When Hubble stared at nothing for 100 hours (2015)
nationalgeographic.com
nationalgeographic.com
This is such a powerful statement from Rob Kirschner. It is science at it's best. Someone (rightfully) opposing an experiment, being incorrect and admitting, without reluctance, shame or regrets that they were wrong.
At the time, Bob's idea was by all available information questionable. But it was right for him to persevere, it was right that he had to face and overcome opposition and it is right that the opposition gracefully admits that Bob was right :)
(meaning roughly: "and there it is" / "and there you have it")
Even more hilariously, I have an uncle Bob.
And of-course, Erich is a lying person. :D
But I think the courage Bob showed in the first place is much more praiseworthy. He actually had to put his butt on the line for this, admitting someone was right after the fact does not usually require that.
The path of least resistance is definitely a draw, and there is incredible business value lost pursuing it.
It was a terrible idea, his colleagues told him, and a waste of valuable telescope time. People would kill for that amount of time with the sharpest tool in the shed
And by 'Bob Williams', we mean the director of the Space Telescope Science Institute, which operates Hubble. Williams chose to use some of the predefined Director's Discretionary Time to explore the limits of the telescope and our understanding of the universe.
I also believe that even if we found nothing at all, it would still advance our understanding of the universe as we could confidently say what limits there might be.
These things are always as much science as they are politics, so the reputation damage would have been real.
Experiments worth doing are worth doing no matter the result.
I mean, if they found nothing? Sure, that's still a question Hubble should be trying to answer. But right after such a rocky start, the politically obvious choice would have been to go for easy wins.
The timing was as ballsy as anything else, if not more so.
> And, to be honest, it didn’t really matter how much his colleagues protested. As director of the Space Telescope Science Institute, he had a certain amount of Hubble’s time at his personal disposal. “The telescope allocation committee would never have approved such a long, risky project,” he explains. “But as director, I had 10 percent of the telescope time, and I could do what I wanted.”
Also:
> “Scientific discovery requires risk,” Williams says. “And I was at a point in my career where I said, “If it’s that bad, I’ll resign. I‘ll fall on my sword.’”
It's not like you would expect galaxies to suddenly stop being found if you took exposures a little deeper. It was a good (and not outrageous) bet. I would liken it to -- if we built a better microscope and looked deeper into a cell, is it likely we'd find nothing new? Probably not.
It's extremely risky to allocate a huge amount of finite resources to these unknowns, when there are so many areas we KNOW we can help advance with those finite resources. The fact that he was ready to retire, if the picture came back with barely anything in it, gives a sense of how bad that waste of resources would have been.
Future us might not think it is such a gamble to send a probe to look for life in the oceans of Saturn's moon Enceladus. There's evidence of abiogenesis from deep sea vents on Earth, and Enceladus has very similar conditions. But present us knows there are so many unknowns and possibilities of failure even if something is there. And there are so many other useful ways to use the finite resources of our space program.
It took a lot of courage on Bob Williams' part to explore this.
So you'd better do it outside of your regular job, adding up to a 120% workload.
I think it's a good hedge for NASA to have this policy, they probably selected a good pick in the first place, and if it went wrong they could probably easily replace the position [source needed].
Its similar to Monarchy vs Democracy. A great monarch can get a lot more done than a leader in a democracy. They can also do a lot more harm.
If you want to maximize the potential of a company, you must choose a great CEO and give them near-unlimited power. The problem is that most boards aren't qualified/able to find one, which is why founders that survive the filter to growing into a mega-company are the ones you listed- they are the ones who've already got one.
Tim Cook is doing fine, but he doesn't wield near the influence Jobs did- look how long it took him to finesse Joni Ive out of the company, despite his choices causing massive problems for Apple.
Too many times I heard things along the lines of getting "low hanging fruit" to get "published" and that "don't try that you won't ever graduate". Why is graduating and publishing papers and tenure and theses the goal of academia, instead of trying the highest possible risk things that even companies wouldn't want to risk? Why isn't academia about doing the most utterly crazy things possible in the name of advancing science for civilization?
Yet, what's good for the academic? Each effort costs potentially years of your life. A great discovery will catapult you to the stars, a small one will advance your career, and a negative finding does nothing. You're not alone, you have peers competing for the next round of funding, tenured position, or residency. There are literally never enough to go around, and each will judge applicants in part on their record of results.
