Rings Around Stars, Laser Space Propulsion, Life on Cold Moons | Q&A 206

How do we determine the velocities of objects in distant space? Can we use a laser a space engine on a spaceship? Can we find stars with rings? Is it possible to see the same star at different stages of its life? All this and more in this week's Q&A.
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00:00 Start
02:21 [Tatooine] Can stars have rings?
07:59 [Coruscant] Can we see stars at different life stages with gravitational lensing?
11:29 [Hoth] Why not launch payloads from orbit?
14:30 [Naboo] What would happen if time stopped?
16:20 [Kamino] Does Elon/Twitter impact spaceflight confidence?
18:28 [Bespin] How can there be life on cold moons?
22:49 [Mustafar] What if a meteor hits the Moon while astronauts are there?
25:58 [Alderaan] Shouldn't ETs be benevolent like Vulcans and not malevolent like Klingons?
27:51 [Dagobah] How do we determine the speeds of objects in space?
30:06 [Yavin] Why go back to the Moon?
32:08 [Mandalore] Do you ever get tired of speculating and not lending your intellect to progress?
34:14 [Geonosis] Wen JWST Deep Field?
35:20 [Corellia] Why is Sag A* disk not aligned with the galaxy?
37:23 [Crait] Will there be a Mars colony this century?
39:43 [Endor] Could we use a laser as an engine on a spaceship?
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[@pikachu5188]

@Fraser, By examining the spectrum of light from a galaxy, you can determine whether the galaxy is moving towards or away from Earth, and how fast. You probably heard the expression 'red shift' meaning the direction of the galaxy is moving away from us and also the greater the shift of the basic element's absorption lines found in it's light's spectrum resolution the greater it's speed of doing so. The Andromeda galaxy is 'blue shifted' and heading towards us.

[@beesod6412]

You've been my space news guy for the last 20 years, heres to 20 more!

[@handsomeblackmuscle9845]

WOW that's amazing. Fraser has been my space guy for the last 20 days! I'm excited to see what comes next for him and his team!

[@christophermullins7163]

​@@handsomeblackmuscle9845black Hercules? Lol A few months now and he has quickly become my main content binge on KZbin. Space is everything.

[@fep_ptcp883]

The work of a journalist today is more important than ever before

[@Czeckie]

the Coruscant question/answer is so cool. we have a prediction we will see a supernova, how awesome is that

[@boredgrass]

Hi Frazer, i'd like to share an observation that has to do with a *distractin effect of background. However first let me assure you that I nevertheless love your videos dearly and nothing can stop me keeping watching! What happened: The background music kicked me out after 1 minute. That had nothing to do with my music style preferences. Since the cause is not well known, a description of the issue: A hearing impairment effects the brain's ability to isolate the spoken word from additional noises present at the same time. That can make listening challenging, annoying or impossible. The closer the background noise is to pitch, volume and rhythm of the speaker the stronger the effect. This phenomenon effects many. You probably know people who complain they only hear indistinguishable noise at gatherings or loud public venues. I'd like to share an observation: I understand that the music is intended to create a certain atmosphere. And despite my problem, I think it fits that purpose very well! What I observed is that in videos where the music is restricted to points which introduce a new video segment, or paragraph intros of the narration, I can "retain" this atmosphere! Another factor is that the background has a significantly lower volume than the narration. In this video you've done that, so I count that one on my ears having a bad day;-)

[@MaryAnnNytowl]

Fraser, you are one of my favorite science communicators on YT. Thank you so much for all you do! Here's a like and comment in return for the care and feeding of the Almighty Algorithm. 🙏 ❤️❤️

[@a59x]

The best content out there hands down! I love the background music and the work done on the graphics as you answer the questions, this is really worth much more praise. Thank you!

[@jimsmith9251]

Thank you Fraser, Happy New Year Brother, much love from the UK

[@Cbockhoff]

Really enjoy these episodes. Most of the stuff you talk about goes way over my head but still really enjoy.

[@TheyCallMeNewb]

Tatooine was the winner in my estimation, possessing as it does, usefully, the superficial and the complex. The Asteroid Belt is what remains of the Sun's ring (planets too not altogether dissimilar).

[@Dr.Wael.Alrifai]

I vote for all answers! Thank you for doing this, you are amazing.

