NASA spacecraft films crazy vortex while flying through sun's atmosphere
mashable.com
mashable.com
Link??
186,000 km/h will cover the sun’s diameter in 7.5 hours.
https://www.wolframalpha.com/input?i=%28diameter+of+sun%29%2...
Meanwhile, Parker is supposed to be moving substantially faster when close to the sun.
This is much faster than Voyager!
The speed of light is 670,616,629 miles per hour in a vacuum. We're starting to get into the not insignificant percentage territory here.
That's nearly 0.1%!
430K miles per hour is obviously a big number. And I have previously heard of this slingshot approach to increase speed so I am familiar with it.
However, I believe energy is constant (it can be transformed but unlikely to be created or destroyed). For some object to gain a speed of 430K miles per hour, it must come from elsewhere, obviously it did not burn its own fuel (and I am assuming the slingshot theory). So the Sun transferred it a bunch of energy. I presume that is gravitational energy and to my mind it implies Sun gave away that energy. However, isn't that based on mass? But I do not think the mass would have changed.
ELI5 please in terms of energy exchange. Who gained and lost and how?
That's correct, the energy comes from the body the spacecraft is slingshotting around (the Sun in this case). It's not mass or gravitational energy or anything weird like that, it's actually just a momentum transfer, the same as if the two objects had collided and bounced off each other elastically (i.e. without loss of energy to heat). So a (miniscule amount) of momentum (velocity x mass) is being transferred from the Sun to the spacecraft, and that's where the energy comes from.
(source: I studied physics and had a grandparent at NASA who worked on Voyager II and talked about this issue with me; but it's been a while since both of those things, so anyone with more fresh experience feel free to chime in!)
One thing I'd like to expand on to those who don't know how greater energy means greater speed.
The kinetic energy equation is 1/2massvelocity^2=KE
Since the KE increases from the momentum transfer, and mass of the object stays constant, the only thing that can change is velocity, where it has to go up.
ex: KE=2, m=1 2=1/21v^2, v=2
Now if some momentum were transferred, and the kinetic energy increased to KE=8,
8=1/21velocity^2, velocity=4, since the mass can't change
(also both scared and curious of what might result from dropping below 0 karma)
sorry kshacker, I may have thrown you off the scent here. My explanation of the slingshot effect is right, but it doesn't look like slingshotting is what the spacecraft is using to increase its speed:
the original article doesn't actually mention this at all, but it links to another one which tries (so vaguely it's misleading IMO) to explain the maneuver: https://mashable.com/article/nasa-parker-solar-probe-speed
tl;dr: the spacecraft is just falling into the Sun, which is why it speeds up. It isn't gaining speed relative to anything else, and it loses that speed again once it flies away from the Sun. It is using Venus to get closer to the sun each time around by damping its angular momentum, which works but I don't know how to explain that in an ELI5 way.
so it's actually a little anticlimactic.
BlarfMcFlarf and pfdietz got this right below in their comment thread:
"What the Venus flybys did was not add energy so much as remove angular momentum. The hard part about getting close to the Sun is that conservation of angular momentum prevents it."
...and icehawk and vl correctly point out that you can't really use the Sun to increase your within-solar-system speed. Thanks to them for prompting me to look into this further. The cool slingshot maneuvers all involve planets, not the sun.
...but I think the key answer that none of us quite articulated to your question:
How is the spacecraft using the slingshot effect to increase its speed each time around?
...is that it isn't!
...the article dramatically describes it as "picking up speed" each time it goes around the sun, but that is misleading. It is just getting closer to the sun every time around, so of course it goes faster the closer it gets.
the cool part if any is how it uses Venus to get closer to the sun (by sapping angular momentum), but that's hard to explain in a nutshell and doesn't really relate to your energy question.
so that is hopefully now a better answer to this mystery that brings together what some of the other commenters have pointed out.
Within solar system you cannot increase speed by slingshotting around the sun.
Total energy within system stays the same, some energy is transferred from the planet to the spacecraft.
The silliest way to describe it is kind of like stepping in front of a bus, but instead of actually getting hit you just get close enough for gravity to pull you along with the planet. Orbital mechanics is really just not intuitive so you can’t get an easy explanation as one doesn’t exist, your life experience with momentum and gravity is just too different for it to make sense easily.
