The creator of the GIF above used a data from a range of different telescopes and wavelengths, whereas I made this with using data only from same telescope (Keck), instrument, and wavelength (3.5 microns; near infrared).
That’s right. We only have images take every year or so, so I did a motion interpolation between the images using Keplers laws. Diffraction close in gets pulled around by the interpolation.
I've always hated speculation based on this equation because most of the variables are complete shots in the dark.
Sure, we can measure stellar formation and planetary occurrence, but that's about it.
Planets within habitable zone? How do we know what habitable is? We've examples of extremophiles on earth that could potentially live well outside the habitable zones we typically draw, and who's to say that life can't form in a Jupiter style atmosphere just because it didn't happen here (that we know of)? What's the habitable zone for hypothetical non-carbon life forms?
Fraction of suitable planets that develop life? Well, we've got n of 1 on that. We've found other earth-likes within habitable zones and we simply can't determine whether they do or ever did develop bacteria because they're too far away and our sensors are not sensitive enough.
Fraction of life-bearing planets that develop intelligent life? Technically, every planet we know of that bares life bares intelligent life. Does that mean the variable is 1? Not likely.
Fraction of intelligent lifes that create interstellar comms? Again, so far, 100%. Is it likely to be 1 in reality? Probably not.
Length of time such beings transmit in total from first to last broadcast. We've literally no way to determine this. Thus far universal average is, what 120 years? But those very first broadcasts were so weak and not intended for space interstellar comms. The first message sent to space deliberately wasn't until ~50 years ago, so the average space communication time of all known species is ~50 years, but again it's only n of 1 and so means effectively nothing.
AND it doesn't even calculate the thing we really care about which is the odds that we get to interact with or observe alien intelligence. There is no control for "ah, yes, as the universe ages, there will be more communicative species, but your species will have died before then, or will have died in the length of time required to establish back and forth communication. It doesn't tell us what the odds are of their having been a species that sent it's last broadcast before we started recording. It doesn't tell us how long we should expect to wait before it is overwhelmingly likely that we receive a broadcast...
It just feels like a uni bloke got high one night and said, right, well there'll have to be planets, and they'll have to have life, and that life will have to develop intelligence, and that intelligence will have to reach out, and it will have to reach out for long enough for us to hear it. Like...yeah, duh? What about species that have colonized and spread beyond their own planet due to overpopulation? The number of planets in the sky doesn't really matter if a single planet spawned 117 different communicative interstellar communities, does it?
Worth being very clear that this is not a real video of the system, it's 10 static images with a few hundred interpolated "fake" frames. Still very cool though.
It indeed is very worth being very clear about the limited data that makes the images.
It is also very cool.
..Nothing to add, simply echoing your sentiment :-)
The Roman Coronagraph is designed to detect planets 100 million times fainter than their stars, which is 100 to 1,000 times better than existing space-based coronagraphs. The Roman Coronagraph will be capable of directly imaging reflected starlight from a planet akin to Jupiter in size, temperature, and distance from its parent star.
If this remains a long term design limitation it'll be interesting to see if people design satellite hardware that consists of multiple individual rectangular slab sized things (generally same size/shape per piece as starlink v3 test satellites which have unfolding PV/antenna), that can latch together once dispensed, and further unfold.
Such an architecture might not be an impossible design consideration if the goal is to have something big like the sun-shade/cold side of the Webb telescope.
I can't imagine that there will not be other versions. The Pez dispenser is just solving the problem at hand. Eventually, I wouldn't be surprised to see cargo bay doors similar to the shuttle's.
That seems likely. Best guess is the relatively small slot sized door is a cautious design while they're working out issues with re-entry heating and stresses and sacrificing ships into the ocean. Once they're very confident they have the configuration for the 'hot' side of the starship working well on re-entry (and probably after they've returned and caught a few), it could be expanded in size.
Yeah, they'll have more versions for sure. There are two main designs that have been discussed / shown before (one where the entire nose hinges "backwards" and exposes the payload, and one that looks like the shuttle bay doors). And I think that for NASA decadal projects (i.e. JWST-like big telescopes) they could even go with a non-reusable Starship, with "regular" fairings that get dropped.
