[HN Gopher] First Ever Image of a Multi-Planet System Around a S...
___________________________________________________________________
First Ever Image of a Multi-Planet System Around a Sun-Like Star
Captured by ESO
Author : rbanffy
Score : 499 points
Date : 2020-07-22 14:44 UTC (8 hours ago)
(HTM) web link (www.eso.org)
(TXT) w3m dump (www.eso.org)
| [deleted]
| Diederich wrote:
| A recent video talking about what it could take to get high
| resolution imagery of exoplanets. The video title is a bit hand
| wavy, but it basically involves using the sun as a gravitational
| lens:
|
| https://www.youtube.com/watch?v=NQFqDKRAROI
| trentnix wrote:
| Amazing video. Thanks for sharing.
| nsxwolf wrote:
| Why do they appear so large and so close together in the photo?
| (Assuming that is an image of the star and one of the planets).
| Are they really point sources, blooming to cover more pixels?
| pavlov wrote:
| Click on the image to reveal the entire image: there's a star
| and two planets.
|
| (It's ridiculous that they would publish the image cropped like
| this.)
| ChuckMcM wrote:
| This is nice work. I am amazed at the advances in planet
| discovery from "other stars 'might' have planets" to post Kepler
| "more than half the stars have planets."
|
| The other "unknown" is under what conditions can intelligent life
| evolve? Once you know that window, the Drake equation gets even
| more interesting.
|
| The notion that we are the only intelligent species in the galaxy
| seems more and more unlikely.
| runarberg wrote:
| Question: What do you consider 'intelligence'?
|
| I mean, we don't need to look outside our own planet to find
| traits of what I consider intelligent behavior in other
| species.
|
| I have a feeling that if we find an alien species it wont be
| intelligent, simply because we won't define it as such. They
| might even have technology we couldn't even begin to
| understand, but at the same time they will probably fail at
| exhibiting something we consider basic. And worse, they will
| have no way of being taught.
|
| Aside: I suggest in the future--if you want to avoid pedantic
| comment like these--that you reword your last sentence to
| include intelligent life on earth, e.g. _"The notion that earth
| is the only planet to harbor intelligent life..."_
| ChuckMcM wrote:
| Its a fair question. My take on it is more toward the
| introspection/self-analytical side of the argument than the
| tool-using/self-awareness side. Though both are clearly
| "intelligent" in the dictionary definition.
|
| In casual conversation however, per Gretchen McCulloch's book
| "Because Internet"[1], I tend to stick with phrases that are
| most accessible rather than those that are most precise.
|
| My experience is that being overly precise in my speech can
| be off-putting to people. Enough so, that when I have
| encouraged feedback, both positive and negative, on my
| communication skills it came up more than once as "making you
| seem like you are showing off how much you know about
| something and making others feel dumb."
|
| [1] Really a great read, my daughter got it for me for my
| birthday and I thoroughly enjoyed it.
| runarberg wrote:
| Fair enough. I do think that finding evidence of extra-
| terrestrial life would be amazing enough. If we could then
| later explore how life outside our own planet behaves, I am
| in no doubt that our minds will be blown. And if we find a
| way to communicate with one of these species... perhaps by
| that time any philosophical speculation on _what_
| intelligence is will be rendered obsolete.
| Vysero wrote:
| I think it's super cool personally, and inspiring. Imho, the
| notion seems rather silly at this point.
| charlesdenault wrote:
| Not to mention these are gas giants at a relatively nearby star
| (300 lightyears away) and we consider the universe is something
| shy of 100 billion lightyears in diameter. We're not even
| scratching the surface!
| rkagerer wrote:
| The pictures are much better quality than I expected! I thought
| I'd be lucky to see a couple specks. These are reminiscent of
| (and a bit better than) looking at Jupiter through a small
| refractor.
| eclaircissement wrote:
| How do they determime how heavy thr exoplanets are?
|
| The team also found the two exoplanets are much heavier than the
| ones in our Solar System, the inner planet having 14 times
| Jupiter's mass and the outer one six times.
| eclaircissement wrote:
| This is awesome!!
| etxm wrote:
| I kind of love that the first system photographed(?) is in a
| different orientation and that we have a "top" down view of it.
| swiley wrote:
| It doesn't have to be in a different orientation, it could be
| parallel with ours but not coplaner. The important thing for
| this kind of picture is that a normal with the tail near the
| system from plane of rotation points roughly in our direction.
| Johnjonjoan wrote:
| I think the multi-planet system part is what makes it a first.
| dylan604 wrote:
| How do you mean? That it it was photographed in such a
| manner? We definitely know of plenty of several systems with
| multiple planets.
| Johnjonjoan wrote:
| Yes that's exactly how I understood it. Otherwise anyone
| who has taken a picture of the night sky probably beat this
| image.
| davedx wrote:
| Incredible. 300 light years away and photographed by a ground
| based telescope. We keep pushing the boundaries. I'm excited for
| the next couple of decades of astronomy. What more will we see?
