Edit: Oh, you can click through the image and see technical details. Very cool.

I'm sorry, but this is making me laugh so hard. I don't know a lot about astrophotography, but one thing I've experienced so far is that astrophotographers love to talk about their equipment and process.

It's like asking a grandparent, "Oh, do you have pictures of your grandkids?" It kind of makes their day. :)

1. The scope they used is roughly equivalent to shooting with an 800mm telephoto lens. But the fact that it's 8" wide means it can let in a lot of light.

2. The camera [2] is a cooled monochrome camera. Sensor heat is a major source of noise, so the idea is to cool the sensor to -10deg (C) to reduce that noise. Shooting in mono allows you shoot each color channel separately, with filters that correspond to the precise wavelengths of light that are dominant in the object you're shooting and ideally minimize wavelengths present in light pollution or the moon. Monochrome also allows you to make use of the full sensor rather than splitting the light up between each channel. These cameras also have other favorable low-light noise properties, like large pixels and deep wells.

3. The mount is an EQ6-R pro (same mount I use!) and this is effectively a tripod that rotates counter to the Earth's spin. Without this, stars would look like curved streaks across the image. Combined with other aspects of the setup, the mount can also point the camera to a specific spot in the sky and keep the object in frame very precisely.

4. The set of filters they used are interesting! Typically, people shoot with RGB (for things like galaxies that use the full spectrum of visible light) or HSO (very narrow slices of the red, yellow, and blue parts of the visible spectrum, better for nebulas composed of gas emitting and reflecting light at specific wavelengths). The image was shot with a combination: a 3nm H-Alpha filter captures that red dusty nebulosity in the image and, for a target like the horsehead nebula, has a really high signal-to-noise ratio. The RGB filters were presumably for the star colors and to incorporate the blue from Alnitak into the image. The processing here was really tasteful in my opinion. It says this was shot from a Bortle-7 location, so that ultra narrow 3nm filter is cutting out a significant amount of light pollution. These are impressive results for such a bright location.

5. They most likely used a secondary camera whose sole purpose is to guide the mount and keep it pointed at the target object. The basic idea is try to put the center of some small star into some pixel. If during a frame that star moves a pixel to the right, it'll send an instruction to the mount to compensate and put it back to its original pixel. The guide camera isn't on the technical card, but they're using PHD2 software for guiding which basically necessitates that. The guide camera could have its own scope, or be integrated into the main scope by stealing a little bit of the light using a prism.

6. Lastly, it looks like most of the editing was done using Pixinsight. This allows each filter to be assigned to various color channels, alignment and averaging of the 93 exposures shot over 10 hours across 3 nights, subtraction of the sensor noise pattern using dark frames, removal of dust/scratches/imperfections from flat frames, and whatever other edits to reduce gradients/noise and color calibration that went into creating the final image.

[1] https://www.astrobin.com/w4tjwt/0/

[2] https://astronomy-imaging-camera.com/product/asi294mm-pro/

> They most likely used a secondary camera whose sole purpose is to guide the mount and keep it pointed at the target object.

I did use a guide camera with an off-axis guider, I'm not sure why it wasn't in the equipment list. I've added it.

> The RGB filters were presumably for the star colors and to incorporate the blue from Alnitak into the image.

This is primarily an RGB image, so the RGB filters were used for more than the star colors. This is a proper true color image. I could get away with doing that from my location because this target is so bright. The HA filter was used as a luminance/detail layer. That gave me a bunch of detail that my local light pollution would hide, and let me pick up on that really wispy stuff in the upper right :)

> The processing here was really tasteful in my opinion.

Awe shucks, thanks :blush:

It's consumer level, but not cheap at all.

The size and shape of the observable universe also changes. A moving observer, say someone doing 30% of lightspeed, will see further in one direction than another. Accelerate quickly enough and the "dark" side of your custom observable universe might catch up with you, causing all sorts of havoc.

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

It’s better to think of the Big Bang as describing a point in time rather than a point in space.