It is not a long term limitation. One might design any number of stages to fly in place of Starship on top of the Super Heavy booster.
Also, large science payloads can be launched by SLS. Back in the days of the Ares program, there were proposals to launch an 8 meter reflector (ATLAST-8m)[1] using Ares V. SLS anticipates payloads of such size as well.
So there are at least two viable platforms on which enormous space mirrors might launch, and one of them is likely to be highly cost effective. It's up to the science establishment to propose such missions and get them funded.
A. I watched a documentary on the plane about SpaceX where they showed the Pez dispenser working and it was amazing.
B. You could have multiple panels operate as a swarm. There could be many "mirrors" that focus images on one central "collector". That would be larger than any telescope that needs to be shipped as one unit e.g. James-Webb.
> B. You could have multiple panels operate as a swarm.
Is that level of precision even remotely achievable with today's technology?
My understanding is that orbital insertion accuracy is in the ±10-50 meters range, with the most advanced formation flying satellite swarms hitting 10 cm to 1 m precision between satellites with the help of optical navigation.
But the precision between the panels on a telescope like JWST is in the sub-mm range, no?
Also, I'd assume stuff like orbital decay, atmospheric drag, gravitational perturbations, and solar radiation pressure would make it difficult to maintain precision over time.
I'm sure/hopeful there's some people here at HN working on stuff like this, please fill in and correct me!
Interferometry can be used to effectively combine multiple telescopes into one large imager. The technique becomes much more difficult at higher wavelengths, but there has been recent advances in infrared systems.
It would be nice to see a swarm of satellites advance astronomy for once!
Amazing. Scrolling down one of the comments has an animation of starts around the center of the Milky Way. I have seen a few short ones of nebulae. There should be much much more of this sort of thing.
I appreciate that scientist are not always after the pretty pictures. They can be expensive, do not always give the data needed, and the experiments do not always produce data that has obvious pretty picture potential. Still, for the average non professional scientist (me) the pictures are about all I will ever get out of the science.
A good chunk of science communication centres around how one conveys the wow factor to folks who aren't already obsessed with the particular field. Images like this really help sell it to the rest of us
The galactic center data actually proved there was a supermassive black hole at the center of the Milky Way, and weighed it precisely from those stars motions. The name of the account that posted that animation (Sagittarius A*) is the name of that supermassive black hole.
Black holes probably disappear due to Hawking radiation, but I don’t think we have observational evidence and the process takes forever for the black holes you can observe.
The term I would use instead is that the data provided observational support of a hypothesis. It didn't "prove" anything- proofs only exist in math. (yes, I know people use "prove" is colloquial way, but it's misleading, especially in observational work where you can't control variables to find causality.
When you think about it, it's so mindblowing that we humans can study and talk about these unimaginably large objects in the universe. Yet they just exist there regardless of what we do or think about them and will continue to exist way past whatever happens to our species.
> There should be much much more of this sort of thing.
As more telescopes come online, there'll be more data available for this type of stuff. You gotta realize that when a telescope only looks at something once per year, it takes a long time to gather enough data for these types of images to be created. My go to example is the motion of stars around SagA*.
Imagine living on a planet circling a star circling a black hole. This thing in the sky just growing bigger and smaller in your sky on a 12 year, or longer, cycle.
I wonder what Sag A* would look like in the night sky.
Somewhat related, but probably more fascinating: a time lapse animation of stars orbiting the blackhole at the center of our galaxy (Sagittarius A*) https://www.youtube.com/watch?v=TF8THY5spmo
Also check out the Simulated Observation of the Solar System by the Habitable Worlds Observatory (under "Videos"), expected to be launched in the 2040s, the first to be able to detect Earth-like planets around Sun-like stars! https://habitableworldsobservatory.org/multimedia
Space and the enormity of it breaks your mind when you start thinking about it.
The star in the middle of the animation, is approximately 20AU (Astronomical Units) in size looking at the scale line. 20AU is approximately 1.8b miles/3b kilometres or approximately the distance from the Sun to Uranus.
