James Webb Space Telescope reveals Fomalhaut's disk in detail(skyandtelescope.org)
skyandtelescope.org
James Webb Space Telescope reveals Fomalhaut's disk in detail
https://skyandtelescope.org/astronomy-news/the-james-webb-space-telescope-reveals-fomalhauts-disk-in-unprecedented-detail/
24 comments
Comparing diameter to radius is a little misleading, the ring is actually closer than Voyager, at 120 AU. On the same scale, Pluto is 78 AU and Voyager is 320 AU.
> Comparing diameter to radius is a little misleading
Nah. It is comparing a distance with a distance.
Besides I assume more people reading my comment are familiar with the concepts of radius/diameter than the meaning of astronomical units. But now, thanks for your clarification, even the geometrically challenged will have the correct mental model. You never know.
> On the same scale, Pluto is 78 AU and Voyager is 320 AU.
Have to disagree. You take your pocket tape measure, carefully hook the end of the tape on the Sun and slowly walk to Pluto. You read what it says. That is a distance.
Then you walk to the disk, hook one end of the tape on one side (carefully, since it is made of dust) and walk to the other side. That is a distance.
Where do I hook my tape measure to measure 78 AU for Pluto? Orbits are not real. You cannot kick them, you cannot lick them, you cannot hook a tape measure on them.
“See where that planet is? Now imagine how far it will be in 124[1] years in a sun fixed coordinate system!” does not quite have the same impact on me as “See that blob? It is huuuge!”
Doubling the number with Voyager makes even less sense. You cannot even say that you are measuring the antipodal points of its orbit, since it is not orbiting the Sun. So the “diameter” of what are you even talking about there?
1: half of Pluto’s orbital period.
Nah. It is comparing a distance with a distance.
Besides I assume more people reading my comment are familiar with the concepts of radius/diameter than the meaning of astronomical units. But now, thanks for your clarification, even the geometrically challenged will have the correct mental model. You never know.
> On the same scale, Pluto is 78 AU and Voyager is 320 AU.
Have to disagree. You take your pocket tape measure, carefully hook the end of the tape on the Sun and slowly walk to Pluto. You read what it says. That is a distance.
Then you walk to the disk, hook one end of the tape on one side (carefully, since it is made of dust) and walk to the other side. That is a distance.
Where do I hook my tape measure to measure 78 AU for Pluto? Orbits are not real. You cannot kick them, you cannot lick them, you cannot hook a tape measure on them.
“See where that planet is? Now imagine how far it will be in 124[1] years in a sun fixed coordinate system!” does not quite have the same impact on me as “See that blob? It is huuuge!”
Doubling the number with Voyager makes even less sense. You cannot even say that you are measuring the antipodal points of its orbit, since it is not orbiting the Sun. So the “diameter” of what are you even talking about there?
1: half of Pluto’s orbital period.
> Have to disagree. You take your pocket tape measure, carefully hook the end of the tape on the Sun and slowly walk to Pluto. You read what it says. That is a distance.
By that measure then, you carefully hook your tape measure to Fomalhaut and slowly walk out to the outer ring, whereupon your ancient eyes perceive the distance to be 120 AU, not 240 AU (since 240 AU is the diameter). A given rock in the outer ring is therefore less distant from Fomalhaut than Voyager is from the Sun.
That's all the parent is saying, and I agree with them - I, too, know the difference between radius and diameter but a quick read of your comment left me thinking that Fomalhaut's outer ring is orbiting further away from Fomalhaut than Voyager is from the Sun.
It's clearer to compare a radius to a radius, is all.
By that measure then, you carefully hook your tape measure to Fomalhaut and slowly walk out to the outer ring, whereupon your ancient eyes perceive the distance to be 120 AU, not 240 AU (since 240 AU is the diameter). A given rock in the outer ring is therefore less distant from Fomalhaut than Voyager is from the Sun.
That's all the parent is saying, and I agree with them - I, too, know the difference between radius and diameter but a quick read of your comment left me thinking that Fomalhaut's outer ring is orbiting further away from Fomalhaut than Voyager is from the Sun.
It's clearer to compare a radius to a radius, is all.
>It's clearer to compare a radius to a radius, is all.
The OP wasn't comparing a diameter to a radius, he was comparing one line to another line: the diameter of the outer ring (line going from one end to the other passing through the middle) and the distance between Pluto and the Sun (line between two points). The fact that Pluto orbits the Sun is just a coincidence for the purposes of this comparison.
The OP wasn't comparing a diameter to a radius, he was comparing one line to another line: the diameter of the outer ring (line going from one end to the other passing through the middle) and the distance between Pluto and the Sun (line between two points). The fact that Pluto orbits the Sun is just a coincidence for the purposes of this comparison.
The "Sun-Pluto distance" is colloquially understood as both of those things - a distance in a straight line right now, and the radius of its orbit on average. I think it's far more common for people to assume the latter as I did, but feel free to ask around and find out for yourself. Note that the instantaneous Sun-Pluto distance varies considerably due to the eccentricity of its orbit, and the distance OP quoted is the orbital semi-major axis (what one might refer to as the orbital radius for the sake of brevity), not the present distance.
OP was mathematically correct, just a bit unclear. We really don't need to spend so much time on this.
OP was mathematically correct, just a bit unclear. We really don't need to spend so much time on this.
I guess we have a different understanding of the word “diameter.”
FTFA, quoted by you above: “The outer ring is about 240 astronomical units in diameter.”
Pluto’s orbit is 60-98 AU in diameter. Voyager 1, if it were orbiting the sun, would have an orbital diameter of 320 AU.
FTFA, quoted by you above: “The outer ring is about 240 astronomical units in diameter.”
Pluto’s orbit is 60-98 AU in diameter. Voyager 1, if it were orbiting the sun, would have an orbital diameter of 320 AU.
No one cares about a factor of two in astronomy.
It's true - the Universe is 13.7 or 27.4 billion years old, whatever.
It's interesting that there's potentially a bit of a pattern forming with the stars we've observed, with an outer belt being around 10x the diameter of an inner belt.
Though out of fashion, the various power laws of Bragg, Richardson, Armellini building on the Titius–Bode rule come to mind, namely that there may be physical reasons to see orbital patterns emerge consistent with some sort of power law.
Below data includes candidate planets/disks still being verified.
