First Ever Image of a Multi-Planet System Around a Sun-Like Star Captured by ESO

https://www.eso.org/public/news/eso2011/?lang

by rbanffy • 6 years ago

654 171 6 years ago

davedx• 6 years ago

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• 6 years ago

Proof of life outside earth would be the coolest

throwaway0a5e4• 6 years ago

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.

arethuza• 6 years ago

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

peroporque4• 6 years ago

Step 1: define "life"

VikingCoder2• 6 years ago

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• 6 years ago

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...

mturmon3• 6 years ago

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]

raducu3• 6 years ago

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?

s1artibartfast6• 6 years ago

For your first question:

Tan^-1[(160/2 Au)/(300 lightyears)] = 2.4×10^-4° 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.

VikingCoder2• 6 years ago

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.

jackfoxy• 6 years ago

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

etxm• 6 years ago

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• 6 years ago

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.

Johnjonjoan3• 6 years ago

I think the multi-planet system part is what makes it a first.

dylan6042• 6 years ago

How do you mean? That it it was photographed in such a manner? We definitely know of plenty of several systems with multiple planets.

throw12346512342• 6 years ago

Why a picture of this and not Alpha Centauri at ~4 ly?

peroporque4• 6 years ago

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".

throw12346512342• 6 years ago

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.

rbanffy3• 6 years ago

We don't know for sure of any planets around Alpha Centauri but, if there were any, SPHERE should be able to resolve a 5000 times fainter (the system is 75 times closer) IR source orbiting as close as 2 UA (roughly the same angular separation from the star as the closest planet detected at 160 UA) from Alpha Centauri A or B.

As for Proxima, Proxima b orbits at 0.05 UA (which is very close). I don't think we could separate its light from the parent star.

peroporque4• 6 years ago

Great. And now let's build a telescope on the dark side of the moon!

michael_j_ward• 6 years ago

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

nickff3• 6 years ago

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.

dylan6042• 6 years ago

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.

peroporque4• 6 years ago

Sunlight is reflected from earth too.

smoorman1024• 6 years ago

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• 6 years ago

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.

hanoz2• 6 years ago

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?

Roboprog5• 6 years ago

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.

SiempreViernes2• 6 years ago

No, this was actually shot with SPHERE, which is a single telescope instrument: https://www.eso.org/public/teles-instr/paranal-observatory/v...

hanoz2• 6 years ago

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.

ilyagr• 6 years ago

That star system is young, and the planets are therefore hot enough to produce their own infrared light. That light is what the telescope saw.

So, there was no need for the planets to pass in front of the star to be detected.

In fact, if you click on the picture in the article, you see two planets and the star quite a distance from each other. Those planets are much further from their star than any of the (known) planets in our own solar system.

m3kw9• 6 years ago

2 dots one white and one orange.

glouwbug• 6 years ago

You could say the same about us - the blue dot

colanderman2• 6 years ago

Make sure to click the lead image to see the star also.

HorizonXP• 6 years ago

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.

oska2• 6 years ago

The image literally sent chills down my spine.

colanderman2• 6 years ago

Aha, apparently there is an image sidebar which is hidden on mobile, where is given the following reason for the star's haloed appearance:

"The image was captured by blocking the light from the young, Sun-like star (top-left of centre) using a coronagraph, which allows for the fainter planets to be detected. The bright and dark rings we see on the star’s image are optical artefacts."

sosuke• 6 years ago

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.

hammock• 6 years ago

HDR for astrophotography

semi-extrinsic2• 6 years ago

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...

JoeSmithson• 6 years ago

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?

dmead• 6 years ago

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.

throwaway2048• 6 years ago

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• 6 years ago

For varying definitions of pratical. For example, you can use a star as a gravitational lens.

webmaven• 6 years ago

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.

ChuckMcM3• 6 years ago

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.

charlesdenault• 6 years ago

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!

Vysero• 6 years ago

I think it's super cool personally, and inspiring. Imho, the notion seems rather silly at this point.

rkagerer• 6 years ago

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.

runarberg6• 6 years ago

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...”

ChuckMcM3• 6 years ago

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.

holoduke• 6 years ago

if we find an alien species they would indeed be equal or less intelligent. a more intelligent species would find us first.

oxed• 6 years ago

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...”

Pedantic note on "I suggest in the future": you didn't suggest it in the future. If you want to avoid pedantic comments like these, I suggest you assume good faith and stop being an ass, or, take an English class. Also, Earth, in your usage, is capitalized.

simonh• 6 years ago

I've gone back and forth on this. As a kid I read plenty of older SF where humanocentric biases were laughably prevalent. Aliens were amazed at our incredibly advanced mathematics because we used the clearly superior Base 10. Or aliens adopted English because it was so much more sophisticated than their own languages. Aliens all being basically humanoid was explained because it is clearly the only body form suitable for developing advanced technology.

