[HN Gopher] New Webb image captures clearest view of Neptune's r...
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New Webb image captures clearest view of Neptune's rings in decades
Author : pseudolus
Score : 297 points
Date : 2022-09-21 16:04 UTC (6 hours ago)
(HTM) web link (www.nasa.gov)
(TXT) w3m dump (www.nasa.gov)
| cl42 wrote:
| Wow! If anyone is curious as to why Triton is so bright...
|
| > Covered in a frozen sheen of condensed nitrogen, Triton
| reflects an average of 70 percent of the sunlight that hits it.
| It far outshines Neptune in this image because the planet's
| atmosphere is darkened by methane absorption at these near-
| infrared wavelengths.
|
| That's pretty neat!
| bcbrown wrote:
| The fact that methane absorbs infrared/near-infrared
| frequencies is also the mechanism that causes it to be a
| greenhouse gas.
| ajross wrote:
| Also explains why the rings are brighter than the planet here,
| when they were all but invisible to Voyager 2.
| MiguelVieira wrote:
| > 70 percent of the sunlight that hits it
|
| It looks like that's comparable to fresh snow or a glacier?
| Cerium wrote:
| Better than a glacier but worse than fresh snow. "More than
| 80 to 90 percent of the sunlight falling on fresh snow is
| reflected back into space, compared to 15 to 35 percent of
| the sunlight reflected by most ice."[1].
|
| [1]https://earthobservatory.nasa.gov/features/DirtySnow/page2
| .p...
| pastor_bob wrote:
| woah
|
| I originally thought it was a star
| stoicjumbotron wrote:
| Have they released any high resolution version? I tried finding
| on their website, but did not find anything.
| dwringer wrote:
| I tried comparing this image with some from the Hubble and this
| one appears to be slightly sharper (not to mention much more
| detailed in terms of the atmosphere thanks to the infrared
| wavelengths). I don't think it gets _too_ much higher-res than
| this without a probe getting close to the planet.
|
| A google search indicates Neptune's largest apparent size in
| the sky is 2.4 arcseconds[0], and a commentor below suggests
| JWST's resolution is approximately 0.1 arcseconds (.068 at a
| wavelength of two microns[1], from some google searching),
| which would suggest a rough maximum resolution of about 35
| pixels, while this image is 80. I'm unclear on the exact
| reasons for this difference.
|
| [0]
| https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact....
|
| [1]
| https://www.stsci.edu/files/live/sites/www/files/home/jwst/a...
| nowahe wrote:
| Looks like the image in the article is a crop of this[1] view,
| which can be accessed in high res.
|
| You can find all the JWT images in full res on here[2].
|
| [1]: https://stsci-opo.org/STScI-01GCVNZ68YTC7FPTBSNA3QDGYW.png
|
| [2]: https://webbtelescope.org/resource-gallery/images
| dwringer wrote:
| Thanks for the links! I checked out the source image and it
| still appears to be 80 pixels high in the "full resolution
| for display" image, same as the article's crop. There is a
| "close up" view which shows Neptune as 300px high, but I
| can't resolve any detail that isn't in the 80 pixel version.
| I think this is as detailed as it gets based on the apparent
| size of Neptune and JWST's angular resolution.
| sbierwagen wrote:
| NIRCAM has a resolution of 0.031 arcsec per pixel, and
| Uranus is between 4.1 and 3.3 arcseconds wide as viewed
| from Earth, so it would only ever be between 132 and 106
| pixels wide.
|
| https://jwst-docs.stsci.edu/jwst-near-infrared-camera https
| ://nssdc.gsfc.nasa.gov/planetary/factsheet/uranusfact.h...
|
| If you want a higher resolution image, we'll either need a
| bigger telescope or a Uranus orbiter.
| [deleted]
| [deleted]
| mbauman wrote:
| Holy cow the whole field is so amazing. Galaxies everywhere!
| sizzzzlerz wrote:
| Those are the first things I look for in space images. If
| you haven't seen it, go find the Webb deep field image that
| they released a month or two ago. It will blow your mind!
| layer8 wrote:
| This seems to be the highest-res closeup:
| https://webbtelescope.org/contents/media/images/2022/046/01G...
