[HN Gopher] NASA spacecraft films crazy vortex while flying thro...
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NASA spacecraft films crazy vortex while flying through sun's
atmosphere
Author : bookofjoe
Score : 157 points
Date : 2024-04-06 12:50 UTC (10 hours ago)
(HTM) web link (mashable.com)
(TXT) w3m dump (mashable.com)
| bookofjoe wrote:
| 'Three-Body Problem'
|
| https://archive.ph/B1Kui
| throwup238 wrote:
| Can anyone find a scale for the photo? How big is this vortex?
| bookofjoe wrote:
| >First Direct Imaging of a Kelvin-Helmholtz Instability by
| PSP/WISPR
|
| 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 20deg and latitude of 10deg.
|
| >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...
| Levitating wrote:
| ELI5?
| jeroenhd wrote:
| Average sizes seem to range from 36000km to 174000km. For
| reference: the earth is almost 13000km in diameter.
| bregma wrote:
| Unfortunately the banana froze and carbonized at the same time.
| JKCalhoun wrote:
| Very cool. Any point to false-colorizing this footage?
|
| 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.)
| vrighter wrote:
| sound does not travel through space. So that is just
| sonification of data. It is, in general, bullshit
| akira2501 wrote:
| > is just sonification of data.
|
| Block frequency down conversion.
|
| > It is, in general, bullshit
|
| It's incredibly useful for a species that has limited sensory
| capabilities.
| ed_mercer wrote:
| Well that was disappointing. No color, no sense of scale and
| super short. I have no idea what I just saw.
| beeeeerp wrote:
| This probe is flying through an _incredibly_ harsh environment,
| and it's likely tuned for certain brightnesses /wavelengths to
| show features better. It's also why a lot of space probes use
| false color; your eyes just wouldn't be able to see features
| otherwise.
| pavlov wrote:
| It's footage captured inside the Sun's corona with a scientific
| instrument, not a Hollywood VFX sequence.
| echelon wrote:
| It's one of the coolest science images I've seen! I don't
| understand how one can't be in awe.
|
| 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.
| jcims wrote:
| If you watch this video it might help provide some orientation
| and context for the field of view.
|
| 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.
| echelon wrote:
| > Later this year, the spacecraft will reach a whopping 430,000
| miles per hour.
|
| 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%!
| kshacker wrote:
| A novice question.
|
| 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?
| exitb wrote:
| I mostly got the speed from multiple Venus flybys, which
| slowed down in its orbit a minuscule amount.
| testoo wrote:
| hi kshacker! This is my understanding:
|
| 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!)
| aio2 wrote:
| I'm studying physics right now, I can say I agree with
| everything you said.
|
| 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 1/2 _mass_ velocity^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=1/2 _1_ v^2, v=2
|
| Now if some momentum were transferred, and the kinetic
| energy increased to KE=8,
|
| 8=1/2 _1_ velocity^2, velocity=4, since the mass can't
| change
| ShamelessC wrote:
| Why did this get downvoted so much? Seems accurate enough.
| testoo wrote:
| i was wondering too! Do you think it might be because of
| citing family as a source? I barely ever post here, so
| don't have a good muscle memory for norms and best
| practices.
|
| (also both scared and curious of what might result from
| dropping below 0 karma)
| big_paps wrote:
| Potential energy was converted into kinetic energy, not
| unlike when an apple falls to the ground. So the sun doesn't
| really give away this energy, but its the system including
| these two masses.
| vl wrote:
| Increasing speed with slingshot works because you leave
| vicinity of the planet in the same direction planet travels.
| Basically this allows you to add planet's speed to your own.
|
| 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.
| colechristensen wrote:
| Flybys to boost speed take a tiny tiny tiny part of a
| planet's orbital kinetic energy and exchange it with a
| 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.
| BlarfMcFlarf wrote:
| The slingshots used to deorbit were around Venus, so it
| slightly gained velocity while the Parker probe lost it to
| get closer to the sun without expending as much fuel.
|
| 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.
| pfdietz wrote:
| 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.
|
| 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.
| testoo wrote:
| there's another cool aspect to your question too!
|
| "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)
| fxj wrote:
| When I did my PhD in the late 80s we were simulating Kelvin-
| Helmholtz Instabilities on supercomputers with application to
| solar dynamics. It is very nice to see that they exist and behave
| like predicted. There are plenty of other plasma instabilities
| that were predicted at that time and have now been confimed by
| space probes.
| jakeinspace wrote:
| Given that video is 7.5 hours start to finish, and Parker is
| moving at several hundred thousand mph relative to that vortex,
| is it on the order of the diameter of the sun?
