Deep Space Questions - Episode 10 - Relativistic Aerodynamics, Thermonuclear Warheads & Red Dragon

[@TheRedbeardpirate]

"If humanity were meant to live in Minnesota they would have fur" Scott Manley 2021

[@chraffis]

But but but I live in minnesota and I don't have fur!... on most parts at least.

[@bvanlaer]

Ghe! "If humans were meant to shower they would have armpits facing upwards..."

[@kira_the_cat1187]

Beat me to it

[@WildWestRaider]

Pictured: Fargo Which is close, but not in Minnesota.

[@Shivaho]

Hehe Here in Vermont its a Prerequisite for Men to Be Covered in Fur

[@dsdy1205]

1:50 I'd like to point out that drag scales as the velocity SQUARED, so if the density is 10^-14 times that in the atmosphere a flat plate would "only" really need 10^7 m/s to get the same drag as it would travelling at 1 m/s on Earth. Arguably it would be worse if we considered relativity because momentum scales nonlinearly near the speed of light. That being said, the drag you'd get at 3% the speed of light amounts to a stiff breeze on Earth, which would be the least of your problems considering the energies of said particles are literally cosmic-ray-level, so in the words of Winchell Chung it's like "flying down the barrel of a particle accelerator"

[@colinwarn4606]

Was about to come here and say the same thing.

[@matthewnewell2392]

@@colinwarn4606 haha same, this guy said it better than I would’ve!

[@Garryck-1]

Thanks.. I had a gut feeling that Scott was mistaken on this, but couldn't put my finger on it.

[@evertbunschoten2930]

That law for drag only holds true for a continuum fluid. This means that the particles not only interact with the craft, but with other particles in the medium. In deep space, the latter is not true. The individual particles are too far apart to undergo any interaction. Therefore, the phenomenon of stagnation pressure would scale very differently.

[@dsdy1205]

@@evertbunschoten2930 the v^2 correlation of drag does not only hold for particles that interact with other particles in a medium; indeed at hypersonic velocities where the particles already approach Newtonian behaviour the v^2 assumption still holds, simply because the momentum flux of the particle stream scales with v^2; it's just the coefficient of drag that will change as your flow goes from subsonic to supersonic to hypersonic to relativistic EDIT: Ok I realise my own argument means my calculation is wrong because I assumed equal Cd, but arguably you'd achieve equal drag at an even lower speed because assuming a flat plate shape, you don't have the back-pressure from the recirculation zone at relativistic speeds so the Cd will be higher than at subsonic speeds.

[@Astronist]

3:25 - reversing direction using the galactic magnetic field. The reference is: Mallove and Matloff, "The Starflight Handbook", p.73-77. I once checked their figures and found a confusion between gauss and tesla, as the result of which (according to my calculation) the galactic magnetic field would be 10,000 times too weak to generate enough Lorentz force to move the ship as described.

[@EricDKaufman]

god damn it, why do I generally understand what you are talking about. Also, how does such a mix up make it through peer review, let alone their own work. Seems like a pretty big mistake. Like sending a satellite to Mars and forgetting to covert the European metric units to the American standard units. Oh wait...

[@lostpony4885]

Worked for Superman.

[@Astronist]

@@EricDKaufman - People may want to check my claim. My physics career came to an ignominious end a long time ago. I may have made a mistake. I'm just reporting what I found. You've got the reference there, if you're interested.

[@brandonlink6568]

As a Minnesotan I can confirm that fur would be a nice addition when it's -40 in January, not so much when it's 105/40 in August.

[@christophergruenwald5054]

Same goes for SD. Bring on the fur.

[@the_Backdoor_Siders_Crew]

Fun fact for someone who hasn't been in those temps- at -40 degrees, you don't have to distinguish between Fahrenheit or Celsius as that's where the two are equal values!

[@refindoazhar1507]

just shed your winter fur, easy right

[@heh2393]

@@refindoazhar1507 *Authentic Minnesotan wool shawls*

[@erideimos1207]

@@refindoazhar1507 Or they could get shorn. That would be a sight: 100s of large naked Minnesotans lining up at the shearing houses every spring.

[@CuriousMarc]

Unfortunately the Achille’s heel of a magnetic core bi-stability has always been its sensitivity to temperature. The first core memories could only work in an oil bath with precisely controlled temperature. Later on, thermistors were used to sense ambient temperature and make the required fine current adjustments in the drivers. And then of course, above the Curie temperature, there are no good magnetic properties left. So not a viable candidate for Venus electronics unfortunately. They are very insensitive to radiation though, very good for that.

[@amanwithdope]

Oh, hi Marc.

[@heh2393]

Hello Cark! (It's a joke about Starbucks Baristas)

[@MatthijsvanDuin]

that radiation-insensitivity is also why one of the technologies you'll find when searching for radiation-hardened non-volatile memory is magnetoresistive memory (MRAM), which is kinda just miniaturized core memory stuffed into an integrated circuit!