| Gys wrote:
| Proof of life outside earth would be the coolest
| throwaway0a5e wrote:
| Give it 20yr. Between Mars and the gas giant's moons there's
| almost certainly some, possibly long dead, bacteria out
| there. Whether we share a common ancestor is anyone's guess.
| ryanSrich wrote:
| Even finding dead alien bacteria would be a miracle. Time
| is the great constraint of finding life. It's less about
| where are the aliens, and more about when.
| arethuza wrote:
| Some people think that would be _very bad_ as it would
| suggest that the Great Filter is in our future rather than
| our past:
|
| https://en.wikipedia.org/wiki/Great_Filter
| bosswipe wrote:
| Maybe the Great Filter is global warming, or other similar
| planetary pollution. Once a civilization ramps up
| Moloch[1], the self-reinforcing self-perpetuating
| structures necessary to organize industry at a planetary
| scale, it becomes too difficult to pull back and stop it
| before it's too late.
|
| [1] https://www.lesswrong.com/posts/TxcRbCYHaeL59aY7E/medit
| ation...
| airstrike wrote:
| That was a really interesting read. All of the examples
| were incredibly insightful, but the cancer one felt like
| the most similar to a great filter, perhaps because it
| can very easily be used to explain the issue abstractly.
| [deleted]
| eloff wrote:
| I don't see this as likely. Global warming is not an
| extinction level event (for humans! for a lot of other
| life, it will be, although habitat loss may well play a
| larger role in that.)
|
| My own speculation on the Great Filter is that any
| intelligent alien civilization is almost certainly a race
| of social predators that evolved - and thus are in
| competition for resources.
|
| I worry that competition between individuals and
| individual states necessarily ends in the destruction of
| the environment on which they depend and quite likely in
| direct destruction in war with advanced technology.
|
| Us humans need to find some other paradigm under which to
| move forward, capitalism and competition, which have
| brought us such amazing results to date could well also
| be our undoing.
| [deleted]
| throwaway0a5e wrote:
| Unlikely.
|
| We're going to have a hard time dumping enough anything
| into the atmosphere (or causing some other kind of
| pollution) to kill ourselves entirely. We'd osculate
| around an equilibrium where we dump some pollutant into
| our environment to the point where our population
| decreases, natural processes remove it and our population
| increases, wash, rinse, repeat. You can see similar
| population and resource usage patterns in many
| ecosystems.
|
| And before anyone tries to twist my words to saying
| global warming isn't a bad thing, that's not what I'm
| saying. I'm just saying that humans as a species will
| likely survive it.
| bosswipe wrote:
| It's not species extinction that makes life undetectable,
| it's extinction of the civilization. For a civilization
| to be detectable it has to be at least at our level, or
| maybe a century beyond our level. If our civilization
| collapses it would mean that we were only detectable for
| a couple of centuries and then it could take millennia
| for us to get back to our level, especially if we've
| extracted all the easy to extract natural resources
| making it harder for our ancestors to rev back up, or if
| large parts of the planet become uninhabitable.
| macintux wrote:
| This seems like humanity's last advanced civilization:
| the easy energy is all tapped out.
|
| Maybe some other life form could have one after enough
| time has passed, but we can't bootstrap ourselves a
| second time.
|
| (Edit: to be clear, I'm agreeing with you.)
| throwaway0a5e wrote:
| >This seems like humanity's last advanced civilization:
| the easy energy is all tapped out.
|
| That's probably what someone said in the middle ages when
| they finished deforesting Scotland.
|
| We still have nuclear. There's an obscene amount of
| energy in it. It's just not attractive while we still
| have other "easy" options.
| macintux wrote:
| If this civilization collapses, how are we going to get
| to the point where we can build nuclear fission reactors?
| Roboprog wrote:
| Is it that hard to enrich isotopes enough to make a steam
| engine that runs on radium, thorium or uranium instead of
| coal?
|
| If you know that radioactive isotopes exist, it sounds
| like steampunk, 1850s, level tech could build a power
| plant, but perhaps not a bomb.
| macintux wrote:
| I'm not qualified to answer, but there was a bit of
| discussion about the idea on Reddit:
|
| https://www.reddit.com/r/worldbuilding/comments/57peek/ca
| n_y...
| throwaway0a5e wrote:
| >it's extinction of the civilization. For a civilization
| to be detectable it has to be at least at our level,
|
| My point is that we won't go extinct, we'll bounce back
| and get another try.
|
| >especially if we've extracted all the easy to extract
| natural resources making
|
| Would you rather hollow out a mountain to mine minerals
| or dredge through what used to be a major city? We've
| concentrated all sorts of useful things on earth's
| surface. If anything the next civilization will have it
| easy.
|
| >harder for our ancestors to rev back up, or if large
| parts of the planet become uninhabitable.
|
| Large parts of the planet _were_ more or less
| uninhabitable. The few people who lived in the arctic and
| the deserts mostly just followed food /water sources.
| They contributed little to civilization's progress
| (mostly in the field of astronomy because desert nights
| and polar winters give you plenty of time to look at the
| starts) because they didn't have the spare resources to
| engage in those pursuits because they were too busy
| surviving. Progress has always come from the places that
| are easy to live in and therefore have resource
| surpluses.
