At 110 light-years distance you would need a telescope ~450 kilometers across to image this planet at 100x100 pixel resolution--about the size of a small icon. That is a physical limit based on the wavelength of light.
The best we could do is build a space-based optical interferometer with two nodes 450 kilometers apart, but synchronized to 1 wavelength. That's a really tough engineering challenge.
1. https://en.wikipedia.org/wiki/Solar_gravitational_lens
2. https://www.nasa.gov/general/direct-multipixel-imaging-and-s...
Parker at its highest velocity could make it there in a century, but it doesn't have to slow down and stop. Or station keep.
When we have a power source that can do 5kW (I just doubled Hubble, 542 AU would probably require much more for communications) for 100 years I'll agree that its design can be refined and its lifespan extended to 200 and 542 AU is within our reach.
As far as power requirements go, assuming a doubled power demand from Hubble might be a bit excessive. A telescope that far out would have to be nuclear powered, so thermal regulation is 'free'/passive and RCS load is reduced (don't have to constantly adjust to point away from the Earth), which I expect are the biggest power draws on Hubble.
If we assume a 150 year lifetime, with a 3kW draw by EOL and current RTG tech... RTGs have ~6% efficiency, so for 3kW electricity, you need 50kW in heat. RTG electricity output drops ~2% per year, so after 150 years, you have 5% of the initial electrical output, and you get ~0.57W/g of Pu-238. Meaning, you need ~600kg of it to power the telescope this way [https://www.mathscinotes.com/2012/01/nuclear-battery-math/].
That's not a politically feasible amount, but it's not technically impossible with current/near future tech whose development could be spurred on by serious interest in this kind of mission.
'Proper' fission reactors can also do the job, you get higher efficiency and don't have to run the reactors for the entire 150 years besides accounting for decay (e.g. an RTG that needs to provide enough power to keep some clocks running, the electronics and batteries warm, and trigger whatever mechanism would start up the reactor). Probably less than 100kg of Pu-238 just by better reactor efficiency.
It is indeed spherical frictionless cow-ly possible if we spend a trillion dollars to increase ORNL's annual Pu production capacity so that it doesn't take 200 years to make 600kg of Pu-238.
When someone demonstrates a complex device (let's set aside power generation how about a valve? Or a capacitor?) that can last a century in space I'll agree that it is actually possible.
That's what "current level of technology" means. The lego bricks exist, now, today, preferably in stock ready for immediate shipment on Digikey, and can be snapped into place.
Oh come on, we used to make so much more of it.
I see estimates that it costs 4 million dollars per pound, plus some scaling costs?
A trillion dollars is not even close to "spherical frictionless cow" when the benchmark is "humanity's current technological capabilities", and a few billion is basically nothing at that scale.
> When someone demonstrates a complex device (let's set aside power generation how about a valve? Or a capacitor?) that can last a century in space I'll agree that it is actually possible.
Is a bunch of stuff lasting 50 years not good evidence? What is your threshold for "demonstrate", do we have to wait 200 years before you can be convinced?
It wouldn't take nearly that long. The proposal is to use solar sails. There is a nice video about the details on YouTube: https://www.youtube.com/watch?v=NQFqDKRAROI
Why, you ask?
How do you point it? Where do you point it?
You have a "telescope" with a field of view of one-planets worth of pixels. But the planet is in orbit, so it drifts away from the imaged field of view within minutes.
Meanwhile your sensor is travelling away from the "lens" so transverse velocity would be needed to track the orbit at a delta-v and direction that is unknowable. Unknowable, because you have to know where the planet is, within a radius, to put your "sensor" in the right place in the first place.
Imagine taking a straw, place it in a tree, walk away a few km and focus a telescope on the straw and hope to look through the straw to see an airplane flying past. You have the same set of unknowables.
So, for scale, Voyager 1 is about 2.5 x 10^11 regulation football pitches away although they vary in size so it could be anywhere between 2.08 x 10^11 and 2.8 x 10^11. Now, see how much more relatable that is for a common person?
Of all the possible space probes or missions we could do. I want this one more than any of them!
But of course, the initial delta-v costs a lot of propellant because it has to push an almost full tank. By the time we have to decelerate the ship will be a lot lighter.
That’s why you needed a full Saturn 3rd stage to send Apollo to the moon, but just the service module to get back to Earth.
I realize now that “a lot of delta-v” is an understatement. 500 AUs is ridiculously far. To get there in under a century you’d need fission-fraction reactors, well beyond our current tech.
Voyager 1 is 166 AU away, it launched about 50 years ago. So wouldn't we just have to do about twice as well as that, or launch 2 of them in opposite directions? That sounds _very_ hard (Voyager is amazing), but it can't be beyond our current tech, right? We did fairly close to that 50 years ago.
Or use two (or more) telescopes that are 450km apart:
Then you could do observations outside the solar system's orbital plane with a 2 AU synthetic aperture. And maybe even do double duty as a gravitational wave observatory.
(And yes, this is currently more science fiction than science, but it's at least plausible that we can build such a thing one day).
Also, could the image be created by “scanning” a big area and then composing the image from a bunch of smaller ones?