| dwringer wrote:
| I think that's been upscaled, as it shows Neptune being over
| 300px in diameter. Unless I'm misinterpreting something (a
| distinct possibility), that would require an angular
| resolution of nearly 10x what the JWST is capable of. I don't
| know what kind of processing they applied to get it to that
| size but I can't resolve any detail in that closeup that
| isn't visible in the version where it's 80px. By my naive
| calculations (which I explain in another comment), Neptune
| should be about 30 pixels wide - is there anyone who can shed
| light on this mystery?
| [deleted]
| cletus wrote:
| I really hope to see a Cassini or Juno like probe to visit
| Neptune and Uranus in my lifetime.
|
| As good as JWST is and these images are, these objects are so
| distant the only high-res imagery you can get is by visiting
| them. Prior to New Horizons, our best image of Pluto, for
| example, was a few blurry pixels and that remained the case even
| until New Horizons was 99% of the way there.
| nkoren wrote:
| You may be in luck with Uranus:
| https://en.m.wikipedia.org/wiki/Uranus_Orbiter_and_Probe
| dylan604 wrote:
| I would say I'd like this for all the planets. What Cassini and
| Juno brought us is simply stunning. Some of the details visible
| in Jupiter's clouds or Saturn's rings have just been amazing.
|
| The images Voyagers and New Horizons brought are nice and not
| to be discounted, but fly-bys vs orbit insertion missions just
| not the same. We should have oribters parked around each of our
| local major bodies. We should then have rovers on all of the
| solid bodies (that won't melt the thing in mere hours) after
| that. The MRO is such a great example.
| WalterBright wrote:
| If I had Bill Gates' money, I'd be funding that.
| BurningFrog wrote:
| Elon is fixing the launch cost side of it.
|
| If you have a probe design process that doesn't go through
| the US congress, it should be substantially faster and
| cheaper.
| m3kw9 wrote:
| I'm wonder if they can miniaturize a camera and propulsion
| system enough that can travel fast enough to just take pics and
| bring them back instead of needing large antennas/power modules
| to transmit back in say a year or so?
| Sharlin wrote:
| You don't need a very high-powered radio if a) you have
| plenty of time to transmit the data back and b) you can
| afford to build large receiving telescopes back on Earth. The
| latter we already do have, although bigger the better, and
| the former is just a case of patience. _Galileo_ , famously,
| was unable to fully unfold its high-gain antenna and had to
| transmit everything via the much lower-bandwidth low-gain
| antenna. The ability to batch the probe software to use
| higher-efficiency data encoding and modulation meant this was
| not as disastrous as it could have been. This failure mode
| was also likely the reason that both _Cassini_ and _New
| Horizons_ opted for a more traditional rigid dish antenna.
| reggedtorespond wrote:
| It's like 12 years to get there and another 12 years to get
| back. Sending information back at the speed of light is
| preferable.
| nappy-doo wrote:
| No. It's very hard to go fast, and to get to Neptune, you
| need to burn a lot of fuel to get there. Getting home needs a
| whole lot more fuel too. Space travel is hard. You can go
| with lower energy transfer orbits, and wait forever to get
| there, or you can go high-speed and carry a ton of fuel with
| you.
| gpm wrote:
| If you plot your trajectory so that you will just slightly
| in front of neptune, shouldn't you be able to use it's
| gravity to slingshot you back towards the inner solar
| system?
|
| I'm skeptical that it's worth it... because higher powered
| radios just aren't that expensive, but it's not obviously
| (to me) impossible either.
|
| Actually _capturing_ your probe back in earth orbit...
| probably would be prohibitively expensive. But it seems
| like you could at least get it close by for a shorter
| communication distance.
| Sharlin wrote:
| At the speeds needed to reach the outer Solar System in
| the first place, you would need to intersect the planet's
| surface (atmosphere, whatever) to get anywhere near the
| slingshot effect needed to throw you back to where you
| came from. Essentially it would only be possible with a
| black hole or another anomalously dense object.
| eesmith wrote:
| Getting home requires no additional fuel if using a free-
| return trajectory and you don't want to be there for long.