Our Sun: - Mass 1 M - Inner Planets: 0.39 AU to 1.52 AU - Inner Disk (Asteroid Belt): 2.1-3.2 AU - Gas Giants: 5.2 AU to 30.06 AU - Outer Disk (Kuiper Belt): 30-55 AU
Formalhaut: - Mass: 1.92 M - Hot Disks: 0.21 AU to 1.08 AU - Inner Disk: Around 8-12 AU - Outer Disk: Previously around 133-158 AU but now suggesting around 120 AU? (Surrounded by a larger halo)
Vega - Mass: 2.135 M - Planet: 0.05 AU - Inner Disk: Around 8 AU - Outer Disk: Around 80-120 AU (Surrounded by a larger dust halo)
Epsilon Eridani: - Mass: 0.82 M - Inner Disk: Around 3 AU - Planet: 3.48 AU - Potential Additional Disk: Around 8-20 AU (and may revise inner disk & planet) - Planet: 40 AU - Outer Disk: Around 35-75 AU
Proxima Centauri - Mass: 0.1221 M - Planets: 0.03 - 0.05 AU - Hot Disk: 0.4 AU - Inner Disk: 1-4 AU - Planet: 1.5 AU - Outer Disk: 30 AU
HR 8799 - Mass: 1.43 M - Inner Disk: Less than 16 AU - Planets: 16.25 AU, 26.67 AU, 41.39 AU, 71.6 AU - Outer Disk: 135-360 AU
Beta Pictoris - Mass: 1.75 M - Planet: 2.7 AU - Inner Disk: 6.4 AU - Planet: 10 AU + Potential Planetary Belts: 14/16, 28/30, 52, 82 AU - Outer Disk: 130 AU (Surrounded by a larger disk/halo)
55 Cancri - Mass: 0.905 M - Planets: 0.01-0.7 AU - Speculated Planets: 0.9-3.8 AU - Planet: 5.9 AU - Disk: Around 40 AU (Would be interesting if a second disk around 4 AU)
Tau Ceti - Mass: 0.783 M - Planets: 0.1-1.334 AU - Planet: 3-20 AU - Disk: 35-50 AU (Would be interesting if a second disk around 3-5 AU)
Though out of fashion, the various power laws of Bragg, Richardson, Armellini building on the Titius–Bode rule come to mind, namely that there may be physical reasons to see orbital patterns emerge consistent with some sort of power law.
Below data includes candidate planets/disks still being verified.
Our Sun: - Mass 1 M - Inner Planets: 0.39 AU to 1.52 AU - Inner Disk (Asteroid Belt): 2.1-3.2 AU - Gas Giants: 5.2 AU to 30.06 AU - Outer Disk (Kuiper Belt): 30-55 AU
Formalhaut: - Mass: 1.92 M - Hot Disks: 0.21 AU to 1.08 AU - Inner Disk: Around 8-12 AU - Outer Disk: Previously around 133-158 AU but now suggesting around 120 AU? (Surrounded by a larger halo)
Vega - Mass: 2.135 M - Planet: 0.05 AU - Inner Disk: Around 8 AU - Outer Disk: Around 80-120 AU (Surrounded by a larger dust halo)
Epsilon Eridani: - Mass: 0.82 M - Inner Disk: Around 3 AU - Planet: 3.48 AU - Potential Additional Disk: Around 8-20 AU (and may revise inner disk & planet) - Planet: 40 AU - Outer Disk: Around 35-75 AU
Proxima Centauri - Mass: 0.1221 M - Planets: 0.03 - 0.05 AU - Hot Disk: 0.4 AU - Inner Disk: 1-4 AU - Planet: 1.5 AU - Outer Disk: 30 AU
HR 8799 - Mass: 1.43 M - Inner Disk: Less than 16 AU - Planets: 16.25 AU, 26.67 AU, 41.39 AU, 71.6 AU - Outer Disk: 135-360 AU
Beta Pictoris - Mass: 1.75 M - Planet: 2.7 AU - Inner Disk: 6.4 AU - Planet: 10 AU + Potential Planetary Belts: 14/16, 28/30, 52, 82 AU - Outer Disk: 130 AU (Surrounded by a larger disk/halo)
55 Cancri - Mass: 0.905 M - Planets: 0.01-0.7 AU - Speculated Planets: 0.9-3.8 AU - Planet: 5.9 AU - Disk: Around 40 AU (Would be interesting if a second disk around 4 AU)
Tau Ceti - Mass: 0.783 M - Planets: 0.1-1.334 AU - Planet: 3-20 AU - Disk: 35-50 AU (Would be interesting if a second disk around 3-5 AU)
What's interesting is if you express 1 AU as "8 light minutes" it doesn't sound so far away, but of course it is.
(240 AU is 32 light hours)
(240 AU is 32 light hours)
> One astronomical unit (AU) is (roughly) the Earth-Sun distance.
I guess that's just one of those cosmic coincidences.
I guess that's just one of those cosmic coincidences.
Anyone know what the black blob in the center is? It's conspicuously left out of the labeled diagram, and doesn't seem mentioned in the article either. I imagine it's the central sun in question, but isn't it odd to never mention it?
That's the coronagraph that blocks out the star itself so that everything else is visible.
https://blogs.nasa.gov/webb/2023/03/24/how-webbs-coronagraph...
https://blogs.nasa.gov/webb/2023/03/24/how-webbs-coronagraph...
There has been a lot of confusion about this but it is actually overexposed pixels deleted in software. From the lead author of the paper:
https://twitter.com/AndrasGaspar/status/1655680076103716878
https://twitter.com/AndrasGaspar/status/1655680076103716878
To be clear, they were using the coronagraph: https://arxiv.org/pdf/2305.03789.pdf
>The 23.0 µm coronagraph of MIRI uses a classic Lyot mask to achieve high contrast imaging near bright sources. The mask is rather large, providing an inner working angle (IWA) of ∼ 3.3λ/D, i.e., ∼ 2. Our data is the first complete reference PSF subtracted set of observations taken with JWST using this mode.
There's some residual light and diffraction effects around the Lyot mask which they have manually deleted.
>The 23.0 µm coronagraph of MIRI uses a classic Lyot mask to achieve high contrast imaging near bright sources. The mask is rather large, providing an inner working angle (IWA) of ∼ 3.3λ/D, i.e., ∼ 2. Our data is the first complete reference PSF subtracted set of observations taken with JWST using this mode.
There's some residual light and diffraction effects around the Lyot mask which they have manually deleted.
Some images used a mask and some did not. The 25.5 micron image at the top of the article is one that did not use a mask.
Why make overexposed pixels black instead of white? Just to make it extra clear that the pixel data exceeding overexposure threshold is not mistaken for valid data?
> Just to make it extra clear that the pixel data exceeding overexposure threshold is not mistaken for valid data?
Saturated pixels are not necessarily "invalid" the way cosmic ray bit flips and stuck pixels are, but setting them to zero does make the other bright but not saturated pixels much easier to identify.
Saturated pixels are not necessarily "invalid" the way cosmic ray bit flips and stuck pixels are, but setting them to zero does make the other bright but not saturated pixels much easier to identify.
Does the precise line dividing "bright but just barely not saturated" from "bright and saturated" actually matter?
Yes, because a saturated pixel might be 101% full scale, but it might also be a hundred million percent and you have no way to know. The same reason that a camera might substitute zebra stripes or a bright colour for a blown highlight in a preview as opposed to just making it white.
When using a coronagraph, it's possible that that value is all over the place (diffraction around edges, noise, etc) but you know any data "under" the coronagraph is bogus and you know which pixels are covered, because you know how the device was made, so you can mark them as bogus yourself.
