Asteroid Strike Probabilities, Propulsion Breakthrough, Methane on Mars | Q&A 247

How sure can astronomers be when estimating asteroid strikes? Why is Jupiter so radioactive? What happened to the methane on Mars story? Are black holes 2D or 3D? Answering all these questions and more in this week's Q&A show.
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00:00 Start
00:24 [Andoria] Can you prove that there's no life in the Universe?
04:14 [Vulcan] How certain can we be about asteroid strikes?
08:52 [Risa] Why is Jupiter so radioactive?
10:36 [Aeturen] Is there gravitational lensing for planets from their own stars?
13:45 [Vendikar] Wouldn't it be cheaper to send multiple satellites to deep space at a single time versus one at a time?
18:10 [Remus] What's my opinion on the shape of the Universe?
22:01 [Janus] What happened to methane on Mars?
24:27 [Cait] Will a major propulsion breakthrough happen soon?
28:26 [Betazed] Does Jupiter protect us from asteroids?
30:08 [Cheleb] Are black holes 2D or 3D?
32:28 [Nimbus] What's the most important resource on the Moon apart from water?
34:37 [Belos] How do gravitational wave detectors know where the signal came from?
37:50 [Lyar] Do Sun-like stars with tidally locked planets make sense?
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[@marklewus5468]

A tip about avoiding low quality YT content. Go to the channel tab and see how often they post new videos. Junk AI channels typically post >4x per week, some post multiple times per day. High-quality channels, especially small ones, rarely post more than once a week.

[@bjornfeuerbacher5514]

Fraser Cain _does_ post more often than once a week, and he _does_ provide high quality nevertheless.

[@Robbadobbsoldier]

But is he really human? He looks strange

[@TheBiggreenpig]

"What is the shape of the universe"? Fraser Cain: Donut, because I'm hungry. Also I'm destroyer of worlds.

[@HuntersDad.]

"His name is Cain... some say he's the devil himself...." 😄 Anyone else remember seeing the Highlander 2 preview all the time? Also, Fraser, you would make an excellent live action Homer Simpson. I pronounce you Space Homer! Much love lol keep up the great work and thank you.

[@gregor-samsa]

Hi Fraser, Germany here, please be tollerant for my English... my question is... honestly, I can't stand the Kardashev scale any more - not at all because it was from a Russian - but because it seems oversimplified! - Are there no other accepted measurements or scales to benchmark or classify extraterrestrical live and zivilisations. Example - Travel Speed (with or witout live) , - Capability for (Asteroid-, Planet-, Star) - mass movements, - Infomation processing capability for universe observation, tollerance of live against temperature, pressure, radiation, liquids.... you name it? If not, lets collect and develop some more criteria :-).

[@GlutenEruption]

Great question! I've always thought the exact same thing. (And no need to apologize because your English is excellent)

[@dougirvin2413]

Gregor your so right! Think of all the different things we humans have set up as goals throughout time and over all our different civilations...today we'd call to crazy to go to war over Helen of Troy, but it made sense to Menelaus. Why would we think alians would share our same goals?!? Makes no sense! Just a decade ago who would have believed that in 2024 we'd use all this energy mining crypto?

[@gregor-samsa]

@@GlutenEruption Well thanks and what would be your criteria then? .... - Size of known star maps, - Trade with or - knowlege of even other aliens ? (.... in fact that woul be my inital questions: What want they to trade and are there some others?) - biodiversity, - number of individuums, - calculation capacity, - integral of communication throughput, - surface area of inhabited land or living space, - lifespan ? ..

[@ASlickNamedPimpback]

Travel Speed (with or without life) --> We could get to significant fractions of the speed of light within the century (like with Project Starshot and the much older Project Orion), and anything after a millenium would just be infinitely harder to beat records as a civilization adds 9's to their 99.999999...% Capability for (Asteroid-, Planet-, Star) - mass movements --> Depends on how this is classified. A civilization which controls a million stars and a civilization which controls just one could be ranked the same if all they could do is move planet-mass objects, since moving entire systems requires purpose-built megastructures and would be alot of effort for little gain (whilst Kardashev scale is an organic growth sort of thing). Infomation processing capability for universe observation --> Information processing requires energy, which just loops back to Kardashev scale. tollerance of live against [hostile conditions] --> This could rank some stone-age society which developed on a tidally-locked world on the same level as a society that rules an entire galaxy. Since any life that evolves on a tidally locked planet would have to contend with very hostile conditions, and thus would naturally be hardy, whilst a technologically advanced space civilization would never need to modify themselves to adapt to such conditions as they would have robots (or could just terraform a planet to their whim if need be).