[@erikowren7894]

You had me at Curie Temperature

[@paulhaynes8045]

I'm old enough to have used computers with magnetic core memory ( which, IMS, wasn't exactly reliable). But luckily that was in Romford, not Venus...

[@markwerley6965]

Spite has been shown to have a societal benefit. In games where all participants benefit from cooperation, but freeloaders can bring everyone down, adding a spiteful element can bring all players back into cooperation. There's a cost to the spiteful player, and no obvious benefit except the satisfaction of teaching the freeloader a lesson, but everyone's scores eventually go up. Personally, I don't want to be the spiteful player, but I guess I'm glad they're there.

[@PinataOblongata]

Thanks, that's an interesting bit of behaviourism to know :)

[@inemanja]

Of course! -- The Prison system is also a form of spite. You spend your own resources and "gain nothing". But it is actually pretty important and indirectly useful.

[@Digital-Dan]

Yes, one of my favorite hobbies is biting off my nose to spite my face. Haven't achieved it yet.

[@russc788]

@@inemanja Some might argue you gain safety and deterence from prisons. I am not really one of those people as it doesn't tend to work out that way.

[@inemanja]

@@russc788 i've actually spent some time in prisons... But I'm way past that ACAB phase in my life. Yes - prisons are useful (as are cops)

[@ritaloy8338]

I hope you can do this every month.

[@nirbhay_raghav]

Every week

[@starship9874]

Every day

[@Lasersplitter]

I really need to remember "My favourite pice of music is always the piece of music I've never listened to", I'm totally with you on that one.

[@jeffevarts8757]

Newtons as the "correct unit"... ask the people at Wikipedia about this. Someone once wrote a clever robot that visited each page and changed all the "miles per hour" to "kph" and "pounds" to "kilograms", etc... Good idea, except... I once found an agricultural page that listed the yield of grain in a locale... *in kilopascals* ... the unit converter had seen "tons per acre" as the grain yield, and said "hrm, that's force per area... which is newtons per square meter... which should be listed in Pascals..." not the right unit.

[@GewelReal]

"6 kilopascals of corn please!"

[@youkofoxy]

Well, if you convert the weight of grain into newtons and acre into metres. You do get kilopascal. And it kinda works.

[@jeffevarts8757]

My apologies... that it is AN appropriate unit (from a certain perspective) was my intended point. If someone is giving someone else a hard time for "not using the right units", it's probably down to an argument about Point of View, which is subjective, and therefor anathema to the purist doing all the shouting. Keep up the good work,

[@epremeaux]

@@jeffevarts8757 right. This is a peeve of mine. There is no such thing as "the correct unit of measure". There are however appropriate and inappropriate units of measure. Like "I did the Kessel run in less than 12 parsecs!" is an inappropriate unit of measure (using a unit of distance when a unit of time or possibly speed is called for). Of course that got retcon'd to say that Han found a shortcut to a standard route and thus really meant he cut the route distance down to 12 parsecs. The beauty of measurements is that you can make them up, and as long as they are appropriate and consistent, they are legitimate. Anyway, If we all knew the length of one Scott Manley, we could measure the height of rockets in Manleys. And though it is considered poor form to choose the same named object for the scale of two different units of measure, there is no law that says you cant. So, if we knew the weight of one Scott Manley, we could say something like "This 230 Manley tall rocket could lift 1500 Manleys to L.E.O."

[@MariaMartinez-researcher]

Okey... I am a Wikipedia editor (picture me horrified). I looked for your story and couldn't find it anywhere. Now, if ever someone had done such a thing, it would have been considered large-scale vandalism. The problem of the "right" units of measurement has (had) a page of (heated) debate, now kept only for historical purposes: Wikipedia:Measurements_Debate This page links to the Manual of Style for Dates and Numbers, which are the rules to follow by all editors in that matter. I would say your robot tale is the reason why human editing is preferred: a human has more understanding of context, as to pick the right measurement units, words, quotes, pictures, sound bits, to better illustrate an article. I get the purpose of your story, but, it appears to be fictional, and, if it was factual, such robot was utterly counterproductive, as the story itself signals, and the editor who used it surely was kicked out of Wikipedia at warp speed. :-)

[@EthanPricco]

4:42 as someone living in Minnesota, having fur would really help in the winter.

[@armr6937]

recovering a S-V booster in the 70s-80s would give the whole "suicide burn" thing a new meaning.

[@paulhaynes8045]

Restarting the engines would have been fun too!

[@rwdavidoff]

They looked at mostly wings (with jets or a retro-burn for RTLS), or parachutes, but there's a pretty solid case to be made they could have landed one propulsively if they'd wanted to.