The actual value in the data isn't black (0,0,0), it'll be some obviously special value that won't otherwise happen, because black is a valid value.
I suppose the idea that not-misleading data trumps aesthetically-pleasing data continues then to the press release image, even though a solid white central spot would look more familiar to people who have accidentally included the sun in a photo.
When using a coronagraph, it's possible that that value is all over the place (diffraction around edges, noise, etc) but you know any data "under" the coronagraph is bogus and you know which pixels are covered, because you know how the device was made, so you can mark them as bogus yourself.
The actual value in the data isn't black (0,0,0), it'll be some obviously special value that won't otherwise happen, because black is a valid value.
I suppose the idea that not-misleading data trumps aesthetically-pleasing data continues then to the press release image, even though a solid white central spot would look more familiar to people who have accidentally included the sun in a photo.
Additional bits of information? You cannot see what shape is that area if it is surrounded with a light yellow and you will miss some info if you'll do it after JPEG conversion.
I'm baffled as well. I think it's fairly understood that any white pixel is always understood to be probably overexposed.
Astronomy often also deals with wide ranges of pixel exposure such that it can be hard to tell the difference between overexposed and "brighter than the max on the color scale". Better to be extra clear and remove all doubt.
Because that’s what the person who was dealing with the data did
Any idea why it's not a perfect circle? Aberration in focus? And would that be pretty much equivalent to the true size of the star's corona? (seems huge..)
What's odd is even when downloading the full res image, the central colors are decidedly not all #000. There is a faint yet distinct radial gradient. It does not appear to be a compression artifact (format is png anyways).
images released to the press sometimes get another, um, aesthetic pass. I bet if you could get ahold of the actual image file it would have the proper sentinel sentinel value (if they're still using fits files it'd be something ridiculous like -9999.)
Black Hole Sun? There was a camera that "suffered" this problem, but can't remember the model to look it up.
Film in general used to "solarize" in some situations, which would turn some over-exposed areas black.
Maybe, but there was a specific video camera that would do this which earned the black hole sun moniker that I was thinking of. I want to say it was in the DV era, but I was never a connoisseur of that format so it was all just fuzzy memory from hearing/reading about it. I do remember looking at DV shooters with side-eye jealousy at their tiny camcorders while I was heaving full sized broadcast cameras on my shoulder.
An mspaint.exe adjustment
Thanks.
Silly me for believing NASA.
Silly me for believing NASA.
Redacted by the CIA, because it contains evidence of extraterrestrial life.
The most stunning and accessible comparison between Hubble and James Webb for me is still the pillars of creation images. A few weeks ago I was in the planetarium at the U.S. Space & Rocket Center in Huntsville where they faded from the Hubble image into the James Webb image. That was truly a sight to behold. In general the presentation there was one of the best I have ever seen.
Edit: I think this video is exactly what they showed. Of course, in this case the bigger your monitor the better. https://youtu.be/f8q8ZIXf_Rw?t=67
Edit: I think this video is exactly what they showed. Of course, in this case the bigger your monitor the better. https://youtu.be/f8q8ZIXf_Rw?t=67
That is wonderful - all those stars! Oh for a warp-capable spaceship and a lifetime to explore.
Years ago, for my Impacts Project, a scientific illustrator created a similar image (page 7):
https://impacts.to/downloads/lowres/impacts.pdf#page=7
The middle of the disc has our star having burned away everything close by, leaving an empty area behind, which the JWST cannot show because of the blindingly bright star. Each of the rings in the illustration represents paths for our rocky planets (yet to have fully formed).
https://impacts.to/downloads/lowres/impacts.pdf#page=7
The middle of the disc has our star having burned away everything close by, leaving an empty area behind, which the JWST cannot show because of the blindingly bright star. Each of the rings in the illustration represents paths for our rocky planets (yet to have fully formed).
Incredible, my kids will love this..! Thanks!
Thanks! The illustrators did an incredible job and the physical book itself is in lay flat format.
https://impacts.to/
Here's the book's bibliography, in case you're wondering about the science:
https://impacts.to/bibliography.pdf
https://impacts.to/
Here's the book's bibliography, in case you're wondering about the science:
https://impacts.to/bibliography.pdf
Care to name your illustrators? I love the work they have done.
EDIT: nevermind, they are listed here: https://impacts.to/credit.html
EDIT: nevermind, they are listed here: https://impacts.to/credit.html
Just think what space telescopes will be like if the Starship reduces cost/kg to orbit to 1/10th or less of Falcon 9's already low cost. They'd get very big, and it would likely make sense to assemble and maintain them in space by workers in space suits. It might even make sense to have telescopes in high Earth orbit with a maintenance station located nearby.
Webb isn't in an earth orbit though, it's at a Lagrange point that humans have never visited, and it's there because that's where it can get the best images. I don't think Starship can even get there at all without orbital refueling.
Sure, and it's also there because there was no plan to ever repair or service it. And that was because as it was being planned, launch was very expensive, so no satellite beyond LEO (where it could not be, for heating reasons) could reasonably be serviced.
That's not the main reason. Webb is viewing wavelengths where it has better viewing by being that distance away from the Earth. Putting Webb in similar Hubble orbit would diminish its abilities. If you want to build bigger visible wavelength platforms, then this might be a discussion to have with Starship capabilities.
WISE was another infrared telescope but in a low-ish Earth orbit (480km).
Putting it at L2 gives a more consistent thermal environment and means it doesn't have to repoint as often, but doesn't really make it any cooler. (After all, it's just barely past the Earth) At equilibrium the hot side of the Webb is around 300K. (80F)
Putting it at L2 gives a more consistent thermal environment and means it doesn't have to repoint as often, but doesn't really make it any cooler. (After all, it's just barely past the Earth) At equilibrium the hot side of the Webb is around 300K. (80F)
Yes, and it has better viewing at that distance because close to Earth, thermal radiation from the Earth would make it too warm.
But why is it at the Lagrange point in the first place? Wouldn’t ultra-high orbit be equally enough?
Because it is an infrared telescope, and in earth orbit there are three very bright infrared sources that would mess up the instruments or heat up the telescope too much if they ever shone on the sensitive parts. (Sun, Moon and Earth.) When the telescope is placed in the Sun-Earth L2, all three sources are always very close to each other in the sky, and you can shield against all three with a single directional sunshield.
I always thought L2 was chosen for Earth to cover up the sun. But apparently Earth covers it only to 84%.
https://www.quora.com/Is-the-L2-point-of-Earth-in-a-permanen...
https://www.quora.com/Is-the-L2-point-of-Earth-in-a-permanen...
It’s so the sun and the earth will always be in the same direction and both can be hidden behind the sun shield.
It needs solar power
The coldhead of one of these sensors (MIRI) functions optimally at temperatures less than 7˚K (i.e. 7˚ above absolute 0). The other sensors run at temperatures under 40˚K.
For reference, the melting point of nitrogen is, 63˚K.
Any sunlight at all would overwhelm this sensor and severely reduce the operational lifetime (and results!) of the telescope.
