New 10 Terapixel Image of the Night Sky Contains 1B Galaxies(viewer.legacysurvey.org)

523 pointsby soheilpro5 anni fa252 comments

viewer.legacysurvey.org

New 10 Terapixel Image of the Night Sky Contains 1B Galaxies

https://viewer.legacysurvey.org/#IC%203206

258 comments

Counting the number of galaxies in these image datasets is actually a highly non-trivial, supercomputer-scale problem. I worked on this a few years back! Paper link for those interested: https://arxiv.org/pdf/1801.10277.pdf

pachico5 anni fa

I am constantly amazed by the people that participate in HN. Everything I do seems so trivial compared to what some of you guys do.

fariss5 anni fa

Well, you're not alone.

oh_sigh5 anni fa

Why supercomputer? Isn't this kind of classification task embarrassingly parallelizable?

holycrapwhodat5 anni fa

Modern supercomputers are obscenely parallel machines built to chew through embarrassingly parallelizable tasks.

vsgzusnex5 anni fa

Forgive me if I'm wrong but I thought supercomputer time was usually not allocated to embarrassingly parallel tasks. While they certainly can do those tasks well they're a waste of a distributed system with expensive, high bandwidth fiber connections between nodes.

When I spent (a relatively small amount of) time working with one this was the main thing the director drilled into my head. Use it to solve large, parallel problems that require lots of intranode communication of intermediate results. Embarrassingly parallel problems can be solved on cheaper hardware like GPUs.

lldbg5 anni fa

When the data no longer fits inside a compute resource (a node, or even a rack), you are by necessity going to be distributed. Communication is a fact of life when the problem-size grows. This is true also for GPU-based computing.

GreenHeuristics5 anni fa

So is a GPU

nevi-me5 anni fa

Might depend on the level of embarrassment.

Interesting that they did this with Julia, with 83% of instructions being AVX-512 (if I'm reading it correctly).

Does anyone know if Julia's GPU capabilities could have been leveraged on say a cluster of NVIDIA A100/V100?

KenoFischer5 anni fa

This work is four years old (with development happening before that), so the Julia GPU capabilities probably weren't good enough at the time. If you wanted to do it today, that'd probably be the way to do it, but would need some benchmarking.

maeln5 anni fa

A lot of modern supercomputer use/have GPUs. But most GPUs had very bad fp64 compute capabilities, so they were not really used for anything requiring precision for a long time.

KenoFischer5 anni fa

It's not entirely embarrassingly parallel because photons from nearby light sources interact, so you need to do a parameter exchange. That said, it is true that it doesn't need the low latency fabric that supercomputers traditionally used (though these days the architecture isn't all that different from what you'd have in a traditional data center). We were actually approached by Microsoft to duplicate the demo on Azure, but they ended up being unable to find enough spare capacity for us to run it at full scale, so we showed off a small scale demo. In this particular case, the supercomputing center was quite interested in our application because they wanted to test their setup with more "data analysis heavy" workloads, since they had invested a lot in SSD caches for this kind of work, but most of their workloads didn't require it.

hi415 anni fa

Congratulations! Thank you for making the world better with such amazing work!

qatanah5 anni fa

Not the world, but the universe!

p1mrx5 anni fa

We can only improve the subset of the universe that lies within our future light cone, and even then only with a significantly better space program.

kstrauser5 anni fa

I mentioned this elsewhere, but...

Pick a region at random. Zoom in, scroll a little, zoom in, scroll a little, repeat until you find a galaxy. There. You're likely the only human who has ever seen it and all the wonders it may contain. It's yours to hold. That's your little galaxy.

khazhoux5 anni fa

For some reason, 20% of the galaxies I zoom into wind up being just this purple flower: https://upload.wikimedia.org/wikipedia/commons/thumb/1/16/As...

[deleted]5 anni fa

ardy425 anni fa

> Pick a region at random. Zoom in, scroll a little, zoom in, scroll a little, repeat until you find a galaxy. There. You're likely the only human who has ever seen it and all the wonders it may contain. It's yours to hold. That's your little galaxy.

This one's mine: https://viewer.legacysurvey.org/?ra=165.0972&dec=28.9753&lay...

warent5 anni fa

I like it! Very rotund and hearty.

Here's mine: https://viewer.legacysurvey.org/?ra=95.9367&dec=-52.7034&lay...

It's not a galaxy so much as a hyper-dimensional string wormhole network nexus created by one of the most advanced races in the cosmos.

buu7005 anni fa

I picked this one: https://viewer.legacysurvey.org/?ra=148.9435&dec=69.6899&lay...

This one right under it is also neat: https://viewer.legacysurvey.org/?ra=148.7892&dec=69.0730&lay...

ihattendorf5 anni fa

Sorry to be the bearer of bad news, but those have been known for at least a couple hundred years ;)

https://science.nasa.gov/galaxy-wars-m81-and-m82

dilippkumar5 anni fa

This one is mine.

https://viewer.legacysurvey.org/?ra=264.9876&dec=74.0333&lay...

isaacimagine5 anni fa

Here's mine :) https://viewer.legacysurvey.org/?ra=124.7540&dec=83.2675&lay...

Another one: two feeding off each other: https://viewer.legacysurvey.org//?ra=187.6434&dec=41.6737&la...

kstrauser5 anni fa

BTW, I absolutely love that everyone is running with my post and claiming their galaxies, and they’re all so pretty!

I like mine too: https://viewer.legacysurvey.org/?ra=25.0865&dec=9.8563&layer...

antoinexp5 anni fa

Mines: https://viewer.legacysurvey.org/?ra=167.2301&dec=26.6135&lay... I may be completely wrong, but it looks like these two galaxies are on the verge of merging together.

ghostDancer5 anni fa

You're all invited to visit mine, you'll be welcome : https://viewer.legacysurvey.org/?ra=317.9835&dec=-51.6970&la...

fsnowdin5 anni fa

This spot definitely went out with a bang here: https://viewer.legacysurvey.org/?ra=194.0271&dec=65.9466&lay...

dwaltrip5 anni fa

I'm guessing that is a star in our galaxy that is crashing the photo.

Medox5 anni fa

Mandatory watch: Gigapixels of Andromeda https://www.youtube.com/watch?v=udAL48P5NJU

With sound.

soheil5 anni fa

I pick the Milky Way since it's likely no human has ever seen it.

fludlight5 anni fa

You jest, but the percentage of humans have never seen the Milky Way with their naked eyes, since they live in or around some sort of city. Light pollution is so widespread that most people alive today have never experienced a truly clear sky.

Anecdotally, the first time I saw the Milky Way with my bare eyes was almost a religious experience.

psychoslave5 anni fa

Isn’t that exaggerated? I mean, light pollution is a thing, but you can easily escape it if you go at reasonable distance from most towns. It doesn’t require to go into the middle of a desert nor demand an excessive cost.

I think the expression you might be looking for is "a contemplative state".

ericbarrett5 anni fa

I don’t think it’s exaggerated at all. Many urban dwellers in the US have never overnighted outside city limits. Camping trips and boy/girl scouts and such aren’t even on the radar. I would say that a significant number of people don’t even understand what the night sky looks like—to them, it’s always been a gray/orange fog with a few dozen faint stars. So there’s not even a concept of what they’re missing.

kstrauser5 anni fa

You're so right. I grew up a couple of miles outside a small Midwest city, and then that was enough to hide a lot of the dim stars. Being in the middle of the Pacific ocean at night, and caught been the phosphorescent bacteria churned up behind us and the Milky Way above us was the most spiritual experience of my life. It was so beautiful that I cried.