|
| Jones, Drew Ryan, 2016, "Trajectories for flyby sample
| return at Saturn's moons",
| https://hdl.handle.net/2014/46163, Root, V1 at https://data
| verse.jpl.nasa.gov/file.xhtml?fileId=53873&versi...
|
| > Here an alternative and novel mission concept is analyzed
| to return a sample from either Titan or Enceladus, without
| capturing at Saturn. Instead, ballistic free return
| trajectories are sought which also incur a close encounter
| of the icy moon. The spacecraft could sample a plume (or
| upper atmosphere) during the hyperbolic flyby.
|
| The time frames are on the order of 20 years.
|
| OTOH, you would only have a few dozen hours near the
| planet. ("This 16 year mission, has the Titan flyby
| occurring about 10 hours prior to Saturn closest
| approach").
| jackmott42 wrote:
| The mass to get the ship back and land safely is probably
| more than the antenna
| guhidalg wrote:
| For a second I thought this was Saturn and said "don't we have
| better images of this?" Then I actually read it's Neptune and
| realized all our good images of it come from probes. It's crazy
| JWST can just see the rings and the moons, incredible
| observatory.
| anigbrowl wrote:
| My understanding is that this isn't even the 'good' camera,
| just the comparatively low-resolution infrared one.
| adastra22 wrote:
| JWST is meant to see in infrared. That's it's good (only?)
| camera.
| NHQ wrote:
| Those don't look like rings to me!
| WalterBright wrote:
| That's no moon!
| aero-glide2 wrote:
| Its a pity we don't already have an orbiter around every planet!
| anigbrowl wrote:
| Now that we have this wonderful tool, I really hope astronomers
| will dedicate 1 week of each year or one day of each month
| (depending on what orbits allow/make worthwhile) imaging bodies
| in our own solar system. I think it's a crime that this is the
| first new image of Neptune in _30 years_.
|
| Every advance in astronomical equipment or technique gives the
| lie to 'we already know about X, it's not that interesting'
| arguments. Longitudinal observation of our nearest neighbors are
| likely to significantly increase our knowledge, and these are the
| only bodies that are accessible to us barring some massive
| revolution in physics.
| WalterBright wrote:
| There was a recent HN thread where I pontificated that a twin
| JW telescope could have been built and launched at 10% of the
| cost of #1. One of the (vehement) arguments against this was
| there weren't enough things to look at.
|
| I just have to shake my head in amazement.
| Sharlin wrote:
| I wonder why you were downvoted. It's absolutely certain that
| all the big telescopes get way more proposals than there is
| available observation time. And not all the proposals that
| get rejected are of low quality.
| WalterBright wrote:
| Everywhere the JW scope points, even at areas thought to
| contain nothing, a lot is discovered. Given that it looks
| at the sky through a soda straw, there's no way that one
| machine could survey the universe. A fleet of them would be
| needed.
| layer8 wrote:
| > the first new image of Neptune in 30 years.
|
| In Neptune years, it's less than a fifth of a year. ;)
| cl42 wrote:
| This isn't the first new image of Neptune in the last 30 years.
| Astronomers have imaged Neptune since Voyager, and the Hubble
| Space Telescope was used for this as well. See here:
| https://hubblesite.org/contents/media/images/2021/047/01FM0Q...
| anigbrowl wrote:
| Thanks, I misread something on the NASA page. But still, I'd
| like more emphasis on studying reachable heavenly bodies even
| if it slightly delays our speculation into more distant ones.
| floxy wrote:
| Here are images of Neptune taken by Hubble last year:
|
| https://esahubble.org/images/heic2113e/
|
| from 2020:
|
| https://www.nasa.gov/feature/goddard/2020/dark-storm-on-nept...
|
| from 2018:
|
| https://www.nasa.gov/feature/goddard/2019/hubble-reveals-dyn...
|
| 2016:
|
| https://www.nasa.gov/image-feature/hubble-sees-new-dark-spot...
|
| 2013:
|
| https://esahubble.org/images/opo1330c/
|
| 2011:
|
| https://www.nasa.gov/mission_pages/hubble/multimedia/hubble-...
|
| If you are more interested in images from ground based
| telescopes, here is Neptune from 2018 taken with the ESA Very
| Large Telescope:
|
| https://solarsystem.nasa.gov/resources/936/neptune-from-the-...