If Google's correct, if everyone on Earth lived on that star - each and every one of us could have a backyard larger than the surface area of Earth ;p
I don't think you should infer the radius of the star from the blacked out region. I think they just do that because the luminosity of the star is so intense it would blow away the sensitivity needed to see the planets. So they set everything to zero for a certain zone on the lens/sensor. It's not the physical surface of the star.
There are a handful of known red supergiant stars around 15 AU in diameter, 20 AU would be pushing past the boundaries of what we believe would be possible.
The star in the video, HR 8799, is about 50% larger than the sun.
It looks like HR8799 that the animation is based on is about 1.5x the radius of the sun.
That being said, my silly point still holds - there are stars that are truly massive. Stephenson 2-18 is approximately the size I mentioned, which is genuinely impossible to comprehend.
Yeah, but remember that those red supergiants' outer envelope is extremely sparse. The density is compared to the very upper layers of Earth's atmosphere - basically vacuum. Around 90% of a supergiants' radius is taken up by that ultra-thin gas envelope.
Wow, in terms of angle, how far are these planets separated from the star?
I always thought we would never be able to image something like that. The distances would be too small and the contrast too large to figure something at the resolution we can get on earth. I'll need to read up on how this was done.
Yea, the planets are gigantic, and in distant orbits from their star. I don't think we even have the ability yet to directly image exoplanets much smaller than, say, Saturn, or closer to their stars than Saturn.
The scale bar (20 AU) represents 20 time the distance between the Earth and the sun. This star is about 41 parsecs away, so the angular size of that scale bar is about half an arcsec. (One degree is split into 60 arcminutes, one arcminute into 60 arcseconds. Just like a clock).
That angle is about the diameter of a US quarter coin seen from 11km (7mi) away.
The noise from the blocked-out star noticably decreases in 2017. Is that due to changes in the stars' activity cycle, or is that due to better processing/capture technology?
Not stellar activity — a flare wouldn’t be visible on this scale of image.
The main concerns are the observatory —- how aligned all the many dozens of optics are — and the earths atmosphere on the nights the target was observed.
In 2017 we captured five nights worth of images and averaged them. Some early years only had one night.
Around 2019 we also figured out some better observing strategies— all the later data is taken without a coronagraph. Turns out the coronagraph was hurting more than it helped, close in. Not to say coronagraphs aren’t useful, but some aspects of the observatory control software aren’t in place to get the benefits out of the coronagraph.
I swear I'm not trying to criticize, but, uh--why only 10 or so photos? Why not just film it long term? Is it our position in earth's orbit that only lets us image that system once a year or so?
I would also assume it's not just "okay hit the button, okay there's that snapshot", it's likely sitting there collecting photons for a _while_ to get each picture.
The instrument is operated according to a detailed schedule that spans years. It takes a committee to create the schedule, and each separately scheduled observation is then organized by a team, with different teams organizing different observations.
They cannot simply aim the instrument at one system and forego everything else. The result you see is a campaign credited to at least four team members, and enough schedule time committed to make approximately one observation per year.
The main reason, is why bother? We know there’s four planets, we know they orbit according to Keplers laws, we know how bright they are. The public outreach is reasonably well handled by this motion smoothed video. Better to use that telescope time to look for new planets instead!
That said yes there is something about earths orbit. There’s a few month window that gives the best observation of this star. We time the observations to be roughly June- November most years.
What are the odds of there being smaller exoplanets that are effectively being outshone by the others? Since each one these is more massive than Jupitar.
But I doubt they’re outshining other planets — other planets on the same orbit would be unstable, and most likely be ejected from the system very quickly. The system is about fifty million years old, so a good guess is that the orbits have been stable for about fifty million years.
I will just say that this short movie is something most beautiful I've seen in last several years. To be able to see this, for real, not as a side-effect to the star is absolutely mind blowing.
My mother's high school graduation present was a fully illustrated, complete set of the World Book Encyclopedia. It played second fiddle and competitor to Encyclopedia Britannica. Many families would purchase these as a limited subscription, where one volume would be delivered per month, until they collected the entire A-Z set.
