New Webb image captures clearest view of Neptune’s rings in decades
nasa.gov
nasa.gov
Tomorrow (23rd) marks the 176th anniversary of the discovery of Neptune (~ 1.07 years on Neptune; 164.8 Earth years).
Johann Gottfried Galle an astronomer at the Berlin observatory found Neptune at the behest of Urbain Le Verrier who calculated its position by hypothesizing that some body must perturb Uranus orbit to explain the distinct deviation from the predicted motion by Newton's law of universal gravitation.
Le Verrier couldn't find a single French astronomer willing to take a look out at the sky after presenting his extensive calculations to the French Academy on 31 August. On 18 September he then wrote a letter to the German astronomer Galle at the Berlin observatory.
After receiving the letter 5 days later Galle immediately set up his telescope the same night and found a +8 mag star (within 1 degree of the Le Verrier's calculation) not listed on the official Prussian star chart. The next night he managed to measure the star itself moving by 4 arcseconds, finally confirming Le Verrier prediction of a new planet (and to this day last).
At ~30 AU (30x the distance sun-earth; Uranus being at ~20 AU) the discovery instantaneously made the solar system 1.5x bigger ;)
The follow up (correct me on the details here) is that they later measured Mercury’s orbit to a high precision, estimated that some body was disturbing Mercury’s orbit, and went looking again to repeat Sir Isaac’s miraculous math. But… nothing was there. It turned out Mercury orbits at relativistic speeds and Newton’s model wasn’t taking that into account.
Vaguely remember this from Kuhn’s Structure of Scientific Revolutions
In the case of Neptune, Le Verrier hit the nail right on its head (where others suggested a limit to Newton's theory of gravity). This tremendous feat gave him all the reason to search for other perturbations around the sky to find unknown objects.
So, by 1859 he was the first to find Mercury not completely adhering to Newtonian mechanics (anomalous rate of precession of the perihelion[0]), therefore he postulated smaller unseen objects in its vicinity, even naming a possible planet Vulcan.
But there, he was wrong and Newton's law really hit a limit here at such proximity to the sun.
Ironically not at "long distances" as suggested in the anomaly of Uranus' orbit. Also, Einstein within his GR framework correctly predicted the value of deflection of "starlight passing very close to the sun" in 1915 which was validated by the measurements of Eddington taking advantage of a total eclipse in 1919 --- a natural occurring coronagraph (a big moon) of the Sun from Earth's view ;)
P.S.: I forgot to mention D'Arrest[1] role in finding Neptune in the sky:
> While still a student at the University of Berlin, d'Arrest was party to Johann Gottfried Galle's search for Neptune. On 23 September 1846, he suggested that a recently drawn chart of the sky, in the region of Urbain Le Verrier's predicted location, could be compared with the current sky to seek the displacement characteristic of a planet, as opposed to a stationary star.
[0]https://en.m.wikipedia.org/wiki/Tests_of_general_relativity#...
[1]https://en.m.wikipedia.org/wiki/Heinrich_Louis_d%27Arrest#Bi...
Meanwhile, my same country mail takes up to 2 weeks to arrive. No wonder I'm not making any ground breaking advances.
But, yes - if you will - the area of the solar system consequently has more than doubled; which has nicer ring to it :)
To be exact if my numbers are correct:
πab = πa² √(1-e²)
Uranus (a = 19.19126 AU; e = 0.04717)
⇒ ~ 1155.755 AU²
Neptune (a = 30.07 AU; e = 0.008678 (what a neat circle!))
⇒ ~ 2840.54 AU²
i.e. approx. 2.46x the former area
> 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!
I originally thought it was a star
It looks like that's comparable to fresh snow or a glacier?
[1]https://earthobservatory.nasa.gov/features/DirtySnow/page2.p...
> "At a depth of 7,000 km, the conditions may be such that methane decomposes into diamond crystals that rain downwards like hailstones.... the top of the mantle may be an ocean of liquid carbon with floating solid 'diamonds'."
This image is from NIRCAM, so it's the highest res Webb can do. Neptune is small in the image because it's very far away. The images you see of detailed nebulae are so high res because, even though they're further away, those nebulae are enormous.
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.
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.
If you have a probe design process that doesn't go through the US congress, it should be substantially faster and cheaper.
Those that have no competition inevitably end up there.
https://www.esa.int/Science_Exploration/Space_Science/Rosett...
Launch: 2 March 2004
Mission end: 30 September 2016
Then, a bit lower on the page: 786 days in space
Huh? Anyone got insights on what type of math was used here? Is there mm/inch type conversion problem? Am I just dumb? 12 years * 365 > 786.
Jones, Drew Ryan, 2016, "Trajectories for flyby sample return at Saturn's moons", https://hdl.handle.net/2014/46163, Root, V1 at https://dataverse.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").
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.
Getting a probe like New Horizons to do a flyby requires a massive rocket. But to also have it be capable of slowing down to enter orbit and stick around means either it was moving slower on it's path to get there (so it takes a lot longer) or it has to carry a huge amount of fuel to burn to slow down (so it takes an even bigger rocket).
Neither option is great.
Pluto obviously was a fly-by. There were several reasons for this. Distance is a big one. Also, the more distant planets are the lower their orbital velocity. More distance = longer travel time. A higher velocity can reduce the travel time but you need to speed up at launch and slow down on arrival and that requires a higher delta-V budget. That requires extra mass of fuel, which becomes a vicious circle.
Pluto is tiny and far so a fly-by was really the only option. Even then it took 10 years to get there.
Neptune is more massive, closer and heavier. All of these help but if I'm reading [1] correctly, you'd still be realistically looking at a 30 year travel time for an insertion orbit. Having instruments hibernate for that long and work on the other end is really the biggest problem.
We're entering an era of super-heavy lifters. Maybe these will meaningfully increase the practical delta-V budgets.
Inserting a probe into orbit around Uranus (let alone Neptune) seems currently impractical just given how long it would take but that doesn't make me want it any less. Even a fly-by is better than nothing.
But the delta-V for Saturn, Uranus and Neptune are all roughly the same
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”
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.
In Neptune years, it’s less than a fifth of a 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-...
I just have to shake my head in amazement.
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 × 2040 × 2040 pixels
Pixel scale 0.031"/pixelhttps://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.
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).
I wonder how dark it would be out there if you saw it with your own eyes. I would guess it’s pretty dark.
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.
Eyes dynamic range is good enough that the "background" isn't black either, consider the view of the night sky from outside a city.
I don't actually know though.
Think you got your nouns mixed up there ;)
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.
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...
You can find all the JWT images in full res on here[2].
[1]: https://stsci-opo.org/STScI-01GCVNZ68YTC7FPTBSNA3QDGYW.png
The debate of "do other galaxies even exist?" wasn't definitively settled until 1923, 99 years ago, with Edwin Hubble's observations of Cepheids in Andromeda.
Now, you can just, like, look at them. (With a good telescope.) Every single place you look.
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.
("Please submit the original source. If a post reports on something found on another site, submit the latter." - https://news.ycombinator.com/newsguidelines.html)
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
And when I view source on that black screen it's all external JS calls. There are no img or href tags of HTML I can find that contain the images.
More likely though that this user just does what any fanboy does - spew FUD on the "other side".
If you now further discuss Android camera quality, you'd just be off-topic.
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).
Thx for the links though.