| bosswipe wrote:
| Separate from the details of the consequences of global
| warming itself, more generally my hypothesis is that in
| order for a civilization to become aware that it is
| consuming too many natural resources requires a level of
| advanced development that can only be achieved by
| consuming too many resources. In other words, it might be
| more likely than not that when a planet produces a
| civilization that enters an industrial revolution it ends
| burning through its resources in an unsustainable way and
| ends up collapsing. For us it's not just global warming
| pollution that is a problem, there are many other
| resources that we are overutilizing in an unsustainable
| way, and it seems that we are completely incapable of
| coordinating as a planet to make the necessary
| sacrifices. The only hope I see at this point is that
| technology will save us, it's a race between technology
| and over-consumption with civilization on the balance.
| Maybe the odds when this situation comes up across the
| universe are in favor of over-consumption.
| gorkish wrote:
| We can't honestly have any practical discussion about the
| concept of a Great Filter until we get to the point that
| our observational capability would be sufficient to
| reliably detect another civilization at a similar level of
| development to our own within a sufficient size search
| space: within our own galaxy for instance. Considering that
| 68% of the universe's energy and 27% of its mass is still
| basically unaccounted for, it's clear we have a very long
| way to go before this idea is worth bringing out of the
| halls of existential philosophy.
|
| Let's say for the sake of argument that a civilization
| exists in our nearest neighbor system, Proxima Centauri.
| Let's assume that it has developed with a similar impact to
| their system as humans have had to our own -- radio
| emissions, a handful of interplanetary and interstellar
| space probes, nuclear tests, etc. Could we detect them?
| Everything I have read concludes that we currently could
| not. The concept of being able to receive interstellar TV
| transmissions is such a sci-fi trope I don't think very
| many people consider that it is essentially impossible.
| simias wrote:
| Even if we passed _a_ Great Filter it doesn 't necessarily
| mean that there wouldn't be an other one in front of us.
|
| Also not finding other civilizations wouldn't be a proof
| that we passed any filter at all, maybe plenty of
| civilizations have been incredibly successful already,
| they're just so far beyond our comprehension of the world
| and consciousness that we can't meaningfully interact with
| them.
| anonAndOn wrote:
| Perhaps the Great Filter is not a single event? Perhaps it
| can happen more than once and occasionally shows up as a
| large space rock. [0]
|
| [0]https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleoge
| ne_e...
| birdyrooster wrote:
| Why is this very bad? What is wrong with society not
| existing if it's inevitable. Is dying very bad or is it an
| inescapable reality that isn't good or bad? What is
| inherently good about life existing or spending the finite
| energy of the cosmos? It all comes to an end eventually. Is
| that bad? Can humans offer anything to the universe other
| than parasitism?
| s1artibartfast wrote:
| One persons parasitism is another's enrichment.
|
| Supporters of ethical hedonism hold that the enjoyment of
| life holds axiomatic value, and life itself is a
| prerequisite for enjoyment.
|
| https://en.wikipedia.org/wiki/Hedonism
| macintux wrote:
| It seems odd that the universe would be as vast and
| fascinating as it is but there be no one to appreciate
| it.
|
| I want humanity to reach another galaxy someday.
| simonebrunozzi wrote:
| Scary.
| piptastic wrote:
| Hmm, maybe I'm missing something, but the main argument for
| the Great Filter is that we haven't observed any
| extraterrestrial life. If we started observing that life,
| that might just mean that so far our observation technology
| has not been good enough previously.
| dyingkneepad wrote:
| Yeah, detecting life could mean many things:
|
| - The filter is ahead us
|
| - There is no filter
|
| - The filter is behind us, but ahead of the other planet
|
| - Both planets have successfully got past the filter
|
| We'll still be debating :). Then we'll go crazy trying
| find evidence of life in more planets.
| adventured wrote:
| An addition to there is no filter (yet):
|
| - We're one of the first nearby and we're going to help
| build a filter
|
| The various AI we give birth to over the next two
| centuries are going to dominate several galaxies. There
| are many filters - competing standards - throughout the
| universe, our galaxy doesn't yet have one. Humans will
| cease to exist as we think of them now, within those two
| centuries (and not due to climate change or any other
| similar event).
| catwind7 wrote:
| that said, the likelihood of there being _no_ filter is
| still lower than the others.
|
| if we detect life so near to us and _yet_ we still have
| yet to encounter life from another planet means there's
| likely still _some_ kind of filter. So I don't think the
| likelihood of no filter is high if we detect life
| majkinetor wrote:
| Rather then apocaliptyical filter, the most probable
| reason is that space is so wast that even if advanced
| life was common, chance of meeting/observing one would be
| next to 0. Think about our civ living on a sand grain in
| the desert - the chance is almost 0 to encounter another
| civ living on sand grain on random desert location no
| matter how advanced your tech is.
| est31 wrote:
| We can't detect life at our stage of development from
| afar, or from earlier stages, but things that extremely
| advanced civilizations build like dyson spheres can't be
| hidden really.
