It’s definitely harder to decay the orbit into the sun directly than it is to get to escape velocity. But to play devil’s advocate, there is probably a way to get them into the sun while being a similar cost to escape velocity. All you need to do is burn prograde to a super high aphelion, ride all the way out there to Pluto or whatever and then do a small retrograde burn to bring your perihelion inside the sun’s photosphere. When you then get back towards the sun years later you would slam into it with a sick velocity that I think would be worth the decades-long wait.
Launches
Submitted 7 months ago by fossilesque@mander.xyz to science_memes@mander.xyz
https://mander.xyz/pictrs/image/456d2855-e586-4ae5-b9ce-0f90ba453e7b.jpeg
Comments
Bumblefumble@lemm.ee 7 months ago
SARGE@startrek.website 7 months ago
This definitely reads like one of my KSP exploits…
dQw4w9WgXcQ@lemm.ee 7 months ago
Gravity assist with one of the larger planets to make a very narrow orbit seems to be the most efficient way. But you need the planets to align correctly to have an efficient route.
“I’ll launch you into the sun once there is an appropriate transfer window to Jupiter” just doesn’t have the same ring to it.
Delta_V@lemmy.world 7 months ago
What if we catch a gravity assist off Jool, and do the retrograde burn at perijool to catch some Oberth Effect?
Ziglin@lemmy.world 7 months ago
Jebadiah is always so happy to spend 52 years only to find be stranded on Bop.
JackbyDev@programming.dev 7 months ago
I remember there was a trick where you could transfer fuel around to move your center of gravity then rotate the ship.
BurningRiver@beehaw.org 7 months ago
I scrolled down specifically looking for a KSP comment, thank you.
Anticorp@lemmy.world 7 months ago
That’s what I was thinking too.
vithigar@lemmy.ca 7 months ago
Alternatively you do like the Parker Solar Probe and do 7 Venus flybys, bleeding off a little speed reach time with an inverse gravity assist.
Windshear@lemmy.ca 7 months ago
Not an expert, but I’ve read it’s easiest to use jupiter to bleed off enough velocity to fall into our sun.
Bumblefumble@lemm.ee 7 months ago
Yeah it probably is, my comment was really about raw deltaV numbers without using gravity assists.
Maturin@hexbear.net 7 months ago
Haven’t you basically done everything needed to escape the solar system by the time you do the burn to turn back again?
Bumblefumble@lemm.ee 7 months ago
Yeah, you would only need to burn a little bit more on your initial burn, that’s why I said the cost would be similar.
OpenStars@discuss.online 7 months ago
Why is that - wouldn’t you be working against solar gravity? Like you don’t have to get them there quickly, just launch them in some orbit that will decay and be taken in?
ilinamorato@lemmy.world 7 months ago
Because the Earth is really cookin’, and
anythinganyone you hurl toward the sun will inherit that orbital velocity as well, meaning that they’ll actually end up going around the sun, instead of into it. And due to the speed it would pick up on its way in, it would basically take up a stable yet highly-eccentric elliptical orbit.“Well, what if we throw them in the other direction, to make up for it?” That’s called retrograde, and that’s basically exactly what you’d have to do: cancel out the Earth’s entire orbital velocity. Which would take a lot of energy, plus a couple of really exacting gravity assists from planets on the way in.
By contrast, even though the escape velocity from the solar system is no slouch (42 km/s), you get to start with the Earth’s orbital velocity (30 km/s)–meaning you’re already a little under 3/4 of the way there. Plus, if you can make it to Jupiter and Saturn, you can get a significant gravity assist, and they’re much bigger targets for such a maneuver than Mercury or Venus are.
So, yeah, bottom line: you only need a delta-V of about 12 km/s to get out of the solar system, but a delta-V of 30 km/s to get to the sun without going into orbit.
OpenStars@discuss.online 7 months ago
That’s a great explanation, thanks! 🙏
sushibowl@feddit.nl 7 months ago
So, yeah, bottom line: you only need a delta-V of about 12 km/s to get out of the solar system, but a delta-V of 30 km/s to get to the sun without going into orbit.