[@EinsteinsHair]

The Why Files did an episode on the Kardashev Scale, but also mentioned another microscopic scale that measured how small the objects were that a society could manipulate. I do not remember the name of the scientist who proposed that scale.

[@stevenlafavor9823]

Love the Monty Python reference, "just a wafer thin mint".

[@millie_willcox__]

How AWESOME that you'll start highlighting small content creators! I'll definitely be checking each of them out as you share. Great video today, I don't know who to vote for!

[@BitcoinMeister]

Love the small GOOD channel promo idea!

[@fnln-namaemyouji]

Here's a bit of an unusual suggestion for a small space content creator. The channel is 宇推くりあ -★Clear Rocket ch.★-, which is read as Usui Clear. She's a Japanese vtuber, which if you're not familiar with the concept, is basically a live streamer with an anime-esque avatar. She has the unusual niche of being super into rockets, to the point that her custom avatar is loaded with references to things like RCS thrusters and hydrogen rocket plumes. When rockets are going to launch, what she does is restream the launch stream, but then do live translations into Japanese from English. She's also been an official liaison with JAXA on several of their space missions and and rocket launches, like the H3 recently, which has led to some rather surreal looking press events if you're not used to that sort of thing, but if you can understand enough Japanese she's genuinely a quite good source of information on Japanese missions.A bit more on the rocketry than the science side, but figured I could drop in a multicultural suggestion.

[@PsRohrbaugh]

I love how your brain works. You covered it right as I was writing this "One thing people forget about the transit method - is it takes time. Earth's orbit is an entire year" and bam you covered it.

[@RectalRooter]

I follow you. Kinda like how people started saying the universe is full of hot Jupiter's because that was all we could see at first. Now we're seeing longer orbit planets, with people now saying the universe more even amount of hot Jupiter's and other types of planets.

[@powerofanime1]

If we were alone in the universe, that itself would make us special. It seems to me like presuming such a thing even if we're definitely alone in the galaxy would be kind of arrogant.

[@blackwolfe638]

would be very arrogant.

[@ronald3836]

And the question was asking for life in the universe, which contains 200 billion galaxies which are visible to us but too far away to ever hope to detect the absence of biosignatures. But most likely we'll detect life on Venus or some of the moons of Jupiter and Saturn, hopefully in our lifetimes.

[@leonmusk1040]

Indeed it would also be pretty arrogant to assume we're close enough in space or time to ever meet them too.@@blackwolfe638

[@emceha]

What if galaxy is full of bacteria and primitive plants?

[@ronald3836]

@@emceha perhaps we could detect that (seems nearly impossible, but what do I know!), but we won't be able to determine that there is no planet with microbial life. Life could even be present below an ice cap (see the moons of Jupiter and Saturn, maybe).

[@dougieh9676]

Love your show. Been watching since 2015. ❤️❤️❤️

[@kevincurnick]

Thanks for answering my question! 🤙

[@PsRohrbaugh]

8:30 I understand this is a simplistic explanation, but that's not how the statistics work at all. If an asteroid hits 1 million years on average, then after 100 million years you'd expect to see around 100 hits. But assuming it's actually random and there's not some mechanism with a 1 million year period (like how long it takes to orbit the galaxy), it'd be quote normal to see impacts very close together followed by huge gaps.

[@davehoward22]

If you look at some of the photos of earth from the windows of the apollo missions, you can see how lucky a major asteroid hit would be on this little speck of light in space.

[@ladydustin7811]

Concerning the last question: the search for EarthLike planets around sunlike stars, the European Space agency is going to launch the Plato telescope in 2026 that will do exactly that. It will observe 100 000 sunlike stars uninterrupted for 2 years to look for earthlike planets up to the habitable zone. I am a bit surprised you do not know this when you are aware of Ariel. But I understand you can not know everything.

[@bbbenj]

Thank you for your dedication!

[@theblackswan2373]

Many thanks for all of the great content.

[@djopdam199]

Great episode!

[@olliverklozov2789]

Alone in the 'galaxy' maybe, the universe is a little beyond us. This would be like saying we found no one else on a tiny island, therefore the world is empty.

[@emceha]

My favourite scenario is that life is abundant in the universe, but not a single alien life crossed the border of single cell organism. Absorbing mitochondria in Earth life past would be extremely rare type of the event on galactic scale, that allowed life on earth to flourish.

[@dougirvin2413]

Aeturen. Hi Fraser, can't thank you enough for answering my question yesterday about gravitional lensing & you even worked it into a ride share with Conner Campbell's today! WOW... your pretty smart! Now I'm wondering is this micro-lensing the same thing that astromoners used in 1925 to confirm Einstein's relativity as they observed the presession of Mercury's orbit and the missing 43 seconds of arc. Or is that a different phenomena?