What do you mean by that last claim? Any observable region is bigger at later times than it is at earlier times. The reason all points always appear to be moving away from all other points is that that is in fact happening.

What's the significance of claiming that the size of the infinite plane never changes? It's just as true that if you start with the unit interval [0, 1] and let it evolve under the transformation f(x) = tx, the size of the interval will never change -- every interval calculated at any point in time will be in perfect 1:1 correspondence with the original (except at t=0). But this doesn't mean that the measured length of the interval at different times isn't changing; it is.

    f(x,y) = (c * x, c * y)
    f(x,y) = c * (x,y)
    f(P) = c * P

> We may not know the exact size at the start, but we know it was infinitesimally smaller than it is today. So the size of the initial universe isn't a big factor in the equations about how big it likely is today. Weather it started as a few centimeters across or a few thousand light years across, both are functionally zero compared to the current size.

Most things you're saying are correctly rooted except for what's beyond the observable universe. I'm not sure why the staunch belief that you can confidently claim this. To be clear, you aren't provably wrong - likewise not provably right either.

The replies to you are just fine, they represent a significant portion of the scientific community that says our universe is likely infinitely big and that, possibly, the big bang was infinitely small, yet still, still infinitely large. An infinite expanding into infinite still results not knowing what's out there.

PBS Space time talks about it in terms of "scale factor"[0] instead of absolute diameter.

Still, these are all debatable theories, so your take _could_ be valid, but generally, it points infinitely large.

[0] https://youtu.be/K8gV05nS7mc?t=271

I uncovered this for myself when asking, "where is that point now?" and discovering it was never a point at all, space is expanding from all points simultaneously.

The unobserved universe is likely to be many orders of magnitude larger than the observed universe. It is possible that it is unimaginably larger.

Technically, it is possible that the unobserved universe is infinite, however whether that is a credible option depends on individual scientists informed intuitions. We simply have no experimental or theoretical evidence either way at this point.

So there is no estimate of how many galaxies there are in the universe in toto.

As has already been pointed out, our best current model of our universe is that it is spatially infinite. That means an infinite number of galaxies.

The finite galaxy numbers that astronomers give are for the observable universe.

> The size and shape of the observable universe also changes.

Not the way you are describing, no. The observable universe does increase in size as time goes on, because there is more time for light to travel so the light we see can come from objects further distant. Its shape, however, does not change.

A good reference is Davis & Lineweaver's 2003 paper:

https://arxiv.org/abs/astro-ph/0310808

> A moving observer, say someone doing 30% of lightspeed, will see further in one direction than another.

I don't know where you're getting this from. What part of the universe you can observe from a given point does not depend on your state of motion.

> Accelerate quickly enough and the "dark" side of your custom observable universe might catch up with you, causing all sorts of havoc.

This is nonsense. The Unruh effect is (a) nothing like what you are describing, and (b) irrelevant to this discussion anyway, since the Unruh effect only applies to objects which have nonzero proper acceleration, which is not the case for any galaxies, stars, or planets in the universe.

That is correct. The only tenable answer to "where did the Big Bang take place" is "everywhere".

My understanding is that, at the largest scales, clusters of galaxies are organized along a series of gravitationally bound filaments, sometimes called the cosmic web.

So they aren't distributed like random noise, but more like a web. I have no reason to think this changes anything about calculating average densities, but it is notable that there's the general density but probably a significantly different density within that structure.

But for now we can't really say if the universe in its entirety has a finite size.

It seems like GWB is a superposition of infinite overlapping waves that would be impossible to single out and "unwind" in order to form a map.

And big bang neutrinos are very weak, which makes them undetectable. My assumption was we'd need a breakthrough in measurement sensitivity but is there more to it?

It is now, but up until a few billion years ago, it wasn't, it was decreasing. Many of the objects we currently see are far enough away that the light we are now seeing from them was emitted while the universe's expansion was still decelerating.

> that assumes the observable universe is homogeneous, which it isn't

No, the models cosmologists use do not assume the universe is homogeneous period. They only assume it is homogeneous on average, on large distance scales (roughly scales larger than the size of the largest galaxy clusters).