[@bikerchrisukk]

Thank you for the book recommendation Fraser, I've just bought it! 👍

[@michaelmclean4958]

34:08 brutal honesty: always a scientist in my eyes bro. This is why I love youtube, amazing manufactured channel with incredible content, and yet there is some personal stuff here that makes the cut. An interesting portal in the the psychology of Fraser: good cut.

[@Madash023]

Huge fan of Revelation Space! If you liked the first one, then I highly recommend the rest of the series! The first one was decent, but they get much better in the middle of the series.

[@frasercain]

I thought the story was over and then I realized there are three more!

[@UrbanPorcupine]

Is it possible that a captured planet could lurk in the Ort Cloud? Also, could we determine this mathematically?

[@truvc]

That’s the premise of the predicted planet 9. There are a few TNOs whose orbits are aligned and that’s the basis for predicting a roughly Neptune-sized very distant planet with a highly eccentric orbit.

[@bloodybobbygamecatx2532]

Coruscant! Thank you, always great videos!

[@olorin4317]

Tatooine! I love accretion disks. That picture collection is mind blowing.

[@GrouchyHaggis]

Coruscant - fascinating question and answer, I didn't know this was possible!

[@H8FULL1]

Love the content. BTW. During Dagobah, DR asked How can we determine how Fast an object is travelling away from us. He was asking more about how they measure red shift. Not what the object was doing while the light was traveling.

[@blablubb8752]

On the question about being hit by a meteor on the moon: What about bringing an air defense system to the moon for that purpose? I can imagine that modern radar tech could detect a meteor in time and then launch a missile "against" it? When it only occurs very rarely, i think this could be an option? What do you think?

[@vertigo2893]

Hey Faser, I want to follow up on the "rockoon" question from QA206. You are correct that the hard part of getting in to orbit is achieving high velocities, however, if a balloon or some other form of lighter-than-air ship can carry a vehicle above most of the atmosphere, the main benefit is not so much the lack of air resistance, but the fact you are not fighting gravity losses and the rocket equation doesnt apply. Instead of having to accelerate quickly to reduce gravity losses, you can accelerate veeery slowly and something like ion propulsion might be viable, even allowing you to use solar panels for energy and air molecules as propellant to accelerate gently. Maybe it would take weeks or months to get anywhere near orbital velocities, and you may still need a an actual rocket for final insertion burn, but wouldnt that be far more efficient? I imagine a ion engine on a giant inflatable lighter-than-air flying wing, allowing you to convert speed in to lift and skip off the upper layers of atmosphere, maybe dipping in and out of the atmosphere as you build up speed (and shed heat and gather propellant). Have it covered with solar panels. The only real issue I can see is friction heating, though Im not sure how much of a problem that is at very high altitudes.

[@VRnamek]

Oh, I do find value in you podcasts here, man. I don't engage much, but I do enjoy listening to the news, interviews and opinions... keep it up.

[@rsablosky]

coruscant - just such a beautiful idea

[@vansdan.]

so glad you got to read Revelation Space! I'm a huge fan of Reynolds, so I recommend the entire series, but one of his standalones, House of Suns, is my all time favorite hard sci-fi book. Check it out yal!

[@gwenever7286]

Coruscant - Interesting to hear the answer and with James Webb likely to discover other examples a good introduction to what may come in the near future

[@baarni]

Hey, so cool, thanks Fraser for featuring my question 😁 obviously I vote Bespin…

[@realzachfluke1]

lol you go, John

[@wernerboden239]

Those were some pretty excellent questions. And Fraser answered them with such finesse. I wonder if he missed his calling. He could be a great teacher or even proffessor, imo.

[@thingsandstuffwithinmebrai5938]

Naboo was my favorite. Question for the next Q and A: Because every two body system has L points, is it possible to make use of the moon's L2 point? Maybe a radio telescope that is blocking unwanted noise from the Earth?? (Sorry to add another "Lagrange point" question to the pile haha)

[@charleslivingston2256]

When China put a lander on the far side of the Moon, they put a relay satellite in a halo orbit about the Earth-Moon L2. The halo orbit radius was larger than the Moon's radius, so there was always line-of-sight to it from the Earth (and from it to the far side of the Moon).

