Always a bit special to see science come from a spacecraft I had the pleasure of working on. Honestly there were a lot of issues during the build of Euclid that I was very glad to not be a part of, but seeing the images coming out of it now is pretty damn impressive.
Hope all of the engineers that struggled to get this mission spacebourne can enjoy!
Thanks for sharing a human moment, honestly inspiring to contemplate. I have a few interview questions if you find the interest:
1. What was testing/safety/static checking culture like? I have experience within a NASA software contractor that spent a lot of time and stress on balancing classic “aerospace-y” engineering practices with the more modern ones out of SV, which are paradoxically both more and less rigorous than the old ways across different situations. In other words: in a project like this where “groundbreaking” is expected, how closely did you stick to tradition?
2. I’m dumb and just realized: did they pick Euclid because it’s in the EU??
E: 3. What’s it like to be “accomplished”? Like, more so than any random app ceo or sales consultant or whatever, you have now accomplished what would be many young people’s dream: to help build a spacecraft that’s advancing science significantly. I’m assuming all stress dissolves and any sacrifices resolve into being definitely worth it? Asking for a friend, of course.
1. The testing culture is very thorough. I was involved on the propulsion side of things, and as such the safety is taken very seriously, for the safety of the test/production engineers and of course the spacecraft. Propulsion systems are typically integrated in such a way that it is very difficult (nigh impossible at times) to separate them if an issue is found at a later stage, so the testing goes through things with a very fine comb. And even still things can go wrong and can sometimes only be found at a later stage.
From the spacecraft Assembly Integration and Test (AIT) side of things, which is where I work, things are traditional but pragmatic. If a new way can be shown to be more reliable we will adopt it. But not before it is very well understood and characterised. In space, heritage is king, the best way to know if something will work in space is to already know it works in space. So it can take a lot of evidence for a new method/system to be adopted, and when we think we are moving quickly, it probably looks like a glacial pace to others.
During the build and test, we are often so far from the end goal of a spacecraft, its not possible to see the "groundbreaking" aspect of things. Perhaps the payload designers and engineers can see this better.
2. I believe it is named after Euclid, as the father of geometry, as the mission goal was to measure the geometry of the universe. And also yes, go Europe.
3. Christ, accomplished? I love the idea of being accomplished in many ways, but its also a scary concept. Wouldn't want to be having notions of grandeur either. I am very lucky to have worked on many great projects, in many countries, and in a job that I honestly think I am good at and enjoy. But I am always surrounded by so many people who have done so much more, so it mostly feels like I am trying to catch up really.
The science missions really are special to me, I have a background in Astrophysics, and sort of fell into spacecraft engineering. So it is always a real pleasure to get to work on something I understand on a deeper level. But most of the missions I have worked on have not been so special. Most spacecraft are to make money or do something for a military. Its why I have so much time for ESA. Even with their issues (cost, time, etc.), they really feel like they do the important missions for humanity. Nasa and Jaxa too, but they mix in a higher amount of the less special stuff in my experience.
The stress and sacrifice was stressful and sacrificial(?). I wouldnt say it was worth it, or not worth it. Its an odd one. Mostly I have just tried to do cool shit as often as I can, and I have been damn lucky.
Thanks for the kind words though, and I hope I wasn't rambling too much in my response.
I wouldn't want to go into specifics, as it's easy to look like I was slinging mud.
But if you have seen the issues that Starliner has had recently, I would echo the statement from there, that valves are hard. Very hard. Everything to do with pressurised systems in space is hard. But the propulsion team worked it through and are now seeing the fruits of the long hours.
Where did OP say failures? Don’t attack random strawmen with a prosecutorial line of questioning.
It’s completely fine to be working on software, witness a huge hardware issue that teams scramble to fix, be proud that they fixed it and happy to be part of the team while simultaneously being happy to not have to deal with that type of stress.
In this case, it found dozens of rogue planets in the Orion nebula, which is only 1,500 ly away.
I am presuming there are also going to be great numbers of rogue planets in deep space, not tied to any star or galaxy. But there would be no way for Euclid to spot them at that distance. Stars were hard enough.
I presume, in due time, there will be some sort of calculable estimation or projection of orphan stars and rogue planets per cubic parsec or kilosparsec.