[@bjornfeuerbacher5514]

That's a different phenomenon.

[@deant6361]

Thanks for sharing Fraser another great show I think there are some great channels out there but I think that your channel is the best one so thanks for all you do for space science. 🇦🇺

[@oldmandoinghighkicksonlyin1368]

I liked the response to question no. 1. It would have been easy to dismiss with a brief statement, but you made it a fulsome and complete verbal essay.

[@arbodox]

Here's a few of great small astronomy channels (with the exception of one which is more focused on planetary/earth science than astronomy) that I watch---three of them astronomy grad or postgrad students, so they're really deserving of support! AsianAstrophysicist, ICQ Comets (and Cousins), Kyle Kabasares, Nora's Guide to the Galaxy, GEO GIRL

[@adamward9310]

Fraser love we all your videos. Except this one worried me, only because that asteroid crash you animated lands right on my house in Bell, Florida 😮😮😮😮😮❤❤❤😊😊❤❤❤

[@MageSkeleton]

How did i get here from an ABL video??? Literally selected to watch/listen to ABL an ad played and now im here.

[@frasercain]

What's ABL?

[@stevenscharmer1765]

@@frasercain I think they meant ABL Space Systems launch company.

[@josephsheehan6450]

Hey Fraser! Love the content! It sucks that the malfunction of Kepler’s reaction wheels has left this gap in the exoplanet pipeline for future missions. Would there be significant savings to constructing and launching a new, identical, Kepler to finish the mission? They’ve already designed it and developed the technology.

[@BoomMC_Inc]

I'm probably an odd duck, but the more I learn about space, the more convinced I am in my faith.

[@daos3300]

confirmation bias lol

[@brucehansensc]

Not odd at all. Cosmology inspires humility and awe.

[@KGTiberius]

#Nimbus 📍 Deep Mine Geothermal potential power. The deepest active mine in the Earth is Mponeng @ 4km. @2 km deep, the moon is estimated to be 200-400’C. Use the mine spoils/material used as building material, minerals/ore, and usable volume for habitats. Drop a boring machine from The Boring Company up there (moon/mars).

[@PsRohrbaugh]

Lot of work but it'd be awesome

[@AdamosDad]

In general relativity, the curvature of space is dependent upon the density of the Universe, and for Ω

[@philswede]

Greetings from Sweden! Best interviews, best topics and the smoothest voice on KZbin 🎉

[@dougirvin2413]

Thanks!

[@cavetroll666]

Salute from Toronto cheers

[@Purplebass]

Hello wonderful person. Antov! Hes awesome

[@DanouNauck]

I vote for the Jupiter Question, RISA. Because there i really learned a lot i didn't know before

[@patkintromso]

I think Plato telescope from ESA will look for new exoplanets around sun-like stars

[@GadZookz]

The Enterprise must have visited numerous planets that were never mentioned in a Star Trek episode or movie. To avoid running out of planets, it might be a good idea to write to the studio and get a list of those planetss in advance. 🤔

[@supercal333]

Just because observations at this point in time don't reveal life in the universe, doesn't mean there isn't life. It can take millions of years for the technosignatures from distant civilisations to reach us.

[@zlm001]

Thanks

[@tarumph]

Cait - Orion Drive! :)

[@clarksonjones6474]

Hey ! Let's fold space-time ! :)

[@music100vid]

We CAN find sunlike stars so a catalog of those would be the first thing to do. 2nd, determine distances to them and calculate the probability of detecting earth size planets at those distances with the new earth based telescopes. 3rd, eliminate having to look at the many that only show radial movement and would not be detected by the transit method. A few small sensitive telescopes placed in space positioned by laser and measuring star positions 4 times in say, however the maximin length of time a planet in the habitable zone would take to make an orbit. 4th, yes, then you do need a dedicated telescope to just stare at all these candidates in a likely place in the sky, or....use an array of small telescopes, each dedicated to a certain star. Use our mass production methods as we do in many other manufacturing scenarios as Space-X does with cube sats to accomplish that. Lets get on it folks! :)

[@neiladlington950]

In regards to other life, I agree. Any probability equation that starts with zero equates to zero because we are not 1, we are the starting point where 1 is actually 0 (eg, 0,1, 2, 3.... etc.). The second number must be greater than 0 even if it is as minuscule as .00000000000000000000000000000000000000000000000001 or some other smaller number.