[@kylemear]

Naboo!! I love that answer, I can explain this to my friends

[@rebellion-starwars]

I really liked when you declined to answer on the question about conspiracy theories, I've seen that. I believe that everyone who is following you closely would be pretty disappointed but the way you handle it is the correct way 👏 Basically we believe in science, we all know what it takes to make real discoveries and confirmation of every discovery is needed by the scientific community so you need to lay down clear evidences or you just say it's hypothesis based on this, that and so on and it has to fit in to all other confirmed discoveries and even then it's not evidence until we have the evidence so yeah, keep it up. Maybe you can explain next time when something like that pops up how discoveries are made and what makes real science so people can understand and maybe, just maybe we can win another believer in science and not in the conspiracy theories.

[@parkey5]

Mustafa Coming up with strategies to overcome problems like this is half of the excitement of taking on these challengies like setting up a research station on the moon. ? Please do an in depth video on Uranus, its fascinating how its oriented and how thongs orbit it

[@bizpo2713]

I appreciate your journalism very much and I appreciate your positive, practical approach. Thank you. Vote = Mandalore

[@jimsmith9251]

The asteroid belt is a ring around our star

[@unvergebeneid]

Never voted before but Coruscant was fascinating!

[@trevinom69]

Most interesting question/anser :Bespin. Follow-up question: What kind of pressures would the diver experience if they went diving below the ice? The gravity on these moons are a fraction of earths, so, just wondering what depth one would need to go to get to earth equivalent.

[@Myrddnn]

The Moon is the jumping off point for the exploration and utilization of resources for expansion into our Solar System. H3 for instance. We cannot find much of it here but we have identified a LOT of it is on the Moon.

[@SPR8364-0]

Naboo. I never would have wondered that. But, I love it.

[@olorin4317]

27:31 that performer is making a lot of interesting acting choices.

[@mylittlebirdhouses]

Hi Fraser, love your space bytes. In a quest to understand Dark Energy, could it be related to Gravity? Specifically, is it possible calculate the friction (conversion) of energy created from the kinetic energy of two attracting gravity fields (or wells) that are contacting (overlapping) eachother?

[@mrxmry3264]

some book recommendations i got from steve gibson from the security now podcast (not about computers): - currently reading the silver ships series by scott jucha (20 books) - the frontiers saga by ryk brown. he plans to write 5 seasons with 15 books each, or 75 books in total. currently in the middle of the 3rd season - books by michael mccollum: antares series, gibraltar series (3 books each), euclid's wall, sails of tau ceti, lost earth, ... - project hail mary by andy weir - the rho agenda and 2 follow-up series (3 books each) by richard phillips - the lost fleet series (AFAIK 6 books) by jack campbell - some books by daniel suarez - peter f. hamilton: commonwealth series, the void series and others - the bobiverse series (currently AFAIK 4 books) by dennis taylor - the expanse series by james s.a. corey (at least 7 books) - the honor harrington series by david weber ok, that should keep everyone busy for a while.

[@joelcabeleiracosta3764]

Naboo. Top and deep question! 👍🏻

[@CPD432]

Book Recommendation. 'Cosmosapiens' By John Hands. Not a book you can read only once but it had me engrossed. He challenges the dogma that's crept into todays science subjects like astronomy, cosmology, biology and examines where these subjects dare I say, fail and he provides possible solutions to inherent problems. As always I enjoyed your video and a Happy New Year to you and yours. Lang may yer lum reek.

[@jeroenk3570]

Not a book but a comics series, as a kid in the eighties I loved reading Yoko Tsuno from Roger Leloup. I forgot about her , but I noticed there are still albums made. I wonder if still find them as great as I did back then.

[@benbriedis]

Hi Fraser, I love your channel. Here's a question for you... let's say we wanted to transmit the essence of a human mind to a receiver in another star system. How long would it take?

[@michaelblacktree]

Doesn't our Sun technically have rings? (for example, the asteroid belt and the Kuiper belt)

[@VictorGarcia-sk5lf]

i have a question : we know that the moon is slowly moving away from us more and more every year , would putting space stations or mining the moon change the rate of it moving away from us ? also would the moon ever stop being tile locked to the earth and how would that change the effects it has on earth? thanks love your channel love this show !

[@granthudson5447]

I seen a gravitational lensed photo but there were 3-4 parts of it, i said those are different points in time for that galaxy, literally time machine we have here. I can see before when the dinos are rolers and when there no longer. (if it were our galaxy)

[@steverobbins4872]

Larry Niven wrote two novels about a star with a ring so dense it had a breathable atmosphere: The Integral Trees; and The Smoke Ring.

[@rustyhaas5025]

Yavin: My thought is that if we need building materials to get to Mars or use on Mars, we would be smart to have s mine / refinery that is free of an atmosphere and most of the gravity - less energy to get those materials to other locations.