| hackernewds wrote:
| no
| esaym wrote:
| >Given that video is 7.5 hours start to finish,
|
| Link??
| toufka wrote:
| Timestamp in the videos: 21:03-4:33 => 7.5hrs
| zmgsabst wrote:
| Seems like.
|
| 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.
| akira2501 wrote:
| Everything moves substantially faster when close to the sun.
| rkagerer wrote:
| Totally looks like a wormhole. Kelvin-Helmholtz Instability or
| Einstein-Rosen Bridge; could have fooled me.
| ben_w wrote:
| Outside of sci-fi (as in: in physics based renderings)
| wormholes look like lenses, and a lens free-floating in space
| with only point-like stars behind it is hard to notice.
|
| ERBs in particular are unstable in a universe containing
| literally anything else including a single photon, so you can't
| ever see one.
| verisimi wrote:
| At this point in history, with the economies of scale in
| production from phones etc, surely it's cheaper to put in a
| colour camera?!
| hanniabu wrote:
| The conditions it's operating under and level of reliability
| needed are completely different
| kataklasm wrote:
| Modern day tech often reaches spaceflight circles decades after
| it becomes ubiquitous in normal use. For spaceflight purposes
| it is extremely vital that any and all components and tech is
| matured amd that takes a long time. Add in a ton of
| certification and paperwork processes and there you go.
| verisimi wrote:
| You don't think colour photography is mature?
|
| 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
| ceejayoz wrote:
| The probe's purpose is not to determine the color of the
| sun; we are readily capable of doing that from here.
|
| https://en.wikipedia.org/wiki/Parker_Solar_Probe#Instrument
| s
|
| https://en.wikipedia.org/wiki/WISPR
| mcbutterbunz wrote:
| In addition to all the other replies on this topic,
| monochrome sensors are capable of higher detail and higher
| sensitivity than color sensors. There's no scientific
| benefit to using a color sensor. In fact, a color sensor
| would be detrimental.
| kryptiskt wrote:
| Yes, no professional telescope uses a color sensor,
| because the on-chip filters on those are terrible and
| doesn't go away when you don't want color. All color
| images are either done by combining images with different
| filters or are false color images.
| tekla wrote:
| Only on HN do we find so many people that have so much high
| regard of their own intellect over a army of Engineers.
| verisimi wrote:
| Only on HN do we find an army of people who justify
| scientific authority over the testimony of their own
| intellect.
|
| Just ask yourself, if you were in charge of the mission,
| in what world would you decide to use a black and white
| camera rather than colour to capture the data of what is
| probably a multi-billion dollar mission? Is it really the
| case that there is no room for a colour camera, in
| addition to a b/w one, if necessary?
| schoen wrote:
| Here's an article by the scientists who created the
| camera that took this picture, introducing it and
| describing its design.
|
| https://orbi.uliege.be/bitstream/2268/200751/1/The%20Wide
| -Fi...
|
| It's very much not an off-the-shelf camera; it seems to
| have involved years of custom engineering work.
|
| This article doesn't seem to address the specific
| question of "why is this camera monochrome?" but you can
| see that it wasn't trivial to make an instrument that
| would work well in this difficult environment. So it's
| definitely not like "and let's throw a commercial digital
| camera on there too just for fun!".
|
| It's a legitimate question why some kind of color camera
| wasn't considered worth including, but lots of space
| missions have sensors that are something other than a
| simulacrum of human vision. That's why so many
| astronomical images end up getting published in false
| color.
|
| https://en.wikipedia.org/wiki/False_color
|
| In almost all of those cases, the justification for the
| false color seems to be some form of "true color wouldn't
| have been possible or appropriate for the scientific
| purposes of this imagery".
| verisimi wrote:
| Thank you for acknowledging this is a legitimate
| question.
|
| I've no issue with all sorts of cameras and scientific
| instruments being placed on a space craft. I don't expect
| to get access to all the data that is sent back - though
| - as it is from the public purse - I think it should be
| made available.
|
| My point is that the only interaction us great unwashed
| have with these missions is with the imagery that is
| provided.. How difficult would it be to have a colour
| camera?!?! I have a crap mobile and it has 3 cameras! And
| one on the front! When colour cameras have been available
| to everyone for so long, its simply inconceivable that
| NASA can never provide decent imagery! Its 2024 ffs,
| surely we can have colour by now! No? If not now, when?
| mulmen wrote:
| > How difficult would it be to have a colour camera?!?!
|
| As has been exhaustively explained to you already "more
| difficult than it is worth". At this point you are
| willfully ignorant on this topic.
|
| > I have a crap mobile and it has 3 cameras!
|
| And I own a spatula. Both devices are equally capable of
| taking color photos in this environment.