That puts a basic limit on the smallest thing you can resolve with a given aperture. You can use the angular diameter of the planet and the resolution you're after. For Alpha Centauri A it's 8.5 milli arc-second, so O(1 μas) for a 100px image? That's just for the star!
The Event Horizon Telescope can achieve around 20-25 μas in microwave; you need a planet-scale interferometer to do that. https://en.wikipedia.org/wiki/Event_Horizon_Telescope It's possible to do radio measurements in sync with good clocks and fast sampling/storage, much harder with visible.
I'm not super up to date on visible approaches, but there is LISA which will be a large scale interferometer in space. The technology for synchronising the satellites is similar to what you'd need for this in the optical.
https://www.edmundoptics.com/knowledge-center/application-no...
Let's say you build single photon detectors and ultra precise time stamping. Would that get us near? Today, maybe we don't have femtosecond time stamping and detectors yet. But that is something I can imagine being built! Timing reference distribution within fs over 100s of km? Up to now, nobody needed that I guess.
The way that timing works for EHT is each station has a GPS reference that's conditioned with a very good atomic clock - for example at SPT we use a hydrogen maser. The readout and timing system is separate from the normal telescope control system, we just make sure the dish is tracking the right spot before we need to start saving data (sampling around 64 Gbps).
I'm not sure what the timing requirements are for visible and how the clock is distributed, but syncing clocks extremely well over long distances shouldn't be insurmountable. LISA needs to solve this problem for gravitational waves and that's a million+ km baseline.
Some problems go away in space. You obviously need extremely accurate station keeping (have a look how LISA Pathfinder does it, very cool), but on Earth we also have to take continental drift into account.
If you only wanted 10x10 resolution you could get by with a 1.8 kilometer telescope.
Wikipedia has more: https://en.wikipedia.org/wiki/Angular_resolution. The Rayleigh criterion is the equation to calculate this.
https://www.ligo.caltech.edu/page/facts
> At its most sensitive state, LIGO will be able to detect a change in distance between its mirrors 1/10,000th the width of a proton! This is equivalent to noticing a change in distance to the nearest star (some 4.2 light years away) of the width of a human hair.
So I think two telescopes at 450km distance synchronized to "merely" (haha) a visible light's wavelength should be doable, if we throw a fuckton of money on that.
Is that a case of un redshifting this pixel, or needing the optical inferometer you mentioned with multiple single frequency filters.
Or something new? like a LHC style accelerator, or space based rail gun, to fire off a continuous stream of tiny cube sats towards the target, and using the stream itself as a comms channel back.
Yeah I know, this planet is burning, and all that effort for a RGB wallpaper seems crazy, but 'space stuff' also brings knowledge and hope.
My (tenuous) understanding of interferometry is that you receive light from two points separated by a baseline and then combine that light in such a way that the wavelengths match up and reinforce at appropriate points.
Wikipedia has a decent summary: https://en.wikipedia.org/wiki/Aperture_synthesis
the image on the linked website is more than 1 pixel across: what are you saying? it's false/fake?
That’s in addition to gravitational lensing effects.
If, like me, you believe the future of any civilization (including ours) is a Dyson Swarm then you end up with hundreds of millions of orbitals around the Sun between, say, the orbits of Venus and Mars. It's not crowded either. The mean distance between orbitals is ~100,000km.
People often ask why would anyone do this? Easy. Two reasons: land area (per unit mass) and energy. With 10 billion people, that'd be land about the size of Africa each with each person having an energy budget of about the solar output hitting the Earth, a truly incomprehensibly large amount of energy.
So instead of a telescope 450km wide (fia optical interferometry), you have orbitals that are up to ~400 million kilometers apart. The resolution with which you could view very distance worlds is unimaginably high.
Why does this eliminate Fermi Paradox proposed solutions? One idea is that advanced civilizations hide. There is no hiding from a K2 civilization.
Not that the Milky Way is a small place, but even most sci-fi featuring FTL and all sorts of handwaves has to content itself with shenanigans confined to a single galaxy due to the mindblowing, and accelerating, gaps between galaxies.
That the stars are beyond reach might be depressing, how aggresively we are gambling our little boat is on the other hand actively scary and perhaps the dominant limit on humanity's effective reach.
In a way we're kind of still like an ancient village who can only travel by boats made of reeds
Further more I don't think technologically advanced civilizations will be wasting their time and resources in colonizing new works, space is simply too big for that. And that they would conduct their explorations with telescopes, not probes, space is simply too big for probes.
Just to ring the point home, we are technically (but not yet economically) capable of creating small telescopes which use our sun as a gravitational lens, which would be able to take photographs of exoplanets. In the far future we could potentially build very large telescopes which can do the same and see very distant objects with a fine resolution. That would be a much better investment then to send out self replicating robotic probes.
Such as?
" I think a sufficiently advanced civilization will always prefer telescopes over probes for anything more distant then the nearest couple of solar systems."
What part of "immortal" don't you understand? traveling at 1% of c doesn't feel slow if you just turn off or slow down your brain during the trip.