In a kind of allergic reaction to this sort of thing, there was a movement in SF that aliens would be likely to be so different from us that we would be unlikely to even recognise them as intelligent. Stanislaw Lem's Solaris is a well known example, and the Pandora sequence by Frank Herbert was interesting. I never quite bought it though, and Nemesis by Isaac Asimov seemed to me to be a particularly lazy example that pretty much put me off the whole idea. (I'm a fan of Asimov, but this one didn't work for me).

On the one had we can look at life on earth to see the huge variety of biological forms that are possible even just on our own planet, with fundamentally the same core biology throughout. On the other hand, any life in our universe is going to be constrained by the same basic principles of chemistry, physics and emergent constraints such as thermodynamics, information theory and natural selection. The problem with most of the efforts at 'truly alien' aliens is they emphasise their alien-ness by showing them violate such principles to show how 'we don't know as much as we think we do'.

I don't buy it. Thermodynamics, natural selection, information theory, etc - we know these things. They're real constraints that any life, anywhere must contend with and they constrain what can or can't work within comprehensible limits. I'm not at all saying that genuine alien life can't be surprising, that we won't learn anything new from it. We learn new stuff form like here on earth all the time. I'm just saying we actually know a pretty decent amount about how the universe works at a basic level and this will give us a decent chance at figuring this stuff out.

That's where I am this this now, but it's a complex issue. I really need to watch Arrival though.

kazagistar3• 6 years ago

The more unlikely it gets that we would be the only intelligent life, the more dire our future outlook, due to the lack of signs of intelligent civilization in the stars. If they must have existed, then there must also be a reason they don't anymore.

ShamelessC• 6 years ago

There's also the Dark Forest theory which suggests any space faring civilization which broadcasts signals too loudly is "quickly" eliminated/threatened by a more advanced civilization. All that remain are the civilizations smart enough to remain silent.

misja111• 6 years ago

It can simply be that civilisations, no matter how intelligent, do not send out any signals that are strong enough for us to detect from our distance.

credit_guy• 6 years ago

the lack of signs of intelligent civilization in the stars

And what would such sings look like? The only conceivable sign that we could observe with our current technology is Dyson spheres. It's however entirely reasonable that intelligent civilizations can advance to quite highly technological levels and not develop Dyson spheres.

If a civilization like ours were to inhabit the nearest star system, Proxima Centauri, and zip happily in rockets from one planet to another (of which there are at least 2 confirmed), and beam radio messages back and forth among themselves, would we be able to tell?

defnotashton23• 6 years ago

Nah we are just out in the sticks.

ChuckMcM3• 6 years ago

There are other, albeit more far fetched, ideas about the situation.

One I find interesting is that we are like a chick pecking away at our egg shell. As we get closer to being multi-planetary do we get to be more or less warlike? Do we settle on one ruling class and everyone else in bonds, or do we settle on a shared bounty? Do we destroy the world that birthed us, or do we come to grips with our own needs and develop what we need to live in perpetuity on the world we started on?

On a much larger scale it doesn't seem all that much different than the growth of a person from child, to teen, to young adult, and adult. And in those stages of growth the perception of the world and one's place in it changes. Some learn self restraint, others do not, Etc. Even before young people start to drive they get to point where doing stupid things can kill them.

The theory I find interesting is that civilizations are out there watching and the history is that some civilizations "grow up" and survive, and others don't. Some do something stupid in their "teen years" and kill themselves off, some develop a personality that results in them doing something that kills them. Some make it through that and become adults with a reasonable understanding and nominal "acceptance" of the things one has to do to stay alive and be civil.

Maybe when we're "old enough" as a civilization, and we certainly will have enough science to understand that other civilizations could exist and how. They will introduce themselves.

visarga• 6 years ago

I would like to see your calculations for the number of intelligent civilizations in our galaxy. How many? What percentage? Do they exist on any kind of scale? Are there any major differences between them?

Thanks!

defnotashton23• 6 years ago

I think simply based on size, you would be crazy to not think there is life out there.

I think that if we were truly the only ones out here that would be the best evidence for God..

Diederich• 6 years ago

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• 6 years ago

Amazing video. Thanks for sharing.

fadedasmygenes• 6 years ago

This was great. Thanks for sharing!

driton• 6 years ago

That was a great, informative video, thanks for sharing.

nsxwolf• 6 years ago

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• 6 years ago

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.)

dekhn2• 6 years ago

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.

867-53092• 6 years ago

few pounds
350 tons

what is the significance of this?

nitrogen3• 6 years ago

Shows the scale of the telescopes by comparing the massiveness of a homemade vs. state-of-the-art whole-building altitude-azimuth mount. It's amazing that something that ways 350 tons can be aimed with precision at photographic targets that are constantly moving with the rotation of the earth.

hoseja• 6 years ago

So it's more like a triple star system of two brown dwarfs and one star?

First Ever Image of a Multi-Planet System Around a Sun-Like Star Captured by ESO

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