Mom's encyclopedia contained some amazing anachronisms, by the time I started reading the books in the 1980s. The most interesting one to me was the Kingdom of Hawaiʻi. It included black-and-white photographs of natives in grass skirts and the ocean surf.
Imagine an app that could go back into Wikipedia's article revision history and present them, as they were, 25+ years ago. That's actually sort of impossible for technical reasons.
From ~0:04 - 0:05, two dots at ~10 and 8 o'clock fade in and out simultaneously, with roughly the size and brightness of the planets. They peak at observation ~2016-07-06. Any idea what they are?
Their balanced position and simultaneous changes make them seem like an artifact of the imaging.
They're present for multiple dates at the bottom, and fade in and out. Are those dates and the fading fabricated as some sort of intermediate state and inserted into the animation? I did briefly look for something stating how the animation was made but didn't see anything.
Also, they are too regular in position and in their timeing (simultaneous) to be random noise, but could be an artifact of some part of the imaging and processing chain.
Yes, they were not very clear about this but my understanding is that there are only 10 real images, i.e. less than one per (earth) year. All other frames are interpolated, which can pretty accurately animate the positions of the planets, but is presumably completely inaccurate for anything else.
Thanks for the animation, which is amazing to see, and for your responses!
> Indeed the video is almost entirely “fabricated” by motion smoothing and interpolation between images taken a year or two apart.
That's fine but you might say that in your post (and maybe you did and I overlooked it). There's nothing wrong with it - the animation is great, just be open. In a world of misinformation and disinformation, it's more essential than ever.
The professional space community publishes so much artistically enhanced media that for me, it's guilty until proven innnocent. When I do trust it, like in this case (yes, I didn't really stop to think about the number of actual frames), I feel a bit deceived.
And the vast public less experienced in these matters already has doubts about science, the space program, conspiracy theories, etc. When they learn something is 'faked', we lose them.
Good spot! It’s an error in the primary mirror segment phasing.
The observatory has to phase the mirror segments periodically, and it’s a bit of an art as well as a science. For a while, something was happening with their algorithm and procedure that was leaving those spots. Some of us (hi) did complain and it was fixed for the most part. It did come back a couple times though….
The slightly incorrect phasing produces those spots. It’s conceptually like a diffraction spike.
Not to self-plug, but here's my video of the same four planets:
https://sefffal.github.io/images/orbital-animation.mp4
The creator of the GIF above used a data from a range of different telescopes and wavelengths, whereas I made this with using data only from same telescope (Keck), instrument, and wavelength (3.5 microns; near infrared).
I’m curious what that blight red smoke flickering around the star is. Some kind of interplanatory gas?
I think it might just be diffraction artifacts animated by the interpolation (I hereby invoke cunnignhams law)
That’s right. We only have images take every year or so, so I did a motion interpolation between the images using Keplers laws. Diffraction close in gets pulled around by the interpolation.
omg both animations are gorgeous; those far out orbits sure take a long time to complete
How come both videos only go up to 2022 or so? Did we stop watching this star? Or is there just a delay on releasing the data?
I think there’s a couple new images. I’ll upload an updated one some time.
You should post it on hn
For those that don't know, the Drake equation [0] included a term for "percentage of stars with at least one orbiting planet".
That was originally assumed to be non-zero but very low. Modern planet hunting techniques have revised that number to be close to 100%. [1]
0 - https://en.wikipedia.org/wiki/Drake_equation
1 - https://en.wikipedia.org/wiki/Drake_equation#:~:text=Fractio...
I've always hated speculation based on this equation because most of the variables are complete shots in the dark.
Sure, we can measure stellar formation and planetary occurrence, but that's about it.
Planets within habitable zone? How do we know what habitable is? We've examples of extremophiles on earth that could potentially live well outside the habitable zones we typically draw, and who's to say that life can't form in a Jupiter style atmosphere just because it didn't happen here (that we know of)? What's the habitable zone for hypothetical non-carbon life forms?
Fraction of suitable planets that develop life? Well, we've got n of 1 on that. We've found other earth-likes within habitable zones and we simply can't determine whether they do or ever did develop bacteria because they're too far away and our sensors are not sensitive enough.