|
| The issue is that the universe is extremely old compared
| to how long it took for earth to develop life. It's ample
| time for civilizations to develop technologies extremely
| far more advanced than ours. So why isn't there a single
| civilization that's so advanced that it builds these
| things?
|
| So there must be some "filter" that prevents
| civilizations from doing that, whether they are alive or
| dead. Maybe they just don't want to, but then ALL of them
| have to not want to do it, which would be weird.
|
| If we detect life close to us, it makes it more likely
| that there is tons of life around the galaxy, which makes
| it more likely that the filter is ahead of us. If we
| detect no life close to us, it makes it more likely that
| the filter is past us.
|
| See this Kurzgesagt video about the topic:
| https://www.youtube.com/watch?v=UjtOGPJ0URM
| TremendousJudge wrote:
| I don't like that theory, it's completely limited by our
| current understanding of how a "more advanced"
| civilization would look like. If we haven't seen signs of
| what we think more advanced civilizations would look
| like, the simplest explanation is that what we think
| advanced civilizations are like is wrong
| baja_blast wrote:
| > The issue is that the universe is extremely old
| compared to how long it took for earth to develop life
|
| I wouldn't call the universe very old. It's only like
| 13.x billion years old. If you take into account the
| amount of time it takes for heavier elements to be
| created, the time for the universe to settle down I'd say
| we are in the first cohort. It took us 4.5 billion years
| to evolve and if humanity got wiped out life on Earth
| would most likely continue on as it has for millions of
| years before with megafauna.
|
| Looking at how life appeared immediately after the planet
| cooled down and had liquid oceans most likely indicates
| abiogenesis is common, multicellular may be much more
| rare and intelligence probably is exceedingly rare given
| how expensive big brains are. I just don't think there
| was enough time in the early universe for intelligent
| civilizations to have evolved.
| olmideso wrote:
| > If we detect life close to us, it makes it more likely
| that there is tons of life around the galaxy, which makes
| it more likely that the filter is ahead of us.
|
| Isn't is the other way around? I though that the main
| argument for the filter ahead of us is that we haven't
| found any civilization, which means civilizations cannot
| develop past some level at which they can be detected by
| us. But if we'll have found one, this means that such
| level of civilization can be passed, and therefore
| reduces the chances that there is a filter.
| bdamm wrote:
| I think by "life" the parent was talking about microbes
| on Mars or waterbears on comets or something. Technology
| developing life is a different thing entirely. If we find
| primitive life nearby, then there probably is primitive
| life everywhere, and very little technology developing
| life (because of the "filter").
| vkou wrote:
| My preferred solution to the great filter is to assume
| that things like Dyson spheres can't feasibly be built,
| at _any_ level of technological development.
|
| So there may be millions of civilizations that can get
| into orbit with chemical or nuclear rockets, but not a
| single one that can carry out a megaproject that could be
| seen from Earth.
| [deleted]
| rrrrrrrrrrrryan wrote:
| I've always thought it made more sense that microbial
| life with took billions of years to develop, and
| originated someplace other than earth. The reason we
| don't see hyper-advanced civilizations is because
| intelligent life is only just starting to pop up
| alongside us, right now, and perhaps we're one of the
| earlier manifestations.
|
| It's not my domain, but there are apparently some markers
| of genetic complexity that give some weight to this
| theory:
| https://arxiv.org/ftp/arxiv/papers/1304/1304.3381.pdf
| est31 wrote:
| Personally I think life originated on earth. We shouldn't
| look at contemporary prokaryotes to determine how complex
| prokaryotes were at the start of life. They had billions
| of years to develop as well and if the more complex ones
| are fitter than the less complex ones, they will win.
| E.g. you think rotting plants is a normal thing but there
| was a time when plants wouldn't and just form giant
| heaps, forming the coal reservoirs of today.
|
| Anyways, let's assume life originated at some other
| planet and it has started life at half of the galaxy at
| the time it reached earth (so we weren't lucky to be
| "close" to the origin).
|
| Earth is 4500 million years old, and life is assumed to
| have existed here since 4400 million years. So
| intelligent life took 4400 million years to "develop"
| here on earth. Light speed allows you to colonize the
| milky way comfortably within a million years. What if it
| takes 100 million years less on some other planet? Or it
| took just 10 million years less?
|
| Either earth is very close to the real origin (or has
| been at the start of life), or the filter is in the past,
| or some other explanation.
| majkinetor wrote:
| This theory is actually proposed by Nick Lane et al - it
| says that microbial life is probably ubiqutuous and that
| complex life is not and was a happy accident on Earth,
| which means its very improbable on other planets. The
| prereqs for it happened only once on Earth, when one
| microbe swallowed another and the smaller one became
| mitochondria enabling complex cell structure and shape.
| Given that microbial life exist in extreme environments
| on Earth and that its prereq is just a hot molecular
| soup, its probable it exists everywhere. On the other
| hand, the 'happy incident' didn't repeat on Earth to
| create another complex cell form - all higher life uses
| the same cell structure.