The images that combine all of the frequencies from Chandra X-rays, Hubble's optical, and now Webb's IR make for some truly fascinating images.

I remember seeing Jupiter in colors when looking at it from the backyard of a friend of mine.

That telescope didn't have a motor and we were constantly chasing Jupiter manually. It stays inside the ocular only for a few seconds, then Earth points us into another direction.

Before you jump to "bonkers" maybe give the people you reply to some credit- I'm an amateur astronomer with facts at his disposal.

As am I, and any time I use an eye piece, it is nothing but b&w for DSOs even for something as bright as Orion's Nebula. The spirit of the conversation is if people can see the true color the way images from large telescopes posted in articles like this. They cannot. You take the reaction from the average person that has only seen processed images after looking through a telescope for the first time, and they will almost always have a bit of disappointment in their voice. I have taken my scope to rooftop bars and let patrons look through at whatever can be seen at the time. I have yet to do this and not meet someone that's never looked through a telescope with their own eyes--which is the point of my effort.

For demonstration, I always attach a DSLR to prime focus and display Live View.

How tiny are we (Humans, Earth, Solar system)... less than a speck of dust in the Sahara.

I used to look up in space when I was growing up and there wasn't any light pollution to the small town I was growing up in. At some point I think I started suffering from 'cosmic horror'. In later years I would pay attention only to the moon, and that reduced my stress significantly.

Nowadays (like in this bit of news, with photos) when I stick to the small photo in an article, I feel ok. When I see it in full size and I zoom in, and I realize that "sh*t! these 5-10-50 tiny white marks are GALAXIES.. and I have to change topics/tabs to keep the cosmic horror at bay.

What's more amazing is when you share this fact to most people "did you know each dot here is a GALAXY, not a star!" they go "heh... interesting" and shrug.

For some reason that makes the whole thing even crazier to me

I don't travel much but when I go to remote areas star gazing is up there on my list of things to do; watch the stars until you're about to pass out from hypothermia, go back inside, make some tea, enjoy the fireplace, forget about the daily (non) problems, it never gets old

I went to sleep thinking about the unignitable size and age of what's all around us in every direction, but particularly that I had just looked at our own galaxy... a galaxy that has been there for billions of years, has always been there my entire and is there right now and there's only this tiny invisible thin bit of atmosphere separating us from it.

Then I thought about the fact tha our solar system is orbiting it right now, and we're orbiting the sun on an invisible track, and the moon orbits us on its own invisible track too.

That's quite a lot to deal with when you only woke up for a pee in the middle of a night in a camping holiday in Wales.

https://www.youtube.com/watch?v=TkVprNB5XbI

What is really, really neat to notice isn't just the detail in that final image.... look behind it, and there are whole edge-on spiral galaxies in the distance. Not stars. Galaxies.

The nebula is about 1375 light years away. Those galaxies in the distance.... are billions of light years away. It's hard to comprehend.

just to add to the awe of that, pretty much every "dot" in one of these images is going to be another galaxy. individual stars from within the Milky Way will have diffraction spikes and very obvious as a single item.

This is so far away from our concept of counting things that the mind just gives up. There's no comparison, no dumbing down to X amount of football fields, just nothing.

I find it depressing, confusing but also inspiring and fascinating at the same time.

In ways the bacteria on the dust are oblivious to the scale and nature of the world around them, we seem similarly lost and hopeless in the pursuit of comprehending the universe. We just weren’t built to grasp this kind of scale. We can enjoy images of the tiniest little slices of it, though. I’m actually very grateful for that. I think it’ll be a source of endless wonder for my entire life.

It seems like it is already quite zoomed in to start with, but I can't tell how much.

Every single time I see one of these amazing space pics, it's hard not to get all philosophical and wonder about the size of space & time on cosmic scale, how small our earth is and how insignificant our regular problems are.

I don't care if I don't get to see flying cars or AGI in my lifetime but I will be very disappointed if our knowledge of space remains more or less the same as today without much progress.