As for its velocity around the sun, it’s intuitively like pendulum. When far away, it’s like the raised pendulum, and when near the sun, it’s like the pendulum at the bottom of its swing. Its a strained metaphor, but if you look at the orbit, it’s a very deep swing and a very large object it’s swinging towards, so it ends up quite fast at the bottom.
Related to this: a minimum energy transfer between two circular orbits is normally the two-burn Hohmann transfer: an elliptical orbit that is tangent to each circular orbit. But if the radii of the two circular orbits have a sufficiently large ratio, it takes less delta-V to use three burns: go into an elliptical orbit that goes out to very large distance, do a small burn to lower (or raise) the periapsis to be at the other orbit, then circularize with a third burn. This is because doing a burn at large distance adds or removes a very large amount of angular momentum.
"Who gained and lost [energy] and how?"
>there actually is no objective answer as to which body gained and which lost energy! Energy is always conserved, but which way the transfer happened depends on your reference frame!
this isn't too difficult to demonstrate: pick an inertial reference frame A such that the spacecraft is at rest following the "collision" (aka the slingshot). In this frame, the spacecraft has 0 kinetic energy post-slingshot; therefore, it lost energy in the slingshot, which was transferred to the Sun. Likewise, pick a frame B such that the Sun is at rest after the slingshot (this would be the more usual frame to pick). In this case, it's the Sun that lost energy, and the spacecraft that gained it.
(depending on one's mechanics background this might appear anything from obvious to very weird and unintuitive)
We are 100% sure for one side of energy transfer: both spacecraft and Sun are going to higher energy level first, then to lower energy level.
Other part of equation is unknown. It's called "Gravitational potential energy", but it's unknown what stores this energy. However, we have few hints: objects creates gravitation waves, gravitational waves are propagated at c (speed of light), there is Higgs field (nature unknown), which is presented everywhere and gives mass, Higgs boson connects objects to Higgs field, gravitational force is proportional to 1/d^2. So, we have a medium (Higgs field), to which objects are connected via Higgs bosons. We can assume that energy can be transferred to/from the medium via bosons, so medium can store the energy and release it. We can speculate that when bosons somewhat connects to medium, it may create a tension in the medium, like bubbles on water, via unknown physical process. As result of that tension, bosons which are closer are spending less energy to create same tension, which makes closer position energetically favorable, so any random motion (because of noise in the medium) in direction of another boson will release some energy, while any movement in opposite direction will require to apply some energy.
https://iopscience.iop.org/article/10.3847/1538-4357/ad2208
>To characterize the spatial scales involved (e.g., radial size, width, and separation of the eddies) we use exclusively observations from WISPR-I, the only instrument where the eddies were discernible.
>From the GCS reconstruction, we estimated that the CME propagated radially in a direction with a Carrington longitude of 20° and latitude of 10°.
>Since all the features exhibited a rather elliptical shape, to characterize the typical scales involved, we measured the length of the major and minor axes (the major axis is along the propagation direction, while the minor axis is perpendicular to this direction).
> From the time-lapse considered, we estimate that the lifetime of the eddies (i.e., the temporal period) is less than 30 minutes.
>Table 1. Average Sizes (in Mm) of the Minor (top row) and Major (lower row) Axis of Observed Eddies
https://iopscience.iop.org/0004-637X/964/2/139/suppdata/apja...
https://content.cld.iop.org/journals/0004-637X/964/2/139/rev...
https://content.cld.iop.org/journals/0004-637X/964/2/139/rev...
A slightly embarrassed normie asking.
(Weirdly too, I want sound — maybe those long, low-frequency whistles you hear radio astronomers pick up from the sun.)
Block frequency down conversion.
> It is, in general, bullshit
It's incredibly useful for a species that has limited sensory capabilities.
https://twitter.com/NASAExoplanets/status/156144251407831449... :
> The misconception that there is no sound in space originates because most space is a ~vacuum, providing no way for sound waves to travel. A galaxy cluster has so much gas that we've picked up actual sound. Here it's amplified, and mixed with other data, to hear a black hole!