I took my kid camping in Joshua Tree last year and we spent a lot of time just taking in all the stars and waving at the occasional satellite zipping overhead. If someone's never done this, I cannot possibly over-recommend it.

perl4ever5 anni fa

Something that's been on my mind forever is, given the amount of photos and other data that's been gathered, if we put it all together with a really powerful computer/algorithm, could we generate a simulated picture of the Milky Way as if seen face on, at a few million light years above? Without it just being a generic galaxy.

I think I remember reading about the latest and greatest direct measurement of stellar distances, and how it's a huge number of stars but a very small radius relative to our whole galaxy. And of course there's all the dust and stuff in the way of viewing. So my belief is that what I want is impossible, but I think I have heard that we're fairly certain our galaxy is a barred spiral?

turtletontine5 anni fa

The latest and greatest survey at that range is probably GAIA, which has a very important data release coming soon I think. (Unless it came out and I missed it)

I have no sense of how much of the Galaxy it maps, but I know it's crucial for distance ladder measures because it will constrain the distance to the large Magellanic cloud better than ever before, so I think it's measuring individual stars at that range

Doing astrometry and proper motion measurements for more stars than ever before, very cool

sega_sai5 anni fa

We've had the early data release 3 from Gaia, There are several others incoming. The distances are good up to ~ few kpc which is ~ 1% of the size of the galaxy. And it sees ~1% of stars in the Galaxy

DiogenesKynikos5 anni fa

A few kpc is much more than 1% the size of the Milky Way. For reference, the Sun is about 8 kpc from the Galactic Center.

For bright stars, Gaia can measure parallaxes (and therefore distances) throughout a sizeable fraction of the Milky Way. But the fainter the star is, the closer it has to be for Gaia to measure its parallax. The other issue is that there's dust that obscures much of the Galaxy, limiting the range that Gaia can see to. If you take all these effects into account, you find that Gaia can "only" measure parallaxes for about 1% of the stars in the Milky Way. Still, that's orders of magnitude more stars than had parallaxes just a few years ago.

astronewman5 anni fa

It turns out many properties of the Milky Way are still poorly known. We can take what we do know and find galaxies that may match, though.

An early version of this work with a gallery of objects that might match what the Milky Way looks like (given all the observational uncertainties) is discussed at https://www.news.pitt.edu/milkywaycolor .

A couple of the resulting scientific papers are at https://ui.adsabs.harvard.edu/abs/2015ApJ...809...96L/abstra... and https://ui.adsabs.harvard.edu/abs/2016ApJ...833..220L/abstra... and

flukus5 anni fa

I think the problem with doing that is that we've only seen the milky way from one angle (earth + rounding error). The smartest algorithms like the ones that make 3D images from pictures need a lot of pictures from different angles to stitch things together. Maybe if we sent out some deep space probes we could do it, but even then the dust in the Milky way makes it a problem.

soheil5 anni fa

1. Can we create a sufficiently powerful telescope that allows us to see our own reflection perhaps from a body of water on a distant planet or at least our image from millions of lightyears ago?

2. Can gravitation lensing work in a daisy chain fashion by having multiple galaxies positioned ever so precisely to cause the light from our galaxy to travel in a semi-circle arc back to us?

kstrauser5 anni fa

1. No. We haven’t found large scale curvature of the universe yet. If it’s curved such that you could eventually see yourself from behind, it’s way more than 13 billion light years around.

2. See 1.

soheil5 anni fa

I think you answered 2 first. Someone mentioned this link so I just wanted to post it again [0].

Regarding the first question why can't there be a planet let's say in Andromeda with a lake that would reflect back the light from our galaxy? That's only 2.5 million lightyears x 2.

[0] https://physics.stackexchange.com/questions/52167/since-ther...

labawi5 anni fa

Didn't do the calculation, but I don't think you would get any meaningful light back.

kstrauser5 anni fa

Oh, oops. I somehow managed to completely misread that question.

[deleted]5 anni fa

canadianfella5 anni fa

1) No

2) Kinda maybe https://physics.stackexchange.com/questions/52167/since-ther...

Ninjinka5 anni fa

This one's mine, back off: https://viewer.legacysurvey.org/?ra=235.8839&dec=50.4910&lay...

Moru5 anni fa

Not to disappoint you but it already has a name, "PGC2374574"

(I'm totally faking knowing the tool though that's what comes up when I klick it with show galaxies active)

kstrauser5 anni fa

Dang it, I had that one!

BuildTheRobots5 anni fa

Any idea what these little green lines are?

https://viewer.legacysurvey.org/?ra=165.1234&dec=28.9911&lay...

kstrauser5 anni fa

Huh! Great question. There are quite a few of them right there.

dalmo35 anni fa

Seeing as those lines look like pure R/G/B, I'm guessing sensor fault.

ySteeK5 anni fa

most likely these are cosmic rays hitting the sensor

01acheru5 anni fa

Is there a place where one can browse known objects? I've picked mine and wanted to see if by any small chance it has been catalogued before: ra=200.6660 dec=76.8674

Anyway, yours is a beautiful comment

Moru5 anni fa

If I understand how this works, that should be this:

http://leda.univ-lyon1.fr/ledacat.cgi?o=PGC46727

I clicked the bright objects on the right and then Siena Galaxy Atlas.

psychoslave5 anni fa

Man, what a wonderful remark. Thank you.

Here is what I found : https://viewer.legacysurvey.org/?ra=147.3584&dec=53.5565&lay...

I wonder what kind of astronomical object it is. Given the color, the term red dwarf pop in my head, but I actually have no idea: given red shift, aren’t all sufficiently distant objects all red or bellow by the time they arrive at us?

dstndstn5 anni fa

According to the Sloan Digital Sky Survey, it's a star of type M7III, so a red giant

21125 anni fa

My brain just threw an error.

johnohara5 anni fa

And probably doesn't exist anymore if it's far enough away.

megous5 anni fa

https://viewer.legacysurvey.org/?ra=343.4832&dec=-6.5823&lay...

This one ^^^ is curious. Kinda looks like it's burning. (I know, all are burning, but whatever.)

https://viewer.legacysurvey.org/?ra=346.0946&dec=-4.8791&lay...

ordu5 anni fa

I've found better. =)

https://viewer.legacysurvey.org/?ra=32.2993&dec=-43.5177&lay...

Though seems like an artifact for me.

dstndstn5 anni fa

A very bright star (well, you'd barely be able to see it with your own eyes in a very dark spot). Wreaks havoc on our detectors and data processing algorithms!

dvh5 anni fa

Except that what you thought was stars are galaxies. Stars are things with exposure cross on it. Everything else is galaxy.

There are 4 or 5 stars in hubble ultra deep field and 10000 galaxies.

neogodless5 anni fa

The key, of course, is making sure the choice is truly... random.

[deleted]5 anni fa

RcouF1uZ4gsC5 anni fa

You forgot the birthday paradox.

There are a billion galaxies.

So roughly 2^30 galaxies.

Thus, there would be a 50% chance of collision after roughly 2^15 or 30,000 people picked a galaxy.

kstrauser5 anni fa

Even then, 29,998 of 30,000 people (assuming it was exactly that many at p(.5)) chose a unique galaxy. That’s still pretty likely.

Dylan168075 anni fa

That's the chance of someone having a collision.

The chance of you having a collision at that point is still about 2^-15.

And how many people do you expect to follow these directions, anyway?

LMYahooTFY5 anni fa

This seems like one of those probabilistic phenomena that's completely counter intuitive so my brain doesn't know how to comprehend it.

Could you elaborate?

kstrauser5 anni fa

It’s completely unintuitive. See https://en.wikipedia.org/wiki/Birthday_problem

The basic idea is simple enough: if you have a random collection of people, and keep adding more, eventually 2 of them will have the same birthday. If you run that experiment a bunch of times, eventually you’ll get the average number of people where there’s a 50% chance of having a “collision”. The surprising part is that the number is so small: in this case, it’s 23.