This is true, but the possibility of gravity assists mostly nullifies the difference. If you can get out to Jupiter you can basically choose: either let it sling you out of the system, or let it cancel out all your orbital velocity so you fall into the sun.
Venator@lemmy.nz 7 months ago
Why would you need to entirely cancel the earths orbital velocity, surely you just need to cancel a tiny bit of orbital velocity?
Donjuanme@lemmy.world 7 months ago
That’s assuming all cows are a point on a frictionless 2 dimensional plane.
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you don’t need to hit the sun dead center to be incinerated.
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the sun is huge
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you aren’t in a frictionless environment, your orbit will decay into the sun.
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psud@aussie.zone 7 months ago
You can just change the shape of your orbit (but not your orbital energy) with the help of a sufficient gravity well from solar orbit, so it intersects with the Sun. Drag within the Sun will slow whatever is left of you enough to sap your orbital energy
rockerface@lemm.ee 7 months ago
the issue is not counteracting gravity, the issue is decelerating enough to hit the sun
MF_COOM@hexbear.net 7 months ago
What’s wrong with them striking the sun at full speed?
Contramuffin@lemmy.world 7 months ago
That’s the thing - in space, orbits don’t decay. Orbital decay only happens if there’s dust or atmosphere that you bump into along your orbit to slow you down. But in interplanetary space, there’s no dust or atmosphere, and certainly not enough to decay your orbit fast enough to achieve results (otherwise, the Earth would have already decayed and melted in the Sun)
You need to spend fuel to lower your orbit to hit the Sun, and you need to spend fuel to raise your orbit to escape the solar system. It turns out to be really freaking difficult to hit the sun because it simply requires so much fuel to lower your orbit enough to hit the Sun.
captainlezbian@lemmy.world 7 months ago
Sir Isaac Newton is the deadliest son of a bitch in space
Donjuanme@lemmy.world 7 months ago
You are making 2 opposing assumptions there, 1) there is nothing to bump into in outer space, the earth picks up 43 tons of new mass every day.
- the earths orbit would decay, the earth is absolutely massive compared to the amount of mass gained, and also off gasses a significant amount of mass every day.
If orbits don’t decay, why do even high orbit satellites need to make elevation corrections?
If you put a small body into outer space it would absolutely be (slowly) effected by the miasma of particles out there.
And let’s not forget we don’t have a time table for reaching the sun, and we aren’t aiming for the middle of the sun to see results. And as you approach the sun you will bump into more and more particles as they too are being drawn around the sun.
snugglesthefalse@sh.itjust.works 7 months ago
Orbital decay isn’t just friction from particles, you also have imperfections in the orbit and other objects influencing the eccentricity over time. The moon has gravity too for instance.
jballs@sh.itjust.works 7 months ago
Zwiebel@feddit.org 7 months ago
You’re starting with the speed of the earth
OpenStars@discuss.online 7 months ago
Ah… centrifugal force, ofc!:-)
Blaubarschmann@feddit.org 7 months ago
Why would an orbit decay without something to slow the spacecraft down like an atmosphere? The problem is that any object we launch from earth has a lot of orbital velocity, which makes it almost impossible to hit the sun directly, you would have to use a lot of complex gravity assists from the inner planets to take away enough momentum. Using gravity assists to accelerate outwards is much easier
Donjuanme@lemmy.world 7 months ago
Why do you need to hit the exact center of the sun to have the desired results? Get it within the orbit of Mercury and I’ll be happy enough.
lugal@lemmy.dbzer0.com 7 months ago
I remember watching a video about that. The gist is that you have to leave earth orbit or something idk.
snugglesthefalse@sh.itjust.works 7 months ago
You leave earth orbit into a solar orbit that is slightly shifted depending on which direction you were facing when you left earth’s orbit
excral@feddit.org 7 months ago
To escape a body of mass you need to have enogh velocity (kinetic energy) to overcome the gravitational pull of that body. You can imagine it like a ball sitting in a bowl. With little velocity it will just roll back and forth but if it’s fast enough it can roll out of the bowl and escape it’s influence.
That critical speed is called “escape velocity” and it depends on mass and distance from a body. The escape velocity of earth (from the surface) is about 11.2 km/s and the sun’s escape velocity (from earth orbit) is about 42.1 km/s. Earth orbits around the sun at about 29.8 km/s. If you launch in the direction of Earth’s orbit, you will orbit the sun already at about 41 km/s, so you “only” need 1.1 km/s more to escape the sun, too.