Edit: typo

I am pretty sure there is a dimension of life that we have yet to discover and learn about. And for the time being Buddhism is the only “religion” that openly discusses this progression.

Hinduism has the same but in my experience it’s a lot more reserved. Bali is a great example of this (which has a strong Hinduism foundation), of how you can create “paradise on Earth” and yet 99.99% of tourist’s don’t ever encounter the root of that paradise.

Humans will learn the full extent of life long before they go extinct.

But given the universe in total may be unimaginably larger than our observable universe, and the total universe may well be an insignificant feature of an unimaginably larger reality, its quite possible that versions of us appear in a fractal-like way, over and over across reality.

Also, given the many worlds interpretation of quantum mechanics, which is the most basic (Occam's razor) interpretation of the equations, we are constantly spinning off a foam of combinatory alternatives of ourselves and everything around us, because the particles that make us up are doing that. So we live many lives, and even when we die in one perceived timeline, other versions of ourselves continue their journey.

Both of those are scientifically plausible, especially the second - which many scientists already believe to be true.

Although they sensibly tend to focus on interpretation at the particle level, avoiding the hype and wishful mysticism that would tend to crop up around its implications for us as individuals. Too many imaginative people and popularizers have a tendency to jump from actual equations/constraints they don't understand, to non-scientific psychologically motivated "implications" and ideologies. Quantum mechanics has been abused enough that way.

By and large, to really have success with this is to learn meditation (not master it by any means), because even basic meditation will naturally provide insight that is outside of the scope of the mental framework you are accustomed to as a mind.

Even in science, there is a lot of focus on what happens to the person on a physical and a mental level, but little on what happens outside of it, which can only be learned by being quiet/still.

I like your reply and it is balanced, and I am not sure that I could reply to it in any other way than I did now. My personal experiences transcend a lot of such discussion, even what I am saying myself, but those are the elements of being human, being bound by something.

I think manipulation of elements (for example) will be considered as a very primitive thing in the grand scheme of evolution!

My response is staying with science, which just means staying with evidence and reasoning that avoids our unbounded ability to fool ourselves. I.e. repeatable experiments by others, tested model predictions, mathematical and statistical checks, etc.

That is all science and math are. An accumulation of tools and systems that improve the reliability of our thinking. They increasingly help us mitigate our exceptional talent for fooling ourselves.

If we find another way to "know", it will get included into science too.

I am a big believer that our personal experience and relationship with life is improved by meditation, staring by learning to quiet our minds and focus/refocus on one simple thing at a time (breathing for instance, or nothing). Then use our ability to focus to mindfully listen to our bodies, then our feelings, then our beliefs, our values, our situations, finally what it all means.

But our minds/brains don't internally track providence of information. What is real and beyond us, vs. what we imagine or want. It is all mixed up in our heads, thus the ease with which we trick ourselfs, and others.

I am a big believer in imagination, to the sky and beyond anything we see. But the very unboundedness of imagination is why just because we can imagine something, and it seems right, fulfills some deep balance, and seems vivid, desirable, and makes clear sense that must be true, ... that doesn't actually make it true, real, or coherent, not even a little bit.

> I think manipulation of elements (for example) will be considered as a very primitive thing in the grand scheme of evolution!

Evolution created multicellular creatures, nervous systems, and brains, which in turn have created a species/society that is actively searching for knowledge and putting it to work for survival at higher orders of organization. I.e. science, economics, politics, technology, etc. Limited resources (at any given time) continue to drive us to solve new problems and learn more, to continue surviving even as we complicate and expand the environment we survive in.

So in that sense, life is already moving past biological chemistry into other substrates, and we are already learning to harness the arrangement of atoms to go further. And eventually, perhaps, harness the fine structure of space-time, and beyond.

Is this yet another one of those scientific facts that does not require a proof?

> Too many imaginative people and popularizers have a tendency to jump from actual equations/constraints they don't understand, to non-scientific psychologically motivated "implications" and ideologies.