Specifically the Perseus cluster reported on here has a mass of around 10^15 solar masses in total. Of that ~10% is in the form of stars, 20% is intergalactic gas and the remainder is dark matter.
The report here says 1.5 trillion of these stars in this cluster which is ~10^12 solar masses (assuming average star mass is similar to the sun's.)
So the newly observed stars reported here are around 0.1% of the total cluster mass, or around 1% of the total mass of stars in the cluster. All very approximate of course.
I suspect the current contents of a solar system is a poor proxy for everything that’s been ejected from it. Pluto is 0.0006 light-years from the sun, there’s a great deal of space between stars we don’t know that much about.
Further we dramatically underestimated the number of expo planets for decades. Quite reasonably we don’t put a lot of weight on stuff we can’t detect.
Close it’s ~99.85% excluding the ort cloud. However there’s a major bias towards smaller stars because they last longer though conversely they are harder to detect.
“A brown dwarf is an object which is made of the same stuff as stars, but does not have enough mass for hydrogen fusion (combining hydrogen atoms into helium atoms). Hydrogen fusion is what makes stars glow. Brown dwarfs are not massive enough to do this, so they are not stars. On the other hand, they are not regular giant planets, because they do glow.”
While very young they generate heat from both deuterium fusion but that only lasts millions to tens of millions of years. Energy from radioactive decay and their slow contraction lasts for much longer.
The nebulous space the Brown dwarf occupies in terms of classification is fascinating to say the least. I'm a passing not even hobbyist on the subject but that they glow but not like that is really interesting.
When I think of the brown dwarf I am also reminded of the hypothesized black dwarf. This would be the stage after white dwarf. It's hypothesized because it takes longer for the white dwarf bodies to cool than exists presently in the history of the universe. It's only a handful of sentences and will largely repeat the previous paragraph but there's the wiki page for black dwarf.
If I am reading this correctly, it seems like Euclid was able to see the light from individual stars ripped from their galaxies in Abell 2390. Which is quite the accomplishment.
Please let me know if I am reading too much into this, or reading it incorrectly.
The stars near us in the Milky Way are tens of light years away, and we’ll have to do some incredible science and technology to visit them.
How much worse would it be if you were an intelligent life form on a planet orbiting one of those orphans, and the nearest star was a thousand, ten thousand, even a million light years away?
At some point, given the universe's expansion, galaxies will be moving away so fast that the observable universe will be just one galaxy. Already, the effective rate from galaxies far away is actually faster than the speed of light. Even at light speeds, we cannot reach 94% of them as we would never catch up if we left today. In cosmic scales of many billions of years, observers on every galaxy will eventually think that their galaxy is the only one that has ever existed.
Indeed, the only hint they would have that they were not alone would be the "weak" gravitational effects of all other existing matter pulling at the fringes of their visible universe. Perhaps they'll refer to this phenomenon as "dark energy".
> In cosmic scales of many billions of years, observers on every galaxy will eventually think that their galaxy is the only one that has ever existed.
Unless of course some of them manage to find ways to preserve information and keep records over those billions of years. The lost galaxies will be known from that.
But the information would still be forever locked away in its own galactic island. Even transmitting at the speed of light, the information could never reach any other galaxy. So no, in this far future, a galaxy would only be able to know itself.
We have records of other galaxies right now. Assuming we manage to preserve those and humanity over these kinds of time scales, our descendants would be able to access those records and learn that other galaxies once existed that are beyond their cosmic horizon now.
Might be much harder to bootstrap your astronomy in that situation as well.
As I understand, we built much of our picture of the universe on the fact that we can do precise parallax measurements of nearby stars.
Then we used that to see how far the nearby Cepheid variable stars are, and used the patterns those exhibit to measure distant galaxies. Then at some point we could determine the distance to a certain kind of supernova, and now we have a 3D model of the whole observable universe.
But it starts with parallax measurements which are limited in range.
Ooh, this is super interesting! This video by The Science Asylum lays out the "distance ladder" in great detail: https://www.youtube.com/watch?v=zrpdwJNNskk This wikipedia article also lays out the distance ladder: https://en.wikipedia.org/wiki/Cosmic_distance_ladder so if our hypothetical "intelligent species on a planet orbiting an orphan star" were more than 30,000 light years away from the nearest star, they wouldn't be able to measure that distance with accuracy using the technology we have now. That might not apply to ranging whole galaxies? And they could get better with time? In any case, my idea that they might take off for a "nearby" star "only" ~100 light years away because they don't know better is foolish.
