James Webb Telescope

[Skeptic Ginger]

Should we be surprised?
Same amount of material, including the current unobservable universe, which could be 256 times the observable, in a small volume?
A related question I have not seen addressed, is the 80% that is dark matter good for the manufacture of black holes?

I may not be picturing the same thing you are describing.

But it is an interesting thought. If after the big bang not everything expanded all at once but instead there were more black holes than today accounting for a large bit of the mass. Then how do you get from all those black holes to the current observable universe that doesn't have them all?

 

[jonesdave116]

This mission is not just looking for exoplanets. It's looking for exoplanets with the conditions suitable to support Earth-like life. There's only one planet we know of with those conditions. Finding another one would be stunning.

What would be more stunning would be spectroscopic observations of an exoplanet atmosphere that strongly indicated that life was indeed present on such a planet. I'm not necessarily talking about advanced civilisations, but just a marker that shows that life has evolved elsewhere.

Dr. Becky is confident for such a discovery in 2024!

www.youtube.com/watch?v=tJ3ZJjqu3NQ&t

@8:48.

Whether that is wishful thinking on her part, or she knows something we don't, is anyone's guess!

 

[Samson]

What would be more stunning would be spectroscopic observations of an exoplanet atmosphere that strongly indicated that life was indeed present on such a planet. I'm not necessarily talking about advanced civilisations, but just a marker that shows that life has evolved elsewhere.

Dr. Becky is confident for such a discovery in 2024!

www.youtube.com/watch?v=tJ3ZJjqu3NQ&t

@8:48.

Whether that is wishful thinking on her part, or she knows something we don't, is anyone's guess!

If JWT fails to find such evidence we are stuck on the second singularity, self replicating molecules occurring as often as the big bang.

 

[Samson]

I may not be picturing the same thing you are describing.

But it is an interesting thought. If after the big bang not everything expanded all at once but instead there were more black holes than today accounting for a large bit of the mass. Then how do you get from all those black holes to the current observable universe that doesn't have them all?

I am picturing all matter created in the big bang, including dark matter.
That is a lot of stuff in a tiny volume. Black holes should be easy to make. Dark matter is the elephant in the room, no one discusses it in the context of the big bang, either it was all made then, or is doing a Fred Hoyle thing.

 

[theprestige]

What would be more stunning would be spectroscopic observations of an exoplanet atmosphere that strongly indicated that life was indeed present on such a planet.

For me that would not be stunning at all. Our current theories about the emergence of life on Earth all strongly imply that similar processes must be occurring hundreds of thousands of times over in the Milky Way alone. On Earthlike planets that our current planetary theories and observations tell us might exist in the billions.

I'm not going to be stunned by discovering something I fully expected to discover, that tells me nothing more than that my current theories are doing just fine.

The bigger cosmological questions, having to do with the Hubble Tension, galaxy formation, and high-energy particle physics, represent known gaps in our current understanding of reality. New discoveries in those areas are much more likely to tell us things we don't already know, and cause upheaval in our current theories of how things work.

Dr. Becky is confident for such a discovery in 2024!

www.youtube.com/watch?v=tJ3ZJjqu3NQ&t

@8:48.

Whether that is wishful thinking on her part, or she knows something we don't, is anyone's guess!

Discovering it within the year might be wishful thinking, but, again, we're predicting that Earthlike planets with some form of life will be found if we go looking for them.

 

[3point14]

For me that would not be stunning at all. Our current theories about the emergence of life on Earth all strongly imply that similar processes must be occurring hundreds of thousands of times over in the Milky Way alone. On Earthlike planets that our current planetary theories and observations tell us might exist in the billions.

I'm not going to be stunned by discovering something I fully expected to discover, that tells me nothing more than that my current theories are doing just fine.

Until we find one there's nothing at all to indicate that <earth like planet> = <life>

Until we find life out there somewhere, all this speculation about life on other planets is just drawing a best-fit line on a graph based on one data point - pointless.

 

[theprestige]

Until we find one there's nothing at all to indicate that <earth like planet> = <life>

I would say that the fact that there's an earth like planet with life on it is something to indicate it.

What we know of life on earth suggests that it needs an anti-entropic energy gradient. Some large gap between the energy coming in from the star and the energy's lowest state on the planet. A gap large enough and with conditions suitable for that energy to enable complex chemical reactions. And we know that a rocky planet with liquid water is to some degree conducive to this kind of process.

I doubt that this is the only scenario in which a large energy gradient and complex chemistry can occur. But it's one scenario in which we know it can occur.