"Physicists demonstrate how sound can be transmitted through vacuum" https://www.sciencedaily.com/releases/2023/08/230809130709.h... :
> In a recent publication they show that in some cases a sound wave can jump or "tunnel" fully across a vacuum gap between two solids if the materials in question are piezoelectric.
"Complete tunneling of acoustic waves between piezoelectric crystals" (2023) https://www.nature.com/articles/s42005-023-01293-y
Helmholtz resonance https://en.wikipedia.org/wiki/Helmholtz_resonance :
> Helmholtz resonance is one of the principles behind the way piezoelectric buzzers work: a piezoelectric disc acts as the excitation source, but it relies on the acoustic cavity resonance to produce an audible sound.
They’re not in space. They’re in the Sun. There is presumably some acoustic transmission in that medium.
ERBs in particular are unstable in a universe containing literally anything else including a single photon, so you can't ever see one.
Even though they had Kip Thorne as a scientific advisor and he made a scientifically accurate rendering of various environments, if they'd not made it a swooshy tunnel in the middle then the transit would have been somewhat boring (or sudden) cinema.
https://youtu.be/yTpbZ_Psbeo?si=S6RjCd7vFaWrqUQe
vs.
Look at the time scale. Look at how big that structure is!
We're traveling at nearly 0.1% the speed of light, at temperatures of 2,500 degrees Fahrenheit. This is an incredible testament to science and engineering.
You know what else might look boring but is actually insanely cool? Emission spectra from exoplanets. Peaks on a graph, but we're sensing atmospheres from worlds our ancestors could never have imagined.
Just think what lies ahead for our species. It's incredible to ponder.
https://www.youtube.com/watch?v=IQXNqhQzBLM
The Parker Solar Probe has a very eccentric orbit around the sun and mostly operates behind this large head shield which always faces the sun. So imagine it like horse blinders and the instruments are facing in the direction of travel and to some extent 'to the right' away from the sun.
In the video the sun is always to the left and the probe is going through its closes approach of the orbit (aka perigee) which directly correlates to the velocity telemetry in the bottom left. At the highest speed, it's closest to the sun.
So in the video of the vortex the sun is to the left, the axis of the vortex is likely pointing directly at the sun and the probe is flying past it.
And even if that were the case, do you not think there would be some scientific value to having the photo in colour that it would be worth the risk?
Personally - I think its ridiculous that NASA get so many billions but are unable to put in a decent colour camera. I can't see any acceptable reason for this.
PS first colour photo was in 1890.
PPS I mean 1861! https://www.bbc.com/news/13411083
https://en.wikipedia.org/wiki/Parker_Solar_Probe#Instruments
One of the great things about ChatGTP is as a framing point — I can now use it as a standard by which to say: "this thing we all keep rolling our eyes at for its mistakes? It's knows more about this than ${person} does" (sometimes I'm that ${person}, helps point me in the direction of intellectual humility).
It's not "extremely vital", it's just how NASA has been doing things for a good while.
Sometimes ultra perfectionism makes sense.
Sometimes you can aim for an 85% mission success rate and launch 5 probes for half the price a decade earlier.
…Which NASA also does.
That’s the helicopter on Mars, and the first Starship mission.
Which 85% success rate space mission did you pull off?
So you agree with me that it's viable, great.
I guess I should have been more clear that the perfectionism is how NASA almost always operates these days.
> the first Starship mission.
Not NASA.
> Which 85% success rate space mission did you pull off?
What's with this hostility?
All I said is that it's not extremely vital. I didn't even say NASA definitely did anything wrong, just that there are options.
I really don't get why my original post is downvoted and being disputed. It seems such a basic point.. It such an oversight on the part of NASA, it borders on intentional.
This is why you are being downvoted. You clearly do not understand the difficulty of these achievements. Yet you claim NASA is incompetent for doing something literally nobody has ever done before.
A color camera has no scientific value so they didn’t send one. It’s that simple.
Assuming you know more than NASA is rightfully going to earn downvotes. You don’t know more than NASA.
Approach this with an open mind and some curiosity and you’ll get a much warmer response. You might even learn something.