Fraction of life-bearing planets that develop intelligent life? Technically, every planet we know of that bares life bares intelligent life. Does that mean the variable is 1? Not likely.
Fraction of intelligent lifes that create interstellar comms? Again, so far, 100%. Is it likely to be 1 in reality? Probably not.
Length of time such beings transmit in total from first to last broadcast. We've literally no way to determine this. Thus far universal average is, what 120 years? But those very first broadcasts were so weak and not intended for space interstellar comms. The first message sent to space deliberately wasn't until ~50 years ago, so the average space communication time of all known species is ~50 years, but again it's only n of 1 and so means effectively nothing.
AND it doesn't even calculate the thing we really care about which is the odds that we get to interact with or observe alien intelligence. There is no control for "ah, yes, as the universe ages, there will be more communicative species, but your species will have died before then, or will have died in the length of time required to establish back and forth communication. It doesn't tell us what the odds are of their having been a species that sent it's last broadcast before we started recording. It doesn't tell us how long we should expect to wait before it is overwhelmingly likely that we receive a broadcast...
It just feels like a uni bloke got high one night and said, right, well there'll have to be planets, and they'll have to have life, and that life will have to develop intelligence, and that intelligence will have to reach out, and it will have to reach out for long enough for us to hear it. Like...yeah, duh? What about species that have colonized and spread beyond their own planet due to overpopulation? The number of planets in the sky doesn't really matter if a single planet spawned 117 different communicative interstellar communities, does it?
Worth being very clear that this is not a real video of the system, it's 10 static images with a few hundred interpolated "fake" frames. Still very cool though.
It indeed is very worth being very clear about the limited data that makes the images. It is also very cool. ..Nothing to add, simply echoing your sentiment :-)
I'm excited for the leap in this tech that the Nancy Grace Roman telescope's new chronograph promises.
https://www.jpl.nasa.gov/missions/the-roman-coronagraph-inst...
The Roman Coronagraph is designed to detect planets 100 million times fainter than their stars, which is 100 to 1,000 times better than existing space-based coronagraphs. The Roman Coronagraph will be capable of directly imaging reflected starlight from a planet akin to Jupiter in size, temperature, and distance from its parent star.
I am as well and hopefully Starship allows even larger telescopes!
Starship can do it.
As long as the telescope can fit through the Starlink Pez dispenser.
If this remains a long term design limitation it'll be interesting to see if people design satellite hardware that consists of multiple individual rectangular slab sized things (generally same size/shape per piece as starlink v3 test satellites which have unfolding PV/antenna), that can latch together once dispensed, and further unfold.
Such an architecture might not be an impossible design consideration if the goal is to have something big like the sun-shade/cold side of the Webb telescope.
I can't imagine that there will not be other versions. The Pez dispenser is just solving the problem at hand. Eventually, I wouldn't be surprised to see cargo bay doors similar to the shuttle's.
That seems likely. Best guess is the relatively small slot sized door is a cautious design while they're working out issues with re-entry heating and stresses and sacrificing ships into the ocean. Once they're very confident they have the configuration for the 'hot' side of the starship working well on re-entry (and probably after they've returned and caught a few), it could be expanded in size.
Yeah, they'll have more versions for sure. There are two main designs that have been discussed / shown before (one where the entire nose hinges "backwards" and exposes the payload, and one that looks like the shuttle bay doors). And I think that for NASA decadal projects (i.e. JWST-like big telescopes) they could even go with a non-reusable Starship, with "regular" fairings that get dropped.
> If this remains a long term design limitation
It is not a long term limitation. One might design any number of stages to fly in place of Starship on top of the Super Heavy booster.
Also, large science payloads can be launched by SLS. Back in the days of the Ares program, there were proposals to launch an 8 meter reflector (ATLAST-8m)[1] using Ares V. SLS anticipates payloads of such size as well.
So there are at least two viable platforms on which enormous space mirrors might launch, and one of them is likely to be highly cost effective. It's up to the science establishment to propose such missions and get them funded.