If you tried to reach the sun, you could launch in the opposite direction leaving you orbiting the sun at about 18.6 km/s. Since there is almost nothing in space you won’t slow down from friction and the orbit won’t decay. Instead you’d have to accelerate opposite the direction you’re traveling. Now, calculating exactly how much you’d need to decelerate isn’t trivial since you don’t want a stable orbit but an elliptical orbit that just touches the sun at the closest point (perihel). I don’t know how much deceleration that takes, but it’s propable that it’s easier than accelerating by 1.1 km/s to escape the sun.
Donjuanme@lemmy.world 7 months ago
It’s an easy talking point from the Internet and high school text books, it is disregarding of many actualities of our universe. It would be true if the sun were an infinitely small point on a 2 dimensional plane with a perfect lack of friction.
And while for instantaneous results it would be easier to get something out of the sun’s gravity well rather than hit the exact middle of the sun, practically, if you have time, and you don’t actually need it to hit dead center of the sun, it’s much cheaper and easier to incinerate something proximal to the sun than it is too send it out of the solar system.
Also let’s not forget gravity sling shots work in both directions.
Simmy@lemmygrad.ml 7 months ago
Short answer; the earth is orbiting really fast around the sun.
lud@lemm.ee 7 months ago
Launching someone straight into the sun is very very expensive but doing a gravity assist around Jupiter or something to redirect your orbit into the sun is much cheaper.
Etterra@lemmy.world 7 months ago
Huh. I would have thought that once they break orbit that the sun’s gravity well would do the heavy
liftingpulling.Cornelius_Wangenheim@lemmy.world 7 months ago
If you care to learn orbital mechanics, Kerbal Space Program is a great teacher.
kamen@lemmy.world 7 months ago
That one’s been sitting unplayed in my library for a very long time. I guess it’s time to give it a shot.
Daxtron2@startrek.website 7 months ago
“Breaking orbit” still leaves you in almost the same orbit around the sun as the earth. You need to slow down a lot to bring the periapsis of the orbit within the suns surface.
chiliedogg@lemmy.world 7 months ago
Imagine that you’re standing on a train and have a baseball. If you throw the ball off the train, the ball will still have momentum in the direction of the train’s movement.
If you want to throw the ball to a friend the train just passed, you have to be able to throw the ball faster than the train is moving or it will never reach them.
Deepus@lemm.ee 7 months ago
Now all im imagineing is a ball floating mid air and it’s beautiful
dQw4w9WgXcQ@lemm.ee 7 months ago
The vessel would still have a lot of speed after escaping earth’s orbit, so the trajectory would become a large orbit around the sun. You still have to slow down by about ~30km/s (or ~100 000 km/h) to make that orbit intercept with the sun’s surface.
FiskFisk33@startrek.website 7 months ago
once you break out of earth orbit you are now in an orbit around rhe sun, similar to earths.
Klnsfw@lemmynsfw.com 7 months ago
Even with the explanations given here, it’s still very counter-intuitive for me.
I think the best thing would be to cut the person in half, send one half towards the sun and the other half out of the solar system.
smeenz@lemmy.nz 7 months ago
The issue is that you’re starting from earth, and the earth already has a lot of momentum that keeps it from falling into the sun. To get an object from here to the sun you would need to counter the majority of that momentum it already has.
Jumi@lemmy.world 7 months ago
It’s not about the propellant, it’s about sending a message
sexual_tomato@lemmy.dbzer0.com 7 months ago
I legitimately want to be cremated by the sun after I die. Doesn’t matter how long it takes.
Sas@beehaw.org 7 months ago
When the sun dies it will take the earth with it iirc so if you can wait until then you’re good
psud@aussie.zone 7 months ago
We might fix that with a bit of star lifting, disappointing sexual_tomato
geogle@lemmy.world 7 months ago
Don’t worry, we all will. We all came from a sun, and will all return to one.
JasonDJ@lemmy.zip 7 months ago
Instructions unclear. I’m going to the moon on Delta IX.