Similarly, too many imaginative people who lack adequate depth in epistemology and non-binary logic like to practice both on the internet as if they know what they're doing. And the beauty of it is: if the minds of the population have been adequately conditioned, no one notices.

But wait, there's even more Oracle level soothsaying of the unknowable below:

-------------

My response is staying with science, which just means staying with evidence and reasoning that avoids our unbounded ability to fool ourselves. I.e. repeatable experiments by others, tested model predictions, mathematical and statistical checks, etc.

That is all science and math are. An accumulation of tools and systems that improve the reliability of our thinking. They increasingly help us mitigate our exceptional talent for fooling ourselves.

If we find another way to "know", it will get included into science too.

-------------

I'm sorry to be such a party pooper, but when religious or mystical people make epistemically unsound claims, the knives almost always come out for them, a little in the opposite direction shouldn't hurt too much. And besides: "science" claims to welcome criticism, much like religious people claim to follow their scriptures. But then, who doesn't like to have their cake and eat it too?

And I understand why so many humans fall back to something like religion to cope. It's the only way it seems to become complacent with our role in the cosmic horror.

I know all the intellectual arguments for optimistic nihilism. I vote in elections even though my "one vote" doesn't matter amongst millions, and in some degree my single human life is the same on a timescale of (hopefully) trillions of humans by the time we get to the point of worrying about the receding observable universe.

And yet...

Indeed!

Never a bad time to re-watch Cosmos and (in my opinion) the awesome sequel(s) by Neil de Grasse Tyson. Is it weird to admit I even choke up during some of the episodes?

(As an aside, why is it so hard to find the sequels to Cosmos in any streaming service. In my country it's not on Netflix, Disney+, Apple, HBO/Max, Star+, Prime Video. What the hell...? I just want to re-watch the damned thing and I don't own a Blu-ray player. Do I have to pirate the stuff?)

The only thing that might be disappointing if you're already into astrophysics is that it's rather dumbed-down compared to his books, which are more earnest, closer perhaps in style to Feynman's Lectures.

I'm not a physicist of any kind so I'm ok at the "science divulgation" level.

If "we" ever get out there, some form of mechanical AI will. And we will never know it because once we send those ships off, we'll be long gone before the return signal gets to us from some far of locale. Imagine a voyager who can self-repair, mine asteroids, print circuits, etc. Now imagine giving it a 1 million year mission. Maybe by then we'll all have given up on biology and we'd be the "robots" on that ship.

Sometimes the universe makes beings like us, but not often, and probably makes all manner of interesting beings that will most likely be forever out of reach, and us out of their reach. Kudos to some life on a faraway planet, I wish we could meet.

Also its fun to think of the universe as a system. Here's this incomprehensibly large thing constantly in motion, constantly having stars die out and explode, and new ones born, etc all the time but to us at incredible slow speeds, everywhere, yet at incredible distances from each other. Its like this bellows that keeps a fire lit, over and over, non-stop. But not quite non-stop because this great furnace too will (probably) have a proper death. This universe life cycle chart is both a feat of science and an incredible work of a permanent and grim mortality of all things.

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

The heavens declare the glory of God; the skies proclaim the work of his hands. Day after day they pour forth speech; night after night they reveal knowledge. They have no speech, they use no words; no sound is heard from them. Yet their voice goes out into all the earth, their words to the ends of the world.

Sometimes I think that life could well have been just my soul and no one else, but here I am sharing this world with billions of other people, trillions of other lifeforms on this planet alone. So it is possible that more than one lifeform exists, that they share this universe and communicate in it. Why shouldn't this also be possible on millions of other earth-like planets out there?

If a farmer plants a single tree in the middle of a square mile plot and rips up anything else that grows, any Fermi approximations done by the tree are going to be quite misleading.

There are a few answers to the “Where are they?” question. One is that the parameters to the Drake equation mean life is so rare we actually are alone (as another commenter linked to). Another group of answers is that there is life, but something about the relationship between us means we don’t observe them. Maybe they’re hiding from us. Maybe they’re hiding from everyone.