I think you're describing a conflict between what's valuable for a system at scale and what's valuable for individual actors within it.
For topics with a large number of practicing labs that make use of relatively accessible tooling you might be able to pull off such an approach.
Other fields require customized, incredibly expensive instrumentation. Physics and certain areas of biomedical research are examples of this. It's not uncommon that fewer than ten labs in the entire world will have the capability to perform a particular highly specialized technique.
Even in the largest fields though, it will be your peers reviewing your grant applications at the end of the day.
What you don’t do is sum the 10000 different requests, nor the 100 requests that also want to use 100 hours each.
Novel trials are big risks, are institutional (or worse, multi-institutional), and searcch spaces are large, well-picked-over, and huge gains improbabble. Though aversion to novelty is a long-standing behaviour, see "Resistances to the Adoption of Technological Innovations", by Bernhard J. Stern (1937):
https://archive.org/details/technologicaltre1937unitrich/pag...
Markdown https://pastebin.com/raw/Bapu75is
This sort of proposal pressure (over 9:1 oversubscription) leads to very conservative proposals, where we request absolute minimums and emphasize that even a non-detection will lead to publishable science in such and such a way.
Getting over 60 orbits to point at a blank field would have been frankly impossible through the regular time allocation process, not because the science wasn't excellent, not because it wouldn't be recognized as excellent, but because it would crowd out other science that could be done with far fewer orbits per project.
The telescope administrators explicitly recognized this problem when they set up the Director's Discretionary Time process (and this is common to all telescopes now) - sometimes you need someone with the authority to just roll the dice on a long shot.
[1] https://www.stsci.edu/contents/newsletters/2019-volume-36-is...
Speaking of scale a new large structure was discovered a supercluster which has been named "South Pole Wall" it;s 1.5 billion light years in length.
The paper he linked to is not very long: https://iopscience.iop.org/article/10.3847/1538-4357/ab9952
I never really understood how XDF is only that tiny patch of the sky and yet it has a godzillion of galaxies inside it!
They perfectly align and all you see is a thin ring from the sun flares.
In that perfect eclipse, you can look at the sun with the naked eye and it’s beautiful and humbling. Like the day suddenly turns into a night for a few minutes.
The TV series “Heroes” was all about this eclipse. It’s a fun show if you enjoy this kind of things.
Not recommended.
https://astronomy.com/magazine/ask-astro/2000/10/why-is-the-...
Unlike the lower resolution versions National Graphic scoldingly claims are under copyright when you right click to try and view the full image.
If I understand correctly, the universe is approximately 13.8 billion years old. As is mentioned frequently when staring at deep space, we are looking at the universe not as it is, but as it was, since it takes so long for the light to travel to us. Some objects in the Hubble Deep Field are over 9 billion years old, and some within 1 billion years of the beginning of the universe.
My question, as best I am able to ask it, is assuming the big bang theory is true, how can it be that we on Earth can be looking at something simultaneously so old and so far away? If everything originated from the same point, how can it be that we pick an object in the sky and say "that is what the object looked like 12 billion years ago"? Doesn't it beg the question, "well then where were we 12 billion years ago?" As in, how can we be here, observing something close to the beginning of time? Didn't both objects start at the same place?
I hope that makes sense.. Articles and videos much appreciated
Hope that helped a little bit..
For unrelated reasons, we cannot see back past further than about 10^-6 seconds after the big-bang, because the universe prior to that point was so hot and dense that photons would be reabsorbed almost immedietly.
Once you avoid everything being in literally the same place, the problem just becomes having the photon move towards us faster than the expansion of the universe.
Many depictions of the big bang show the entire universe - something which may not have a finite volume - collapsing to an entire point.
It might be more illustrative if you imagine when you look at one of those drawings that it is in fact "merely" depicting all of the space within a finite volume today collapsing to a particular point in the past corresponds to the big bang. Conversely, things arbitrarily close together in the big bang can be arbitrarily far away now. There is no "center" of the universe, it's more like the shriveled up balloon analogy. Draw a bunch of dots on a blown up balloon and let it deflate, everything gets closer together but no one point is the center. So it doesn't make sense to ask "where were we 12 billion years ago?" The answer is: closer to everything we can see.
This explanation corresponds to a universe whose shape has zero curvature or negative curvature. WMAP and other experiments have suggested the curvature of the universe is very close to zero, but even a slight deviation above or below has dramatically different implications.