Dylan168075 anni fa

It's intuitive if you do it visually. Connect each person to every other person with a piece of string. 10 people each have about 10 connections. 50 people each have about 50 connections. 1000 people each have about 1000 connections.

When you're handing out 250 pieces of string it's easy to tell that something with a 1/365 chance per string is likely.

For this situation, if you put 50 thousand people in a room then they each have 50 thousand ways to pair up, so you're looking at over a billion opportunities to have a one-in-a-billion coincidence. (50k * 50k / 2 = 1.25 billion)

kstrauser5 anni fa

That's a great visualization, thanks!

thomasrognon5 anni fa

Mine has interesting spots and colors, I'm really curious why that is: https://viewer.legacysurvey.org/?ra=197.6961&dec=29.7091&lay...

JetSetWilly5 anni fa

That one seems to be called IC4210, it was discovered on 13th March 1785 by William Herschel, and so it has a german wikipedia page but not an English one: https://de.wikipedia.org/wiki/IC_4210

It is a "starburst galaxy" which means it is undergoing a lot of intense star formation, I think that's why it has pretty colours from all the gas clouds and activity: https://en.wikipedia.org/wiki/Starburst_galaxy

kstrauser5 anni fa

Ooh, that one’s beautiful!

mumblehat5 anni fa

My one's got something similar going on: https://viewer.legacysurvey.org/?ra=188.1737&dec=29.7119&lay...

[deleted]5 anni fa

koheripbal5 anni fa

I love collisions...

https://viewer.legacysurvey.org/?ra=167.4707&dec=24.2626&lay...

xwdv5 anni fa

Wish we had something that was similar except with human faces of every human in the world.

conanbatt5 anni fa

But can you name it and claim the rights of the land to it?

kstrauser5 anni fa

Sure! I mean, the claim’s only as good as your ability to defend it, but why not?

rixed5 anni fa

Isn't that amazing how quickly the idea of appropriation come to mind?

Jakobeha5 anni fa

The size of this image is comparable to Google Maps.

Go to Google maps and zoom out as much as possible. The bottom right hand corner should display a line measuring 1000 miles. Then zoom in so that the line measures 1 mile.

This is the same as zooming out on this map so to 30 degrees, then zooming in to 100 arcsec.

Google maps can zoom in a bit more to 20ft, but it's still impressive.

aduitsis5 anni fa

The vastness of the cosmos we are living in, is simply unfathomable. I'm not even sure we have the ability to really appreciate the scale here. After a certain point it becomes just numbers.

unavoidable5 anni fa

I agree, unfathomable. But one interesting thought that I usually entertain is that based on our best estimates there are more stars in the universe than there are grains of sand on Earth. Now imagine every time you step foot on a beach and think - there is potentially a star system for every grain!

https://www.worldatlas.com/articles/are-there-more-grains-of...

prawn5 anni fa

Also a bit incredible is that it's believed that in the last 60 years, we've manufactured more transistors than there are grains of sand. Sand grain estimate is 7.5x10^18. Transistor estimate between 1960 and 2018 was 1.3x10^22.

abiogenesis5 anni fa

It is ironic that transistors are (kind of) made of sand too.

Maursault5 anni fa

> > Sand grain estimate is 7.5x10^18. Transistor estimate between 1960 and 2018 was 1.3x10^22.

> It is ironic that transistors are (kind of) made of sand too.

Shouldn't we have run out of sand years ago?

Dylan168075 anni fa

Every square millimeter on a silicon wafer has fit tens of millions of transistors for a while. Since the wafer is a under a millimeter thick that's about one grain of sand. So we wouldn't have run out even with those numbers.

Also it doesn't have to be sand, exactly, and more than half the earth's crust is silica.

But more importantly, that number is very wrong. https://web.archive.org/web/20150310025854/http://www.hawaii...

Leaving aside the issue of whether 1mm cubed is a good estimate for an 'average' grain, this is only an estimate of beach sand. Also it seems to be underestimating shore length by a lot, 200 million meters when other sources say 1.2 or 1.6 billion meters.

His estimate for beach surface area is 6000 square kilometers.

The sahara alone is 9 million square kilometers, with sand much deeper too. The first estimate I see, just for that one desert, is 1.5e24 grains of sand.

Another way to look at it is that we apparently use 50 billion tons of sand per year. That's less than a thousand square kilometers worth of sahara. And making 10^22 transistors with 2012 tech would take only 750 thousand tons of sand.

_spduchamp5 anni fa

Mind blown

gattr5 anni fa

On a similar note [1], there is a few times more trees on Earth (ca. 3 trillion) than there are stars in the Milky Way (100-400 billion).

[1] https://eu.usatoday.com/story/news/2015/09/02/earth-three-tr...

psychoslave5 anni fa

Thanks, I always love this kind of comparisons giving perspective on big numbers with something familiar to us.

rixed5 anni fa

In the _observable_ universe. My understanding is that, as far as we know, there could be an unlimited number of stars beyond that limit.

raattgift5 anni fa

That hardly matters. Anything observable is in the observable universe. Anything outside the observable universe is not observable even in principle.

We might in principle be able to see beyond the surface of last scattering using ultracold neutrino or ultra-low-frequency gravitational radiation astronomy some decades from now, but that just gives us a view of the universe before there were molecules (let alone stars and galaxies), and we could only surmise that what we see at such a huge redshift evolved into the sorts of things (galaxies, stars) close to here-and-now. That might justify a "as far as we know" comment like yours; for now, however, it is better to say that we really just don't know because we don't have nearly enough data yet.

Unless there is a violation of Lorentz invariance available to us very near hear-and-now, there is no hope of seeing long distances at our scale factor (which is a spacelike hypersurface in the standard cosmology's comoving frame, which means essentially that it's a collection of things all at the same "time", but that's coordinate time, and in this case the scale factor is the coordinate). Consequently we can't even be certain about highly-redshifted galaxies' fates at a(t)=1. To be sure would need to outrun the metric expansion of space, or equivalently, we would have to move much more quickly towards a cosmologically-redshifted source of the fastest known messengers than those relativistic neutrinos, photons, or gravitational waves that it emits have been moving towards us. There is an enormous amount of indirect evidence that shows that nothing observable moves like that, and plenty of direct tests of the relevant part of the equivalence principle that require Local local invariance everywhere in the universe since the electroweak epoch moments after the hot big bang.

So while most astrophysicists and physical cosmologists would bet that that there is physics like ours at great distances, including "just one metre, or just one megaparsec" (or even much further) outside our Hubble volume, there is no honest way to assign a probability of that being correct at this time. We can only say that it is consistent with the data we have on cosmic inflation (mainly from the cosmic microwave background's inhomogeneities), and it is exceptionally hard to produce a consistent theory allowing for very different physics just beyond the farthest galaxies we can see, yet still match the overwhelming majority of the data we have collected.

https://en.wikipedia.org/wiki/Scale_factor_%28cosmology%29

https://en.wikipedia.org/wiki/Particle_horizon

https://en.wikipedia.org/wiki/Modern_searches_for_Lorentz_vi...

So, the tl;dr is that wondering about what's outside the observable universe might be fun, but it's not scientific because any hypotheses one might generate can never be verified by observation, even in principle, by the very definition of "observable universe". At best we can only hope that the observable universe is bigger than we think today (e.g. by a very surprising resolution to the tensions in the cosmic-distance ladders, by the discovery of wormholes and comparable topological "defects" in the universe, or by the discovery of faster-than-light travel). I happen to hope some of that, but have no honest basis for that hope.

dmje5 anni fa

This. Just mindblowing. It either means we're 1) completely insignificant or 2) incredibly significant.

Or, I suppose 3) a sort of mediocre level of significance.

Damn.