I think the range of possible answers that people think of for this scenario is generally much too narrow. The power imbalances can be wildly greater than “they’re avoiding us”. We experience power imbalances this large every day. What’s the relationship between a Petri dish of bacteria and a person? Imagine a culture of penicillin reasoning how it came to be.

Maybe this universe is a total construction. Maybe it’s partially constructed, in the same way a farmer “makes” a farm from the Earth. If anything like that is the case, stochastic models are completely the wrong way to reason.

It would be like if I wove a basket. There’s now at least one basket made by Travis Jungroth. Surely there must be more? Out of the millions of baskets made across time, what’s the probability that only one was made by me? Even for a low probability of any individual basket, the numbers start getting decent there’s another out there.

But there’s not. I just… decided to make only one.

It's a compelling idea but there is no evidence helping it.

For me, it's easier to take what we see in our own "lawn" and expand it outwards to the cosmos as a whole. A frog evolved from a single-cell as well as an elephant did, and the geological landscapes we see are the result of physics, time and random fluctuations. I apply that to every other galaxy and that's it.

Of course, one could think that single cell to be "planted" like a seed would be but no supporting evidence for now (or ever?).

> For me, it's easier to take what we see in our own "lawn" and expand it outwards to the cosmos as a whole.

The uncomfortable thing about reality is that it’s often different from what is easier for us.

What you choose to expand out into the galaxy or even the entire universe is a critical choice. You could choose to extend the relationships between plants, or how power structures develop, or the explosion of complexity localized on Earth, or the human tendency to purposefully create environments for life.

> the geological landscapes we see are the result of physics, time and random fluctuations

Most of them. Not all of them. Bingham Canyon Mine is an open pit 4km wide and 1.2km deep. El Teniente mine is 3,000km of tunnels up to 2km deep. There’s Mount Rushmore and the Hoover Dam. There are artificial islands and nuclear test sites.

That’s all just in the last 150 years. Draw the trend of human progress and where does it end up a billion years from now?

That’s even just assuming the conditions that created the universe mirror the conditions here on Earth, which is a tremendous assumption. It might be like having a letter dropped through your door slot for the first time and reasoning the postal service is entirely made of paper folded and stuffed into other paper. The actual reality of mail carriers with pensions, trucks with antilock breaks and sorting machines bigger than any animal that has ever existed would be unfathomable. Anyone suggesting it would be easily dismissed in favor of a simpler and less correct explanation.

  a(1): belief and trust in and loyalty to God
   (2): belief in the traditional doctrines of a religion
  b(1): firm belief in something for which there is no proof
   (2): complete trust

Second, we could come to seriously believe in this theory through consensus direct interactions with these higher powers. That wouldn't require a leap of faith at all. If robots showed up and were like "we were sent by your creators, they say you're doing great" and gave us a second moon as a present, that would be very strong proof of more powerful beings.

I'll grant you that once we have found a single other planet with life. Until then we're doing statistics on a single data point and no, the number of planets and galaxies etc are not sufficient to statistically determine the prevalence of life because as yet none of them are confirmed to have life. This is wishful thinking and statistical truthiness.

Is the single one in a million dimensional one-hot vector special? Why?

If only intelligent life can have this conversation then it will always be "but why us?!?!" well, it was random. Just the other random values don't get to ask the question...

"It was random" in my opinion explains little. If it was sentient, maybe the dice would say "why did I land showing my '6' face? Why me?" and the answer would be many other dice landed showing their '6' faces. Random, but given enough dice rolling you'll get another '6'.

The universe is finite but it's mind-boggingly large. I think Earth is special because a- I was born there, enough said, and b- it has just the right conditions and luck for life to exist. But I don't think it's so special that it's the only planet in the whole mind-boggingly large universe to be this way. There must be other planets/dice rolling out there.

Until we find another such planet we cannot know for certain, but in my opinion it seems unlikely that these conditions don't exist anywhere else but on Earth. Why? Well, because the universe is so large -- the dice pool is very, very large.

In my case, my gut feeling, but is it so unlikely?