At L2, the telescope has the sun and the Earth behind a layered sunshield. It's easier to maintain position there and to have both objects always in the sol-ward direction while looking outwards.
For reference, the melting point of nitrogen is, 63˚K.
Any sunlight at all would overwhelm this sensor and severely reduce the operational lifetime (and results!) of the telescope.
At L2, the telescope has the sun and the Earth behind a layered sunshield. It's easier to maintain position there and to have both objects always in the sol-ward direction while looking outwards.
There are telescopes on Earth that cool their detectors (not optics, though) well below that temperature. The SPT-3G at the South Pole, for example, has detectors at 3K.
The cryocooler assembly on the JWST is one of the coolest marvel of engineering ever built (pun intended).
I can't find it now, but about a year ago there was an article by some professors with an extensive analysis what Starship could do for space science.
Their point was that Starship has a big potential to significantly reduce cost by enabling the development of devices that are less optimized for size and weight. For example, the extremely expensive JWST could have been built with a much cheaper, non-foldable mirror, since the Starship fairing has a quite large diameter.
But they also argued that there is an unfortunate tendency in science to overoptimize everything, which leads to exploding cost. So it is well possible that scientists won't use Starship to reduce the cost of their spacecrafts, but to optimize them for maximum performance like they did before, e.g. by designing complex foldable mirrors which barely fit into the Starship fairing.
So I guess if they do that, Starship would enable an even stronger cost explosion than in the past, not a cost reduction. More available mass and size means more opportunity to spend money on complex engineering. The launch costs themselves are not a significant factor here.
Their point was that Starship has a big potential to significantly reduce cost by enabling the development of devices that are less optimized for size and weight. For example, the extremely expensive JWST could have been built with a much cheaper, non-foldable mirror, since the Starship fairing has a quite large diameter.
But they also argued that there is an unfortunate tendency in science to overoptimize everything, which leads to exploding cost. So it is well possible that scientists won't use Starship to reduce the cost of their spacecrafts, but to optimize them for maximum performance like they did before, e.g. by designing complex foldable mirrors which barely fit into the Starship fairing.
So I guess if they do that, Starship would enable an even stronger cost explosion than in the past, not a cost reduction. More available mass and size means more opportunity to spend money on complex engineering. The launch costs themselves are not a significant factor here.
Interesting consideration:
Starship is monolithic right now, ie it’s unclear how it can unload payload of its own size. There are no bay doors a-la shuttle.
I guess they will have to do tilt-away nose section or something.
Starship is monolithic right now, ie it’s unclear how it can unload payload of its own size. There are no bay doors a-la shuttle.
I guess they will have to do tilt-away nose section or something.
From the official Starship users guide:
> The Starship payload fairing is a clamshell structure in which the payload is integrated. Once integrated, the clamshell fairing remains closed through launch up until the payload is ready to deploy. An example sequence of payload deployment is shown in Figure 3. To deploy the payload, the clamshell fairing door is opened, and the payload adapter and payload are tilted at an angle in preparation for separation. The payload is then separated using the mission-unique payload adapter. If there are multiple payloads on a single mission, a rotating mechanism can be provided to allow each satellite to separate with maximum clearance. Once separation is confirmed and the payload(s) have cleared the fairing, the payload fairing door is closed in preparation for Starship’s return to Earth.
Figure 3: https://i.stack.imgur.com/D3MYv.png
Full PDF: https://www.spacex.com/media/starship_users_guide_v1.pdf
> The Starship payload fairing is a clamshell structure in which the payload is integrated. Once integrated, the clamshell fairing remains closed through launch up until the payload is ready to deploy. An example sequence of payload deployment is shown in Figure 3. To deploy the payload, the clamshell fairing door is opened, and the payload adapter and payload are tilted at an angle in preparation for separation. The payload is then separated using the mission-unique payload adapter. If there are multiple payloads on a single mission, a rotating mechanism can be provided to allow each satellite to separate with maximum clearance. Once separation is confirmed and the payload(s) have cleared the fairing, the payload fairing door is closed in preparation for Starship’s return to Earth.
Figure 3: https://i.stack.imgur.com/D3MYv.png
Full PDF: https://www.spacex.com/media/starship_users_guide_v1.pdf
Or, it means teams and organizations that can't control cost don't make the discoveries, and are weeded out.
Currently NASA makes most space based discoveries, while not at all being able to control cost, as JWST has shown. The reason NASA isn't weeded out is that they have a quite large budget and only competition that is also bad at controlling cost: other space agencies.
> they have a quite large budget
That is a hilarious statement.
That is a hilarious statement.
> FY 2023, the National Aeronautics and Space Administration (NASA) had $32.37 Billion distributed among its 1 sub-components.
https://www.usaspending.gov/agency/national-aeronautics-and-...
Pretty sure there is no space organization which comes close.
https://www.usaspending.gov/agency/national-aeronautics-and-...
Pretty sure there is no space organization which comes close.
Cost control is largely about correctly predicting costs. So teams that correctly predict costs will select lower performing but affordable instruments. Teams that fail at that may well under predict costs, over engineer their systems and end up with super expensive but super capable systems.
Forget everything else, we need to build THIS :
https://www.youtube.com/watch?v=NQFqDKRAROI
A telescope array that can use our sun's gravitational lens would enable us to resolve the surfaces of extrasolar planets. We could resolve surface features as small as 10 km across at a distance of 100 light years.
JPL is actively investigating this. It's incredibly promising.
https://www.youtube.com/watch?v=NQFqDKRAROI
A telescope array that can use our sun's gravitational lens would enable us to resolve the surfaces of extrasolar planets. We could resolve surface features as small as 10 km across at a distance of 100 light years.
JPL is actively investigating this. It's incredibly promising.
It would make sense to have telescopes in orbit at Lagrange points around various gas giants and in far corners of space. The maximum definition of the Event Horizon telescope is based on the physical distance of each of the observatories on Earth. Moving observatories to all parts of our system will allow us to have vastly higher resolution.
Orbital dockyards and asteroid mining would be in reach if Starship delivers on its (admittedly pretty steep) promises.
Orbital dockyards and asteroid mining would be in reach if Starship delivers on its (admittedly pretty steep) promises.
the cost of launching a scope is not the bottleneck.
High cost of launch prevents economical repair (especially in high orbits), which requires extreme reliability. It also creates incentive for extreme weight reduction. Both these drive up the cost of a satellite. At low launch cost, there's no reason a space telescope should be much more expensive than a terrestrial telescope of the same size.
Do you work in the field of space? I don't mean to be dismissive but claiming that space telescopes cost about the same as terrestrial scopes if you subtract out the launch costs and can maintain them with crews, isn't really consistent with what I've heard from space telescope astronomers.
No, that goes way too far. Radiation hardening and heat dissipation are really difficult problems that remain for any space telescopes.
(I'm at the University of Washington Department of Astronomy, and work on telescope software).
(I'm at the University of Washington Department of Astronomy, and work on telescope software).