[@Allan_aka_RocKITEman]

There were proposals -- including wind tunnel and model drop tests -- to use large _Rogallo Flexwings/Parawings_ to allow boosters to glide back to Earth and make a runway landing. Even for the first stage of the Saturn V.

[@docpaul]

Love SomaFM!! Not even thought about this station for over 10 years - thanks for reminding me!!

[@elliotrobinson4484]

I think I’d thank the Alien overloads the day Scott gives us a DJ set

[@MrHichammohsen1]

Can you please talk about the physics and math of deorbiting and reentering the atmosphere, precisely on how they predict landing sites when you have such a dynamic atmosphere!?

[@netsch20]

I mean I think the simple answer to the predicting landing sites question is "they don't". They can give a very very broad landing zone based on what the aerodynamics of the reentering object would allow (eg, if a capsule was angled to give maximum lift the entire reentry that would give you the maximum downrange landing spot from the point that aerodynamic effects become dominating), but that's about it.

[@MrHichammohsen1]

@@netsch20 You are moving at a speed of 7.7km/s and they hit a spot of 1km of the landing site. How did they achieve that accuracy were a difference of 0.1 seconds can cost you a km downrange.

[@dougpowers]

At least part of the answer is that the capsule can perform limited guidance and maneuvering during reentry. The movable ballast sled allows Dragon to change its angle of attack and obtain some body lift to push its impact point further out.

[@michaelsommers2356]

In earlier missions, they weren't very accurate at all. Later, though, they got good enough that they could have landed right in the carrier's deck (not that they would have wanted to).

[@petergerdes1094]

From Wikipedia: The Apollo command module reentered with the center of mass offset from the center line; this caused the capsule to assume an angled attitude through the air, providing lift that could be used for directional control. Reaction control system thrusters were used to steer the capsule by rotating the lift vector. So basically, the same way your plane manages to land at the desired location: you use aerodynamic forces to adjust your trajectory...they just used RCS to adjust their orientation instead of ailerons.

[@MykePagan]

Re: magnetic cores for Venus “logic gates” - 1) magnetic cores were memory, not logic gates (the logic was done with discrete transistors). 2) magnets demagnetize at elevated temperature, not sure exactly what temp but they would likely be useless at Venusian temps

[@JohnDlugosz]

I've seen vintage videos posted about using cores to do logic.

[@dreadengineer]

The main use was memory, but there actually is a "transistor-type" device that uses nothing but coils of wire around a piece of iron -- called a "saturable reactor". Basically it's a transformer or inductor that can be made to stop working on demand: you use a DC current in a coil to create such a high magnetic field that it saturates the iron core, which prevents the transformer from working efficiently. So when the DC current is turned on, the transformer stops working, so it can function as a NOT gate. You can also have 2 DC coils that have to BOTH be on to disable the transformer, which effectively creates a NAND gate. And NAND gates can be combined to create all other digital logic. So you could, theoretically, create digital logic with them. (There's also the problem that the input is DC but the output is AC, though with some extra components you could probably get past that.) But, I think they'd be way too bulky and power-inefficient to ever build a computer for a space probe. As Scott says, the solution for Venus will almost certainly just be specially-designed semiconductors.

[@bazedjunkiii_tv]

john peel.... he even played one or two records released on my labels back in the day. unfortunately i never heard the actual shows but i saw playlist arounds and i am forever grateful for that.

[@ValentineC137]

Nebula ram-jet is the single most awesome phrase I have ever heard

[@burntpotatoes999]

I see the "What if?" book in the background Scott :) absolutely fantastic read

[@P3x310]

Loved every page of it

[@ultima8250]

"Mongolian Metal" The HU is 🔥

[@eliasadams1154]

couldn’t be more correct, i knew someone in the comments would know who he was referring to

[@ultima8250]

@@eliasadams1154 Yuve Yuve Yu is such a banger bro

[@jnawk83]

came looking for these comments, wasn't disappointed

[@hillzachary01]

I love these episodes! Please keep these up, I hope you can do them every month as well

[@logic9140]

You forget that drag raises from velocity squared or cubed depending on case, in this case cubed more likely. Vacuum of space is around 10^-9 to 10^-20, and speed of light around 6*10^8 mph which squared is 3.6*10^16, making much vacuum in space equal to about drag from moving 1 mph in atmosphere on earth which can be big for large structures over time

[@und97h70]

We must have an interstellar plane!

[@logic9140]

@@und97h70 this explains star wars better

[@5000mahmud]

So how fast would you need to go for drag in vacuum equivalent to moving 1 mph at sea level?

[@deltalima6703]

@@5000mahmud drag would be pretty high moving through water

[@5000mahmud]

@@deltalima6703 at standard atmospheric pressure*

[@cdfudge1980]

One of my favorite songs for any Space Game Play is Clutch “Space Grass”. Definitely a play list add. Also fun driving song. Rock on Scott

[@williamchamberlain2263]

Thanks!