And our theories about how life emerged on Earth aren't special to Earth. They're supposed to be derived from general principles that apply anywhere in the universe where the physics are the same as the physics we know here.

With billions of earthlike worlds in the Milky Way, what would stun me is if, statistically, none of the others produced even simple life. Everything we think we know, everything we tell ourselves about how life evolved on Earth, includes the implicit assumption, the necessary prediction that if it's happening here it's almost certainly happening in a lot of places. Nothing about the theory of evolution should lead us to the conclusion that it's unique to this one planet. Everything about it should lead us to the conclusion that we'll find it over and over again, if we keep looking.

So no, I won't be amazed if we keep looking and find it once or twice.

 

[Ziggurat]

So no, I won't be amazed if we keep looking and find it once or twice.

I'll be amazed if we find extraterrestrial life in my lifetime (I won't be in a position to evaluate what happens after that). But it's the finding part that will amaze me, not the fact that it exists. My hunch is that life isn't sufficiently common for us to be able to see it from Earth with anything we're currently considering doing.

 

[theprestige]

I'll be amazed if we find extraterrestrial life in my lifetime (I won't be in a position to evaluate what happens after that). But it's the finding part that will amaze me, not the fact that it exists. My hunch is that life isn't sufficiently common for us to be able to see it from Earth with anything we're currently considering doing.

Yeah, fair enough. I can go along with that. In which case I'll reframe my objection that it's not a capability we should be trying to improve right now.

 

[Roboramma]

For me that would not be stunning at all. Our current theories about the emergence of life on Earth all strongly imply that similar processes must be occurring hundreds of thousands of times over in the Milky Way alone. On Earthlike planets that our current planetary theories and observations tell us might exist in the billions.

I'm not going to be stunned by discovering something I fully expected to discover, that tells me nothing more than that my current theories are doing just fine.

The bigger cosmological questions, having to do with the Hubble Tension, galaxy formation, and high-energy particle physics, represent known gaps in our current understanding of reality. New discoveries in those areas are much more likely to tell us things we don't already know, and cause upheaval in our current theories of how things work.


Discovering it within the year might be wishful thinking, but, again, we're predicting that Earthlike planets with some form of life will be found if we go looking for them.

We don't have any way of estimating the rate of abiogenesis on earth-like worlds. It's entirely possible and consistent with everything we know that it's only happened once in our galaxy so far, and even only once in the nearest million galaxies so far. Looking for data on this question is an entirely legitimate scientific undertaking.

 

[Roboramma]

Here's two scenarios consistent with everything we know:

1. Given an earth like world, on average you'll get abiogenesis somewhere on that world 1/100 million years. 90% of those will survive long enough to build up a stable reproductive population. Of those 90% will survive to leave descendants billions of years later. As such, given an earth like world we'd expect to find both life and life with billions year long evolutionary history.

2. Given an earth like world, on average you get abiogenesis 1/10⁴⁰ years. Of those 90% survive long enough to build up a stable reproductive population, and 90% of those leave descendants on the order of billions of years later.

Both scenarios are consistent with the existence of life on earth and with the fact that the conditions of the early earth are sufficient for the emergence of life, they only differ in the chance of that happening per unit time.

Sometimes it's suggested that we do have evidence about that rate: we know that life emerged very early in the earth's history, so this seems to be evidence that given its conditions at the time, the chance/unit time of abiogenesis was high. But this ignores observer selection effects:

From Nick Bostrom's Anthropic Bias:
https://anthropic-principle.com/q=book/chapter_5/#5c

Carter has also suggested a clever way of estimating the number of improbable “critical” steps in the evolution of humans. A princess is locked in a tower. Suitors have to pick five combination locks to get to her. They can do this only through random trial and error, i.e. without memory of which combinations have been tried. A suitor gets one hour to pick all five locks. If he doesn’t succeed within the allotted time, he is beheaded. However, the princess’ charms are such that there is an endless line of hopeful suitors waiting their turn.

After the deaths of some unknown number of suitors, one of them finally passes the test and marries the princess. Suppose that the numbers of possible combinations in the locks are such that the expected time to pick each lock is .01, .1, 1, 10, and 100 hours respectively. Suppose that pick-times for the suitor who got through are (in hours) {.00583, .0934, .248, .276, .319}. By inspecting this set you could reasonably guess that .00583 hour was the pick-time for the easiest lock and .0934 hour the pick-time for the second easiest lock. However, you couldn’t really tell which locks the remaining three pick-times correspond to. This is a typical result. When conditioning on success before the cut-off (in this case 1 hour), the average completion time of a step is nearly independent of its expected completion time, provided the expected completion time is much longer than the cut-off. Thus, for example, even if the expected pick-time of one of the locks had been a million years, you would still find that its average pick-time in successful runs is closer to .2 or .3 than to 1 hour, and you wouldn’t be able to tell it apart from the 1, 10, and 100 hours locks.