With sufficiently cheap launch, you get radiation hardening with shielding. The goal is to use off the shelf hardware as much as you can. If things break, that's why we have servicing, just like on terrestrial telescopes.
Ah. So, I should have said this earlier: there's a whole different world of cubesats that are what you're looking for. We could almost certainly help the astro community by funding and launching large fleets of simple scopes that make observing time available to more researchers.
You don't service cubesats, you just learn from your past mistakes and launch more.
You don't service cubesats, you just learn from your past mistakes and launch more.
The cost of rolling a truck to a terrestrial telescope is several orders of magnitude smaller than the cost of servicing a telescope in space. From that difference flows a greater emphasis on reliability for a space-based scope.
No, but the mass and volume constraints are. See how much effort went into making JWST fold up and how hard they had to try to get the mirrors to be light enough.
That's where in-space assembly comes in.
It's kind of sad that the one real thing the Space Station demonstrated, assembly of large space structures, has been abandoned in the name of feeding the pork pipeline with SLS.
It's kind of sad that the one real thing the Space Station demonstrated, assembly of large space structures, has been abandoned in the name of feeding the pork pipeline with SLS.
Space assembly for a telescope is way harder than the ISS. Telescope mirrors need to be aligned to within a few nanometers of each other, compared to the ISS which just needs airtight seals (so ~1mm + O-ring tolerance).
The alignment would be actively controlled. That's how they make large terrestrial telescopes work.
Why do you say it's been abandoned?
SLS will be delivering segments of Gateway after the first 2 are delivered by Falcon Heavy.
SLS will be delivering segments of Gateway after the first 2 are delivered by Falcon Heavy.
SLS is expending surplus RS-25 shuttle engines. Once they're gone they'll be paying Aerojet Rocketdyne a hundred million each for new ones. The first stage uses four.
Eventually someone with a brain is going to notice, SLS will be canceled, and decades of federal jail time will ensue for the criminals who perpetuated this fraud upon the American people.
Eventually someone with a brain is going to notice, SLS will be canceled, and decades of federal jail time will ensue for the criminals who perpetuated this fraud upon the American people.
ISS involved assembling segments that could be lifted on the Shuttle. Continuing that would involve lifting segments that could be lifted on F9 or FH. There would be no need for something as large as SLS.
How did China lift their space station?
Modules were launched on Long March 5B rockets.
https://en.m.wikipedia.org/wiki/Tiangong_space_station
https://en.m.wikipedia.org/wiki/Long_March_5
Given that SLS works and Starship has failed pretty spectacularly so far (engines failing off the gate and in flight, launch site damage, failed to detonate on demand), I think it's about time to stop saying SLS is just pork.
SLS may be further ahead in development (though the version that launched is far from the final one), but it is much worse than Starship in nearly every other aspect. This is consensus in the space community, it has been discussed to death.
Edit:
The most significant thing Starship is bad at is launching and landing humans. Human launch systems like Falcon 9/Dragon or SLS/Orion have both a launch abort system and a highly reliable "blunt capsule" method of landing humans back on Earth. For Starship, both launching and landing humans is much more dangerous, as it doesn't have a launch abort system and it uses a complex maneuver ("belly flop") in order to land.
Starship will need to do a lot of unmanned satellite launches to prove a safety level acceptable for humans. Or people transfer to and from Starship in space, as in Artemis 3, and start/land with a different rocket.
Edit:
The most significant thing Starship is bad at is launching and landing humans. Human launch systems like Falcon 9/Dragon or SLS/Orion have both a launch abort system and a highly reliable "blunt capsule" method of landing humans back on Earth. For Starship, both launching and landing humans is much more dangerous, as it doesn't have a launch abort system and it uses a complex maneuver ("belly flop") in order to land.
Starship will need to do a lot of unmanned satellite launches to prove a safety level acceptable for humans. Or people transfer to and from Starship in space, as in Artemis 3, and start/land with a different rocket.
SLS basically has a single purpose: funneling money to particular contractors. There is no objective in space that couldn't be done more cheaply with F9 and FH, given propellant transfer and some in-space assembly.
>Given that SLS works
A cost of $27,000,000,000 per launch, and a launch rate of 1 per 132 months is a generous definition of "works". And that's where SLS is right now.
A cost of $27,000,000,000 per launch, and a launch rate of 1 per 132 months is a generous definition of "works". And that's where SLS is right now.
I think it is "just" 4 billion per launch, though of course this doesn't include the development costs. Regardless, the costs are staggering compared to Falcon 9, Falcon Heavy, Vulcan, or Starship.
> the cost of launching a scope is not the bottleneck.
Starship isn't just about price, but also fairing volume. And fairing volume is one of the major factors that drives telescope design.
It's even possible that SpaceX would do a limited run hammerhead fairing for the right price.
Starship isn't just about price, but also fairing volume. And fairing volume is one of the major factors that drives telescope design.
It's even possible that SpaceX would do a limited run hammerhead fairing for the right price.
Not sure a larger fairing would be compatible with the current tower. Though they could use landing legs, then it doesn't have to be caught mid flight.
> Not sure a larger fairing would be compatible with the current tower.
I'd imagine that a hammerhead fairing would mean an expended 2nd stage. There's just too much custom work that would have to be done (for example with the heat shield) to really make it work.
But if the cost is reasonable (I'm guessing ~$25 million for an upper stage), that isn't a bad price to pay to get access to a 12m fairing.
I'd imagine that a hammerhead fairing would mean an expended 2nd stage. There's just too much custom work that would have to be done (for example with the heat shield) to really make it work.
But if the cost is reasonable (I'm guessing ~$25 million for an upper stage), that isn't a bad price to pay to get access to a 12m fairing.
I think 25 million USD is too optimistic, since the Starship upper stage has six raptor engines, and the Falcon 9 upper stage has only one Merlin engine, but a launch price of around 60 million US dollars.
But NASA would pay much more than that if it means they can launch a telescope with a big mirror that doesn't need to be folded in. The main problem I see is that they would likely also have to pay for the entire development of the new upper stage, which would be much higher than the pure launch cost. Since NASA already has JWST, I'm not sure they have much interest in a big new space telescope currently. Other than that, it's not clear what a super large payload fairing would be required for.
But NASA would pay much more than that if it means they can launch a telescope with a big mirror that doesn't need to be folded in. The main problem I see is that they would likely also have to pay for the entire development of the new upper stage, which would be much higher than the pure launch cost. Since NASA already has JWST, I'm not sure they have much interest in a big new space telescope currently. Other than that, it's not clear what a super large payload fairing would be required for.
> The main problem I see is that they would likely also have to pay for the entire development of the new upper stage
I don't see why they'd need to do a full 2nd stage.
I'm sure a limited run fairing (especially a complicated one like a hammerhead) will be expensive - certainly quite a bit more than the $5 million per unit cost of the Falcon fairings. But ultimately a fairing just isn't that complicated, and SpaceX has a lot of experience with them.
I don't see why they'd need to do a full 2nd stage.