[@rcm024]

Can you please put a link in the description to the channels you recommend

[@colinkeizer7353]

Hi, Fraser. Thanks for sharing you time and skills with us through your videos. Have you seen discussions, yet, about rectenna power beaming technology? Angry Astronaut and Trent Telenko mentioned the concept and development status on Ellie in Space, in regards to space solar power and point to point power beaming on Earth via LEO satellite. Like those ideas, but your comments about ion drives lead me to wonder about putting a rectenna on a spacecraft to energize it's ion engines. Seems worth trying for orbit maintenance. Maybe it could work as far out as Mars, if the Earth orbiting source power beam is coherent??? What do your sources think?

[@frankmalenfant2828]

Couldn't we use the temperature differential between daytime and nighttime to generate electricity on the moon? It could be like a concentrated solar power station, but maybe the even hottest days and coldest nights might make it possible to extract even more power through thermodynamics.

[@radsaber8840]

Hi Fraser, RAD here...I just watched a documentary on how & who built the Great Pyramid. They actually found the city & tombs of the workers that accomplished that amazing work. Turns out there was approximately 20,000 dedicated people and it took them about 20 years. The Egyptian state supplied all their homes, food, tools, Healthcare, and embalming services and burial rites when they died. They even tested the ancient DNA and discovered that all the dedicated workers were Egyptian! Where did all the b.s. crap that slaves built the pyramids come from?!!

[@918Boyz]

we are the ancients. The search for life only really matters in our own galaxy and we are probably the first life to get this far.

[@Cryptoweeds]

What happened to Kepler 22B as a kid I was told this was the most earth like planet?

[@grantmyrr581]

Re: Propulsion breakthroughs, often omitted is "Nuclear pulse propulsion" from 1947 and later. See article in Wikipedia.

[@jerryobrecht2630]

Hi, Fraser. I enjoyed your comments regarding the various topographies that could shape the universe. The torus shape (doughnut) is intriguing. Being a little facetious here, can't resist, would that then suggest that the universe might be either cream or jelly filled? Jerry

[@frasercain]

Whichever if more delicious always has my vote.

[@Mobius3c273]

It is taken as a fact that red shift is caused by expansion of the universe. It causes a doppler effect on light as far away objects accelerate. If however space-time itself has an inherit constant energy product within itself then this would behave like a mass and subtly curve spacetime over great distances and scales. Universal curved space-time centred on say the atom everywhere would produce the very same effect of red shift on distance galaxies. Indeed gravitational field is accelerated space. The beauty in this model.. is that the instead of linear Time, Time is curved and the need for a beginning an end or a before is no longer required. In this model Time is a forth dimension both temporally and spatially. In other words as in Relativity, Time and Scale/lengths are intrinsically connected together. The overall topography of the Universe in this model is a tesseract a 4D version of the Mobius strip whereby as we look at increasing distance and scales the Universe slowly curves and the 3D space is curved back onto itself like a figure of 8. Yes we incorporate Time/Scale as 4D manifold curving 3D space into a figure 8. We are an ant walking along a mobius strip as we journey out in space. Here the beginning end and before have no meaning, and the entire Universe is Lorenz contracted in the the direction of accelerated (curved gravitational field) spacetime back into the subatomic appearing as a universal smooth constant energy field around us.. the Cmb. In this model the Big Bang becomes instead random high energy particles randomly being created out of the vacuum ie cosmic rays that decay into lighter elements such as electrons and protons. Over time between galaxies, hydrogen condenses out of the vacuum producing clouds that eventual grow and spin into new galaxies. One other thing is I find it baffling that the effects of electromagnetism Universally is side-lined leaving gravity as the only dominant force. We all hear it only operates locally because here on Earth atoms tend to become neutralised. Is that really true in space which is full of plasma and much of it ionised. Gravity is not even a true force but an effect bought on by spacetime geometry. Nuclear and electromagnetism are the only true forces, it is these forces when in abundance with their inherent energies that curve spacetime. E=MC squared. Gravity does not pull us down, it is the ground accelerating us up in a curved spacetime geometry. Take a look at a typical Spiral Galaxy, isn't it obvious that the stars are being swept around by an electromagnetic field as a spoon does with a cup of coffee. Further planetary formation could occur top down like a Star ie atmosphere first if electromagnetic forces were allowed to operate in tandem with gravity. I think many cosmic mysteries could be solved in this way if we gave a little more weight to the forbidden force of electromagnetism in cosmology. Hey ho that's what I think anyway. Robbie

[@vanessacherche6393]

bluedotdweller good channel i found recently

[@sciptick]