| TremendousJudge wrote:
| That's what the great filter theory means when they talk
| about it being behind us -- we don't see life in other
| places because developing to where we are now is almost
| impossible.
|
| I don't buy it though -- we're in an average planet on an
| average star, nothing about our environment seems to be
| particularly rare.
| s1artibartfast wrote:
| I think the statement that we are on an average planet
| deserves more scrutiny. We have yet to observe another
| planet like ours.
|
| There are a number of Earth's attributes that we don't
| understand and have poor extra-solar data on.
| Particularly, the following:
|
| Technically active plates after 4.5 Byrs. Effective
| magnetic core after 4.5 Byrs. Large amounts of surface
| water, presumably from our late heavy bombardment. Small
| enough to leave with a chemical rocket while meeting the
| above.
| majkinetor wrote:
| All those 'limitations' are too much anthropomorphic for
| my taste - life can probably exist in far more niches.
|
| Also, at our current tech level, planets are very hard to
| even observe for existence, let alone their geographical
| features.
| s1artibartfast wrote:
| I tend to agree with both your points, but was addressing
| the specific claim that Earth-like conditions are
| average, or at least not particularly rare.
|
| We simply don't have data to support that claim, and the
| parameters required to make earth habitable for life (as
| we know it) are vastly more numerous than most people
| acknowledge.
| majkinetor wrote:
| Lets start with Oscam Razor then: its wast universe. Even
| on Earth, there are untouched places. All other theories
| compared to this one, which is easy to understand and
| also already known to be in effect on this planet, are as
| close to the truth as theory that great filter are evil
| pink elephants in the center of the galaxy.
| vkou wrote:
| > I've always thought it made more sense that microbial
| life with took billions of years to develop, and
| originated someplace other than earth. The reason we
| don't see hyper-advanced civilizations is because
| intelligent life is only just starting to pop up
| alongside us, right now, and perhaps we're one of the
| earlier manifestations.
|
| This explanation does not work, because of the
| timescales.
|
| Five thousand years ago, we built the Pyramids. Fifty
| years ago, we landed on the Moon.
|
| In contrast, it took four billion years to go from
| single-celled life, to the pyramids.
|
| The odds of us being first by happenstance are
| astonishingly small. It's much more likely that either we
| are unique, or that civilizations don't leave much of a
| trace outside of their solar systems, regardless of
| whether or not they die out in the blink of a cosmic eye.
| baggy_trough wrote:
| We simply haven't developed enough yet. It wouldn't be
| good game design to encounter other civs at this stage.
| Roboprog wrote:
| Tutorial level civilization.
|
| You must complete energy collection on current planet for
| XP to advance to level 2.
| catwind7 wrote:
| just learned about the "great filter", very interesting.
| I think it does mean that our observation tech is not
| good previously - it also sounds like if we did start
| observing life, the fact that we have yet to be visited /
| colonized by that life form means only re-affirms the
| unlikelihood of interplanetary travel..
|
| according to
| [wikipedia](https://en.wikipedia.org/wiki/Great_Filter):
|
| > So by this argument, finding multicellular life on Mars
| (provided it evolved independently) would be bad news,
| since it would imply steps 2-6 are easy, and hence only
| 1, 7, 8 or 9 (or some unknown step) could be the big
| problem.[4]
| bickeringyokel wrote:
| Imagine that, knowing there's intelligent life out there,
| but knowing we will never meaningfully interact with them
| because it's impossible to travel any useful distance or
| communicate in any real way. Even if we could travel vast
| distances, It seems likely if we discover any life out
| there it may be long dead by the time we get there.
| catwind7 wrote:
| that's really sad :(. 300 light years ... gonna take a
| while. maybe the filter is space travel - no civilization
| is able to amass enough energy to go those distances
| macintux wrote:
| We have an enormous, almost inexhaustible source of
| energy just 1 AU away.
| koheripbal wrote:
| We cannot change the existence of one or more Great
| Filters.
|
| Our best chance of survival is finding out about one as
| soon as possible.
|
| ...so the only path remains forward.
| peroporque wrote:
| Step 1: define "life"
| m3kw9 wrote:
| 2 dots one white and one orange.
| glouwbug wrote:
| You could say the same about us - the blue dot
| throw1234651234 wrote:
| Why a picture of this and not Alpha Centauri at ~4 ly?
| peroporque wrote:
| Alpha Centauri has a binary system with another third sun
| orbiting the other two at half a light-year or so. Not very
| "sun-like".
| throw1234651234 wrote:
| However, it has planets thought to be in the Goldi-locks zone
| around one of the stars. Seems like if they can get that kind
| of resolution at 300ly, they should be able to do infinitely
| better at 4. Just a thought, I am sure I am missing
| something.
| infogulch wrote:
| A comment upthread mentions that one of the biggest
| obstacles to detecting planets is the huge contrast between
| the planet and its host star: detecting 10-14 orders of
| magnitude difference between the luminosity of a star and
| orbiting planet cannot be made simpler by adding in 2
| additional stars.