[@geitemans]

Coruscant for sure! 👏👏

[@bmobert]

A large advantage to launching a rocket at high altitude is the reduced air pressure increases your rocket's specific impulse considerably; as much as 100 seconds.

[@johnashburn7858]

Puzzling question: Say there was a universe identical to ours but differed in that it was heavily populated by primordial black holes of various sizes and with some made of antimatter. What would be some observational differences between the black holes of matter and those of antimatter as they interact with the rest of the universe? In particular should we assume annihilation radiation will not escape an event horizon and therefore the mass of an antimatter black hole should also increase as it absorbs regular matter?

[@Rattus-Norvegicus]

Can we calculate how large the moon around Saturn would have been, if we add up all the mass in the rings?

[@robertgraybeard3750]

At 4:04 "Could you have a ring of dust around a star? Totally." Yes, even in our middle aged solar system there is the zodiacal light and the gegenschein. en.wikipedia.org/wiki/Zodiacal_light#:~:text=Zodiacal%20light%20spans%20the%20entire,but%20slightly%20brighter%20oval%20glow.

[@mbj__]

A follow up on 'Endor' and the Photonic drive: What if a small spaceprobe was made with a long lived RTG and a Laserdrive? Sure, perhaps only a few hundred watts and a couple of hundred kilos of spacecraft being pushed by micronewtons(?). But over years and years of pushing, shouldn't the speed slowly add up?

[@philfox8377]

Hi Fraser, love your shows. What are limits of ultra-high power energy sources & lasers on the moon. Could these propel manned interstellar ships, heat mars habitable zones/melt ice on Mars & perhaps break up approaching astroids?

[@c.i.demann3069]

was there no Q&A last week? I feel like there was a live version, but no edited version showed up later.

[@RafaelDominiquini]

Question about the twin paradox: If Alice remains on Earth, always experiencing the same acceleration (10 m/s²), and Bob goes on a trip, but his ship always maintain the same acceleration (10 m/s²) for the entire trip, holding a speed close to the speed of light for the majority of the time, when Bobs meets Alice again, will be any time dilation between the two?

[@JohnDlugosz]

If they meet again, it means Bob turned around at some point. Bob will be younger. The dilation of the twin paradox is due to motion, which is much larger than that of acceleration. The passage of time on Earth is only a tiny bit slower than the passage of time in deep space -- not enough to shift radio frequencies enough to change their tuning (that's only happened once, and it was due to large relative velocities).

[@RafaelDominiquini]

@@JohnDlugosz I watched a video from Sabine Hossenfelder where she explains that the dilation of time is due the acceleration, and not the relative velocities between the two observers!

[@billmilosz]

A photonic drive powered by 100% conversion of antimatter / matter to gamma rays would work, but advanced technology would be required to create something that would convert the reaction to gamma photons instead of to heat, blast, etc.

[@JohnDlugosz]

Endor: a photon rocket is the highest specific impulse... but _reflecting_ a photon gives you double that.

[@ShadowsDancing]

I so enjoy your channel.

[@frasercain]

Thanks a lot!

[@alexdevey3188]

Just watched, great stuff. There is something I don't really get when thinking about the expansion of the universe. If things further away are moving faster, and the further away the more we look back in time, doesn't that mean the expansion is slowing down, not speeding up. ?

[@FloridaMan69.]

another great video 👍

[@jagmohanchadha1013]

The Kuiper and asteroid belt are rings around our sun.

[@johannesekman]

Thanks

[@martianmurray]

It would be cool if we could send some tardigrades to a protoplanetary disc to seed it with life.

[@richardrigling4906]

Here's a stretch on the "Rockoon". What if the balloon is a LONG double hulled dirigible, with a multi kilometer long rail gun? Divisible lifts the rail gun above most of the atmosphere, the rail gun applies horizontal velocity to the payload. Fundamental question is whether this system is better by cost, payload to LEO, reliability, than a first stage rocket. My suspicion is no, especially with re operable first stages.

[@ywtcc]

Laser propulsion seems like it could work in some cases. Laser is an interesting way to transfer energy from Earth to space quickly. I had thought before that a combination laser/ion drive (using the laser energy to accelerate heavy ions) could be useful for jetting around the inner solar system. Would need line of sight from Earth, though. (Or wherever the laser is located.) And, would also need a source of ions. So, maybe some craft that's designed to hop from asteroid to asteroid, collecting whatever matter is available and accelerating it with laser energy from Earth. Also, lasers could be useful for transferring large amounts of energy to craft in Earth's orbit, like powering a space factory/3D printer, for example.