Marshall Eubanks wants to send a swarm of 1000 flyweight probes to the nearest star, reaching it in 20 years. However: 1. Sending just 1000 probes is fatally timid. We should think in terms of _millions_ of identical probes. Produced in volume, their price-per drops to near nothing. The cost of a million probes is small vs. the cost of the project overall. The entire probe could have just one chip plus a couple of capacitors and coils. 2. Launching just one probe swarm would be supremely wasteful. Given solar-powered, orbital launch apparatus, we have no reason to turn it off: keep launching probes throughout the life of the mission. Over the next 20 years, launch 1000 probes (or more: 10,000, 50,000) _each week._ Having reached cruising speed, probes turn to fly edge-on, minimizing erosion. 3. A launch laser may be a simple laser cavity, or a bundle of billions of laser cavities, pumped with sunlight reflected from an array of monochromatic mirrors ranged around it, with no conversion loss. Monochromatic mirrors are easily produced by depositing alternating layers of transparent material with different dielectric constant but identical thickness. 4. But consider the alternative of launching with an array of masers, instead. Masers are much more easily constructed and operated. An array of independent masers, distributed around the sun, can be held in phase with the aid of atomic clocks, and would present much less possibility of threat to Earth. 5. With the launch apparatus operating throughout the mission, there is no need to accelerate to cruising speed immediately. This allows a much lesser beam intensity (10GW? 1GW?) , and radically reduces G loading on the probes. But we can keep building more launchers indefinitely, and find good uses for them. 6. There is no value in having probes formed up in a plane at the destination. A dispersed cloud of a million probes flying through continuously for 20 years offers enormously greater value. The first few thousand through the system can identify interesting bodies, and subsequent swarms can tack against starlight and concentrate on those bodies. This eliminates the "predict position of planetary bodies" problem. 7. Launching continuously, later probes will be better than the first ones. Those farthest out are more primitive, but those passing the target get increasingly capable, in steps, as in "Ender's Game". Software can be upgraded throughout the mission, with only a few years' latency. 8. Probes spend almost all their flight time close to zero K. This creates design opportunities denied to other projects. The sail surface may be an atomically thin wafer of superconductor, providing perfect reflection of any long-enough wavelength, stiffened by its own field. (Superconductors exhibit perfect reflection up to the photon energy matching their band gap; known materials may reflect microwaves perfectly.) 9. Trying to transmit data home via laser would be a monumental blunder: the starlight behind the probes interferes with any optical signal. Much worse, at optical frequency, phased-array transmission by a swarm of probes is impossible. But at ordinary radio frequency, a swarm may transmit as a phased array with no difficulty, having triangulated their relative positions, and maybe synchronized to a pilot signal from home. Receivers throughout the asteroid belt may remain synchronized to operate as a phased array using atomic clocks (as was used to image M87). They can easily listen to all swarms, in all directions, at the same time. 10. There is no need for probes at the destination to transmit their data all the way home. They need only send to the next swarm coming up a light-day or light-week behind, which relays data to the next. 11. Upon approaching the destination, the swarm may focus incident light (laser/maser/starlight) on a few, selected probes to slow them down enough to enter orbit. Subsequent swarms flying through can provide phased-array communication, and assist altering their orbits, with the occasional additional new probe joining them. Visiting a bright star would be a better choice, for this purpose. 12. With two swarms sent out in different directions, you get a phased-array radio telescope light-years across that could (e.g.) image the surface of a pulsar, using the pulsar itself to synchronize. I sent a version of the above to the address in the paper, but have not heard even a peep back.

[@sciptick]

Make the control chip from a stack of graphene sheets, each rotated just a bit from the one below it. It could mass nanograms. Make it the full size of the mirror, with billions of networked cores. Millions of them may fail, but so what?

[@trickedouttech321]

I think the odds of no life are higher than the odds of life. I know that does not make sense to most because of the number of plants. However, if you look at it without bias and add in some obstacles the odds favor no life IMHO.

[@user-li9ih3yi8m]

Hi Fraser. A question : I've been wondering, if I used up all the mass of the earth to create a straight pillar of mass from where the centre of the earth is (on average) to the centre of the sun, what approximate diameter would that pillar have? And what kind of density / consistency? I love your work. You make a big difference. Thank you.

[@leonmusk1040]

you're premise is flawed but sure it will turn into a sphere to answer your question most steel (high tensile) 1cm diameter melts under its own weight at 1g by 6-8 km depending on hardness and density titanium 11km graphite 22km ... But for arguments sake nanoscopic if it wasn't torn asunder

[@bjornfeuerbacher5514]

You can use high school geometry to calculate that... Earth's radius is (in the mean) 6370 km, hence its volume is about 1 083 000 000 000 cubic kilometers. The mean distance from Earth's center to the Sun's center is about 149 600 000 kilometers. That gives a base area of about 7240 square kilometers for that pillar, and hence a diameter of about 96 kilometers.