If we don’t know the expected pick-times or the number of locks that the suitor had to break, we can obtain estimates of these parameters if we know the time it took him to reach the princess. The less surplus time left over before the cut-off, the greater the number of difficult locks he had to pick. For example, if the successful suitor took 59 minutes to get to the princess, that would favor the hypothesis that he had to pick a fairly large number of locks. If he reached the princess in 35 minutes, that would strongly suggest that the number of difficult locks was small. The relation also works the other way around so that if we are not sure what the maximum allowed time is we can estimate it from information about the number of difficult locks and their combined pick-time in a random successful trial. Monte Carlo simulations confirming these claims have been performed by Robin Hanson, who has also derived some useful analytical expressions (Hanson 1998).

The oceans are going to boil off in about 500 million years, so we're currently pretty close to the cutoff. If there are several critical steps in human evolution, of which abiogenesis is one, we expect them to have been reached with approximately even frequency even if their individual likelihoods are vastly different. So abiogenesis occurring on earth on the order of hundreds of millions of years after it was possible (after the earth cooled off after the initial bombardment) is consistent with abiogenesis being extremely unlikely.

*In Anthropic Bias Bostrom says Carter estimates 2 critical steps, but more recent work I've seen gives more like 4-6. He also uses a cutoff at 9 billion years given the lifetime of main sequence stars, but given increasing stellar output life on earth will be done long before that. Maybe there are reasons to prefer Carter's numbers here, but I think I'm using the more reasonable estimates.

 

[theprestige]

Here's two scenarios consistent with everything we know:

1. Given an earth like world, on average you'll get abiogenesis somewhere on that world 1/100 million years. 90% of those will survive long enough to build up a stable reproductive population. Of those 90% will survive to leave descendants billions of years later. As such, given an earth like world we'd expect to find both life and life with billions year long evolutionary history.

2. Given an earth like world, on average you get abiogenesis 1/10⁴⁰ years. Of those 90% survive long enough to build up a stable reproductive population, and 90% of those leave descendants on the order of billions of years later.

Both scenarios are consistent with the existence of life on earth and with the fact that the conditions of the early earth are sufficient for the emergence of life, they only differ in the chance of that happening per unit time.

Sometimes it's suggested that we do have evidence about that rate: we know that life emerged very early in the earth's history, so this seems to be evidence that given its conditions at the time, the chance/unit time of abiogenesis was high. But this ignores observer selection effects:

From Nick Bostrom's Anthropic Bias:
https://anthropic-principle.com/q=book/chapter_5/#5c


The oceans are going to boil off in about 500 million years, so we're currently pretty close to the cutoff. If there are several critical steps in human evolution, of which abiogenesis is one, we expect them to have been reached with approximately even frequency even if their individual likelihoods are vastly different. So abiogenesis occurring on earth on the order of hundreds of millions of years after it was possible (after the earth cooled off after the initial bombardment) is consistent with abiogenesis being extremely unlikely.

*In Anthropic Bias Bostrom says Carter estimates 2 critical steps, but more recent work I've seen gives more like 4-6. He also uses a cutoff at 9 billion years given the lifetime of main sequence stars, but given increasing stellar output life on earth will be done long before that. Maybe there are reasons to prefer Carter's numbers here, but I think I'm using the more reasonable estimates.

Validating these estimates seems vastly less important than advancing our understanding of cosmological and fundamental particle physics.

Unless we're preparing to seed earthlike worlds with life and hoping for the best evolution has to offer. Which we're not. So why spend NASA's limited budget on it?

 

[Roboramma]

Validating these estimates seems vastly less important than advancing our understanding of cosmological and fundamental particle physics.

Why? Neither has any real world practical implications. We might make technological advances just because of the innovations that arise from building better telescopes, but they won't come about from cosmology itself. We're never going to use dark energy to build a better power plant, or our understanding of abiogenesis to improve medicine. Both of these questions are about satisfying our curiosity about the nature of the universe and our place in it.

Cosmology may inform our understanding of fundamental particle physics and general relatively, but not in a regime with any technological implications. I agree that's also true about discovering life on an exoplanet. Again, there are plausibly spin-offs that could come about from this sort of research, but that's true of both cosmology and explanatory research. Both require cutting edge telescopes with innovative designs.