I'm sure a limited run fairing (especially a complicated one like a hammerhead) will be expensive - certainly quite a bit more than the $5 million per unit cost of the Falcon fairings. But ultimately a fairing just isn't that complicated, and SpaceX has a lot of experience with them.
Well, the aerodynamics are different and the launch abort system would probably have to be somewhat different too. The structural integrity could also be quite different. Of course it won't be a completely new upper stage, as it is just a modification, but a few test launches are probably required.
>I'm guessing ~$25 million for an upper stage
that'll be initial cost submitted. once it is approved and work begins, that number will double, triple, or more before it is completed.
that'll be initial cost submitted. once it is approved and work begins, that number will double, triple, or more before it is completed.
NASA has only awarded SpaceX fixed cost contracts, never cost plus — whether it’s COTS, Crew Dragon or HLS. Same deal with US Air Force.
It’s amazing how wrong facts are asserted with absolute certainty here on HN.
It’s amazing how wrong facts are asserted with absolute certainty here on HN.
SpaceX is just the truck to carry the payload that is built by someone else. It’s the payload that always goes over budget. Facts are facts
> I’m guessing ~$25 million for an upper stage.
That was what you responded to. Since when the upper stage is the payload? Which facts are you asserting?
That was what you responded to. Since when the upper stage is the payload? Which facts are you asserting?
>Just think what space telescopes will be like if the Starship reduces cost/kg to orbit to 1/10th or less of Falcon 9's already low cost.
Falcon 9 is around $60 million/launch (though when contracted by NASA or the military, launches tend to be 2x-4x the price). This is pretty much inline with what you get from Arianespace, and Roscosmos. There is no path to reduce price by another order of magnitude. We've pretty much hit the limit on what we can do with chemical rockets.
Falcon 9 is around $60 million/launch (though when contracted by NASA or the military, launches tend to be 2x-4x the price). This is pretty much inline with what you get from Arianespace, and Roscosmos. There is no path to reduce price by another order of magnitude. We've pretty much hit the limit on what we can do with chemical rockets.
Falcon 9's price is a bit below its competitors. But remember, cost != price. There is not much reason for SpaceX to reduce the price further, if demand is sufficiently inelastic.
There is room to reduce cost much further. Discarding the second stage is a large cost. The propellants used by F9 cost $200K/launch, according to Musk. With full reusability costs should fall at least another order of magnitude.
There is room to reduce cost much further. Discarding the second stage is a large cost. The propellants used by F9 cost $200K/launch, according to Musk. With full reusability costs should fall at least another order of magnitude.
>There is not much reason for SpaceX to reduce the price further, if demand is sufficiently inelastic.
Or they can't, because there are physical limits to the chemical rocket technology.
>There is room to reduce cost much further. Discarding the second stage is a large cost ... with full reusability costs should fall at least another order of magnitude.
Reusability is not a panacea. Falcon 9 is partially reusable and it is not significantly (if at all) cheaper than the competition. There is no evidence that full reusability will provide an order of magnitude cost decrease in prices. Fully reusable rockets imply that you're cutting into your cargo space (because you have to ship extra fuel for the decent), and maintenance is expensive and time-consuming. Don't get me wrong, there may be costs savings there, but not 10x, more like 10%.
Or they can't, because there are physical limits to the chemical rocket technology.
>There is room to reduce cost much further. Discarding the second stage is a large cost ... with full reusability costs should fall at least another order of magnitude.
Reusability is not a panacea. Falcon 9 is partially reusable and it is not significantly (if at all) cheaper than the competition. There is no evidence that full reusability will provide an order of magnitude cost decrease in prices. Fully reusable rockets imply that you're cutting into your cargo space (because you have to ship extra fuel for the decent), and maintenance is expensive and time-consuming. Don't get me wrong, there may be costs savings there, but not 10x, more like 10%.
> Or they can't, because there are physical limits to the chemical rocket technology.
Awfully coincidental it happens to cost just slightly less than than the competitors.
Awfully coincidental it happens to cost just slightly less than than the competitors.
> Falcon 9 is partially reusable and it is not significantly (if at all) cheaper than the competition.
No, that's just you stupidly confusing price and cost.
No, that's just you stupidly confusing price and cost.
Or, since there's no downward pressure on price, it's equally valid to say we've hit the limit of what we can do with capitalism in the current ecosystem.
Price won't approach cost until there's another competitor with similar costs. But China is heading strongly in that direction, working on a F9 clone (and perhaps more than one; there are many quasi-private launch efforts there). I'm sure Musk knows F9's life as a money-printing machine is finite.
>Or, since there's no downward pressure on price, it's equally valid to say we've hit the limit of what we can do with capitalism in the current ecosystem.
There is downward pressure, we're just hitting physical limits on what can be done with chemical rockets.
There is downward pressure, we're just hitting physical limits on what can be done with chemical rockets.
Please stop with this nonsense. It's obviously wrong.
The mere existence of the Starship design, which doesn't break any physical laws, shows your claim is nonsense.
The mere existence of the Starship design, which doesn't break any physical laws, shows your claim is nonsense.
>It's obviously wrong
Obviously wrong how? I saw that Musk was claiming that launch costs for starship will be around $1-2 million at some point - probably after hyperloop launches as a "5th mode of transport" in Neverland.
Obviously wrong how? I saw that Musk was claiming that launch costs for starship will be around $1-2 million at some point - probably after hyperloop launches as a "5th mode of transport" in Neverland.
LUVOIR's planned to launch on Starship or something of its size.
It is not even planned to be built, just a concept.
Ah, now I'm sad. It's a very cool concept nonetheless.
If I may take advantage of the presence of knowledgable people in this thread…
The JWST is located at the L2 point. Does that mean L2 is now “taken”, or could it make sense to host multiple telescopes and spacecraft at or near that point?
The JWST is located at the L2 point. Does that mean L2 is now “taken”, or could it make sense to host multiple telescopes and spacecraft at or near that point?
In short, it orbits the L2 point. There's plenty of room for more!
Here's a 20s YouTube video that should clear things right up:
https://www.youtube.com/watch?v=6cUe4oMk69E
Here's an article with additional info:
https://webb.nasa.gov/content/about/orbit.htm
Here's a 20s YouTube video that should clear things right up:
https://www.youtube.com/watch?v=6cUe4oMk69E
Here's an article with additional info:
https://webb.nasa.gov/content/about/orbit.htm
There's already multiple telescopes there, including the Gaia telescope. See https://en.wikipedia.org/wiki/List_of_objects_at_Lagrange_po...
As I understand it, it's more of a region around that point in space that spacecraft try to stay close to/within
It reveals an inner belt, akin to the solar system's asteroid belt but dustier and more extended; an intermediate belt; and a previously imaged outer belt that's analogous to our Kuiper Belt.
How could something analogous to our Kuiper belt possibly reflect/emit enough light to be visible as a cloudy ring? There is no way it isn't orders of magnitude more massive than the Kuiper belt.