| smegsicle wrote:
| those pictures suck though
| Sharlin wrote:
| Solar system observations are a explicitly included in the
| JWST's list of use cases, and observation time is allocated via
| the normal proposal process. I'm sure we'll see more pictures
| of solar system objects, even though obviously observations
| will always be science first, public relations second.
| iza wrote:
| Also posted here: https://news.ycombinator.com/item?id=32926283
| dang wrote:
| Thanks! I think we'll merge that thread hither since this one
| has the original source.
|
| (" _Please submit the original source. If a post reports on
| something found on another site, submit the latter._ " -
| https://news.ycombinator.com/newsguidelines.html)
| causi wrote:
| JWST's infrared capability is good at showing previously
| invisible details but I find it very odd its images keep looking
| like they're lower resolution and less detailed in the visual
| spectrum than Hubble images. I realize the observation times are
| shorter but jeez the JWST photo of Jupiter was garbage compared
| to a telescope that launched 32 years ago.
| b203 wrote:
| Roughly the angular reolution of a telescope is
| 1.22*wavelength/diameter. See
| https://en.wikipedia.org/wiki/Angular_resolution. Hubble uses
| visual light (0.5 um wavelength) while JWST uses IR (5 um
| wavelength) and beyond. So the wavelength for JWST is 10x
| larger than Hibble, but the diameter is only ~2.7X (Hubble 2.4m
| vs JWST 6.5m dia). So JWST resolution is 1.8x worse than
| Hubble.
| donatj wrote:
| This has been my general feeling, that the JWST photos are less
| visually interesting/detailed than even Hubble photos. I'm sure
| they have a ton of invisible data that scientists find
| invaluable, but they have thus far been largely visually
| unimpressive.
| adgjlsfhk1 wrote:
| IMO, the JWST deep field is really impressive. There are
| something like 4x more galaxies in the background that just
| were invisible in Hubble due to redshift. JWST is heavily
| optimized for spectra, far away objects, and looking through
| gas clouds. For other stuff, you're probably better off using
| giant ground based telescopes.
| mixmastamyk wrote:
| It's a near infrared telescope, on purpose. Not optimized for
| non-receding objects.
| sbierwagen wrote:
| The more spectacular Hubble photos are mosaics assembled from
| weeks or months of observation time. JWST is brand new and
| has been spending most of its time doing science observations
| rather than images for the press office. Give it a few years.
| BurningFrog wrote:
| Sure, but you can't usefully observe Jupiter for that long,
| since it rotates.
| ck2 wrote:
| I love there are technical documents for each of the cameras:
|
| https://www.stsci.edu/jwst/instrumentation/instruments
|
| https://jwst-docs.stsci.edu/jwst-near-infrared-camera
|
| (still trying to find the megapixels)
|
| aha Pixels 8 x 2040 x 2040 pixels
| Pixel scale 0.031"/pixel
| KerryJones wrote:
| Love everything coming out of James Webb telescope
| Victerius wrote:
| I hope to see pictures in real color later, if not with my own
| eyes. I'd be down for a 2 year round trip to Neptune.
| spaetzleesser wrote:
| 2years is a little optimistic.
|
| I wonder how dark it would be out there if you saw it with your
| own eyes. I would guess it's pretty dark.
| fshbbdssbbgdd wrote:
| The eyes have impressive dynamic range.
|
| Moonlight is 250000x dimmer than sunlight, but you can still
| see things illuminated by moonlight once your eyes adjust.
|
| Neptune is 29 AU from the Sun, so by inverse square law, the
| sunlight is 29^2=840x dimmer on Neptune than Earth.
| Visibility should be decent out there. Neptune will stand out
| pretty well against the perfect blackness of space.
| gpm wrote:
| > perfect blackness of space.
|
| Eyes dynamic range is good enough that the "background"
| isn't black either, consider the view of the night sky from
| outside a city.
| fshbbdssbbgdd wrote:
| I figure the diffuse glow up there is light being
| reflected around by the atmosphere, which isn't present
| in most of the solar system.