| Johnjonjoan wrote:
| Another commenter said: "The two gas giants orbit their
| host star at distances of 160 and about 320 times the
| Earth-Sun distance."
|
| Just a guess but perhaps being in the Goldilocks zone the
| planets are harder to discern from Alpha Centauri.
|
| I figure the technology that blocks the star light may mean
| this isn't the case though.
| colanderman wrote:
| Make sure to click the lead image to see the star also.
| HorizonXP wrote:
| Thanks for the notice, I missed it, and it's much more
| impressive this way! I thought I was looking at the star and a
| single planet.
| sosuke wrote:
| I can't continue down this rabbit hole so I'm asking for a
| handout. I remember reading about the limitations of light and
| contrast to resolve smaller details on the moon or other solar
| systems like this. I've since lost the details and links to time.
|
| Is there any upper limit, physically, to this? Would it be
| possible on paper to design a system that could take pictures of
| the moon where you could see individual strands of hair on a
| human?
|
| I'm curious if we might at some point construct enormous arrays
| of telescopes spanning large (human perspective) sections of
| space that could give us a window into our galaxy.
| throwaway2048 wrote:
| https://en.wikipedia.org/wiki/Diffraction-limited_system
|
| There is a fundamental relationship between wavelength of light
| and focus-ability/magnification.
|
| You could in principle build an increasingly larger lense to
| get around the problem, but eventually that hits practical
| limits.
| robin_reala wrote:
| For varying definitions of pratical. For example, you can use
| a star as a gravitational lens.
| webmaven wrote:
| Can't you create ever larger arrays of reasonably sized
| lenses? And "array" just means "two or more widely separated
| by a known distance", so opposite sides of (polar?) orbit
| should work.
| semi-extrinsic wrote:
| There are several physical limits to how small objects can be
| resolved.
|
| Here is a discussion thread with regards to the smallest lunar
| object visible - seems to be around 350 meter resolution for an
| earth bound telescope.
|
| https://www.cloudynights.com/topic/712653-what-is-the-smalle...
| ChrisKnott wrote:
| But could images from several telescopes be combined through
| a Kalman filter or something to resolve higher details?
|
| I am imagining some kind of internet enabled telescope that
| knows it's GPS location and orientation, and phones home it's
| imagery to a central server. If millions of people bought and
| used a product like that, is it theoretically possible to see
| the lunar rover?
| semi-extrinsic wrote:
| https://en.wikipedia.org/wiki/Astronomical_interferometer
|
| TL;DR: for optical wavelengths, with typical image sensors
| that only detect amplitude and not phase of the
| electromagnetic wave, you need to do some really hard work
| to ensure optical coherency. For radio telescopes, it's a
| lot easier since you measure both amplitude and phase.
|
| Another technique that's a lot easier to accomplish for
| amateurs is lucky imaging:
|
| https://en.wikipedia.org/wiki/Lucky_imaging
| SiempreViernes wrote:
| In this context, it's relevant to note that the VLT was
| built with interferometry in mind, and they are now
| getting it to work reliably. See for instance the page
| about the GRAVITY instrument:
| https://www.eso.org/public/teles-instr/paranal-
| observatory/v...
| dmead wrote:
| i'm not expert. i have a back yard observatory with a 12 inch
| and an 8 inch SCT telescopes.
|
| there is a limit to how far information can propagate. but with
| wider and wider scopes we can deal with the wave properties of
| light and how those waves get wider and wider as you go farther
| away. (see the inverse square law)
|
| so, we could probably see a human hair on the moon, but the
| mechanism to do so would be the size of a city like LA or
| something.
|
| the best way we have to deal with that is actually
| interferometry. you take measurements of the light wave emitted
| by a source at several points along it's wave front and infer
| what the source would look like closer up.
|
| it's very fuzzy but gives us pictures of some very large very
| far away structures in the universe.
|
| so, maybe if we had enough telescopes pointed at the moon, we
| could see fine structures like that? but my feeling is that a
| lot of that information on that scale is just lost from the
| perspective of each scope, so you really need to capture all of
| it at a weirdly large scale.
| hammock wrote:
| HDR for astrophotography
| dekhn wrote:
| Telescopes like VLT, the LIGO experiment, CERN LHC and ATLAS, and
| a few others really represent the state of the art in terms of
| precision as applied the science.
|
| I got fascinated with the challenges associated with building
| high precision systems (which has been an ongoing pursuit since
| the beginning of the industrial revolution that has led to untold
| scientific and economic wealth). It's not easy. Progress depends
| on large numbers of people working together across multiple
| fields to build systems that are often only a few percent better
| than the previous generation. Sometimes, there are breakthroughs
| and fields progress rapidly, only to end up stagnated as they
| reach their theoretical limits or other bottlenecks.
|
| What humans have achieved, over the course of civilization is
| really quite extraordinary and we shouldn't ignore that what
| people were doing at the beginning of civilization required
| precision as well, but the precision depended far more on the
| physical skills of the artisan, than their ability to use their
| brain and capital to make highly precise objects.