How could something analogous to our Kuiper belt possibly reflect/emit enough light to be visible as a cloudy ring? There is no way it isn't orders of magnitude more massive than the Kuiper belt.
I was going to ask the same thing -- maybe someone more astronomically inclined has an answer to this...
If one were to take a phot of our solar system, would our asteroid belt really be dense enough to show up in any wavelengths?
If one were to take a phot of our solar system, would our asteroid belt really be dense enough to show up in any wavelengths?
The most likely explanation to me is that the author is just wrong in describing it that way and it's a much more massive debris disc slash protoplanetary disc.
Maybe because it's still gas and dust, whereas if the same mass coalesces into large objects it's much less reflective?
At a guess - very long exposure times. Even if it's only sending one photon per second in our direction, if we stare at it long enough then eventually we'll have an image.
As a layman I get the feeling that JWST is showing us more detailed things we'd already seen than brand new ones. I remember being moved by the Hubble deep field, where a long exposure revealed that what looked like an empty patch of the sky was anything but.
Are we reaching the point of diminishing returns of what a reasonably sized (for our current rockets) space telescope can see?
Are we reaching the point of diminishing returns of what a reasonably sized (for our current rockets) space telescope can see?
> Are we reaching the point of diminishing returns of what a reasonably sized (for our current rockets) space telescope can see?
In terms of sensitivity, yes. Collecting more light needs more light-collecting material, which ultimately means more mirror, or detector, surface area. Little more gain to be had there. We're not going to see much more that's really, really faint.
But we're just getting started with resolution. Apertures can be synthesized in software. Theoretically, a handful of space telescopes, orbiting the Sun, linked together, could have an angular resolution equivalent to that of a physical telescope with a mirror the same diameter of the orbit. Not the light sensitivity (since the "mirror" is mostly empty space), but it would have the ability to distinguish between two points like such a giant telescope would.
This has been done with radio astronomy already; things have just recently gotten fast enough for aperture synthesis at infrared wavelengths; optical is probably not too far behind.
In terms of sensitivity, yes. Collecting more light needs more light-collecting material, which ultimately means more mirror, or detector, surface area. Little more gain to be had there. We're not going to see much more that's really, really faint.
But we're just getting started with resolution. Apertures can be synthesized in software. Theoretically, a handful of space telescopes, orbiting the Sun, linked together, could have an angular resolution equivalent to that of a physical telescope with a mirror the same diameter of the orbit. Not the light sensitivity (since the "mirror" is mostly empty space), but it would have the ability to distinguish between two points like such a giant telescope would.
This has been done with radio astronomy already; things have just recently gotten fast enough for aperture synthesis at infrared wavelengths; optical is probably not too far behind.
I think optical is pretty far behind. EHT was already dealing with 100s of TB of data per telescope. Going to visual turns that into ~10s of PB. I think the more likely advance is some way of doing space based radio wave interferometry.
Discovering brand new things at a constant rate is probably not a realistic expectation. The 20th century has been an extraordinary journey for astronomy that cannot possibly continue indefinitely (same with other parts of fundamental science). We went from barely a sense what our galaxy is about, to discovering an extraordinary number of exotic astronomical objects by progressively expanding the window into radio, x-ray, gamma rays, gr waves etc.
But I don't think its true that future astronomers / space telescopes are condemned to boring hires pictures of known stuff. The excitement is not in the visual impression but in what it might tell us about the universe. In the end what matters is whether we understand what is happening (e.g., in this instance how planetary systems like our very own are forming). So while the visual impression might not alter much, the quantitative detail may be fixing the physics or even prompting completely new theories. Remember sometimes even the stuff you don't see can bring about a revolution (dark matter, dark energy).
But I don't think its true that future astronomers / space telescopes are condemned to boring hires pictures of known stuff. The excitement is not in the visual impression but in what it might tell us about the universe. In the end what matters is whether we understand what is happening (e.g., in this instance how planetary systems like our very own are forming). So while the visual impression might not alter much, the quantitative detail may be fixing the physics or even prompting completely new theories. Remember sometimes even the stuff you don't see can bring about a revolution (dark matter, dark energy).
They did discover several galaxies beyond redshift 11 that Hubble cannot see. I'm not in the field, but venturing a guess here that they might want to prioritise getting images of known objects first, because there must be so much active research that can immediately benefit from the new detail. Over time I hope they will dedicate time for some wild hunches like Hubble did and open up something yet unknown.
JWST is an infrared scope of a magnitude never before employed. Astronomy is more about collecting data than anything else, pretty images are a welcome side-effect. JWST will be extremely beneficial for deep-space exploration. It's worth reading about!
> Are we reaching the point of diminishing returns of what a reasonably sized (for our current rockets) space telescope can see?
No, not as far as I know (also a layperson). It's just that we've already seen the incredible leap of "there's nothing here" -> "there's things here". The JWST is still a massive leap in capabilities, but you aren't going to be as impressed at seeing intricate structures inside a galaxy that once appeared smooth. The JWST is truly a new era of exploring the early universe, but it might not have the same "wow" factor.
No, not as far as I know (also a layperson). It's just that we've already seen the incredible leap of "there's nothing here" -> "there's things here". The JWST is still a massive leap in capabilities, but you aren't going to be as impressed at seeing intricate structures inside a galaxy that once appeared smooth. The JWST is truly a new era of exploring the early universe, but it might not have the same "wow" factor.
The Hubble deep fields take many days/weeks/months of exposure time. The deep fields released from JWST so far have been just hours long...
There are a lot of different proposals being rapidly shot in these early year(s) of the telescope. Later on there will certainly be longer exposures.
There are a lot of different proposals being rapidly shot in these early year(s) of the telescope. Later on there will certainly be longer exposures.
I'm eager to see what JWST can do with more than 48h of exposure. It should be amazing. I'm wondering why they're choosing to shot other stuff before.
Because telescope time is expensive. If you do a 1 week deepfield, you can't use the telescope for anything else for 1 week. You get more discoveries earlier by doing all of your hour long shots first.
JWT doesn't have much more detail than Hubble, but it observes infrared frequencies, which is a whole new view of the universe.
I don't understand the use of "ruined" in the NYT headline. I guess they don't understand that this is a very young star, and it's likely that our own sun had similar rings before they coalesced into planets.
>The intermediate belt is also where exoplanet hunters once thought they had seen a world they named Fomalhaut b. But in 2020, Dr. Gaspar and his colleagues proposed that what other scientists had once thought was an intact exoplanet was actually an expanding cloud of debris created by an epic collision.
A problem with this idea was that this part of space looked vacant, so it seemed unlikely that two objects had managed to crash into each other. The team’s discovery of the intermediate debris belt has now proffered a solution.
“We now know there’s stuff there,” Dr. Christiansen of the NASA archive said. “OK, so it’s a collision — we can finally put that to bed.”
Cataclysmic melees are not just transpiring close to the star. What looks like a vast maelstrom of dust within the outer belt may be the ghost of another gargantuan impact.
“That’s just cool,” Dr. Christensen said. “What is it? It’s very tantalizing.”