As mentioned in "Cosmos: Possible Worlds", planets may go through a "habitable zone", which is the window in which they are just the right distance from just the right star, and they have the right elements in their surface or whatnot. And then just the right random events have to happen and there's the spark of life. And then a gazillion extinction events must be averted, at times when the Tree of Life (to use the metaphor from Cosmos) is at its most fragile, when all of life could be cut down before its prime.

It sounds unlikely for any single planet, any single star system, any single galaxy, etc. But on the grand scale of the universe, it cannot be that nowhere else but here on Earth did this happen.

I don't know if this is statistics. It surely is gut feeling. But I think it's the right kind of gut feeling...

It's possible that life emerging is so unlikely that it has never happened before anywhere even if it could happen again. We do not have the data to establish how likely and in fact we don't even have enough data to fill in all the gaps of how life on earth emerged in the first place. Our gut feelings are likely heavily influenced by science fiction or other priors and can't be trusted for knowledge but we are as a species very good at deluding ourselves into thinking we know things that we don't.

What's difficult to comprehend is the immense vastness of the universe. It seems unlikely that nowhere else did the preconditions for life arise, and in fact, it seems likely that they must have arisen in multiple places. Immensely many places, in fact. Considered like that, it's more unlikely that life didn't appear anywhere else but in this Pale Blue Dot.

We look at our planet, and all that had to happen for those first lifeforms to come into existence, and it seems so unlikely... but not impossible. And we're playing with a lot of dice here! Very hard not to roll a few sixes with a bag of dice so large.

> What's difficult to comprehend is the immense vastness of the universe.

We know a whole lot about ways life changes once it's there but we haven't observed life emerging from non-life and our hypotheses for how life emerged on earth has more holes than swiss cheese and it doesn't have to be magic in order to be exceedingly improbable. And magnitudes work in both ways, if it is sufficiently improbable for life to emerge, let's say 1 chance in 1E100 against then even if you had dice rolls in proportion to all the subatomic particles in the universe (~1E80) multiplied by the number of seconds since the big bang (~4E17) then it would still be about 3 orders of magnitude against the likelihood of life emerging even once. In this scenario if the probability was 4E97 then we'd expect for life to have emerged once. Until we have the data to infer what the probability actually is we can't determine which scenario is the case.

> but we haven't observed life emerging from non-life

But our laboratory is very, very small, so that proves little.

And we know life emerged at least once, and it doesn't seem particularly improbable. That's what I mean by "not magic"; not that we understand every little step, but we have some idea.

I don't think it's scifi to believe it's unlikely only Earth has sparked life. The one thing that is unlikely is that we will ever witness life anywhere else, but that's a different problem.

For the difficulty of evolution of life, we have a total N of 1-5 of life-could-have-evolved, depending on how optimistic or pessimistic you want to be about life's chances (could life have evolved on Venus? Mars? Titan? Europa? any other moons I'm forgetting about).

At this point, the statistics says more about your priors than they do about actual data, since there's not enough data to actually do any statistics on.

The universe might be infinite, in which case: yes, there is life out there. We know the probably of life forming on any given planet must be greater than zero, or else we wouldn't be here. From this we can deduce the average volume which contains exactly one planet with life, which must be finite. Whether it makes sense to talk about what could be happening beyond the cosmological event horizon is another discussion.

If we are talking about the observable universe or an even smaller volume: How can you say it's statistically implausible without knowing the probability of life forming on any given planet? It might be incredibly small, yet greater than zero. Your line of reasoning is incredibly common but I can't help but feel like it's mainly driven by wishful thinking.

one trivial but powerful observation that von Neumann made was that our galaxy say, is actually pretty small. It's about 100k light years big, which means that any civilization spreading at only a tiny fraction of the speed of light could expand through the entire milky way in only a million years. We could very well spread through the entire galaxy in the near future if we manage to get to like, 1% of light speed in the next few hundred years.