[@bjornfeuerbacher5514]

@@leonmusk1040 Nanoscopic? Why do you think so? I did the calculation and got about 96 kilometers for the diameter.

[@leonmusk1040]

so the sun would be 12 km and you think earth at less than a billionth the mass of the sun is going to be 4 times as large Hmmm mighta mis placed one of those annoying to the numbers on your napkin math their jim@@bjornfeuerbacher5514

[@leonmusk1040]

sorry thought this was in response to diameter of earths mass crushed to neutronium @@bjornfeuerbacher5514

[@patellis8904]

Was really waiting for the USS Voyager to come up over the ice on that Europa shot.

[@DanielVerberne]

Yeah man, I was practically hearing the theme music in my mind!

[@JoelYancey]

Question for Fraser: It has been said that a black hole as massive as the observable universe would approximate its diameter too. How is this possible if black holes are denser than neutron stars?

[@bjornfeuerbacher5514]

Black holes are not denser than neutron stars, actually the mean density of a black hole can be quite small if the black hole is big enough. You confuse the mean density of the whole black hole (that's the whole region inside the event horizon) with the density of the singularity.

[@mhult5873]

Belos Thank you for another great video! :) BR //M

[@Slikx666]

Other channels? Astronomy live. The pictures he gets are amazing, records rockets. Reds Rhetoric. Not everyone's cup of tea but he's trying to be more educational and records rockets. SMA's sky. Not many subscribers but does livestreams looking through a telescope at stuff up there. Scott Manley. He's a Manley man.

[@rocklarsen228]

Jupiter is so our friend! Maybe like a dad that was mean sometimes

[@pureambience1714]

Does a light particle (photon) have a mass and what is its comparison to say an electron? I can conceive the idea that electrons with a mass can be grabbed by gravity of a black hole but light i conceive as immaterial and find it hard to comprehend the idea of being not able to escape a black hole's pull.

[@KarelGut-rs8mq]

Photons are mass-less. The reason that they are affected by gravity is due to their kinetic energy. Gravity is not caused by mass as is frequently incorrectly stated, gravity is caused by energy and mass is just one form of energy. All forms of energy cause gravity, Mass, Kinetic Energy, Potential Energy, Pressure (both positive and negative). All mass-less particles always travel through space at c in vacuum, no particle with mass can ever travel (through space) at c.

[@dionhalic]

"You can assume!" !!! What's the point? What are you so worried about? "95% likely you are alone!"

[@Miata822]

NIMBUS - This is especially the issue with colonizing Mars and the industrial scale in-situ operations.

[@michaelgian2649]

Belos vote. Is a triangular array sufficient to determine the origin direction of a gravity wave? Consider a source lying on the central normal line of the common plane of the three. Isn't four, in a tetrahedral array, the required minimum?

[@leonmusk1040]

any 3d vector can be pinpointed with three receivers

[@rosewoodreadingroom8473]

Please correct me if I am wrong, but I believe the LUVOIR plans are to implement a 15.1m (LUVOIR-A) or 8m (LUVOIR-B) diameter mirror. 50m would be awesome though!

[@frasercain]

It's been turned into the Habitable Worlds Observatory and will be 6.5m like Webb

[@rosewoodreadingroom8473]

Good to know! Thank you!

[@Nomad77ca]

As for the question of life in the universe, I wonder if it might be more accurate to say life in "our galaxy" since detecting life in any of the other billions galaxies would exponentially more difficult. Maybe the ratio is 1 life detection per galaxy. Tho I hope it' not that low. (Andoria) Great Python reference btw. Also, only the event horizon is spherical, which is an effect, not mass, would a spinning black hole really be oblate?

[@bjornfeuerbacher5514]

"would a spinning black hole really be oblate?" Yes.

[@augustvctjuh8423]

Do you think it is wise to commercialize spaceflight, given the risk of a space debris chain reaction?

[@orlandoerickson2439]

Question - do other stars have an Oort cloud? Curious if the formation process is common.

[@KarelGut-rs8mq]

We don't know, we don't even know if our sun has an Oort cloud. It is still unconfirmed and we're not really close to finding out. It's a plausible theory but it's still many years (decades even) to go before we have the technology to find out the truth.

[@MARILYNANDERSON88]

What if aliens are nearby watching the show and laughing that we think that they may be 'out there'.