There is a novel written with that premise as the background! I can share the title with you, if you'd like - that particular premise is a very small part of the novel.
I really find hard to believe how people can say "well, maybe it's not that easy to have other forms of life in the Universe". I mean, we have a cluster with thousands of galaxies, which make it for millions of stars, 240 MILLION light years away. Which means that there is a 240 million years window in which we are basically blind. Any communication from there will never reach the human race, most probably. Philosophically we can say there is no life there as we are concerned, because we will never be able to see any proof of it, but that doesn't mean that there was anyway, or there currently is, and maybe in more than one planet.
People underestimate how dead and hostile the space is to life in general. First of all, you can just swipe most of the available galaxy space off the table because of radiation - the center of the Milky Way, close to our "core" black hole, is just pure hell. This is why we inhabit a remote neighborhood of the galaxy. You can extrapolate that most spiral galaxies are like that and only a small sliver of them are "in play".
Earth won multiple jackpot lotteries in a row, and that's only the variables we are aware of:
* Right-sized star
* Right-sized planet
* Not too far and not to close to the star
* Not too little and not too much water
* Oxygen
* Iron core (magnetic field protects from radiation)
* Right-sized moon (keeps rotation stable, tides)
* Gas giants absorbing a lot of debris coming our away
* A single-star system, with nearly circular, stable planetary orbits (very rare)* ... and so on
Yes, I know there are permutations that might also work, but in general it does not look good for spontaneous life.I like a theory that states that the Universe is just the right size where one single Earth has only a single probability to spring up randomly. The Maker covered their tracks well, if you believe in higher intelligence.
This doesn't seem like the right calculation to me. Doing some quick lookups, I find that the number of galaxies in the universe is estimated to be between 200 billion and 2 trillion. As for stars in a galaxy, there are around 100 billion stars in the milky way galaxy, so lets go with that.
If we guess that only about a quarter of any given galaxy is potentially habitable, that leaves 25 billion possibilities per galaxy. If we go with that and a middling estimate for the number of galaxies then we have maybe (25 billion * 1 trillion) stars, which is a number so big I don't even know how to say or comprehend it.
Even if we take an extremely conservative view that each galaxy only has at most 25 stars with potentially habitable planets (cutting the 1/4 galaxy estimate down by a factor of one BILLION) then we are still left with 25 trillion possibilities, which seems like a pretty good chance to me.
Aka Drake's equation, with sufficiently large numbers, gives a decent chance of habitability. We just don't know what the numbers really are. Those big enough numbers with small enough other names make for a low enough number that it might as well be zero since we can't observe or interact with them.
But I don't think there is anything special on there being oxygen in the cloud of gas that formed the solar system. The distribution of elements following a supernova probably follows some law, and oxygen is low enough on the periodic table that probably quite a bit of it is expected.
"I'll tell you one thing about the universe, though. The universe is a pretty big place. It's bigger than anything anyone has ever dreamed of before. So if it's just us... seems like an awful waste of space. Right?"
It’s a game of numbers. There may be 10^n opportunities for life potentially forming, with the average likelihood for life actually forming being 10^-m for each. The question is, is n (much) larger than m, or vice versa? We really have no idea, in particular with regard to m. It doesn’t help if n is 100 when m may be 1000. And the human brain is really bad at estimating such likelihoods.
If the universe is infinite like we think it is, then there is life somewhere, in fact, there is an infinite number of copies the earth exactly like or own, with a copy of you and me on it. We are just "blinded" by the limits of the observable universe.
So, we are almost 100% sure that there is extraterrestrial life somewhere in the universe, but if there is no possible causal relationship between us, what's the point? It is also the same reason why "the universe" is often shorthand for "the observable universe". There is probably something beyond it, but we have no way to know what it is, so it might as well not exist.
> If the universe is infinite like we think it is, then there is life somewhere, in fact, there is an infinite number of copies the earth exactly like or own, with a copy of you and me on it.
This requires more assumptions than just infinite scale.