[@absurdengineering]

I’d imagine that at a good fraction of c, the “airflow” tends to fuse with the “wings”. As in nuclear fusion. Not the best outcome for longevity of the thing.

[@wesleybantugan5604]

Best birthday upload! Thank you so much for all of your work!

[@bami2]

14:53, the way I understand it, the primary is boosted by injecting some fusible fuel (like tritium) into the core as it is collapsing. For variable yield, this boosting is adjusted (simply less tritium is injected into the core or injected at a different rate or something), so the primary delivers less radiation (pressure) into the secondary, which causes less of the fusion fuel to fuse, hence less total yield. So all of the dial-a-yield is done in the primary, not some constrictor device between the primary and the secondary. It's not like any device could ever hold that back.

[@nexusofjoseph]

Not necessarily. While adjusting the level of boost gas will have an effect on final yields, having physical devices in the interstage will probably be easier to control the radiation pulse from the primary to the secondary (and therefore the level of compression). I think boosting was still a bit of a dark art for a while, which could just mean it's either on or off.

[@chouseification]

There are multiple factors involved in variable yield warheads. Some of them are (and there likely are more): - specific timing of the external neutron initiators, and how many are activated - boost gas (put in before detonation, not during) - adjustable reflective lenses (this is the one people often forget) for the primary - quantity of secondary fuel (is it half full or completely full?)

[@ravener96]

Position of the primary in the reflector should also matter, since some of the secondary might not get the required pressure to fuse well if the primary is out of the sweet spot.

[@jonslg240]

I think all the above could have an impact, however what's being discussed are the methods that have actually been used, not the methods that could theoretically be used That being said, I do like both being discussed, though we should classify them appropriately to avoid confusion

[@lostpony4885]

You lost me somewhere around hit the reset button.

[@jonathanbush6197]

Great video as usual! I have a small quibble. 1:58 "Even if you're traveling at 99% the speed of light, the drag is a million times less" This ignores the effect of time dilation. Once you reach about 71% of c, you will be traveling through one light year's worth of interstellar material within one perceived year. Beyond that, the amount increases to multiple light-time units per perceived time units. So the ratio could decrease significantly below 10^6 once you reach 0.99c BUT this was what the original question was specifically NOT asking about.

[@Invisifly2]

13:10 - If somebody knows that trying to pull petty bull over something minor will wind up causing them a major headache due to spiteful retaliation then they are less inclined to do so. Malicious compliance is the embodiment of this. Inotherwords spite helps make sure you have a good reason to bother people before doing so because they're going to bother you right back. Self destructive spite is just the unhealthy extreme of perfectly functional social behavioral regulation.

[@kingawsume]

Thanks for pointing out SomaFM, this stuff is exactly what I didn't know I wanted.

[@FARLANDER762]

In "The Songs of Distant Earth" (1986) Arthur C. Clarke wrote about huge ice shields attached to the leading surfaces to act as an ablative shield from high speed particles.

[@Max_Chooch]

Arthur C. Clarke is my favorite author.🤔 Maybe we need a Rama with a polar cap 🤣

[@joyl7842]

Very enjoyable episode again! Thank you so much Scott. You are a endless well of knowledge.

[@lucifersatoshi]

The MASS of the rocket is expressed in kilograms, so it makes sense to talk about the thrust in kilograms or metric tons. If we are going to talk about trust in Newtons, then we should talk about the WEIGHT of the rocket in Newtons. This way we can quickly and intuitively derive the Thrust to Weight Ratio without a lot of conversions.

[@simongeard4824]

Exactly, and Elon Musk said much the same thing during his recent interview with Tim Todd... conflating mass and weight-force-in-1G is obviously not correct for a scientific perspective, but it's a close enough approximation that makes it much more intuitive for most practical uses.

[@BrosBrothersLP]

No. Its simply wrong nothing else. A kilogram is not a measurement of force never

[@onebronx]

@@BrosBrothersLP en.wikipedia.org/wiki/Kilogram-force Units of measurement are convention, you can always derive one UoM from another using transformation factors/coefficients (for example "g"). The only true and unconventional physical values are dimensionless constants; any dimensional physical value can be expressed with any convenient UoM of your choice. E.g., you can measure distance in units of time (light years), force in units of mass (weight in kg), energy in units of electric charge and voltage combined (eV) etc

[@rogerstone3068]

Leaving your current reading matter visible on the desk is a great kindness and I hope Iain M Banks, James Corey and Nicholas Schmidle are suitably appreciative.

[@thomasrogers8239]

Words cannot describe how motivational spite is for certain people.

[@km5405]

dont understimate the power of spite. you see it all through history too - spite is underrated as a driving force lol. basically what put a man on the moon as well.