[@billyoung9538]

I think we need to eliminate other life in our system before we start trying to guess about system further away. We never expected to find a second, chemosynthesis based, food chain here on Earth, and yet we did on the mid Atlantic ridge. With the knowledge that that alone is possible, it raises the opportunity for there to be similar chemosynthetic life to be found on some of the moons with potential oceans and tectonics.

[@philiphm282]

Is it possible to use Alpha-Centaury for gravitational lensing? If so, is it being done? Are any interesting discoveries from it?

[@ElitePhotobox]

A metal coated light sail can be used as an aerial !

[@dianewarfield8067]

Noor ! The name means Moon in Arabic! Excellent! My name is Diane and it is from Greek Mythology for Goddess of the Moon, Goddess of the Hunt, and Protector of Women.

[@Temp0raryName]

Fraser, in the era of O'Neil Cylinder construction, could we capture that radiation trapped in the Van Allen belts (and Jupiter's equivalent) to power orbital structures? Could we reduce the radiation danger risks enough that some of the presently uninhabitable moons could become safe?

[@levirivers2772]

Mr Cain a suggestion for KZbin channels for your review; BlueDotDweller and Learn the Sky.

[@rodnee2340]

4:33 we are in a shooting gallery! 🥶

[@joefresh3725]

QUESTION: this is just for fun curiosity. But I would like to know where things like JWST, the Voyagers and Omuamua are in the sky. Is there a sky map that shows their position? So when I'm walking the dog at night I can try to convince myself that I see them?

[@No14_louis]

While not under 10000 I do like parallax nick channel for astronomy. I liked the neighborhood tour of of the stars

[@TheWadetube]

Fraser Cain the illustration at 33:46 is the best design for an off world habitat I have ever seen. It is pressure rated and multi-tiered, insulated and allows for running on an inclined surface to add g force to your work out. It's great, who did it?

[@FLPhotoCatcher]

One way it could be better is if the spin level was on a lower level, not the top level. At the top, it wastes space. at a lower level near the bottom, the floor could be the outside wall.

[@TheWadetube]

@@FLPhotoCatcher Brilliant. Now that you point it out it is obvious that it should be on the bottom one or two levels. I don't believe we can see the bottom most basement level as it is probably for water processing and may even have a tunnel connection leading underground. I think the regolith could be pumped into a long heavy sack tube to contain it with a little water or something added that would help harden it. That's what the illustration appears to convey and that's brilliant too.

[@bbartky]

I can say for certain, but it looks like a lunar base concert study made by the European Space Agency (ESA) a decade or two ago. However, in that study the base was fixed and there was no functionality to compensate for the 1/6 g on the Moon. The idea was to make inflatable modules that were filled with lunar regolith to protect against radiation and micro meteorites.

[@dgillum214]

Could we use our Van Allen Belt or the more powerful one around Jupiter for capturing high power particle physics in a sensor? Is it enough to make Higgs Bosons?

[@Poult100]

Here's a naive question: if you could put more material onto a neutron star to increase its gravity but just suppose that neutrons didn't crush. Would it be possible to increase its gravity enough to prevent escape of light? Like a non-standard black hole? This new kind of black hole would have a physical diameter and an event horizon, slightly larger? Can I further ask, is the event horizon of a real black hole a smaller radius than the preceding neutron star (assuming you could simply add more material to a just-sub-black-hole neutron star) Thank you. Love your channel!

[@KarelGut-rs8mq]

No. The Nuclear Force that is the origin of the Neutron Degeneracy Pressure that holds the Neutron Star up against gravity is not strong enough for that. There is some speculation that there could be a further step, after Neutron Stars, that would consist of quarks and gluons (Quark Stars) but we will likely never observe such a star since they would be inside black holes every one of them. Someone did some calculations off the cuff and stated that such a Quark Star with the mass of one Sun (not a possibility) would have a diameter of 3 millimeter.

[@Poult100]

@@KarelGut-rs8mq thank you. Does that mean the answer to my second question is yes?

[@estraume]

While funding is pumped into preventing low-probability scenarios such as asteroid collision, the far more likely threat of a large volcanic eruption is close to ignored -- despite much that could be done to reduce the risks, say researchers. See article in "Science Daily" titled: "Risk of volcano catastrophe 'a roll of the dice', say experts".

[@artwie]

Fraser: it's nice to know what a 100 m asteroid would do to Earth, but tell me this please: what would Omuamua do to Earth, had it hit us? how much in advance we would've noticed? (let's say the speed of "Omuamua 2" is the same as the original, just the course changes to one colliding with Earth); have we all almost died out a few years ago?