As for the moral reasons to not send out a fleet of self replicating probes. These are an extreme pollution hazard. An ever expanding fleet of robots traveling across the galaxy over millions of years, growing in numbers exponentially, exploiting resources in foreign worlds, with nothing to stop them if something happens to their makers. Over millions of years these things would be everywhere, and—in the best case—be a huge nuisance, but at worse they would be a risk to the public safety of the worlds they travel to. With these risks I believe a sufficiently advanced civilization would just build telescopes for their exploration needs.
And they wouldn't have to be inherently self-replicating.
When you can live millions of years your idea of what is "slow" changes pretty drastically.
What an appropriate name for an astrophysicist. I wonder if she's distantly related to the namesake of the Lagrange point. https://en.wikipedia.org/wiki/Lagrange_point
Incidentally, although I'd never heard of A-M Lagrange before now, she's had an incredible career: https://en.wikipedia.org/wiki/Anne-Marie_Lagrange
Scopus has 390 profiles of people named Lagrange. It is not a very popular family name but it is not uncommon either and some of them are bound to end up in academia, whether they are descendants of Joseph-Louis or not.
https://webbtelescope.org/contents/media/images/01F4STZH25YJ...
However, this is the culmination of the construction of a cathedral to science. Every stone laid one atop another from our first comprehension of the cosmos to our emergence from our long dream as the center of a deity constructed universe has resulted in a discipline that can not only conceive of other spheres we can stand on, to entire other systems of spheres we can now see.
This is magnificent.
You can apply this logic to pretty much anything. The better thing is just around the corner, might as well wait.
I'm sure many other advancements were made by JWST that can be applied to your theoretical better telescope.
I understand the difficulty in what they are doing, but the scale of the error here is amusing. “We thing we took a picture of something, but it might have been billions of things much bigger but further away”
Though at a 50 AU orbit around a smallish star, that might take a while.
Orbital mechanics, orbital period, and minimum determinable arc of JWST.
Though another thought is that doppler might also reveal velocity, if a spectrum could be obtained. Since the system is nearly perpendicular to the Solar System (we're viewing it face-on rather than from the side), those shifts will be small.
The key word "discovery" has been removed from the headline from TFA: "The James Webb Space Telescope Reveals Its First Direct Image Discovery of an Exoplanet". I.e, this is the first time that direct imagery was used to _discover_ a planet we didn't know existed previously.
Submitted title was "James Webb Space Telescope reveals its first direct image of an exoplanet", which I'm sure was just a good-faith attempt to fit HN's 80 char title limit. I've achieved that by compressing to JWST now :)
Don’t get me wrong, I love that we are doing this work and have no reason to doubt that this is indeed an exoplanet image, but I view this kind of modelling as a pretty weak form of support for a hypothesis. Models are built from assumptions, which are influenced by expectations. They are not data.
In contrast, current techniques are biased towards close-in planets. Both Doppler-shift and light-curve methods tend to detect close-in planets.
We’ll get a better idea of the distribution of planets with both techniques.
The moment we have our first, direct-observation photo of an earth-like exoplanet will be a defining point in our history.
https://en.wikipedia.org/wiki/Nancy_Grace_Roman_Space_Telesc...
> In April 2025, the second Trump administration proposed to cut funding for Roman again as part of its FY2026 budget draft. This was part of wider proposed cuts to NASA's science budget, down to US$3.9 billion from its FY2025 budget of US$7.5 billion. On April 25, 2025, the White House Office of Management and Budget announced a plan to cancel dozens of space missions, including the Roman Space Telescope, as part of the cuts.
I think the transit time is likely decades and the build time is also a long time as well. But in maybe 40-100 years we could have plentiful HD images of 'nearby' exoplanets. If I'm still around when it happens I will be beyond hyped.
Not to take anything away from JWST - every one of these is an incredible achievement!
edit: but it's the orange thing not the star
A hypothetical planet beyond Pluto be in a huge part of the sky: Presumably the orbit of such a planet could be inclined about as much as Pluto's. The 17-degree inclination of Pluto's orbit means it could be in a 34-degree wide strip of the sky, which, if I'm doing my math right, is about 29% of the full sky. If we allow for up to a 30 degree inclination, then that's half the sky.
There's also the matter of object size and brightness. The proposed Planet Nine[1] was supposed to be a few hundred AU away, and around the mass of 4 or 5 Earths. The object discovered in this paper is around 100 M🜨, at around 52 AU from its star. Closer and larger. (Of course, there's a sweet spot for exoplanet discovery, where you want the planet to be close enough to be bright, but far enough away to be outside the glare of the star.)
/s
Any direct link on the pic?
I mean, even if there is life it's like 1 in a gazillion. But you could imagine some ML looking through all of its images to find planets, etc.
In sci-fi we see warp drives, worm hole travel, phasers, photon torpedos and energy shields around ships. But what if none of that is possible? In that case, we might even have the technology to defend ourselves today if we manage to detect the attack in time.
It's a huge risk for a civilization to attack us. Even if they have capabilities that are beyond our technology, there might still be limitations based on the laws of physics. And if they attack us, they risk a response.