Both objects started moving at the same time but at different speeds and in different directions- on top of this the universe itself is also expanding, so the gaps between galaxies is actually growing, meaning it takes longer for the photons to get here
First of all, the universe is expanding. A good visual is to paint stuff on the surface of a balloon. Everything on the balloon started off close together. But as the balloon expands, things on the surface of that ballon get farther apart. So it is with the universe.
Where did this happen? Everywhere, and nowhere. The balloon is an analogy for the structure of the universe. The balloon exists in a 3-D world at a time and place. But all notions of time and place are defined within the structure of the universe. So I'm describing what happened everywhere. All places used to be close. And now they are not.
Now the Big Bang theory is this. If you play that tape backwards, everything that we can see was once really close together. But still had all the same stuff. So the universe was a hot, dense place. Then it began expanding, and got large and cool and fairly empty.
So if everything used to be close, why does light only now reach us from somewhere that wasn't that far away originally? Well look at light as being like an ant crawling on the surface of the balloon. At first your journey doesn't look far, but the balloon starts expanding and the trip gets longer. You keep traveling and it gets longer still. That's exactly the plight of light from the early universe.
Did that help?
At that rate nearly every other force (from chemical bonds to gravity) prevent anything but the largest cosmological structures (like galaxies) from being effected. They simply continue with their system as they always have, and the extra space shows up as distance between galaxies.
https://www.quora.com/When-did-gravity-first-arise-in-the-un...
That still sounds measurable though. Has there been any multiyear experiments that try to measure something like that?
Again any "new space" doesn't stick around where it was created. The atomic forces, chemical forces, and gravity maintain the system distances we are used to.
Since light travels all directions, if something was older than presumed aged of the universe, statistically speaking, we'd be able to see some of it from here.
You could define some physical process on the balloon as distance and time, like light moving and atoms vibrating, and call that our ruler. Then measure intrinsic properties like curvature? If hypothetically the speed of light instantly dropped by 5% (with respect to existing objects' distances, I guess), do you just define those objects as instantly 5% further apart now, or do you you say something like the speed of light changed? Then there'd be similar questions about changes in how we define time. This is fun to think about.
Longer answer: Maybe nothing. Maybe it's nonsensical to think of something as being outside of the universe - as it expands, it creates space where there was none. Maybe a true vacuum that our universe is floating through. Maybe other universes. Maybe something else.
We might not be able to ever know the answer to this question - the laws of physics might prevent us from being able to decipher it.
I hope there are more plans for deep space photos. I wonder what a telescope on the other side of the moon could capture.
Being on the other side of the Moon, alone, isn't likely to make a huge difference in image depth.
You say that as if we could tell with any certainty, at that scale. There could be interstellar civilizations spanning several of those galaxies and uncountable intelligent civilizations that simply never pursued space travel or the constant accelerated curve of energy consumption and colonization we assume they would, only because we ourselves would.
We wouldn't know, we don't even really know what we're looking for, and the universe is so vast that even if we did, we'd be all but certain to blink and miss it.
The top of our capabilities is indirect planet discovery. So alien civilization would need to affect ceartain stars on a scale that a planet does and make it look not natural, like prime number periods or something.
On Earth scale it is for all practical purposes.
Well, to get to life, we have to have chemical elements more than just the hydrogen, helium, and a little lithium that came directly from the big bang. So for carbon, oxygen, ..., iron, have to have some big stars form, burn, and explode.
So those galaxies from 12 billion years ago didn't have much time -- ballpark only 2 billion years -- to form the elements of the periodic table.
Coming at it from our end, IIRC our planet and solar system are about 5 billion years old.
Give it, after the big bang, 4 billion years to the periodic table and another 5 billion years for life. So, that's 9 billion years, 5 billion years ago.
So don't expect much in Little Green Men ET from more than 5 billion years ago.
Since we started 5 billion years ago, we are ballpark only second generation life in this universe.
Net, mostly what's in the Hubble deep field images is too old to have much in life (anything like ours). To have a shot at seeing life, don't look back more than ballpark 5 billion years.
Since stars are burning out and the universe is expanding, are we also about the last generation of life?
Yup, it's amazing to look back 12 billion years, to see galaxies already there, with quasars and, thus, likely supermassive black holes. Amazing to guess how such big black holes formed so soon. Lots more that's amazing. Still for life, only look back about 5 billion years.