[1] https://ntrs.nasa.gov/citations/20100004890
A. I watched a documentary on the plane about SpaceX where they showed the Pez dispenser working and it was amazing.
B. You could have multiple panels operate as a swarm. There could be many "mirrors" that focus images on one central "collector". That would be larger than any telescope that needs to be shipped as one unit e.g. James-Webb.
> B. You could have multiple panels operate as a swarm.
Is that level of precision even remotely achievable with today's technology?
My understanding is that orbital insertion accuracy is in the ±10-50 meters range, with the most advanced formation flying satellite swarms hitting 10 cm to 1 m precision between satellites with the help of optical navigation.
But the precision between the panels on a telescope like JWST is in the sub-mm range, no?
Also, I'd assume stuff like orbital decay, atmospheric drag, gravitational perturbations, and solar radiation pressure would make it difficult to maintain precision over time.
I'm sure/hopeful there's some people here at HN working on stuff like this, please fill in and correct me!
Interferometry can be used to effectively combine multiple telescopes into one large imager. The technique becomes much more difficult at higher wavelengths, but there has been recent advances in infrared systems.
It would be nice to see a swarm of satellites advance astronomy for once!
https://en.wikipedia.org/wiki/Astronomical_interferometer
Amazing. Scrolling down one of the comments has an animation of starts around the center of the Milky Way. I have seen a few short ones of nebulae. There should be much much more of this sort of thing.
I appreciate that scientist are not always after the pretty pictures. They can be expensive, do not always give the data needed, and the experiments do not always produce data that has obvious pretty picture potential. Still, for the average non professional scientist (me) the pictures are about all I will ever get out of the science.
A good chunk of science communication centres around how one conveys the wow factor to folks who aren't already obsessed with the particular field. Images like this really help sell it to the rest of us
The galactic center data actually proved there was a supermassive black hole at the center of the Milky Way, and weighed it precisely from those stars motions. The name of the account that posted that animation (Sagittarius A*) is the name of that supermassive black hole.
This work earned the 2020 Nobel Prize in Physics: https://www.nobelprize.org/prizes/physics/2020/summary/
Can you explain the past tense "there was" ? Is there a reason for a black hole to dissapear?
The black hole still exists (probably), the hypothesis that it existed was proven in the past.
Black holes probably disappear due to Hawking radiation, but I don’t think we have observational evidence and the process takes forever for the black holes you can observe.
It’s probably still there, but it’s 26,000 light years away, so the light we’re seeing today left Sag A in the Paleaolithic era.
The term I would use instead is that the data provided observational support of a hypothesis. It didn't "prove" anything- proofs only exist in math. (yes, I know people use "prove" is colloquial way, but it's misleading, especially in observational work where you can't control variables to find causality.
When you think about it, it's so mindblowing that we humans can study and talk about these unimaginably large objects in the universe. Yet they just exist there regardless of what we do or think about them and will continue to exist way past whatever happens to our species.
> There should be much much more of this sort of thing.
As more telescopes come online, there'll be more data available for this type of stuff. You gotta realize that when a telescope only looks at something once per year, it takes a long time to gather enough data for these types of images to be created. My go to example is the motion of stars around SagA*.
Direct link: https://bsky.app/profile/sagastar.bsky.social/post/3mwucitft...
Imagine living on a planet circling a star circling a black hole. This thing in the sky just growing bigger and smaller in your sky on a 12 year, or longer, cycle.
I wonder what Sag A* would look like in the night sky.
A million solar masses of stuff (stars and gases) orbiting within a parsec of the black hole would be quite a view even without the accretion disk.
Somewhat related, but probably more fascinating: a time lapse animation of stars orbiting the blackhole at the center of our galaxy (Sagittarius A*) https://www.youtube.com/watch?v=TF8THY5spmo
There are many more of these : https://en.wikipedia.org/wiki/List_of_directly_imaged_exopla...
Also check out the Simulated Observation of the Solar System by the Habitable Worlds Observatory (under "Videos"), expected to be launched in the 2040s, the first to be able to detect Earth-like planets around Sun-like stars! https://habitableworldsobservatory.org/multimedia
DrBecky's video on it: https://youtube.com/watch?v=z2JIkAPcdnU
Space and the enormity of it breaks your mind when you start thinking about it.