"Mostly Harmless".

postingawayonhn5 anni fa

The passage of time is probably even more unfathomable. On a long enough timescale our species is completely irrelevant.

ac425 anni fa

"Tragula was horrified to learn he had destroyed her mind, even as he proved his point that if life was going to live in such a vast Universe, one thing it could not afford to have was a sense of perspective."

jonnypotty5 anni fa

Our perception gives up way before this scale

dang5 anni fa

We changed the URL from https://kottke.org/21/02/10-terapixel-image-of-the-night-sky to the viewer.

Another article is https://www.syfy.com/syfywire/a-billion-galaxies-lurk-in-a-1...

The FAQ is here: https://djschlegel.wordpress.com/faq-legacy-survey-sky-image...

01acheru5 anni fa

I know that what I'm about to say isn't constructive in any way but after looking at the image and scrolling around a bit I have this echo in my head: that's one of the most beautiful things I've ever seen.

I actually don't have words to describe this feeling, not in any language I know. It's simply incredible!

Lambdanaut5 anni fa

It's akin to the feeling I've gotten from unsettling realizations during psychedelic trips. Beautiful and humbling.

01acheru5 anni fa

True, I still remember that one night: "Time does not exist".

I literally felt it, lived it, it still bugs me after many years.

mensetmanusman5 anni fa

You might enjoy reading about Entropy and its connection to time: https://en.m.wikipedia.org/wiki/Entropy_(arrow_of_time)

warent5 anni fa

Here's a fun little "cluster" I just found: https://viewer.legacysurvey.org/?ra=330.8784&dec=12.6412&lay...

I'm not 100% certain but it seems like this may be an example of severe gravitational lensing, causing the same galaxy to appear as multiple images in different periods of time

EDIT: Update link

astro1235 anni fa

There's no strong lensing there. If the background galaxies were lensed enough to have multiple images they would also be incredibly distorted.

But that does look like a small group/cluster.

Edit: Here is an example of strong lensing - see the very curved object just below the bottom bright galaxy https://viewer.legacysurvey.org/?ra=39.9717&dec=-1.5822&laye... This is https://en.wikipedia.org/wiki/Abell_370

00000111115 anni fa

In November 2013, astronomers reported, based on Kepler space mission data, that there could be as many as 40 billion Earth-sized planets orbiting in the habitable zones of sun-like stars and red dwarf stars within the Milky Way Galaxy.[2

https://en.wikipedia.org/wiki/Drake_equation#Current_estimat...

So at a rate of 40 billion earth like planets in each galaxy. Deep field from Hubble turned up 125 billion galaxies. 125 billion * 40 billion = 5e+21

That means that over billions of years there is allot of time for life creation and death within the universe.

credit_guy5 anni fa

Whenever we talk about alien life, we should always, absolutely always limit our discussion to the Milky Way. Any alien life outside of the Milky Way will remain completely irrelevant for us for any timespan that has any meaning for us as humans. Just hearing "You had me at Hello" back from the Andromeda galaxy would take 5 million years. 5 million years ago humans and chimps were still not distinct species.

mmazing5 anni fa

I get what you're saying as far as "practical" purposes go. It's also arguable that (in the spirit of your argument) the outer reaches of the Milky Way are also irrelvant.

However, when people sit around and think about the possibilities of alien life, or rather - the probability that alien life exists outside of Earth, it's *100%* relevant to consider galaxies outside our own.

billforsternz5 anni fa

However, I absolutely hate it when people say "We are perhaps/probably/certainly alone in the universe" and then go on to explain why (they think) we are perhaps/probably/certainly alone in the galaxy. These two things are not even slightly the same! Even if there's only on average one technological civilization per galaxy (say), we might well be alone in the milky way but share the universe with a wondrous number of other civilizations.

credit_guy5 anni fa

But what is the relevance of knowing that? Why would anyone care? It's a bit like the question of how many angels can sit on the tip of a needle. Existence of aliens in a different galaxy has absolutely zero consequences for us now and forever. We may "share the universe" in a theoretical way, but we don't share anything in the real sense of the term.

billforsternz5 anni fa

I find it much more fun to speculate about and imagine things that potentially really exist. Aliens in other galaxies exist with 99.99% plus probability. Angels don't exist and are of no interest to me.

DesiLurker5 anni fa

no necessarily, assuming a galaxy wide expanding type II civilization that converts every star it encounters to a Dyson swarm as the tracked intelligent civilization. they will easily take a few 10s of Million years to colonize their galaxy. in this process we should be able to see such transformation 'in real-time' via changing radiation signature of the region.

Fermi-paradox is paradox for a reason!

credit_guy5 anni fa

> Fermi-paradox is paradox for a reason!

The Fermi paradox is just a way to have fun at parties (or over the internet, especially on HN). There are so many possible solutions to the Fermi paradox. But each solution has questions, and answers, and more questions and more answers. That's why it's so fun.

But it's not that deep.

To the point, the Dyson swarm is virtually guaranteed to not be used by any advanced civilization. Once a civilization tames nuclear fusion (and we are on the brink of doing so), then harnessing the energy produced by the local star via a bunch of solar panels becomes just a clunky way of getting energy. Controlled nuclear fusion can be many, many orders of magnitude more productive and convenient compared to solar energy. A star is indeed a massive fusion reactor, but it's a very slow one. Our Sun in particular produces about as much energy per pounds as the heat produced by the fermentation of manure. ITER is projected to produce hundreds of millions of time more. And ITER is just the beginning. Sure, the Sun contains most of the matter in the solar system, but plenty exists in the planets. We could use hydrogen stripped from Jupiter to produce trillions of times more power than a Dyson swarm could produce, and we can have that in a portable form that we could take with us in interstellar travels.

Bottom line, whoever is looking to find Dyson spheres out there in the sky, is simply wasting time.

blueblisters5 anni fa

I think nuclear fusion may not be a very efficient method of converting mass to energy for very advanced civilizations. In absence of discovery of large amounts of antimatter, a super-advanced civilization is likely better off taming small black holes that can convert matter into heat. It doubles as a waste disposal mechanism as well.

DesiLurker5 anni fa

its been a few days so doubt you'll read this but, even if you have really advanced fusion tech what people often overlook is that ultimately the civilizations are just heat engines. They would still have a heat signature & as you described that would be orders of magnitude more that their respective stars. you could literally track the growth of a type-II civilization by the radiation signature as long as they are emitting anything above CMB.

Also, yes you dont have to look for Dyson spheres but you'll agree that Sun has 99.9% of the mass of solar system so it would make sense to turn to it after you have 'used up' Jupiter. And yes you can extract mass out of a Star with currently know physics, its just big project. THAT should be visible from far away.

ultimately I doubt there is any stealth for cloaking a type-II civ so whats the best bet? you go the other way & expand as fast as possible. But either way we would have noticed .. at least close to our galactic cluster.

hntrader5 anni fa

Since controlled fusion isn't mutually exclusive to using Dyson Spheres, why not use both?

It seems that constructing Dyson Spheres can only add to the amount of energy that an advanced civilisation is capable of harnessing even if they're also using controlled fusion, so it wouldn't be surprising if they used those unless their energy needs were totally satiated by controlled fusion (or some as yet undiscovered alternative source)

hntrader5 anni fa

It's highly relevant from a perspective of philosophical and scientific curiosity, and mostly (seemingly) irrelevant from a perspective of practical impact on our lives.