Disclosure: I'm not an astronomer!
This contradicts the clue of the article. Sometimes it is worth to step back and try something unordinary, especially in area where our assumptions are so weak - the Universe.
Red dwarfs will still be burning a trillion years from now. The flare stars among them will only become more stable with time. I'm not sure what the prospects for interstellar travel will be by then, though.
all spectra are important for astrological observations—there is a serious lack of radio observations made with large telescopes outside of the earth's atmosphere in particular.
NASA has funded an early study into the feasibility of building such a telescope. https://www.nasa.gov/directorates/spacetech/niac/2020_Phase_...
How did this work? 342 pictures at 25 minutes each is already well over 100 hours. At 45 minutes, it'd be 256 hours.
I don't know, but I'd hazard a guess that the image is 100 hr deep on multiple tiles.
The dataset spans 10 days, which is 240 hr.
I went looking for more detailed information -- It appears they are open enough with the data that you can see exactly how the exposures were taken. Assuming what I found is right and that someone could make sense of the data. There are postscript files listing activity for each of the 10 days, but I am not exactly sure what we're looking at.
https://www.stsci.edu/ftp/science/hdf/project/scheduling.htm...
Observations run from 352:16 to 362:19.
Filter Nexp hours
F300W 100 48.93
F450W 62 36.52
F606W 77 34.94
F814W 49 34.86
As it turns out, empty space isn't dark, but rather illuminated by the cosmic microwave background. This suggests that the space between us and this boundary in space from when photons started to be able to move mostly freely is mostly empty. Otherwise this backround would either be over-shadowed by stars, or obscured by whatever stuff was obscuring said stars.
Of course, it is important to keep in mind the speed of light implications.
It’s amazing we have a giant telescope outside the planet. We know so much about the universe because of Hubble and friends.
When I was young I truly believed in heaven and hell as some distant planets. Then learning about Hubble, cosmic radiation and the fact that we can see millions of lightyears away which is an incomprehensible distance and the fact that our vision is limited by speed of light that seems super slow relative to those distances.
I really had a paradigm shift. Heaven and hell are probably good ideas but don’t actually physically exist. Took me a while to digest that. If they were actually there, we’d have seen them by now.
I have a lot of respect for Astronomy.
This numbers is sheer incredible. Each of them contains 50 billion stars. How come some think we’re alone in this universe?
EDIT: yeah, I know speed of light and all... it’s just a stupid fantasy that is fueled by these numbers
... If there's no communication between you, what else would you call that but "alone"?
Edit: I should say that I think I hear what you're saying, and I further think that there's always hope that you could bridge that gap.
if you don’t believe aliens exist, you are wronggggg!!!
The sheer number of stars seems to make it likely we aren't alone. Whether we're practically alone, and will remain forever separated from our nearest intelligent neighbours, is a more interesting question IMO (though somehow discovering we are completely alone would be fascinating in its own right and raise further questions).
It seems that current estimates for this are higher, such as 100 billion in a 2020 article I saw. Anyone have an authoritative scientific source for the best current estimates?
50 billion galaxies (or 100) somehow doesn't actually seem so many. Considering that's on the same scale as the number of people on our tiny space rock. Yes each one has billions of stars inside, but still, we're talking about the entire universe.
Somehow, intuition suggests there must be more "stuff" beyond our observable universe.
here's https://phys.org/news/2017-01-universe-trillion-galaxies.htm... where it's 2 trillion. Which is 1 galaxy for every dollar in the US Coronovirus stimulus package or 256 galaxies per person. Which makes it also feel like an approachable number for the amount of galaxies in the universe.
> So, with his job perhaps on the line, Williams went off, put together a small team of post-docs, and did exactly as he’d planned. For 100 hours, between Dec. 18 and 28, Hubble stared at a patch of sky near the Big Dipper’s handle that was only about 1/30th as wide as the full moon. In total, the telescope took 342 pictures of the region, each of which was exposed for between 25 and 45 minutes. The images were processed and combined, then colored, and 17 days later, released to the public.
I mean, each image was only exposed for 25-45 minutes. If the full hundred hours was such a huge risk, why not take, like, 5-10 photos first to see if you get much of anything? Seems like they would have been able to know pretty early on whether it was going to be worth it.
For the hubble to point at something, I'd imagine it needed to station-keep and burn some hydrazine.