[@MomirovVojislav]

Is there any plan for the "Vera Rubin" analog for the northern skys?

[@music100vid]

Falcon heavy lift launch is $96M dollars, Keplar cost was $600M dollars when launched - its replacement would be much more today. Lets do a mission to Keplar to attach a booster, pull it back towards Earth, spacewalk or robotically, replace reaction wheels (learn more about their failure modes), batteries, "clean the windshield" refuel and send it slowly back into position. Looks like it would be a big savings AND get the data coming in again. Has someone done the math on this? I'd like to see us start thinking about a space based telescope and repair shop in orbit close to Earth where work could be done without coming into and out of our gravity well. Most space telescopes and satellites should be designed so they are EASY to repair - in space, in an enclosed repair bay. Even just the concept of an orbital dock, such as depicted in the Star Trek films would allow Hubble like maintenance to happen in a more controlled and easier way. I much admire the modularity and ability to repair the Hubble. That has saved it NUMOUOUS times! Meanwhile, we're working on Habitable worlds and others. Never hurts to have more data and a few spare telescopes out there - just in case....

[@nicolasolton]

At a minimum we should design satellites that have mechanisms for replacement or refueling of attitude control thrusters.

[@MarkAllen1]

Question: What do you think about the wooden satellite created by Japan, will it really help combat space pollution?

[@Raz.C]

Heyya Fraser Do you think there will ever be a time when -Earth based- when -terrestrial- umm... when ground based telescopes will ever become unnecessary? Because we've colonised so many extra-solar planets, I mean. So the conceit is - There are people living on so many planets across space. Do you think that there will ever be so many inhabited planets (and traffic between them) that ground-based telescopes will be unnecessary?

[@davehoward22]

No..

[@TheInsaneupsdriver]

Callisto is outside the radiation belt... It's the only one in our system, that also has a ocean, and the largest outside our moon.

[@jasonsinn9237]

What other planet or moon would be the best candidate for terraforming other than Mars? How would we go about it?

[@yoredeerleader]

“Choose Life?” Sounds like a someone has a crush on the lead singer of Wham!

[@toby9999]

We could be on a thousand words within our galaxy but that wouldn't tell us much about other galaxies. Perhaps there's maybe one planet with life per galaxy. I say that because I don't believe well ever reach another galaxy, therefore we'd never know. I'm not even confident we'll reach another habitable star system. The distances just seem too massive. But I'm a pessimist by nature.

[@simfromzim]

Rio 2!

[@roeesi-personal]

I'm sure you know about them and they're probably too popular for this anyway but if you ask for astronomy related channels I like to watch I'd recommend Dr. Becky, Angela Collier and Cool Worlds.

[@Torino1O]

My question, Dark Energy or the expansion of the universe only seems to occur when there isn't any matter or mass present to warp space in the form of gravity, can the complete lack of gravity just be space bending in the opposite direction?

[@leonmusk1040]

yes a little bit but only very marginally as the "Fabric" of space time is very rigid much much less plasticine than muonium.

[@rowshambow]

How long do you think it will be before we have rockets and spacecraft that can travel at 1g constant acceleration and deceleration?

[@peterd9698]

28:00 People always say antimatter is the ultimate.. but isn't it theoretically beaten easily by any form of beamed propulsion.. which also has far fewer advanced physics hurdles? That way you could have up to the entire power of the sun at your disposal without any of its mass. For example something like Project Starshot, just running non stop spitting out 1gram sails that vaporise to push against a plasma sail on your space craft.

[@leonmusk1040]

tight beam propulsion suffers from a thing called log N20 Or diffusion where as anti matter is 20,000 times mor mass to energy effective than perfect fusion which is many hundreds of times more energy dense than fission or hundreds of thousands times more effective per gram of fuel than plutonium and stays as dense the whole time so can use it to slow at other end not just fly by.

[@peterd9698]

@@leonmusk1040 That is why I used the example of Project Starshot launching a continual stream of tiny sails at your vehicle. They can do very minor course corrections over very large distances.

[@leonmusk1040]

Still only starlight braking and gravity wells at the other end though :).@@peterd9698

[@carries6427]

Andoria 🎉

[@benjaminsoos914]

The asztronomer who finds all these asteroids before they hit Earth is Krisztián Sárneczky, from Hungary, not from Romania.

[@Corvaire]

Hmm, I thought the ratio of kicked in vs. gobbled up was balanced towards "gobbled" for Jupiter? Thanks for straightening that out for me. ;O)-

[@AVERAGECONSOLEGAMER]

Scavengers reign best alien ecosystem ive ever seen masterpiece