[@thomasrogers8239]

@@km5405 I know people who are alive today only to spite those that took issue with them earlier.

[@leozanyk368]

This format of videos is awesome, keep up the good work!

[@craigman04]

I enjoyed ya b4 but knowing you also like Hawaiian pizza..! You're now definitely my favourite Scottish space nerd.

[@markhelifreak]

Keep up the good work, the content keeps getting better!

[@eterevsky]

In the first answer, shouldn't gas pressure rise as a square of speed, since kinetic energy of atoms is mv^2/2? That would mean that the energy transferred from the interstellar gas to your spacecraft will be 4 * 10^14 at the speed of 20000 km/s compared to 1 m/s. It looks roughly similar to the ratio of densities that you came up with.

[@scottmanley]

Drag is momentum transfer rather than energy transfer so yes, I guess, but with 10^-14 difference it's still never in a situation where the drag matters. Heating is due to energy transfer, that's much worse.

[@merlin9657]

@@scottmanley But wouldn't the drag still be proportional to v^2, since at an x times greater velocity you would collide with particles at x times greater speed but you would _also_ have an x times greater rate of collisions.

[@roelantvanderbos]

@@scottmanley Stupid question maybe, but based on simple non compressible theory (Bernoulli) the drag is based on the speed squared (which probably doesn't hold at those speeds simply because the medium is going to be compressible due to the density, but let's just use it for now...) but instead of 10e-14 vs 10e8 (taking speed of light here) you end up with 10e-14 vs 10e16 for the drag part. Even when knocking down for the compressibility by a big factor, you need to consider it...

[@roelantvanderbos]

What would be interesting: At what speeds do we actually enter the realm of particle physics, where we don't even talk about radiation anymore, but more along the line of doing a continious form of the large hydron collider type of collisions and what effects would we have then. Having free particles floating around in our "heat shield" would give interesting effects, the least of all would be drag...

[@the_Backdoor_Siders_Crew]

Pineapple and Ham on pizza- Thank you Scott, been my favorite since day 1!!!

[@pedrocrb]

In the first question, dont you have to consider length contraction too? what if the lorentz factor is also 1000000?

[@jimmarburger611]

Hey Scott, thanks for being one of my favorite space content creators. Before I get to my point, I like your selection of reading you have behind you, lol. I have a comment on the thermonuclear bomb you chose as the counter intuitive physics. It is outrageous to think of a device that is destroying itself as it works but in this case as in all of these weapons the time for the actual reaction as the core goes critical is very short. The US designers of the bomb (Fat Man in this example) calculated that it would take .8 microseconds to complete the 80 generations of neutrons hitting atoms, splitting and those going on to hit more. At that point, the core would be so distorted that it would drop subcritcal. I don't know at what speed the explosive forces propagate but I have a feeling that it isn't even beyond the case. With newer weapons I believe with reflectors, neutron sources and boosters it wouldn't even take that long. My speculation though. Thanks Scott! BTW, the time for a neutron to travel the entire diameter of the core was dubbed a "Shake" as in the shake of a lambs tail...

[@jdmillar86]

In a boosted weapon the doubling should be ended by material dilution before core expansion becomes an issue. Analogous to how predetonation can be avoided because a boosted weapon can produce full yield even with a significant neutron population at the moment of criticality

[@jimmarburger611]

@@jdmillar86 Awesome, thanks for the clarification.

[@TheEDFLegacy]

Pizza... and Nuclear Warheads? Now THAT'S a sentence I never thought I'd read. 😂

[@rallymax2]

Variable yield detonation was fascinating to hear about. And I agree that “sorta right” units for broader understanding is the right thing to use.

[@MoonWeasel23]

“I don’t see humans living in space” *welcome to the argument zone*

[@justinweatherford8129]

There are humas living on the ISS. That is in space. Lol

[@craiggilchrist4223]

That first question was a right mind bender. Great question. You have gotta be bumping into something the faster you go. Like a Bow wave. Saying this whilst i'm loading up KSP. I did a gig in Stirling Scotland the Weekend Scott. I live in Birmingham and we drove to Stirling over the Firth of Forth River. It was a Loooooong way but everyone was really friendly.

[@MusikCassette]

but drag increases with the square of of the velocity. So 10% c means 10^7 wich means drag goes up 10^14. I mean really rufly

[@chadthundercock1281]

Only in high density environments. Particles don't interact nearly as much in interstellar space

[@DS127]

​@@chadthundercock1281 Wouldn't them not interacting simplify the problem to adding the force each particle contributes opposite the direction of travel when it hits the ship?

[@cigarboxguitar9519]

I enjoyed that video Scott. Less "scripted" and more of the cuff but still with a solid researched background. I believe this variation is a good addition to your more structured (and very enjoyable) typical scripted content.

[@talyrath]

Scott: I love Hawaiian pizza Me: Well, I know where the 81 dislikes on this video came from.