I'm also cautious to jump to such conclusions given how nascent we are technologically, even though the light speed barrier does seem absolute. Our recent ancestors probably would've thought a similar thing about life orbiting a nearby star, and it's only with the hindsight of recent advances that we're able to conclude that that's not as far out of our reach as once believed. Who knows what one million years of additional technological advances will make us capable of?

jonnypotty5 anni fa

Our understanding of the universe could be arbitrarily rudimentary which means actually advanced technology, say that which improves somewhat like ours for, say, a million years would just look like magic to us.

postingawayonhn5 anni fa

Unless they're some super advanced species that either intentionally or unintentionally destroys or sterilizes the universe.

gbrown5 anni fa

Don’t forget that we can put a lower bound on the size of the actual (ie, not just the observable) universe and it’s many times greater in size. It could even be infinite, but at the very least it’s larger than we can see.

floxy5 anni fa

Two trillion galaxies (2e12) according to:

https://phys.org/news/2017-01-universe-trillion-galaxies.htm...

Koshkin5 anni fa

That would be on average 1 out of every 10 stars - hard to believe.

ksherlock5 anni fa

Our solar system has Earth and Mars. Venus is on the edge of the habitable zone. Had the asteroid belt formed a planet, it would be on the edge as well.

flippyhead5 anni fa

Right, but, what does it all mean?

21125 anni fa

There might be only one way to find out ;

https://en.wikipedia.org/wiki/Magic_mushrooms

todd_t5 anni fa

It means we won the cosmic lottery.

pklausler5 anni fa

If qualifying as a technical civilization can be defined as being able to launch a self-replicating interstellar probe (a/k/a a Bracewell-von Neumann probe), we can be confident that our galaxy has not yet had one. Once those probes are out there, they'll saturate the galaxy permanently; and once a technical civilization can launch one, it'll happen eventually. A modern billionaire could probably fund such a project now.

jakear5 anni fa

> We can be confident that our galaxy has not yet had one

How can we be confident of that? For all we know the Cambrian explosion was precisely that.

mmazing5 anni fa

Or - there's tons of lottery winners and we're bad at finding them.

01acheru5 anni fa

Maybe nothing, but just the fact that we're talking about it is something, IMHO.

tosser00015 anni fa

This is just a wrapper around:

https://www.syfy.com/syfywire/a-billion-galaxies-lurk-in-a-1...

Probably should change the link to that

mmazing5 anni fa

Nah. It's stunning to be thrown directly into that map.

Having to parse a bunch of text to find a tiny link at the bottom of that page kinda takes something away.

stevenhuang5 anni fa

This is another good link https://djschlegel.wordpress.com/faq-legacy-survey-sky-image... , from the webview itself.

dang5 anni fa

Thanks to you both! I've changed the URL above to the image viewer and added https://news.ycombinator.com/item?id=26071672 with those extra links.

dazhbog5 anni fa

I tried to zoom in, and it only went a few clicks.. I was like cool. Then I started zooming out and out and out. The scale is just insane.. Im sure if we had a better camera and a medium to store the pixels, it would be like a Mandelbrot basically.

DiogenesKynikos5 anni fa

The max zoom of the website is pretty much the maximum resolution seen by the telescope. You can tell because you can see the point-spread functions of the stars (i.e., they look like blobs) at the maximum zoom.

In order to get better resolution, you need to put your telescope at a better site (on a higher, drier mountain with a more laminar airflow; or in space), or you need adaptive optics (which limits your field of view, making it unsuited to large surveys of the sky like this).

sixstringtheory5 anni fa

Agreed, I was a bit confused at first! Also, I found it helpful to turn on constellation overlays to get a sense for how much of the night sky is covered.

mattkevan5 anni fa

Perhaps it should have a tiny tiny marker with the legend, ‘You are here’.

01acheru5 anni fa

Where would you place that marker? We're behind the camera :P

h2odragon5 anni fa

it does. it covers the whole planet.

intrasight5 anni fa

When my daughter was in middle school, she participated in the crowd sourced categorization of these galaxies. It's probably a thing. And if you have kids in that age range, they'd probably glom on.

toufka5 anni fa

http://zoo1.galaxyzoo.org/ - looks like it's now been archived.

The newer version is here: https://www.zooniverse.org/projects/zookeeper/galaxy-zoo/

intrasight5 anni fa

Excellent!

Smith425 anni fa

You can also generate similar scale astronomical images with GANs!

I worked on a model that could do this last year:

Paper: https://arxiv.org/abs/1904.10286

7.6 gigapixel image: https://star.herts.ac.uk/~jgeach/gdf

mncharity5 anni fa

> RGB channels corresponding to the F814W, F775W and F606W bands. [from paper]

IR, red, and orange. In case anyone else zoomed in, saw odd colors, and wondered.

Anyone have suggestions for an HDR or zoomable synthetic field that's visually realistic? Last week I was exploring a try-to-stay-motivated covid project of an "if they're lots of stars, why can't I see them?" educational web app. Basically a horizon+sky slice with sliders for ambient light level (day to night to beyond inner solar system dust scatter) and for exposure (pupil narrow to dilated to dark adapted to hubble at pluto), and presets. Synthetic permits optimizing for pedagogy, and avoids issues around selecting some real region. Might be useful when teaching light pollution. I'd like it for an exploratory atoms-up early-primary learning progression variant emphasizing nuclei, thus nucleosynthesis, and a "I've seen skies of stars in video, but stars are almost absent from my lived experience" challenge. Collaboration welcome. :)

wmwmwm5 anni fa

I could look at this in full-res if only I had a multi monitor setup with a million 4k screens!

lionkor5 anni fa

... and enough DP cables to cause a massive fire hazard, I'd assume.

AbraKdabra5 anni fa

There is absolutely no possible way we are alone in the universe.

lm284695 anni fa

It depends on how you look at it, we could very well be alone right now. Humanity is fairly recent and modern human history fairly short. There could have been dozen of other advanced civilizations on other planets just 1 million years ago and we most likely will never know about them. Or dozen advanced civilizations in 1 million years in the future long after we have collapsed. When you add time to the equation everything is possible, a few million years is a lot for us but nothing for the universe

tcldr5 anni fa

So, when you see that picture of 1 Billion galaxies, each with a few billion solar systems, you think it’s more likely than not we’re alone?

lm284695 anni fa

Nobody knows. If only carbon based life is possible and it needs liquid water then, afaik, most of these stars don't have a planet susceptible of hosting life as we know it, and even for the ones with the right conditions we might be a bit early or a bit late.

It's hard to quantify the chances of life existing anywhere else at the same time as us when we don't have any idea of how it came to exist in the first place. We might be the exception, we might not. You can't just make the connection: "billion of stars" = "we're not alone". I don't pretend to know what's "likely" on a universal scale and I don't think anyone should

tcldr5 anni fa

We’re literally looking for evidence that there was carbon life on the planet next door. When you consider that, just in the image provided, there are at least 1B x 1B solar systems. 1e18. Or about as many solar systems as there are grains of sand on the planet earth.

Considering that the building blocks of life have been detected on random asteroids arriving on planet earth (https://www.nasa.gov/press-release/goddard/2019/sugars-in-me...), and the capacity for intelligence to evolve in distinct branches of our own DNA (https://www.nature.com/articles/nature14668), I personally think it’s hard to say that in all likelihood we’re alone.

lm284695 anni fa

> We’re literally looking for evidence that there was carbon life on the planet next door.

And we haven't found any.

> I personally think it’s hard to say that in all likelihood we’re alone.

We simply have no idea. None of our model work at that scale, especially not our intuition or our "statistical" models (we have 1 data point, and it mostly is incomplete). It's like looking at an enormous pile of snow and saying "there must be gold in there, my friend found gold while digging in africa, surely this pile of snow is big enough to contain at least a bit gold".

I wouldn't be surprised if life evolved somewhere else, maybe hundreds of time (either in the past, present or in the future), I just don't see how you can claim with absolute certainty that it happened and that we're not alone.

Saying with absolute certainty that we're not alone is a guess, just like saying we're certainly alone, we don't have the tools to determine it. If someone shows me an advanced math equation and ask me to solve it I'd say "I don't have the tools" not "it's probably 2"

tcldr5 anni fa

> If only carbon based life is possible and it needs liquid water then, afaik, most of these stars don't have a planet susceptible of hosting life as we know it, and even for the ones with the right conditions we might be a bit early or a bit late.