[@sulljoh1]

Maybe I'm naive/unlettered but I found the characters in a Revelation Space unbelievably psychopathic. Everybody else seems to love them! They aren't like Dune's Machiavellian power brokers. They just delight in torturing each other for no apparent reason. There must have been a pre-alpha melding plague that re-wired everybody's brains or something.

[@alleneverhart4141]

Naboo. Its actually not a good example to say that solar photons experience zero time traveling to Earth. This is because the rest frame of a photon doesn't actually exist. Such a rest frame would have the photon both at rest AND moving at c (light moves at c in all rest frames,) which is an unresolvable paradox. Antimatter annihilation produces gamma rays which are nigh-on impossible to focus and control. It may release a lot of energy but in random directions - not a good power source for a spaceship. Fusion energy may be as good as it gets.

[@lawsongnosis]

Coruscant was great!

[@saumyacow4435]

Fraser, I do agree that there's no good reason for ordinary human beings to live on Mars permanently. So thanks for putting that out there. However there are some questions regarding a permanent base or bases. Firstly, Mars is going to do you permanent harm. Those that explore Mars will do so knowing that it will do them harm and will give informed consent to this. However, normal ethics would dictate that no one goes there twice - or stays between mission cycles. The timing is such that if you had a permanent base there may be periods between missions where the base is uninhabited. It's also complicated by the fact that you probably want to explore more than one region. Meaning quite likely you'll see a progression of one-mission bases.

[@Anthony-ru7sk]

Are the asteroid belt and kiuper belts considered rings around the sun if looking from another star ?

[@bbbenj]

Tatooine : the asteroid belts are rings around the sun!

[@delveling]

revelation space is freaking fantastic !

[@winstonmontgomery8211]

Hey Fraser are you going to be attending the Cosmic Summit in June in Asheville North Carolina? I'll be there.

[@stevestrom4411]

Excellent channel! Is it theoretically possible to create an engine for a spacecraft that captures virtual particles as they come into existence, but before they annihilate each other, and use them as a type of fuel?

[@Mike-iv3hy]

The Sun has rings ! Tau Ceti has rings ! Many Stars have rings ! If a Star does NOT have rings, then there won't be life in that system ! Rings create a cool Oasis for life ! DML .

[@CmdrCyrax]

The question of life on moons makes me wonder, what if we find no life, nothing, wherever we look? Everyone seems almost certain there will be something but they said that about Mars. Could there be some as yet unknown factor that earth has but elsewhere lacks?

[@boredgrass]

Best question: Naboo ❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️❤️

[@prawnmikus]

Could we have a spaceship engine that's halfway between a light sail and a chemical rocket? Shoot a powerful laser at a ship where the energy is captured and used to heat a material such as hydrogen to energies much higher than a chemical reaction could generate. And another similar question: Could we build an engine that uses solar energy to directly heat a propellant such as hydrogen? A large parabolic mirror could focus the sun onto a tiny area. This means no oxidizer is needed, and even if the thrust is relatively low, it could be constant. Something in between an ion drive and a chemical rocket.

[@jagmohanchadha1013]

Question about travel to other stars. Since the speed is only relative, why is it restricted to the speed of light. Theoretically a space ship could accelerate for ever.

[@derivious2012]

hi fraser, when do you think we will see the first person born in outerspace or mars assuming its possible? surely that would be a pivotal moment in human history.

[@jlmwatchman]