The star in the middle of the animation, is approximately 20AU (Astronomical Units) in size looking at the scale line. 20AU is approximately 1.8b miles/3b kilometres or approximately the distance from the Sun to Uranus.
If Google's correct, if everyone on Earth lived on that star - each and every one of us could have a backyard larger than the surface area of Earth ;p
I don't think you should infer the radius of the star from the blacked out region. I think they just do that because the luminosity of the star is so intense it would blow away the sensitivity needed to see the planets. So they set everything to zero for a certain zone on the lens/sensor. It's not the physical surface of the star.
There are a handful of known red supergiant stars around 15 AU in diameter, 20 AU would be pushing past the boundaries of what we believe would be possible.
The star in the video, HR 8799, is about 50% larger than the sun.
Good call!
It looks like HR8799 that the animation is based on is about 1.5x the radius of the sun.
That being said, my silly point still holds - there are stars that are truly massive. Stephenson 2-18 is approximately the size I mentioned, which is genuinely impossible to comprehend.
It's harder to comprehend smallness. The journey to planc constant is longer than the size of our observable universe.
Yeah, but remember that those red supergiants' outer envelope is extremely sparse. The density is compared to the very upper layers of Earth's atmosphere - basically vacuum. Around 90% of a supergiants' radius is taken up by that ultra-thin gas envelope.
Wow, in terms of angle, how far are these planets separated from the star?
I always thought we would never be able to image something like that. The distances would be too small and the contrast too large to figure something at the resolution we can get on earth. I'll need to read up on how this was done.
https://en.wikipedia.org/wiki/HR_8799
Yea, the planets are gigantic, and in distant orbits from their star. I don't think we even have the ability yet to directly image exoplanets much smaller than, say, Saturn, or closer to their stars than Saturn.
TL;DR - Two inside (16, 26AU) and two outside (43, 69AU) Pluto's orbit (39AU). They are all estimated to be a bit bigger than Jupiter.
The scale bar (20 AU) represents 20 time the distance between the Earth and the sun. This star is about 41 parsecs away, so the angular size of that scale bar is about half an arcsec. (One degree is split into 60 arcminutes, one arcminute into 60 arcseconds. Just like a clock).
That angle is about the diameter of a US quarter coin seen from 11km (7mi) away.
The noise from the blocked-out star noticably decreases in 2017. Is that due to changes in the stars' activity cycle, or is that due to better processing/capture technology?
I do not know, but my best guess would be an improved post processing algorithm was introduced.
Wouldn't you just post-process all images again at that point?
I believe it's because the star's brightness does fluctuate, so activity cycle based?
Not stellar activity — a flare wouldn’t be visible on this scale of image. The main concerns are the observatory —- how aligned all the many dozens of optics are — and the earths atmosphere on the nights the target was observed.
In 2017 we captured five nights worth of images and averaged them. Some early years only had one night.
Around 2019 we also figured out some better observing strategies— all the later data is taken without a coronagraph. Turns out the coronagraph was hurting more than it helped, close in. Not to say coronagraphs aren’t useful, but some aspects of the observatory control software aren’t in place to get the benefits out of the coronagraph.
I swear I'm not trying to criticize, but, uh--why only 10 or so photos? Why not just film it long term? Is it our position in earth's orbit that only lets us image that system once a year or so?
Telescope time is precious.
I would also assume it's not just "okay hit the button, okay there's that snapshot", it's likely sitting there collecting photons for a _while_ to get each picture.
Yeah each photo is one - five nights of work full time from 3-5 people.
> but, uh--why only 10 or so photos?
The instrument is operated according to a detailed schedule that spans years. It takes a committee to create the schedule, and each separately scheduled observation is then organized by a team, with different teams organizing different observations.
They cannot simply aim the instrument at one system and forego everything else. The result you see is a campaign credited to at least four team members, and enough schedule time committed to make approximately one observation per year.