My point is, there are likely millions or even billions of planets in that photograph alone, with the perfect conditions for sustaining human life.

I can’t say with certainty that there is life, but by God would it surprise me if there weren’t.

hntrader5 anni fa

Everything in my gut says we're not currently alone, and if I was offered a wager that was moderated by an omniscient being I'd be happy to bet at 1:10 to 1:50 odds.

Of course, nobody has specific evidence either way, this is all guesses through Bayesian reasoning (Anders Sandberg has a paper arguing the opposite to my above guess, along Bayesian lines). But no evidence is distinct from no information.

tcldr5 anni fa

I think I’m more impressed that the omnipresent being turned out to be a bookmaker :)

onion2k5 anni fa

That ignores how likely intelligent life is to arise, which is something we don't know.

Shorel5 anni fa

We are alone.

The aliens, they are extremely far away. Probably not even their light can ever reach our "known universe".

They also are alone.

Koshkin5 anni fa

They do not have to be “extremely far away” to be alone. There may even be quite a few of them in Milky Way, in our neighborhood even... The thing is, space is big!

Shorel5 anni fa

Yes. I remember Star Trek Voyager. Just being in a different quadrant of this same galaxy meant they were stranded and unable to reach Earth, even with warp drives.

Space is big.

count5 anni fa

I think most rational people categorize 'somewhere else in the Milky Way' as 'extremely far away' :)

dougmwne5 anni fa

I like the exercise of extrapolating from the history of life on Earth to get an idea of how likely life is to develop elsewhere. Life on Earth likely appeared very soon after the surface cooled enough for liquid water. It was so soon that it seems like single cell life might be downright common in any place with stable liquid water.

On the other hand, it took billions of years for complex multi-cellular life to evolve. The Cambrian explosion was just 541 million years ago and quickly resulted in intelligence on branches as disparate as mammals and cephalopods.

I think it's quite possible that the Cambrian is the rare and special thing and that the universe may be teaming with microbes but not fish.

pndy5 anni fa

We might be alone but destined to escape Earth and reach, spread among stars as species and be the way of the universe to express, experience itself or, we might exterminate ourselves somewhere on the way in the stupidest or terrifying way. That's what I suppose is most probable - until of course we get the pronounced proof that we indeed are not alone here.

jacquesm5 anni fa

In time or in space? Even 'at the same time' has a pretty strange meaning when looked at at these distances.

onion2k5 anni fa

I like to imagine we are the only intelligent life in the whole universe sometimes. It's highly unlikely, but it isn't impossible. Given that possibility, we certainly aren't great at looking after what might be the most significant species on that entire map.

mensetmanusman5 anni fa

According to the known laws of physics, there is a possibility that we are not alone, _and_ that we may never possibly know.

It takes so long to move, that civilizations may go extinct with no evidence of their existence if we left today to visit.

Razengan5 anni fa

Sorry, our science dictates that we are.

Sohcahtoa825 anni fa

You're allowing a lack of evidence to be evidence of the negative.

The incredible vastness of the universe means it's incredibly unlikely we're the only intelligent civilization in existence. But the incredible size of the universe also means that any radio signals being emitted by said civilizations haven't reached us, and even if they did, they'd be so weak they'd just be background noise.

A picture with 1 billion galaxies...each with millions of stars...each potentially with any number of planets...it just seems really unlikely that we're the only ones out there.

But even if we somehow proved another civilization exists, outside of the knowledge that we're not alone, it'd be meaningless. They're way too far away to observe, let alone communicate with.

Koshkin5 anni fa

> each with millions of stars

Almost half a trillion in the case of Milky Way.

AbraKdabra5 anni fa

That's not called science.

tcldr5 anni fa

Source?

NeutronStar5 anni fa

qwertox5 anni fa

This is incredible. But what is even more amazing, is that if you register and then add the overlays, you'll notice that almost any interesting object is already labeled and categorized, leading to photos of that object in even better resolution. And I'm speaking about objects which are found while using the biggest zoom level already.

Those links to further information contain so much additional data, that it left me really surprised how deeply surveyed the sky is, how much work has been put into mapping and categorizing the sky.

I'm baffled.

leemailll5 anni fa

Astronomical survey (https://en.wikipedia.org/wiki/Astronomical_survey) really is an ongoing thing from the beginning of Astronomy (https://en.wikipedia.org/wiki/Timeline_of_astronomical_maps,...). It is also the major project for Hubble telescope

vardhanw5 anni fa

Goes to show how a relatively small set of scientists with perhaps some crowd sourcing can achieve. We have the capability of going much further if all humanity works together on understanding our place in the universe - imagine a million people working on this (annotation, survey, search) to build a catalog even more detailed. Makes one wonder if there will ever be a shared human vision - can capitalism deliver it to us or some other political ideology like socialism has it in itself to best tackle humanities problems and explore opportunities. Will we ever reach that point where the futileness of our daily existence is overridden by greater concerns. How do we ever reach such an "ideal" ideology? Is it only through the painful process of blind discovery? Has enough been done to atleast theorize on the best option? Or will it never be possible to even theorize and come up with a solution, forget about implementation. Space provides direct evidence of the wonders of our universe, while human existence provides one about a host of lost opportunities. Perhaps we must just wait for an advanced benign alien existence to rescue us and preserve our own unique wonder of existence. Perhaps enough of us realize this fast enough not to destroy ourselves before we do that.

Sorry for the rant.

o_____________o5 anni fa

How are you seeing the better resolution photos?

qwertox5 anni fa

For example this section here

https://viewer.legacysurvey.org/?ra=184.7252&dec=47.3225&lay...

when you are signed in, you get the option to add overlays, where the "NGC/IC galaxies"-overlay gives you a link to this page:

http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=NGC+4258

which embeds this image

http://aladin.u-strasbg.fr/AladinLite/?target=M%20106&fov=0....

mncharity5 anni fa

> when you are signed in

"Just works" for me, with no sign in.

yumraj5 anni fa

I find it interesting that while this image in itself is flat, every dot that is there represents light from a different time. Some millions of years old to some probably billions of years old.

redisman5 anni fa

Very excited to see what the James Webb telescope will show us if the launch happens this year as planned

jbritton5 anni fa

Any idea what the colors indicate. There are some patches of mainly blue galaxies on a black background. These stand out as kind of unique. I initially zoomed all the way out, and in the top left is a giant blue and black area that looks like a lamp. I assumed this to be some imaging problem. Upon zooming in though one can see other blue on black areas.

sega_sai5 anni fa

There are some areas where only data in one of the colors is available -- those look either blue/red or green.

sparky_5 anni fa

Does anyone know what causes the "scanlines" we see throughout the image, e.g. https://viewer.legacysurvey.org/?ra=134.9718&dec=32.3736&lay... ?

kryptn5 anni fa

I might be misidentifying it, but they look like diffraction spikes.

https://en.wikipedia.org/wiki/Diffraction_spike

sega_sai5 anni fa

Saturation of the CCD detector and the spillover of the charge across columns(or rows)

elil175 anni fa

The viewer is served using a REST protocol and Javascript library used to display maps. Just thought that was cool!

soheil5 anni fa

Is this red line just noise or perhaps a comet or reflection from a satellite? https://viewer.legacysurvey.org/?ra=287.1524&dec=51.4408&lay...

sega_sai5 anni fa

Looks like a cosmic ray on red exposure.

snomad5 anni fa

Off topic, but only 2 weeks until perseverance reaches mars https://www.nasa.gov/perseverance https://www.youtube.com/watch?v=tITni_HY1Bk&list=PLTiv_XWHnO...

nealabq5 anni fa

In the "Jump to object" box on the bottom-right you can type m13 to find, for example, Messier object 13. Set the zoom-level to about 12 first.

m51 is worth a visit.