t least two questions that reflect a couple of my comments. ‘Endor’ was about Lasers, ‘they are just cool, and I was commenting about how they could push sales or something. I commented to use lasers to push the space behind you, but I thought space is empty so what are you going to push against.?? In the past, I suggested using heat lasers to push asteroids away from Earth or to the Moon to mine… After The Angry Astronaut had a video about using lasers, I had to point out the flaw with having the lasers on Satellites. Fraser replied to the question, ‘Could we use lasers as a propulsion?’ that we could but what fuel would be powering the laser.? Okay, I have kinda been joking that we could use the heat from the Sun to heat the Propellant or the fuel we use to power the laser. If we magnify the light from the Sun, hot enough to heat the Propellant or fuel that powers the laser for the space crafts flying close enough to the Sun. I think I had the idea to have the lasers shining from the rear of the craft and reflecting off dishes that would sharpen the laser. A laser is a light that reflects within a cristal and then it shines like a laser if we want to keep it simple, but there are different kinds of laser beams.?? Different types of lasers are needed for these applications. Based on their gain medium, lasers are classified into five main types: Found @ laserax.com/blog/types-lasers Gas Lasers Solid-State Lasers Fiber Lasers Liquid Lasers (Dye Lasers) Semiconductor Lasers (Laser Diodes) I don’t know what lasers to use to push against the emptiness of space, but I would guess a laser shining in space has pressure so it would need something to resist it to use a laser that would repel asteroids. I was thinking a heat laser shining from the rear of a craft wouldn’t have much push so reflect it from a dish that would magnify its heat to heat the Propellant. There were other good Ansserswers, but ‘Crait’ could have been done better than, “Yes, we will get there sooner or later.” LET’S GET THERE ALREADY…

[@frasercain]

I think your idea of using the heat from the Sun to boil a propellant is pretty clever. I'm not sure how efficient it would be, but I think it would work. That would be separate from a laser, though. Lasers don't need to push, the momentum comes from the individual photons leaving the laser itself, and the spaceship receiving a kick in the opposite direction.

[@jlmwatchman]

@frasercain The Heat Laser Idea is to replace the heat magnified by the Sun. I thought I explained that but what kind of laser you are thinking, IDN? I was thinking basic light that is magnified off dishes or through crystals could be used to heat the propellant.

[@dustyplayz]

Kamino: will we ever see a day that ion engines become powerful enough to be the main form of propulsion for space flight? and if so, how long do you think it will be until it becomes viable to use those same engines on earth or within other planets atmospheres?

[@JohnDlugosz]

"Haven't seen [rockoons] take off." I see what you did there.

[@gordonstewart8258]

Tatooine. What is the asteroid belt if non a thin ring?

[@brucekinghorn4961]

Bespin. Just as a follow up would the inertia of the ice shell of a moon such as Europa result in the ice shell spinning at a different rate than the core of the moon?

[@WthyrBendragon]

I would assert that the asteroid belt could be considered a ring around the sun. So, yes, stars can have rings.

[@remicaron3191]

Here’s a question. Is the expansion of the universe the actual cause of time? Seems to me that without expansion, like say travelling at the speed of light, time stops.

[@irontusk341]

Since electric and Plasma propulsion is making progress, could the Bussard Ramjet RAIR (Ram Augmented Interstellar Rocket) engine be feasible in the solar system?

[@seanb3516]

Our Universe is 'Digital' in its Nature. This means Time will 'Start & Stop' every Planck Time Unit. So yeah, probably unnoticeable.

[@ddanielsandberg]

I liked Peter F. Hamilton - Commonwealth Universe series of books. A bit much "woo", but interesting.

[@cashmoneypwns]

I’d use the laser to initiate the intensity needed to get ions moving with an ion chamber.

[@richardrigling4906]

Why go back to the Moon? Several reasons. First, practice at living in space, which is HUGE - and it's only 3 days away from Earth. Second, It's a resource for further space expansion with a MUCH shallower gravity well. Other reasons will surface with time and practice.

[@samson1200]

I find your channel the most informative and detailed with commonsense thinking. But if we were an advanced space faring species traveling to a destination several light years from us. How would we avoid or detect a newly born sun that just developed that is in our flight path that was not there when we left Earth? Since we travel a sunlight speed?

[@jamescarlisle3770]

Magnetic rails up the side of a steep mountan would seem to be a great rocket launcher

[@resurrectedstarships]

25:00 We have no idea but I would lean towards not-malevolent - if they have the tech for interstellar travel they probably have the tech to get whatever resources they want without the hassle of even bothering insignificant natives like ...yourselves. There are many, many reasons to go out there and explore other than resource exploitation, ahh sometimes these small-minded humans do not understand the pull of knowledge and curiosity.

[@WilhelmDrake]

Air-burst detonations are move devastating then land bursts.

[@disinclinedto-state9485]

Hey, Fraser. A though occurs... If two black holes, by unimaginable fluke had precisely opposite spins, and then they merged, would that cancel out? What would a black hole that doesn't spin be and look like?

[@disinclinedto-state9485]

Obviously it's so unlikely as to be safe to discard out of hand, but as a thought experiment?