? Here on earth certain geological processes took place over millions of years to help concentrate minerals and ores into economically viable levels for exploitation. Usually from geothermal activities involving super heated water or even biological activities. What leads us to assume that the minerals are sufficiently concentrated to make it worth while to mine them? Thanks

[@scottrick7321]

You say we are affected by gravity from everything in the /observable/ universe. Does that mean things beyond the observable universe may not affect us gravitationally? Can you explain that statement please?

[@Lmaluko]

Fraser i was wondering, with Space X reducing the cost of launches, currently, what percentage of a mission funding, let's say to launch a new telescope, for example, is spent on the launch itself?

[@Bland-79]

Fraser Cain I think the question was did "Is it possible Venus had an advanced civilization that time wiped all evidence of away if Venus was ever habitable?".

[@williambays3534]

I was watching some of your past episodes on black holes and gravity. Now since light speed is the maximum speed of energy radiation, what is gravity's force or nature? How does a black hole's gravity get out to effect other bodies if nothing can escape a black hole? Is gravity immune to it's own nature? Is it an unknown energy? Shouldn't gravity from a black hole not have a effect on anything else since it can't escape itself to cause an effect?

[@frasercain]

Gravity isn't a thing that escapes, it's the effect of distorted spacetime. Here's an article for you: briankoberlein.com/2015/08/21/how-does-gravity-escape-a-black-hole/

[@williambays3534]

Thanks, if I understand the article correctly, gravity is a deformation of space-time and not a form of radiation. Which would make it impossible to shield or block. Orbit doesn't count that's a state of free-fall and everything falls at the same rate around the planet. Humm so gravity plating like in SciFy is impossible at present time, since there is no know way to artificially warp space-time to simulate it, at leased not yet. Did you enjoy my fermi paradox dumb pun?

[@twirlipofthemists3201]

Not rocketoon?

[@frasercain]

That's pretty good. :-)

[@twirlipofthemists3201]

Fraser Cain Sadly I didn't make it up. I think it's actually the most common term for It?

[@nielsandersen6164]

Would galaxy clusters really move toward each other? I thought that gravity has no chance against the expansion of the universe at those distances.

[@frasercain]

Yes, depending on their distance, but in this case I was imagining a simple version in a non-moving Universe in response to the question.

[@clintwolf4495]

Great video, as always. Regarding the Fermi Paradox...We know that any civilization that would have the ability to spread throughout the galaxy would have technology far more advanced than ours. Based on the age of the galaxy, such a civilization could be millions or billions of years ahead of us. Their technology would be so alien (no pun intended) to us, we probably would not recognize it or know it was even there. As Paul Davies hypothesized, it could even be buried in our DNA.

[@frasercain]

Sure, maybe for some of them, but that leaves a lot of extra space, energy and matter that another civilization could use. And we'd be able to see them. It only takes one.

[@clintwolf4495]

Very true. Finding even one example of alien intelligent life would be one of the greatest scientific discoveries of all time. I have no doubt that they exist throughout the galaxy and the universe.