The main reason, is why bother? We know there’s four planets, we know they orbit according to Keplers laws, we know how bright they are. The public outreach is reasonably well handled by this motion smoothed video. Better to use that telescope time to look for new planets instead!
That said yes there is something about earths orbit. There’s a few month window that gives the best observation of this star. We time the observations to be roughly June- November most years.
Interesting to see 12 years in 12 seconds, time is relatíve
What are the odds of there being smaller exoplanets that are effectively being outshone by the others? Since each one these is more massive than Jupitar.
They probably have moons.
But I doubt they’re outshining other planets — other planets on the same orbit would be unstable, and most likely be ejected from the system very quickly. The system is about fifty million years old, so a good guess is that the orbits have been stable for about fifty million years.
They need to remove that one frame
I will just say that this short movie is something most beautiful I've seen in last several years. To be able to see this, for real, not as a side-effect to the star is absolutely mind blowing.
When my mother was born, plate tectonics was a hypothesis. When I was born we didn't know for certain if planets existed outside of our solar system.
When my grandparents were born, we didn't know there were other galaxies.
My mother's high school graduation present was a fully illustrated, complete set of the World Book Encyclopedia. It played second fiddle and competitor to Encyclopedia Britannica. Many families would purchase these as a limited subscription, where one volume would be delivered per month, until they collected the entire A-Z set.
Mom's encyclopedia contained some amazing anachronisms, by the time I started reading the books in the 1980s. The most interesting one to me was the Kingdom of Hawaiʻi. It included black-and-white photographs of natives in grass skirts and the ocean surf.
Imagine an app that could go back into Wikipedia's article revision history and present them, as they were, 25+ years ago. That's actually sort of impossible for technical reasons.
In October 2001 Wikipedia only had 12,000 articles, compared to 7+ million today.
https://commons.wikimedia.org/wiki/Data:Number_of_English_Wi...
So all we have to do is send telescope right up and let it record...
From ~0:04 - 0:05, two dots at ~10 and 8 o'clock fade in and out simultaneously, with roughly the size and brightness of the planets. They peak at observation ~2016-07-06. Any idea what they are?
Their balanced position and simultaneous changes make them seem like an artifact of the imaging.
It looks like they're only present for one real frame (of the original 10), so very possible that it's just noise in that frame.
They're present for multiple dates at the bottom, and fade in and out. Are those dates and the fading fabricated as some sort of intermediate state and inserted into the animation? I did briefly look for something stating how the animation was made but didn't see anything.
Also, they are too regular in position and in their timeing (simultaneous) to be random noise, but could be an artifact of some part of the imaging and processing chain.
Yes, they were not very clear about this but my understanding is that there are only 10 real images, i.e. less than one per (earth) year. All other frames are interpolated, which can pretty accurately animate the positions of the planets, but is presumably completely inaccurate for anything else.
As responded above, they were persistent diffraction errors in the primary mirror phasing. Think of it like those diffraction spikes from Hubble.
Indeed the video is almost entirely “fabricated” by motion smoothing and interpolation between images taken a year or two apart.
Thanks for the animation, which is amazing to see, and for your responses!
> Indeed the video is almost entirely “fabricated” by motion smoothing and interpolation between images taken a year or two apart.
That's fine but you might say that in your post (and maybe you did and I overlooked it). There's nothing wrong with it - the animation is great, just be open. In a world of misinformation and disinformation, it's more essential than ever.
The professional space community publishes so much artistically enhanced media that for me, it's guilty until proven innnocent. When I do trust it, like in this case (yes, I didn't really stop to think about the number of actual frames), I feel a bit deceived.
And the vast public less experienced in these matters already has doubts about science, the space program, conspiracy theories, etc. When they learn something is 'faked', we lose them.
Good spot! It’s an error in the primary mirror segment phasing.
The observatory has to phase the mirror segments periodically, and it’s a bit of an art as well as a science. For a while, something was happening with their algorithm and procedure that was leaving those spots. Some of us (hi) did complain and it was fixed for the most part. It did come back a couple times though….
The slightly incorrect phasing produces those spots. It’s conceptually like a diffraction spike.