So our galaxy, which contains a few hundred billion stars almost certainly has no other intelligent life in it for the simple reason that it'd be everywhere. That doesn't mean there's no microbial life or maybe technological life billions of light years out there but the fact that we're so alone in our neighborhood is a pretty strong indicator in the direction that advanced life might be much more rare than some people assume.

By that account another civilisation as advanced as us would say they're equally alone in the galaxy no ? yet here we are. And you forget time, they might have done that 2b years ago and there is nothing left for us to detect, or they might do it in 2b years and we might not be there to witness it. Also there might be barriers we're not aware of, for example advanced civilisations could go through things like extinction through pollution, over consumption of resources before reaching a tipping point to being multi planetary, &c.

Plus we're far from the only galaxy, there might be galaxy wide civilisations out there, far far away. And more important, nothing guarantees the premise of multi-planetary civilisation has any validity outside of sci-fi

It's like going in the woods twice a year, not seeing mushrooms and concluding mushrooms don't exist on earth because surely you'd have seen them by now! The bottom line is that we just have absolutely no clue

13 billion years before me, potentially trillions of years after me. Seems like such a waste of the spark of awareness that I can't take that awareness and experience the galaxy in all its glory.

But you just did. That's what we're doing.

The horse head part that we see is 3x4 LY in size. If you wanted to experience that horse head like you would, say, a mountain -- just a large, field of view dominating visage. You would need to be about 20+ Lightyears away from it.

I don't know how bright the nebula is, but after 20 lightyears, I don't know how much the human eye could perceive it. And, likely, by the time you got close enough to actually see it, it may well just be a hazy cloud with no definition, since you'd be so close.

Things like these may only be able to be experienced by us through artificial means. Through embellishment and enhancement.

You can go and buy a "smart telescope" today that you can push a button, and point it at any of the "local" nebulas or other bright objects in the sky. Yet, if you look through the eyepiece, you won't see much. Even with magnification, it's a gray, fuzzy blob. The smart telescope will automatically capture more light, through longer exposures, and create a composite image with better definition and detail. Even with magnification, we can not experience those objects directly.

Astronomy, for me, is most "personal" with a pair of binoculars, particular a pair of stabilized binoculars. A mundane pair will open up the sky in a breathtaking way. Because it's more "real". It's not a picture on screen, and it wide and sweeping and huge.

But you can't really get those really fun Milky Way photos folks are making, not with binoculars. You CAN see the Milky Way under dark skies, but not like those photo capture them.

So, simply, "you can shut up. Stop typing now. Really", you may well have just experience the nebula as best as it can be done right now. Run that video on a huge TV in a dark room, it will help. Maybe see if any of this stuff is coming to an IMAX theater near you.

I think "dust" is a term of art in astronomy. A cloud of rocks the size of cars could be dust. I suppose that if you can't resolve the particles, then it's dust.

If I look at this part of the Orion Nebula, it looks opaque; I can't see what's behind it. So I guess if I were in the middle of the nebula, then I wouldn't be able to see out of it. There are many stars in the nebula that are not visible (in visible light).

So I suppose that what you'd see would depend on where in the nebula you were sitting; if you were near a star, the dust would be illuminated, and the sky would be bright. If you were not near a star, presumably the sky would be dark, and you'd look up and see nothing, like the inhabitants of the planet Cricket.

There are also emission nebula which are clouds of ionized gases that emit light.

The horsehead nebula is an absorption nebula that sits in front of light-emitting emission nebula. It's fairly easy to image the horsehead with a star tracker and DSLR, though not to this level of detail.

People of the future will ask: "{ "question": "What is this .gitkeep file?" }"

And the sages will answer: "{ "answer": "It is a tomb or religious site." }"

JWST has separate modes for spectroscopy. They’re pretty cool!

But there's a distance where such structures would probably fill the night sky because you were close but not too close. Some of these structures aren't necessarily visible to the naked eye, even if close, but some are. I wonder what that would do if you were on a planet where the horsehead nebula (or something similar) filled the sky and its brightness rivalled the Moon.

For anyone having similar problems, I recommend the source linked at the bottom of this blog post: https://esawebb.org/news/weic2411/