| Dylan16807 wrote:
| > As has been exhaustively explained to you already "more
| difficult than it is worth".
|
| Worth is subjective, and some people in this discussion
| (including you) are saying the worth is 0. "More
| difficult than 0" is not a good answer to "how
| difficult".
|
| And some people have explained why the main camera isn't
| color, which is important information but doesn't answer
| the question either.
|
| Did anyone give a better explanation of difficulty that I
| have overlooked?
| ben_w wrote:
| As someone whose first programming job was processing
| multispectral satellite data[0][1]: if you put me in
| charge of a mission, my first question would be "which
| specific frequencies provide the most scientific value?",
| and then focus on that/those. They won't necessarily have
| anything in common with what you'd normally use for "true
| colour" (quite a lot of what you see in astronomy falls
| into this category: even when you see a colourised press-
| release, it's not what you'd see if you looked at it with
| your natural eye).
|
| As for "what about a colour camera":
|
| First, look at all the noise in the images, all those
| slightly curved streaks. That's radiation going through
| the satellite and hitting the sensor from the side.
| Normal consumer stuff isn't even trying to cope with that
| sort of environment.
|
| Second, look at how low the frame rate is. That suggests
| the data rate is really low, and they probably don't have
| spare capacity for anything merely decorative.
|
| [0] https://en.wikipedia.org/wiki/SeaWiFS
|
| [1] DOI: 10.3354/meps07437
| mulmen wrote:
| > Just ask yourself, if you were in charge of the
| mission, in what world would you decide to use a black
| and white camera rather than colour to capture the data
| of what is probably a multi-billion dollar mission?
|
| In this world, where I choose the best tool for the job.
| Color cameras are worse for this task. I don't make
| engineering decisions based on gut reactions to things I
| know nothing about. I ask questions then make a decision
| based on facts and objectives.
| ben_w wrote:
| I wish. AFAICT, that's the universal human condition.
|
| 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).
| Dylan16807 wrote:
| > For spaceflight purposes it is extremely vital that any and
| all components and tech is matured
|
| 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.
| mulmen wrote:
| > 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?
| Dylan16807 wrote:
| > ...Which NASA also does. That's the helicopter on Mars
|
| 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_.
| mulmen wrote:
| I disagree. There's an enormous amount of bleeding edge tech
| in spacecraft. This camera was a totally custom thing. The
| constraints are simply so limiting that we have to make
| tradeoffs.
| elorant wrote:
| The camera has to be shielded against various forms of
| radiation that are emitted from the Sun and that could be a
| limiting factor for its capabilities.
| verisimi wrote:
| It would be the same shielding requirement for a black and
| white camera as for a colour one.
| mulmen wrote:
| "Cheap" and "first in human history" rarely go together. When
| Apple offers a mass produced solar probe I'm sure it will have
| a color camera. Until then you have to be satisfied by the
| actual achievement instead.
| verisimi wrote:
| We can send probes to the sun, to Mars, collect samples from
| asteroids billions of miles away.... but we can't get decent
| quality colour photos?!? That tech is beyond us? In 2024? ..
| wtf ...
|
| 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.
| mulmen wrote:
| > 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.
| verisimi wrote:
| > A color camera has no scientific value so they didn't
| send one. It's that simple.
|
| I simply don't buy this argument. You are telling me that
| using your visual sense is irrelevant, because of all the
| data that is being collected. Ie scientists like
| spreadsheets of info, databases, rather than imagery that
| is faithful to the human eye.
|
| The issue is that this is a/ patently false, because
| everyone who can use their eyes to judge information will
| do so, and b/ you can do both cos the overhead of a
| colour camera is so low!
|
| It's 2024 not 1964.
| mulmen wrote:
| We already know what color the sun is. Color cameras take
| worse quality images and use more data to do so. The
| black and white images are higher fidelity and thus
| convey more useful information.
|
| > You are telling me that using your visual sense is
| irrelevant, because of all the data that is being
| collected.
|
| I'm not telling you that. Black and white pictures are
| still perceived with the visual sense. The picture is
| data.
|
| > Ie scientists like spreadsheets of info, databases,
| rather than imagery that is faithful to the human eye.
|
| Well, no, clearly they value images because they sent a
| camera. A human eye would be completely obliterated way
| before reaching the sun's corona. It's physically
| impossible for a person to perceive this environment
| "faithfully".
|
| > everyone who can use their eyes to judge information
| will do so
|
| Yes but there is less useful information in a color image
| to judge.
|
| > you can do both cos the overhead of a colour camera is
| so low!
|
| The overhead for a useless instrument is extremely high.
| There are mass constraints, power constraints, and
| communication bandwidth constraints. A color camera would
| be a pointless waste of resources.
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