|
| Two of the most powerful techniques that came from the mastery of
| precision are interferometry (the process of collecting and
| combining multiple light waves) and spectroscopy (the process of
| collecting frequency-resolved photon distributions).
|
| I'm building an alt-az mount for a raspberry pi solar scope at
| home; it weighs a few pounds. Each of the scopes at ESO (there
| are 4, allowing them to exploit interferometry to increase their
| angular resolution) is a building that is an alt-az mount that
| weighs 350 _tons_.
| 867-5309 wrote:
| > few pounds
|
| > 350 tons
|
| what is the significance of this?
| hanoz wrote:
| Do both these planets just happen to be passing in front of the
| star then, because they would typically be a mile or so outside
| the image at that scale wouldn't they?
| Roboprog wrote:
| No, they are imaged in reflected light, rather than a transit
| (silhouette).
|
| The parent star is masked off, and I'm pretty sure it's an
| image generated from multiple telescopes, "interferometry", as
| others have mentioned.
| hanoz wrote:
| Indeed I should have asked if both planets just happened to
| be passing behind the star? Alternatively, have they just
| been superimposed beside the star at arbitrary positions? I'm
| still none the wiser.
| SiempreViernes wrote:
| No, this was actually shot with SPHERE, which is a single
| telescope instrument: https://www.eso.org/public/teles-
| instr/paranal-observatory/v...
| VikingCoder wrote:
| Someone want to do the math for me? How many arc-angles per pixel
| in this image? And then, with those arc-angles, what sized object
| could you resolve (as larger than one pixel) on the moon?
| teraflop wrote:
| Not sure that "per pixel" is the most meaningful metric,
| because in astronomy, resolution is typically limited by
| telescope optics and atmospheric conditions, rather than pixel
| count.
|
| But if I'm reading the paper correctly ([1], table 2) the
| observed angular resolution -- the FWHM, i.e. the "blurriness"
| of an assumed point source -- was on the order of 0.05
| arcseconds. Given the distance from the Earth to the Moon
| (about 384,000 km), that would correspond to a resolution of
| about a hundred meters.
|
| [1]:
| https://www.eso.org/public/archives/releases/sciencepapers/e...
| s1artibartfast wrote:
| For your first question:
|
| Tan^-1[(160/2 Au)/(300 lightyears)] = 2.4x10^-4deg for the
| distance between the inner planet and the star. You can divide
| this by the pixel length.
|
| With respect to your second question:
|
| Resolution is not tied to do pixel size for this type of
| measurement. You can resolve an object of any size if it is
| emitting enough photons.
| VikingCoder wrote:
| I meant resolve as in "determine what it is," like, how big
| would the letters have to be on the moon in order for you to
| read them.
| s1artibartfast wrote:
| So then resolve that two objects are distinct.
| mturmon wrote:
| > ESO ... has taken the first direct image of a planetary
| system around a star like our Sun, located about 300 light-
| years away...
|
| > The two gas giants orbit their host star at distances of 160
| and about 320 times the Earth-Sun distance.
|
| For our purposes, a parsec [pc] is 3 ly, so the host star is at
| 100 pc. The inner planet is at 160 AU, which we'll round to 100
| AU.
|
| So the angular separation is 100 AU / 100 pc = 1 AU/pc = 1
| arcsec, and their resolution must exceed this.
|
| And then we have this handy chart:
|
| https://astronomy.stackexchange.com/questions/20695/how-big-...
|
| This illustrates that the key issue is not resolution itself.
| It's contrast, at this high resolution. Because the planet must
| be distinguished from the host star.
|
| I don't know what the contrast difference here is. For Earth-
| like exoplanets (smaller targets at 1AU), the contrast
| difference is 10^10. That is, for every 10 billion photons from
| the host star, you get one reflected from the exoplanet.
|
| [edited to add: using the link provided by @teraflop, Table 1,
| column 3 seems to show a contrast of about 10-12 in magnitude
| units, which is 10^4 to 10^5 in physical units like photons]
| raducu wrote:
| 300 AU?
|
| Isn't that exeedingly far? Like 10 times farther away from
| Pluto?
|
| Would we even be able to detect such a planet if it orbited
| the Sun?
| vl wrote:
| In the article they say that these planets are young and
| hot and they detected them in infrared by blocking light
| from the host star using special device. We would easily
| detect such super-massive hot planet at 300 AU in the solar
| system, but there is no reason for them to exist here since
| solar system is much older.
| raducu wrote:
| I was thinking that in out case hot or cold is not the
| main issue, but the area where to look.
|
| If you look at a star 300 light years away, you just have
| to search a couple of pixels away from the star.
|
| But if you searched for such a planet at 300 AU from out
| Sun, you would have a massive amount of space to search
| throug -- like a massive cilindrical wall of space around
| the Sun(if it was not exactly on our plane around the
| Sun).
|
| But in anycase, I was wondering if we had such a planet
| in our solar system, but obviously cold by now, could we
| detect it?
| riidom wrote:
| If it has a gravitational influence on other planets,
| then yes, same way as the discovery of Neptune.