[@Garryck-1]

If that was the reason for the dislikes, there's be a hell of a lot more dislikes than that!

[@toddrf4058]

I just finished reading the book you have on your desk. It’s well worth it.

[@marshallgarey2913]

Yes, another Hawaiian pizza fan! I especially loved that kind of pizza in Taiwan (I got it at Costco) since the pineapples are fresh and soooo much better than the pineapples we have in the US.

[@ronenshtein7083]

Hey Scott, about the "Relativistic Aerodynamics"... Relativistic momentum is given by p=γ*m*v, and relativistic kinetic energy is given by K=(γ-1)*m*c^2, where the Lorentz factor γ approaches infinity as the speed of the object approaches c. And, for example, from the perspective of a spaceship traveling at 0.8c relative to the interstellar medium, it is the gas particles of the medium that are traveling towards it at 0.8c, while the ship is at rest (compared to itself). So even a very small particle can pack arbitrarily large momentum and kinetic energy if the ship is travelling fast enough. As you said in the video, I also don't think this will feel like flying thru the atmosphere and will be felt more like radiation and heating. However the momentum / drag calculation in the video do not work in relativistic speeds. Browsing thru recent papers I also found one with an equation for relativistic drag force, and it also seems to explode as v reaches c.

[@SkorjOlafsen]

"kilo-Newtons are a stupid unit, all we ever care about is tons of thrust" Elon Musk

[@Garryck-1]

Pirate-ninja's, on the other hand, are an awesome unit.

[@Gunni1972]

10 Kilo Newtons are 1 Ton of Thrust

[@hexsystem7891]

@17:25 Wasn't there a tether experiment done about a decade ago where the tether broke? It was determined that we couldn't produce a long enough tether with the appropriate tensile strength to make it a practical application at this time, or something like that. I may just be completely misremembering it. It has been a while.

[@destructojo]

Drag is proportional to velocity squared so it should be on the order of 10^16 not 10^8 I think

[@chadthundercock1281]

Depends on your model of fluid dynamics, it will scale linearly in low density environments

[@sfsft11]

Was thinking the same

[@Sanket42]

From a DJ to one of the most NEEDY guy in Aerospace community 🔥

[@waffledraggin]

As a Minnesotan, I can confirm that Fargo is not a bad representation. Considering that it and it's sister city split the ND MN border, it's basically half Minnesotan anyway.

[@fookyu1621]

As someone who been to minnesota i can confirm some of them have fur

[@dazuk1969]

You are a cool dude Scott, your math at the start twisted my melon...but once or twice in the past you were kind enough to answer my doppy questions...peace to ya.

[@bbertsch23]

Scott, listen to king Gizzard and the Lizard wizard, they span many genres, should keep you busy for a while

[@elliotrobinson4484]

Yes!

[@AD_SPACE_2024_...Aditya...]

Wohoo scott manley vid!!!!

[@brymstoner]

I'm surprised nobody's asked you recently... granted, your audience has considerably widened over the years, but do you still play Eve from time to time?

[@TheWindigomonster]

bump

[@myvids4329]

Even isn't really a game you just play "from time to time"

[@brymstoner]

@@myvids4329 It really is though. I've been a casual player now for years, simply due to work.

[@eduardkomarnickiy]

My favorite format. Keep answering! :)

[@lefty8957]

As a Minnesotan, I agree. 🥶

[@austin5060]

DJ Scott Manley Love it

[@RealPunkie]

Scott: "I like hawaiian, that's my thing" me: Nooooooooooooooooooo!

[@EricDKaufman]

Me: FINALLY SOMEONE ELSE WHO LIKES CRISPY NY Style HAWAIIAN!!! Soooo hard to find some who doesn't do your generic papa johns thickness style hawaiian which is NOT good. Trust me brother, get a NY Style thing crust, and while you are at it put some tabasco and ranch on that big boy.

[@kyoteecasey]

@@EricDKaufman Me and my GF are all about the crispy Hawaiian pizza!

[@AhmadHermi]

Pineapple on Pizza is Pizza blasphemy for me. I was also like NOOOOOOOOOO when scott say he love it.

[@dannywilliams23]

No fruit on pizza! Just proper things like tomatoes, olives, peppers, chilis... oh.... 😉

[@TravelingStacker]

Oh no! Someone likes something that you don't. The humanity of it all.

[@marcp6976]

Soma FM! Yes! Its still there, love it.

Travelling at high speed the interstellar particles would be like nuclear bombs.

[@gnaskar]

Nah. At 99.995% of light speed, a particle hits you with ~10^18 times the force it would have if it hit you at while moving a meter per second. That's only 10^-10 J. Now, you're moving through 10^8 meters of particles per second, and in a dense nebula there are 10^6 particles per cubic meter, so each square meter of surface is subject to ~10kW of applied kinetic energy per second. That's about 10 times the energy hitting a square meter of earth from a bright sunny day. Enough that you want a shield, but not enough to be a worry. Note that outside of a nebula, the energy is far less than natural sunlight.