| gpm wrote:
| Hmm, I've always figured it's a bit of eyes blurring
| "bright" lights (the stars you can see), and a bit that
| there are lots of really dim stars that you can't really
| see, but add in some light.
|
| I don't actually know though.
| nicoburns wrote:
| > lots of really dim eyes
|
| Think you got your nouns mixed up there ;)
| gpm wrote:
| Oops, fixed, thanks :)
| trentnix wrote:
| 2 year trip? At that speed, you'd zip by faster than the
| Griswold family vacationed at the Grand Canyon.
|
| We should have something orbiting Neptune or at least on its
| way. I'll be a very old man before anything could get there if
| we want to put something orbit (if I'm not already gone by
| then).
| svnpenn wrote:
| Whenever I think of Neptune, I think of this image:
|
| https://commons.wikimedia.org/wiki/File:Neptune_Full.jpg
|
| This was taken in 1989 by Voyager 2, now 33 years ago. Voyager 2
| remains the only spacecraft to have visited either of the ice
| giant planets.
| adolph wrote:
| 3 cheers for NASA!
|
| I'm amazed by the below UI to show how Neptune's orbit at 30AU is
| proportionately farther from Jupiter (5.2 AU) than Jupyter is to
| Earth.
|
| https://solarsystem.nasa.gov/planets/overview/
| sylware wrote:
| can we get a noscript/basic (x)html link?
| jakzurr wrote:
| https://www.nasa.gov/sites/default/files/for_nasa.gov_imagea...
|
| https://www.nasa.gov/sites/default/files/for_stsci_site_imag...
|
| But really, it's a NASA site, it's probably safe w/o noscript
| (ie, disable restrictions for tab). Or, you can just
| individually enable permanently: nasa.gov; digitalgov.gov;
| foresee.com; gstatic.com; youtube.com (is what makes it work
| for me).
| cwillu wrote:
| "Webb also captured seven of Neptune's 14 known moons. Dominating
| this Webb portrait of Neptune is a very bright point of light
| sporting the signature diffraction spikes seen in many of Webb's
| images, but this is not a star. Rather, this is Neptune's large
| and unusual moon, Triton.
|
| Covered in a frozen sheen of condensed nitrogen, Triton reflects
| an average of 70 percent of the sunlight that hits it. It far
| outshines Neptune in this image because the planet's atmosphere
| is darkened by methane absorption at these near-infrared
| wavelengths. Triton orbits Neptune in an unusual backward
| (retrograde) orbit, leading astronomers to speculate that this
| moon was originally a Kuiper belt object that was gravitationally
| captured by Neptune. Additional Webb studies of both Triton and
| Neptune are planned in the coming year"
| PointyFluff wrote:
| edm0nd wrote:
| We can do both at the same time though.
| brianpan wrote:
| Ah, an optimist! :D
| kloch wrote:
| Have they released any images of the galactic center yet?
| nuccy wrote:
| The galactic center image won't be as fancy, unfortunately.
| Resolution of Webb is far-far-far too low to see anything
| related to the black hole, the best we could do is enhance the
| view of the stars near Sgr A* [1].
|
| 1. https://www.eso.org/public/videos/eso0226a/
| nuccy wrote:
| Webb resolution is about 0.1 arc-seconds (wavelength
| dependent) [1]. Event Horizon Telescope (EHT) resolution is
| about 25 micro arc-seconds (wavelength dependent) [2].
|
| So roughly speaking, since you cannot really compare the two,
| since they observe on quite different wavelengths, EHT has
| ~4000 times better resolution than Webb. Note that we don't
| speak about sensitivity here. ALMA array of radio telescopes
| has a collecting area of 7000 m2, while it is just one of
| many "nodes" of the EHT. Webb total collecting area is about
| 25 m2.
|
| 1.
| https://www.jwst.nasa.gov/content/about/faqs/faq.html#sharp
|
| 2. https://eventhorizontelescope.org/technology
| kloch wrote:
| Understood, but it still would be very interesting to see the
| area with JWST's full range of instruments.
| toastedwedge wrote:
| I imagine that, along with any data for TRAPPIST, is on the
| [very long] list of things to do. Otherwise I'm sure it'd be
| posted here in no time
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(page generated 2022-09-21 23:00 UTC)