|
| https://en.wikipedia.org/wiki/Discovery_of_Neptune
|
| Now, 300 AU is far away, but then, 14 times the mass of
| jupiter is heavy. But I'm not knowledged enough to do the
| math here.
|
| On a 2nd thought, maybe not. How long would a year be for
| a planet that far outside? Maybe several hundred years?
| We'd need to be in the right window of time to spectate
| such effects in first place.
| cgriswald wrote:
| To be equivalent to the gravitational impact of Neptune
| the mass would have to be about 70,000 times the mass of
| Neptune. This is more equivalent to trying to find Planet
| Nine [0], which, although was also "discovered" through
| gravitational effects, those effects are much subtler and
| the planet might not exist and if it does, hasn't been
| found.
|
| [0] - https://en.m.wikipedia.org/wiki/Planet_Nine
| mturmon wrote:
| Just to emphasize one point you made: It appears the
| first companion planet (160 AU) was originally detected
| using direct imaging last year (preprint [1] is dated Dec
| 2019, see sec. 4 for methods).
|
| And I guess the second one was announced in OP, making it
| a multi-planet system.
|
| The point of this comment is to note that these 2 planets
| were _originally_ detected by direct imaging, not by
| other techniques.
|
| [1] https://arxiv.org/pdf/1912.04284.pdf
| jackfoxy wrote:
| The mass of the larger of the 2 planets seems to be on the verge
| of brown dwarf classification
| https://en.wikipedia.org/wiki/Brown_dwarf
| peroporque wrote:
| Great. And now let's build a telescope on the dark side of the
| moon!
| michael_j_ward wrote:
| The dark side is only dark from our perspective on earth. It
| still receives two weeks of sunlight a month.
|
| If you wanted to minimize sunlight, you'd want to put a
| telescope at L2 [1], which is in fact where the James Webb
| Space Telescope will be deployed [2].
|
| It's launch was recently pushed back from March to October of
| 2021 [3] (or [4] for non paywalled version)
|
| [1] https://www.space.com/30302-lagrange-points.html
|
| [2] https://en.wikipedia.org/wiki/James_Webb_Space_Telescope
|
| [3] https://www.nytimes.com/2020/07/16/science/nasa-james-
| webb-s...
|
| [4] https://outline.com/bsWKnf
| nickff wrote:
| The dark side of the moon would be much better for a
| telescope array; given that the moon has no atmosphere and
| isn't seismically active, you could form a massive, scalable
| array with incredible resolution.
| raducu wrote:
| Is the Earth that much of a hassle if we built on the near
| side instead of the far side?
|
| Perhaps for radio astronomy?
|
| Or build it on the far side, near the poles, with a solar
| array just across the pole -- perhaps that way you could
| have solar power all year long.
| nickff wrote:
| Most large telescope arrays (that I know of) are for
| radio astronomy, largely for geographical reasons (as far
| as I know).
|
| Earth is a source of noise throughout the electromagnetic
| spectrum, so I think the benefits of building on the far
| side (eliminating Earth noise), will likely outweigh the
| costs (limited/more costly bandwidth).
|
| I think a mixed array, consisting of "radio" and "light"
| telescopes could present very interesting possibilities,
| especially because you could dynamically allocate sparse
| sets of the array to different tasks.
|
| All of that being said, I am an engineer (with an
| interest in array signal processing), not an astronomer.
| peroporque wrote:
| Sunlight is reflected from earth too.
| dylan604 wrote:
| And at L2, we'll never be able to upgrade it or even service
| if something were to go wrong before end of scheduled
| mission. Something on the moon would be much more accessible
| for upgrades or basic servicing missions. Even with 2 week
| on/2 week off schedule, it would be so useful. During those 2
| weeks off, it would be charging its batteries. Never would it
| suffer from cloudy nights.
| Rebelgecko wrote:
| OTOH, a trip to the moon requires about 10x more fuel than
| going to L2. Although I suppose a moon telescope could
| synergize nicely with other lunar activities
|
| Edit: I think I misread the table I was looking it, it's
| more like 2x or 3x instead of 10x, and that assumes a start
| from LEO
| theandrewbailey wrote:
| There are and have been probes and observatories at L1 and
| L2:
|
| https://en.wikipedia.org/wiki/List_of_objects_at_Lagrangian
| _...
| smoorman1024 wrote:
| I believe the dark side of the moon would be more apt for radio
| astronomy. The obvious reason being that the Moon is blocking
| interference of artificial radio signals on Earth.
| penagwin wrote:
| The moon is interfering with radio signals? Doesn't this only
| happen if the moon is literally blocking line of sight? It
| seems like being outside of earth's atmosphere and ionosphere
| would be the biggest benefit for radio.
| nickff wrote:
| The moon is basically a giant reflector for (many bands of)
| radio. The reason the US government funded so many radio
| telescope arrays was to monitor Soviet ballistic missile
| tests, by looking at signals reflected off the moon.
| JshWright wrote:
| There's still a lot of rf noise that can penetrate that
| far. ~3,400km of solid rock is a much better attenuator.
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