[@rayoflight6220]

Hello Mr. Manley, The "guy at NASA" about project Gemini - was Dr. Gilruth, I believe. He was there pushing for Mercury, Gemini and Apollo, as Chief of the Johnson Space Centre... Thanks for the video! I appreciated every single bit except the ananas on the pizza. Regards...

[@garth.edwards7523]

Love the weekly content keep up the work

[@bobthebomb1596]

Makes me smile the passion with which people will deride someone for expressing a temperature in Fahrenheit, then proceed to give it in Centigrade.

[@fredbloggs5902]

The Réaumur scale is the way to go.

[@bobthebomb1596]

@@fredbloggs5902 Use whatever measurement the people you are talking to understand.

[@tpottrell]

Still amuses me that theres a game in the book case called "f*ck yeah games" :)

[@Blibby-Blobby]

somaFM is my main choice on Tunein radio. The mission channel is still there ... Just relax, stair at the stars and listen to the lucky ones do the thing that people thought couldn't be done.

[@Frequincy100]

Finally someone who likes Ham and Pineapple Pizza!!!

[@alaric_]

Pineapple, the most underrated topping, hated by pizza snobs of the world.

[@vector824]

Hey Tyler.

[@theOrionsarms]

About interstellar drag, it would increase with square of speed, so if you fly 10^6 more faster than a plane you have 10^12 more drag maybe 1% of what is a airplane experience , but you could use something like a parachute to lose speed in theory.(on the second tough 1%of what a airplane experience is huge, because a airplane does not fly with its engines stopped for tens of years, but that is applying only in the most denser region of the space 1^6 particle per cm3 and for 80%or more from the light speed , near our solar system would be much smaller but noticeable still)

[@extremechimpout]

Scott I would love it if the videos were 4K and really zoomed in on your face! Love the content!

[@MrAlexs888]

wut

[@extremechimpout]

@@MrAlexs888 What he's a handsome man!

[@ke6gwf]

When you mentioned Mongolian Metal my throat starts hurting and my head starts banging thinking of The Hu - Wolf Totem. Now I have to watch it again! Lol

[@RogerM88]

To conquer the Solar System and beyond with crew missions, we need Modular Spaceships, assemble in LEO, and powered by Nuclear engines. With a lander dock to it, as Starship, Red Dragon, or the Dynetics lander.

[@joeltashinian5888]

Totally SOMA! "goes well woth most meds" put in 1000s of hours of mission control. Always relaxing when precussion is just too much. I could pass time to this stuff. Also Goa Psy and many more

[@kangirigungi]

The unit of measure I've never understood is specific impulse. I find the effective exhaust velocity much more intuitive. It's the velocity of the exhaust in vacuum. Simple. It's thrust / fuel flow, and now it's immediately important why it's important. Finally, this is the value used in the rocket equation, so it can be used in calculations. But no, we divide it with some arbitrary number so we get something that's only meaningful at ground level, way less intuitive what it means, and can be used in no practical calculations.

[@wulf2121]

I agree basically. I heard (Maybe even in a Scott Manley video) that this is a historic thing which came about because in the early days engineers that were thinking in imperial needed to be able to talk to engineers thinking in metric about this. And dividing the exhaust velocity by g produces a unit that is the same in both systems (the second). Trying to add some interpretation on what the number of seconds mean (how many seconds can a kg of fuel apply the force of weight that this kg has at ground level) indeed is not intuitive at all. I just think of it as a number that you have to muliply by g in your favourite units to get the exhaust speed in this unit. (so basically 10 for me).

[@GewelReal]

16:22 I absolutely love that voice!

[@blacksmith67]

Tzar has been used in the United States to describe senior functionaries in charge of particular areas such as _Drug Tzar Harry J. Anslinger,_ and _Energy Czar Carol Browner._

[@MisterItchy]

Second mention today of ham and pineapple pizza ... LOVE IT!!!

[@RandallReviere]

'Tzar' is not so much a Russian term as a title derived from the nickname of the Emperor Julius (68/69 AD). See the wikipedia article for all the derivative titles (Tzar is on the list, as is Kaiser (German) etc.)

[@ponyote]

Love that shirt, Scott.

[@elektronikzmbrtlar1586]

i wonder if vacuum tubes could work in venus. pressure might be a problem but 400 something celcius shoud make heating cathote a lot easier

[@mrubin3770]

I think that would be only way to do it with present technology. But a tube based system would be very simple and not very capable. Other than the clockwork devices that have been proposed, active cooling with a nuclear power source is probably what would be necessary. This would be a very expensive project.