Messier objects: https://en.wikipedia.org/wiki/Messier_object#/media/File:All...

soheil5 anni fa

Are there any projects to determine if there are any patterns and if the galaxies and stars are perfectly randomly distributed or not [1]? For example could there be rules like there is always an odd number of galaxies within a specific radius of a red giant star. Or could there be a prime number of galaxies in every certain measurement of a patch of the image.

[1] not including the microwave background radiation

sega_sai5 anni fa

The galaxies are not randomly distributed. In fact there are correlations between galaxy distributions at various scales that essentialy can be traced to initial perturbations that arose after the big bang. Multiple projects are now working on exactly figuring out those correlations as a function of scale.

soheil5 anni fa

I understand the galaxies can be traced back to those initial perturbations, but regardless of that, it'd be interesting to see if there are any patterns that can be identified at a large scale and based on similar sky survey images posted here. Are there any projects working on identifying such patterns?

raattgift5 anni fa

Yes, there is a pronounced filamentary structure to galaxy clusters.

https://en.wikipedia.org/wiki/Galaxy_filament

with a concrete rendering at

https://en.wikipedia.org/wiki/Void_(astronomy)#/media/File:S...

and some more at

https://en.wikipedia.org/wiki/Observable_universe#Walls,_fil...

These filamentary luminous matter distributions (and the sparse, dark, cold voids between them) drive our theories of structure formation:

https://map.gsfc.nasa.gov/universe/bb_cosmo_struct.html

There are some patterns at scales of up to a few tens of megaparsecs, but beyond that matter is for all practical purposes homogeneous and isotropic: with a good enough (infrared- or radio-) telescope you will observe a galaxy or a precursor along every line of sight unobscured by objects within our own galaxy, and only the reddening and dimming from the metric expansion of space permits any darkness at all in our sky.

This is important to the standard mode of cosmology, \Lambda-CDM, which relies on Friedmann equations, which model all the matter content of the entire universe (past and present) as a perfect fluid of uniform dust. Because of the "local" nonuniformities like filaments and voids, grains of dust are thus on the order kilo- to megaparsecs. If we find that there are bigger grains, the standard "concordance cosmology" will have to be adjusted to be concordant with the new large-scale evidence.

(There is lots of looking right now, but so far everything points to smoothness at scales much smaller than gigaparsecs, kinda how a sheet of paper looks smooth in your hands, but a tiny piece of it under a light microscope looks very fibrous, and under an electron microscope one might discern the remnants of plant cells, or even see microbes!).

toufka5 anni fa

WMAP went from the cosmic microwave background downwards. So looking only at the largest structures.

The patterns it sees are real, and very cool.

https://en.wikipedia.org/wiki/Wilkinson_Microwave_Anisotropy...

01acheru5 anni fa

I don't know if I understand what you're asking... what meaning would there be in measuring "an odd number of galaxies within a specific radius of a red giant star"? It would be purely from our point of view, those galaxies might look like in a radius in a flat representation but they are incredibly far away from each other and the red giant star it's waaay closer to us than those galaxies. Same kind of reasoning applies to the other examples... could you elaborate a bit?

Not to say you're wrong about anything, I simply didn't get it

edit: grammar

soheil5 anni fa

For example we see gravitation lensing effect even though the galaxy that is causing it is in front of what is being lensed from our perspective. So there may still be reasons to see if there are any patterns even if it's just from our perspective and also because it's the only one we have access to.

dstndstn5 anni fa

As sega_sai said, there are patterns in the way the galaxies are distributed. Around every galaxy, there is a ring where there is a greater chance of finding another galaxy. It's called the Baryon Acoustic Oscillation, and measuring it is the reason we took these images in the first place! Measuring the size of that ring at different times in the past will hopefully help us figure out how dark energy behaves. See desi.lbl.gov, eg.

kangnkodos5 anni fa

There are two very similar galaxies here. I've heard of a gravity lens making a star look like it's two. Is it possible a gravity lens is making a galaxy look like two?

https://viewer.legacysurvey.org/?ra=211.0715&dec=81.6327&lay...

SiempreViernes5 anni fa

Those look like two saturated stars, so not actually galaxies. But in general yes, gravitational lenses can create multiples images of a galaxy, here is an example of four images ( pretty rare, not of galaxies though) https://www.space.com/28744-cosmic-lens-4-supernova-views-ph...

kangnkodos5 anni fa

If you select Overlays, Bright Objects, Tycho-2 stars, they get labelled as Tycho-2 4564-935-1 and Tycho-2 4564-1031-1. So I guess they are stars?

sega_sai5 anni fa

These are bright stars so they are in Tycho catalogue (which is a catalog of 2.5 million brightest stars)

sega_sai5 anni fa

Those are saturated stars. When the stars are too bright the charge tend do spread along the detector producing those lines

protoman30005 anni fa

Compared to winning the jackpot in a standard state's lottery, how unlikely is it that Earth is the only planet containing life?

Sohcahtoa825 anni fa

Three topics you might enjoy:

Drake's Equation [0], the Fermi Paradox [1], and the Great Filter [2].

Drake's Equation basically tries to guess the number of civilizations in our galaxy by multiplying the rate of star formation, the fraction of stars with planets, the average number of planets that could support life, the fraction that actually DO develop intelligent life, the fraction that develop a method of communication that sends signals into space (such as radio), and the length of time those civilizations exist. Obviously, a lot of unknowns here, but if you take some guesses, you can create estimates.

The Fermi Paradox is the contradiction that the galaxy is so vast that it's incredibly improbable that we're the only intelligent civilization in existence, so how come we haven't found any evidence of other civilizations? Considering how relatively young the Earth and our Sun are, some other intelligent life should have expanded into a multi-star species by now, and we should have seen evidence for it.

The Great Filter is basically an answer to the Fermi Paradox. Basically, there are several steps to go from "a star system that might support life" to "interstellar colonization". Life likely needs to start from reproductive molecules, eventually evolving to complex multi-cellular life, to tool-using intelligence, to technology advancement, and eventually towards space exploration and an explosion of space colonies. The question is which step is hardest, least likely to be achieved? Which step is the Great Filter that has led to the apparent lack of evidence of other civilizations? If the filter is, say, the development of complex multicellular life, then it's very possible that Earth really is the only planet with intelligent civilization. If the filter is the final step, then we haven't reached it, and our outlook is bleak, as it would indicate that other intelligent civilizations have gone extinct despite their intelligence.

Obviously, these are very very abridged descriptions. Each of them has entire books dedicated to them.

[0] https://en.wikipedia.org/wiki/Drake_equation

[1] https://en.wikipedia.org/wiki/Fermi_paradox

[2] https://en.wikipedia.org/wiki/Great_Filter

jandrese5 anni fa

IMHO anybody who says we are alone hasn't comprehended the scale of the universe.

It's unthinkable that there isn't life elsewhere on the almost uncountable other star systems. Unfortunately I think we may have also proven that interstellar travel is effectively impossible thanks to the Fermi paradox.

indrax5 anni fa

If the info we have is proof that no species in history could do any of the things that would let us notice them, then it can't also be strong evidence that they must exist.

captainclam5 anni fa

Or the great filter. :/

lwansbrough5 anni fa

Not sure it's possible to answer this question accurately with a sample size of 1. :)

steve_adams_865 anni fa

Honest question: Is it possible to answer this without knowing how life occurs?

aardvark1795 anni fa

That’s a hard question to answer. The Drake equation breaks the problem down by expressing it as the product of other probabilities that might be easier to quantify, but even pinning down some of those is still really hard.

m4635 anni fa

I remember being young and wondering why the sky was black instead of white. Maybe the answer is that it is.

mensetmanusman5 anni fa

Because things are moving away from everything else, the visible light they may (are they gone in our time cone?) be emitting is ‘red shifting’ into longer wavelengths that our vision system can not see.