If you did infinite numbers of 5-10 min studies, you'd burn right out of the fuel store of a spacecraft before you'd get anything done.
From what I hear, hubble telescope times are scoped out, planned out a year or several years in advance - the telescopes and scientific instruments need to be programmed, the spacecraft needed to be moved/pivoted to aim at the right part of space, communications times needs to be booked with receivers/ground stations across the entire Deep Space Network so you can receive the data.
It's nontrivial - if you booked 5-10 min at a time you'd have wasted your most precious resource.
Also, I don't think it needs to change orbital parameters at all for its operation. Station-keeping yea, but I don't think it needs to burn more fuel because of pointing at things.
I know, we're not supposed to complain about downvotes but it just makes me sad that we - as a community - don't value honest questions.
This has been answered already but just to pull some threads together - the suggestion to take a few exposures first and see what comes out is precisely backwards. They already knew, going into it, that what they were looking for was at the limits of sensitivity, so nothing would show up until they accumulated enough observing time.
In the absence of systematic effects, our signal to noise ratio improves as the square root of integration time. Think of a bucket accumulating photons - the signal accumulates in linear proportion to the integration time, while the RMS fluctuations increase as the square root of the integration time, so the signal to noise ratio improves as T/sqrt(T) = sqrt(T).
So the idea was to accumulate enough exposure that the faint galaxies would become visible at the telescope performance limits - can't get to something scientifically useful by imaging only the first few exposures. It might have made a pretty enough picture, sure, but not an informative one, compared to what we could already do from huge ground-based facilities.
We learned new words for things. The decade changed.
The first few pictures came back blurred, and I felt ashamed
For all the cheerful engineers, my father and his tribe.
The second time,
The optics jibed. We saw to the edge of all there is—
So brutal and alive it seemed to comprehend us back.
Smith's father worked on the Hubble telescope, and she would be named US Poet Laureate in 2017. I highly recommend reading her poetic account of this photograph :)
[1]: https://www.poetryfoundation.org/poems/55519/my-god-its-full...
I mean they look relatively close compared to their size, in contrast our solar system’s bodies are really far away from each other (of course relatively).
Andromeda for naked eye is a smudge six time bigger than the moon (3.0 degrees across).
Wow. TIL.
no. they're millions of star-diameters apart.
https://en.wikipedia.org/wiki/Solar_radius compare it to a light year. note that the nearest star is 4 something light years away. the average is about 5 ly.
> while galaxies are of the order tens of galaxy-diameters apart.
i think that's low, but harder to define.
...In total, the telescope took 342 pictures of the region, each of which was exposed for between 25 and 45 minutes. The images were processed and combined, then colored, and 17 days later, released to the public.
The motion of Hubble (and basically everything inside the Milky Way) relative to the galaxies in that picture is ~250,000 km/s, or 0.83 c.
At this speed, it would take ~100,000 years for the galaxy to move its own length, and even then the movement would be in a direction which doesn’t cause much blur.
http://www.wolframalpha.com/input/?i=12e9%20light%20years%20...
1. You put the telescope on a motorized mount that rotates the telescope exactly counter to the rotation of the Earth (or I guess its orbit in the case of Hubble). This cancels out most of the blurry star trails you get from the Earth's rotation causing the stars to move across your frame.
2. For particularly long exposures, you take a series of separate photos (each of which is probably done using step 1). Then you "stack" those in software by aligning all of the images to maximize their sharpsness. There is software that will do this for you automatically. Stacking helps correct for thermal noise and other imperfections and non-linearities that photon sensors have when collecting for a really long time.
It's a good question.
Good learning opportunity here.
We shouldn't think to hard whether he was right or why though.
I am guessing that especially in the extreme deep field,
the distant couple-pixel dots correspond to the back of the room i.e. the oldest/most distant galaxies,
so this is in some real if crude sense looking through a core sample of cosmological time?
You can also use Earth's atmosphere as a lens too! It's an amazing video: https://www.youtube.com/watch?v=jgOTZe07eHA
Going even crazier, I can imagine we could some day use a massive black hole as a giant telescope.
Can anyone cast some light on this?
There is some explanation for Director's Discretionary's purpose here in the Call for Proposals (although given that this Deep Field project seems now unlikely to qualify, this might have been retconned):
https://wayback.archive-it.org/all/20080527200338/http://www...
If someone needs to get ten different kinds of approvals, are they really a "director" for most meaningful senses of the word?