[@halords17]

that "fur" analogy just gave me the motivation that i didnt know i needed

[@MushookieMan]

To grow fur

[@halords17]

@@MushookieMan good idea

[@halords17]

i was referring to how i can explore places i'm not supposed to be in, but that's a good idea as well ngl

dial a yield nuclear weapons have a neutron generator, that generates a burst of neutrons from an electrical impulse that degenerates some material. the timing of when exactly those neutrons arrive where fusion is supposed to happen, needs to be quite exact, but due to the highly nonlinear nature of the reaction, those few neutrons can change the yield by a quite great factor.

[@nexusofjoseph]

All nukes have neutron generators. The W80 even has 6 in a gun carriage. Your description is a little off though, they accelerate tritium or deuterium into a target, which produces high energy neutrons. The literature is fairly open, as they have uses in mining too.

@@nexusofjoseph i didn't try to describe how the generator works. its about the high gain in yield, that can be achieved by comparatively few neutrons, contributed at _just_ the right time, at the very moment the reaction goes exponential, because at that time, they are in the order of neutrons, produced by the reaction itself, just starting, thus making it up to some integer factor bigger overall.

[@Axonteer]

My little pet plush duck loves the new outro and always gives lilke mission control commands "prepare for hyperspace exit" "engine on" and .. waves at Jeb doing Jeb things :D Yes im going crazy No its too late already but thanks for caring :-)

[@Jtc00]

It's scary how well you can calculate things by just thinking

[@ZPositive]

I agree 100% that the secondaries on modern nukes are magical. How they came up with the idea is flabbergasting.

[@bulthy1958]

Mr Peel, how I miss him

[@jimurrata6785]

Those Peel session recordings were some of the best. Great sound engineers at work.

[@Cs137matt]

"If humanity were meant to live in Minnesota they would have fur" love that line Scott Manley... My response usually to those kind of people are if God did not intend us to do something God would not give us such big brains to do it and trying to figure it out for ourselves... And also to add on to your Minnesota reference I would also reply with if humanity was meant to live in Africa we would be born with elephant like ears like nearly all desert animals have

[@_aullik]

When it comes to rockets, there is no point talking about thrust in N when we talk about mass in KG. The whole thing about metric is that you don't have to to do a lot of math with your units. If you have a rocket of mass X, how much thrust to you need to get a TRW of 1.5? Well X times 1.5 thrust in KG or X times 1.5 times 9.81 thrust in N. So obviously everyone is using thrust in KG.

[@MatthijsvanDuin]

This is just a problem in your specification: TWR is not actually dimensionless, dividing thrust by weight gives you a quantity whose unit is that of acceleration (i.e. m/s² in SI units). While specifying TWR in g (i.e. as a multiple of 9.81 m/s²) is conventional, this is not an SI unit hence requires conversion (by multiplying by 9.81) before you get something that works harmoniously with other SI units.

[@realulli]

10:30 Doing bespoke chips - I remember talking to some guys at the University of Freiburg, about 30 years ago. They were showing off their raster tunnel microscope, especially that they discovered they could pick up single atoms if they modulated the current going through the needle in just the right way. Now add the fact that carbon is a semiconductor when it is in a diamond grid. These guys were fantasizing about using their method to build computer chip diamonds (including doping the carbon) from scratch. What makes these chips very interesting for flying to Venus is that they could theoretically comfortably operate at temperatures of up to 800C, so the computers using those could be air-cooled even on the surface of Venus...

[@wulf2121]

you forgot to factor in that resistance by air/some medium increases by speed squared. so if you were to compare a speed where you need aerodynamics on earth (say 100/ms, then at c the drag would be like (3*10^8)² / (100)² = 9 * 10^12 higher. This is near the same order of magnitude as the density difference, so factoring in interstallar-medium-dynamic into vehicel design might actually be necessary close to speed of light. (also relativistic impulse of the molecures and length contraction would probably both increase the resistance further)

[@awilliams1701]

The Enterprise D has bussard collectors so obviously we figured it out sometime in the next couple hundred years.

[@sazeredo26]

😉

[@hinz1]

Ablation pressure from vaporizing the peanut shaped case is a magnitude larger than photon pressure, btw ;-)

[@peterihre9373]

Just loved the quick flipping of numbers😀

[@LaVorAta]

The Hu!

[@starrynayt]

Now I don't feel so alone with my choice of music as well! This was actually a blast! Looking forward to the next month's DSQ.

[@RogerM88]

Would make a great episode talking about spike engines in reusable rockets. Using the engine spike to reentry orbit, not needing heat tiles.

[@Mr2winners]

The complexity and problems of aerospikes just dont bring the benefit for the minute extra eficiency

[@5000mahmud]

Everyday astronaut made a good video on aerospikes

[@scottdorfler2551]

That's the coolest nurd shirt I've ever seen!!!