If your eyes were capable of visualizing 0-1000 THz, it would see a blinding white noise of creation.

01343405 anni fa

Olber's Paradox. You're not the only one.

kgin5 anni fa

Maybe it will be as soon as all the light gets here

m4635 anni fa

my exposure time is too short.

lurquer5 anni fa

Would it be possible to create a bitmap of the night sky such that the data — as stored on the storage medium — corresponded to the stars’ relative locations?

Like a DVD or CD...

Anyway, I think if we created such an image and left the burned DVDs here and there, we could seriously confuse the shit out of some future archeologist.

limeblack5 anni fa

DVD life span is 30 to 100 years[1] so I would try something else.

[1] https://www.sony.com/electronics/support/articles/00009195#:....

lurquer5 anni fa

Sheesh. You have to ruin everything...

Ok...

How about this...

Let’s do it backwards: arrange the data on a DVD so that the one’s correspond to the stars in their relative position. Then, see what the resulting image looks like. Or, better yet, read it as an MPEG; imagine the horror if it outputted as a rickroll.

01343405 anni fa

That was done like 40 years ago: https://www.smithsonianmag.com/science-nature/what-is-on-voy...

W0lf5 anni fa

Related question: Does anybody know if this sort of zooming behaviour (mapping images onto a grid and dynamically load smaller tiles with higher solutions based on current offset) has a concrete, nameable algorithm behind it? Any link to an Open Source implementation would also be interesting.

ipsum25 anni fa

https://viewer.legacysurvey.org/?ra=10.8011&dec=-17.9594&lay... trippy imaging artifacts, looks like abstract art.

macu5 anni fa

I wonder how the ASKAP dataset will compare when it's rendered as an image

TheMagicHorsey5 anni fa

Suddenly everything I do feels very insignificant.

I was up at 4am today to do work because it's the only time I can do work with focus without my kids disturbing me.

At 6:20am I took a break and saw this thread in HN.

Now I'm having an existential crisis.

krupan5 anni fa

Hey, you are the universe to those kids that you are sacrificing for by getting up at 4 am. Call a friend or family member if you need. You are not insignificant.

floxy5 anni fa

Here's an unrelated question. Do we think essentially all stars are contained within galaxies? Or could there be there free-floating stars in the universe that aren't confined to galaxies?

gizmo6865 anni fa

https://en.wikipedia.org/wiki/Intergalactic_star

Such stars have been observed to exist. The common thought is that they formed within galaxies but ejected from them through gravitational forces.

floxy5 anni fa

Awesome. That's a great article:

"...several other anisotropies at other wavelengths – including blue and x-ray – have been detected with other space telescopes and they are now collectively described as the diffuse extragalactic background radiation. Several explanations have been discussed by scientists, but in 2012, it was suggested and shown how for the first time this diffuse radiation might originate from intergalactic stars. If that is the case, they might collectively comprise as much mass as that found in the galaxies. A population of such magnitude was at one point thought to explain the photon underproduction crisis, and may explain a significant part of the dark matter problem."

renke15 anni fa

See https://en.wikipedia.org/wiki/Rogue_star

Also interesting: "The hypothesis that stars exist only in galaxies was disproven in 1997 with the discovery of intergalactic stars."

sanity314155 anni fa

Galaxies aren't always cohesive, they can collide, split apart, etc - so the answer is "no".

jacquesm5 anni fa

Solar system sized intergalactic spacecraft.

person_of_color5 anni fa

Could the fact that life is potentially far flung across a vast multitude of galaxies be part of a purposeful design to ensure it doesn't wipe itself out? Biodiversity, but in space-time.

cafebabbe5 anni fa

It's basically an IRL version of the Total Perspective Vortex.

dalmo35 anni fa

If you want to get rid of the overlay (I wanted a new wallpaper!):

  body { overflow: hidden; }
  .leaflet-control-container { display: none; }

notum5 anni fa

Enjoy it while you can folks, next iteration of this project will only show Starlink serial numbers in great detail.

person_of_color5 anni fa

How many of these galaxies have Earth-like planets?

It's difficult to escape the conclusion the universe is teeming with life.

kraig9115 anni fa

Is it just my mind but there are definitely parts that I feel do not look randomly distributed.

01acheru5 anni fa

How can you perceive not-randomness on such a massive scale? I totally get that some parts might not look evenly distributed, but randomly... it's just too vast :)

DavidSJ5 anni fa

What are all the horizontal bands?

dvh5 anni fa

CCD artefact. In CCD charge from one pixel is carried to the edge of the chip to be read, when the signal is too strong it bleeds into neighboring pixels.

This is how CCD works: https://upload.wikimedia.org/wikipedia/commons/thumb/6/66/CC...

SiempreViernes5 anni fa

Big diffraction spikes for oversaturated stars.

SiempreViernes5 anni fa

Here's an example where you get to see lots of the optics in the telescope along with the sky: https://viewer.legacysurvey.org/?ra=165.4455&dec=56.3941&lay...

sega_sai5 anni fa

Diffraction spikes are different from saturation trails. The saturation goes preferentially along CCD columns/rows, while diffraction spikes are oriented like the support of the secondary mirror.

_yoqn5 anni fa

This makes me feel a little better about the whole "heat death" problem.

Taniwha5 anni fa

OMG it's full of stars

jacquesm5 anni fa

Just as impressive as zooming in is zooming out. Try it!

soheil5 anni fa

Is there a direct link to the entire image?

yread5 anni fa

I wonder why did they choose for Leaflet.js instead of OpenSeadragon.js. Now they have these ugly black squares when loading tiles

peter_d_sherman5 anni fa

Like Google Maps -- but for the heavens!

Brilliant!

vorticalbox5 anni fa

I fine it super interesting that when you zoom out it appears a lot of the galleries are all horizontal across the image.

lb1lf5 anni fa

Whenever life gets you down, Mrs.Brown

And things seem hard or tough

And people are stupid, obnoxious or daft

And you feel that you've had quite enough

Just remember that you're standing on a planet that's evolving

And revolving at nine hundred miles an hour

That's orbiting at nineteen miles a second, so it's reckoned

A sun that is the source of all our power

The sun and you and me and all the stars that we can see

Are moving at a million miles a day

In an outer spiral arm, at forty thousand miles an hour

Of the galaxy we call the 'milky way'

Our galaxy itself contains a hundred billion stars

It's a hundred thousand light years side to side

It bulges in the middle, sixteen thousand light years thick

But out by us, it's just three thousand light years wide

We're thirty thousand light years from galactic central point

We go 'round every two hundred million years

And our galaxy is only one of millions of billions

In this amazing and expanding universe

The universe itself keeps on expanding and expanding

In all of the directions it can whizz

As fast as it can go, the speed of light, you know

Twelve million miles a minute and that's the fastest speed there is

So remember, when you're feeling very small and insecure

How amazingly unlikely is your birth

And pray that there's intelligent life somewhere up in space

'Cause it's bugger all down here on Earth

-Eric Idle

efynn5 anni fa

Had to sing it along :-D

cma5 anni fa

Has anyone taken stuff like this and applied deep learning to cluster it and look for galaxies/other entities with standout features? Any good papers on stuff like that?

hypertele-Xii5 anni fa

Galaxy Zoo [1] applies distributed humans to classify galaxies.

[1] https://www.zooniverse.org/projects/zookeeper/galaxy-zoo/

cma5 anni fa

Seems they may be experimenting with training models too:

https://blog.galaxyzoo.org/2019/05/21/machine-learning-messa...