A problem with this idea was that this part of space looked vacant, so it seemed unlikely that two objects had managed to crash into each other. The team’s discovery of the intermediate debris belt has now proffered a solution.
“We now know there’s stuff there,” Dr. Christiansen of the NASA archive said. “OK, so it’s a collision — we can finally put that to bed.”
Cataclysmic melees are not just transpiring close to the star. What looks like a vast maelstrom of dust within the outer belt may be the ghost of another gargantuan impact.
“That’s just cool,” Dr. Christensen said. “What is it? It’s very tantalizing.”
alternate headline: webb looks at star known to have debris disks and suspected planets, hoping to confirm at least one planet but isn't able to confirm any of them
A side-by-side before-and-after with the "previously best" image to compare against the new image would be great to see.
Here's on which is a composite of the ALMA (millimetre wave telescope) superimposed with Hubble (in blue)
https://www.centauri-dreams.org/2017/05/22/best-images-yet-o...
Here's just that ALMA pic
https://commons.wikimedia.org/wiki/File:ALMA_Explores_Fomalh...
https://www.centauri-dreams.org/2017/05/22/best-images-yet-o...
Here's just that ALMA pic
https://commons.wikimedia.org/wiki/File:ALMA_Explores_Fomalh...
If JWST can do these amazing discoveries and detailed images, I wonder what kind of discoveries we make when starship can launch way bigger telescope than JWST. Future is Awesome!
Bigger is one option, but more of them is another; combining the data from multiple telescopes at, say, 10km apart effectively turns them into a telescope with a 10km diameter (see e.g. the event horizon telescope that made the first image of a black hole: https://eventhorizontelescope.org/ )
You get the resolution but not the light capturing capability of a big telescope. The event horizon telescope had to do a lot of machine learning trickery to get an image. Also, as far I understand, it's much more difficult to do this at the wavelength of visible light.
The EHT has used machine learning techniques, but those were not required to get an image that shows the shadow of the black hole. Just using the "clean" algorithm for deconvolution yielded an image showing the shadow, and that algorithm has been in use for radio interferometry for over 40 years, and has nothing whatsoever to do with machine learning.
I watched a presentation by a researcher that worked on the EHT. She pointed out that there was a lot of machine learning to rule out wrong pictures. It’s not simple interferometry.
I am also a member of the EHT project. I'm not saying no machine learning was used by EHT team members. I'm saying that you can process the 2017 EHT data using standard radio interferometry techniques, and get an image showing the M87 black hole shadow without machine learning or any other type of AI
Manufacturing the JWST was already extremely challenging. Not saying we can't do bigger, but payload size isn't the only limiting factor.
Manufacturing the JWST would be a lot easier if it weren't for the mass/volume constraints.
Perhaps, because of all the moving parts. How big is Starship though? I don't expect a telescope bigger than JWST could go up completely unfolded and expect to be perfectly resilient to launch forces. In addition, even if we had the option of a solid mirror, manufacturing such a massive mirror to perfect smoothness would be a feat. Piecemeal mirrors are probably easier in some ways because if one section is flawed, it can be replaced.
A Google search reveals: Starship has an 8 meter internal diameter. The Hubble mirror was 2.4 meters. The largest ground telescopes with a single mirror are somewhat over 8 meters in diameter. Though these don't have to withstand a rocket launch. JWST has a 6.5 meter segmented mirror with 1.3 meter per segment. It was folded up to fit into the Ariane 5 fairing.
Interesting comment below the linked article:
> Lots of asymmetries involved. The star is off-center toward the lower right, same direction as the partial arc. The major ring could be elliptical, rather than circular. It also varies in brightness around the circumference.
I'm a complete layman, but could this explain the high deviation from circular orbits of our own outer planets? IIRC this was something of an unexplained issue?
> Lots of asymmetries involved. The star is off-center toward the lower right, same direction as the partial arc. The major ring could be elliptical, rather than circular. It also varies in brightness around the circumference.
I'm a complete layman, but could this explain the high deviation from circular orbits of our own outer planets? IIRC this was something of an unexplained issue?
What does the F2300C and F2550W mean? Focal length?
They are the filters used in the observation. Telescopes use filters to select a range of light wavelength/frequency to be observed. See http://svo2.cab.inta-csic.es/svo/theory/fps3/index.php?id=JW... to see their properties.
They are "mask" which only allow some wavelengths so you can see different structure.
https://en.wikipedia.org/wiki/Coronagraph
https://en.wikipedia.org/wiki/Coronagraph
I feel cheated... I glance at the image, see that bulge in the ring and was immediately excited that they had captured the visual image of an exoplanet (even if it was going to be a large brown dwarf).
Nope, just something behind the ring.
Nope, just something behind the ring.
>I glance at the image, see that bulge in the ring and was immediately excited that they had captured the visual image of an exoplanet (even if it was going to be a large brown dwarf).
I was under the same impression. Upon a second look it became clear that blob is roughly 8 AU in diameter [judging by the overall scale]
I was under the same impression. Upon a second look it became clear that blob is roughly 8 AU in diameter [judging by the overall scale]
I'm not sure that an 8AU diameter would be that absurd, if we're talking about a proto-planetary nebula, would it?
But yeh, if I weren't a nitwit, the scale's completely wrong (and it should be hoovering up the ring in short order besides).
But yeh, if I weren't a nitwit, the scale's completely wrong (and it should be hoovering up the ring in short order besides).
A visual of an exoplanet is still beyond the possibility of anything but a REALLY big telescope (100m)+
Actually we've imaged many exoplanets, but typically ones that are much larger than Jupiter.
Here's a famous system: https://en.wikipedia.org/wiki/HR_8799
Here's a famous system: https://en.wikipedia.org/wiki/HR_8799
They were able to detect the planet due to the observed orbital motion on the star, not that they were able to get an image of the planet itself.
Thank you for the link, it's wonderful.
Are there any previous images of the same object from a superexpencive telescops of previous generations to compare James Webb's advance from other telescops?
Wikipedia has a number: https://en.wikipedia.org/wiki/Fomalhaut
Hubble: https://en.wikipedia.org/wiki/File:NASA%27s_Hubble_Reveals_R...
ALMA: https://www.eso.org/public/images/eso1216a/
Hubble: https://en.wikipedia.org/wiki/File:NASA%27s_Hubble_Reveals_R...
ALMA: https://www.eso.org/public/images/eso1216a/
I've read this book, and it doesn't end well for humans.
that's just stunning
Maybe there's a Ruined Portal there
"... She eats and wipes her mouth and says, ‘I’ve done nothing wrong.’"
That is huge. Just reference for those who don't feel "astronomical units": One astronomical unit (AU) is (roughly) the Earth-Sun distance.
Distances to compare with: Pluto is ~39 AU away from the sun. Voyager 1, the furthest probe of humanity right now, is ~160 AU away from the sun.
So in other words: that is mind-bogglingly large.
(If you want to read more about astronomical units: https://en.wikipedia.org/wiki/Astronomical_unit )