NegativeInf@lemmy.world 7 months ago
Well, I guess this applies to me. I say that a lot.
gasgiant@lemmy.ml 7 months ago
Wouldn’t shooting them into Jupiter be the easiest?
I’m sure I’ve read a few things about what an impact that big bugger has on trajectories in our solar system.
Intuitively I feel like a push towards Jupiter would be easier than a push to get all the way out of the solar system avoiding Jupiter.
MelodiousFunk@slrpnk.net 7 months ago
If the idea is to be rid of the person completely, we don’t need to fire them into the sun. Or launch them out of the solar system. They don’t even need to reach earth escape velocity.
Just launch them at the sun. Use whatever method you like. Just get them high enough that after gravity starts to overpower acceleration, there is no chance for survival. Boom! No more person. For the most part.
LEONHART@slrpnk.net 7 months ago
TheReturnOfPEB@reddthat.com 7 months ago
how much to put them into a space suit and a car, strap them to a rocket and then fire them into orbit around Mars ?
Kolanaki@yiffit.net 7 months ago
Launch them into Betelgeuse instead.
UlyssesT@hexbear.net 7 months ago
Vay Hek threatening to hurl the Lotus into deep space just doesn’t have the same punch, though.
intensely_human@lemm.ee 7 months ago
Can a solar sail be used to put a craft into the sun?
LordGimp@lemm.ee 7 months ago
So you’re telling me shooting a space gun at the sun will miss?
finley@lemm.ee 7 months ago
Ummm… quick question: Isn’t that all just a matter of timing?
cm0002@lemmy.world 7 months ago
Exceptions do apply, things like near-immortal beings or cursed objects may require the destructive power of a Sun and no less
asg101@hexbear.net 7 months ago
I would be happy with just dropping them off a cliff, no need to fuck up the atmosphere any more for that.
FuglyDuck@lemmy.world 7 months ago
You could always put them in a co-orbit with earth or something and then just use solar sails to provide the delta-v
But I also like the idea of certain peeps having time to understand the error of their ways before slowly falling into the sun faster and faster.
And before some one says “well, there’s still plenty of time for that with a rocket…”
Naw. We’re talking about a truly idiotic person.
zarathustra0@lemmy.world 7 months ago
Yeah, but propelling them out of the solar system just sounds like the kind of fake-ending that ends up with the super villain coming back stronger in a decade. Have we learnt nothing from science fiction? You have to destroy your foes whilst you can.
grue@lemmy.world 7 months ago
From the tvtropes.org/pmwiki/…/EvilOverlordList
Lev_Astov@lemmy.world 7 months ago
Man, I haven’t thought of the Evil Overlord List in many, many years.
ummthatguy@lemmy.world 7 months ago
Image
The phantom zone ain’t gonna cut it.
noride@lemm.ee 7 months ago
It blows my mind that this was cutting edge, jaw dropping graphics back in the day. A shape-shifting trapezoid with some panicked faces peeking out.
BreadOven@lemmy.world 7 months ago
Which angel is that?
SaharaMaleikuhm@feddit.org 7 months ago
Imploding submarines are far more efficient
Etterra@lemmy.world 7 months ago
Okay when the options are throwing a football down field or up field, the option to hit a softball with a sledgehammer isn’t helpful.
RestrictedAccount@lemmy.world 7 months ago
Going easy on traitors is how Germany gave us WWII.
luciferofastora@lemmy.zip 7 months ago
But we gave him a nice little prison stay to write his manifesto in! Surely he learned his lesson and won’t attempt to overthrow democracy again, right?
…right?
OpenStars@discuss.online 7 months ago
They can still come back from another parallel reality or some such - villains are like cats, they always come back (unless they are bored and then they don’t).
Infynis@midwest.social 7 months ago
Sun’s bad then too. Don’t want them Final Frontiering their way into the past
Fermion@feddit.nl 7 months ago
Yes, one is a final solution, the other is just pushing your problems elsewhere without regard for who else it could affect.
InverseParallax@lemmy.world 7 months ago
youtu.be/zoCvqDd2_C8
Back when RT wasn’t shit.
Rubisco@slrpnk.net 7 months ago
To the depths of Jupiter, then.