I do agree that NASA shouldn't invest exclusively in exoplanet research. There are major questions in cosmology that I'd also like answered, and that seem to be part of NASA's mission to answer. But investigating exoplanets is too.

But maybe the disagreement here is that you see a stronger case for cosmology in general?

 

[arthwollipot]

What would be more stunning would be spectroscopic observations of an exoplanet atmosphere that strongly indicated that life was indeed present on such a planet. I'm not necessarily talking about advanced civilisations, but just a marker that shows that life has evolved elsewhere.

As far as I know, our current atmosphere was created by life. If we find an exoplanet with an abundance of molecular oxygen in its atmosphere, that would be strong circumstantial evidence that life similar to Earth's life exists on that planet.

For me that would not be stunning at all. Our current theories about the emergence of life on Earth all strongly imply that similar processes must be occurring hundreds of thousands of times over in the Milky Way alone. On Earthlike planets that our current planetary theories and observations tell us might exist in the billions.

Might. Yes, we do think that. We thought that antimatter would fall down in the presence of gravity too, but we had to do the experiment to make sure.

Until we find one there's nothing at all to indicate that <earth like planet> = <life>

Until we find life out there somewhere, all this speculation about life on other planets is just drawing a best-fit line on a graph based on one data point - pointless.

Exactly.

 

[Puppycow]

Well, we are approaching the third year of the mission and telescope time for the third cycle of observations has been allotted and announced:

The James Webb Space Telescope's targets over the next year include black holes, exomoons, dark energy — and more

I guess technically we are already into the third year since the launch, which was on Christmas Day back in 2021. We've also reached a period where public interest seems to have waned to a certain extent.

So, of course there are exomoons. The majority of planets in our own solar system have moons, and the larger ones have multiple moons each. It's just that we have yet to conclusively observe any. Which is hardly surprising given how far away they are. Just detecting exoplanets is already a feat.

 

[Puppycow]

A horse-shaped nebula gets its close-up in new photos by NASA’s Webb telescope (AP)

Horsehead Nebula (NIRCam image) (ESA)

It's zoomed in so much that you can't even see the overall horsehead shape without zooming out.

Once again, the cool part to me is the galaxies in the background.

When you consider that the Horsehead Nebula is an object over 1,300 light years away, within our own galaxy, and the distant galaxies in the background are of similar size to the entire Milky Way galaxy, it gives you a sense of just how enormous the universe is.

See also:

https://en.wikipedia.org/wiki/Horsehead_Nebula (for a wide shot of the Horsehead Nebula and more information)

 

[JimOfAllTrades]

Amazing stuff! What is the scale in that closeup? It looks like a picture of a wave coming up the beach (except for the beach is stars!) or dense smoke from the neighbor's barbecue, but what is the width on that shot? Lightyears?

 

[Puppycow]

Amazing stuff! What is the scale in that closeup? It looks like a picture of a wave coming up the beach (except for the beach is stars!) or dense smoke from the neighbor's barbecue, but what is the width on that shot? Lightyears?

According to the second link, the field of view is 2.13 x 2.14 arcminutes.

The Wikipedia article gives a radius of 3.5 light years for the nebula, and 8 x 6 arcminutes for its dimensions. That gives me a rough estimate of 1 light year squared for this image.

I like to start from the third image in the Wikipedia article, which shows "The three bright stars of Orion's Belt with the Horsehead Nebula to the lower left of the belt star Alnitak". You can see those stars with your own eyes on a clear night if you can identify the constellation Orion. You can't really make out the Horsehead nebula though unless you have special equipment (at least, I can't see it with my naked eyes, just the three bright stars of the belt).

There you can see the Nebula in the lower left of the image with the characteristic horse's head shape looking up.

This image zooms in, from a wide shot taken by the Euclid telescope to a narrower one taken by the Hubble, and finally the one taken by the JWST.

 

[JimOfAllTrades]

Thanks for that!

So, about a lightyear square on that close-up would mean (I think) that the sort of fringe area where the dust fades out, the "chopiness" on the very edge of the cloud is bigger than our solar system. And that is a small part of the nebula.

Man, Douglas Adams had it right!

 

[JimOfAllTrades]

And I can see Orion from my yard, it's one of just a couple of constellations I can recognize. But I live in the city and with the light skies I've never seen any sign of the nebula.

I do have an inexpensive 3" reflector on an equatorial mount. If I were to get away from the city lights do you think I could see the nebula with my scope? Or would I need a camera with special filters?