Right, like in math, not all infinite sequences contain every finite subsequence. For example, a non-repeating sequence of 2's and 7's contains no sequence "4". The further condition is that the number be normal[1].
Also, TIL we don't know whether π is normal thus the popular claim that "every string of numbers eventually occurs in π" is not known to be true
I am not aware of any models of the universe that posit an infinite mass.
Edit: Also, "observable universe" is a frequently misunderstood concept. Just because something is now outside the observable universe (the distance between them and us is big enough so that the rate of expansion of the universe between us and them is higher than the speed of light) doesn't mean that we aren't, today, receiving light from a long time ago when the object was closer. If you go far enough back in time you can "see" the entire universe . As time passes, more and more mass moves outside of the observable universe since the size of the sphere is constant relative to the rate of expansion.
this is such a commonly-repeated fallacy. just because something is infinite, doesn't mean everything is possible. the sequence 1,3,5,7,9,... is infinite, and yet it contains no even numbers. there are many such cases.
So an orphan star is one that's been ejected from its galaxy.
If one of those stars had a planet with something capable of "gazing up at the night sky", does that mean their sky would be empty compared to our own?
No, their night sky would be more or less like our own. There would be other stars and galaxies visible, it's just that this planet (along with the other planets of this orphan star) would be outside of a galaxy and they would be travelling the universe in the "void" between galaxies.
Being outside a galaxy doesn't mean that you have a black night sky, it just means that you're a little bit further away from other stars and you're moving in the interstellar medium.
So my understanding is most of the stars that fill our sky are stars inside our milky way and nearby. "The Milky Way" smudge we can see in a dark sky is the collective effort of all the far-off milky way stars.
I assume some of the 'stars' we can see with the naked eye are actually galaxies, but I assume that's a small percentage.
Our closest galaxy, Andromeda, appears barely as a smudge to the naked eye.
I guess my question is more about how far away from their home galaxies are these orphan stars, expressed as a percentage of a hypothetical planet's sky-cover.
eg we see the milky way as a band because we're inside the galactic plane... would these orphan planets see their home galaxy as a fainter band because they've been ejected still in the galactic plane? Would they see part of the sky covered and part of the sky blank because they're outside their home galactic plane? Are they still close enough to their home galaxy that they're still surrounded by enough stars to fill the sky, or would the star density in their skies be seasonal?
I think it would be fun to speculate on different hypothetical cultural evolutions of different kinds of night sky configurations, like "winter is when our planet's night sees our home galaxy, so winter is when the gods send their nightlumination down on us" etc.
I don’t think this is correct. Most of the stars we see in the night sky are close by in our neighborhood of the Milky Way. Being in the void between galaxies, there wouldn’t be many neighboring stars close to the orphan stars. This would make their night sky much emptier to the human eye.
We can see the Milky Way in clear conditions; with light pollution we can only see the brightest stars. Perhaps an orphan star would have a darker sky, without a clear view of a galactic superstructure without using a telescope?
...I was under the impression that there was a faint blue glow coming from everywhere, that was hypothesized to be extra galactic stars. Has there been any follow up on that?
Euclid is bringing together 14+ countries and damn near every related field.
Warms my little nerd heart.
Euclid Consortium
To date 14 European countries contribute to EC activities (Austria, Belgium, Denmark, Finland, France, Germany, Italy, the Netherlands, Norway, Portugal, Romania, Spain, Switzerland and United Kingdom).
Canada and USA through NASA and few US laboratories as well as few Japanese laboratories are also contributing and members of the Euclid Consortium.
In total, more than 2600 members were or are registered in the EC (status early 2023), of which more than 1000 are researchers in astrophysics, cosmology, theoretical physics, and particle physics.
More than 200 laboratories covering all fields in astrophysics, cosmology, theoretical physics, high energy, particle physics and space science that are relevant for the Euclid missions are contributing to Euclid.
I've never heard someone use the long scale, it is only ever mentioned as a novelty. I think the scientific community, at the very least, has standardized on the short scale.
The long scale is far from just a novelty, most European countries other than the UK use it. Actually I thought it was used in all non-English-speaking countries, but Wikipedia showed me that the situation is far more complicated than I thought:
Besides short scale and long scale, there is a sizable "short scale with milliard instead of billion" fraction, and of course some countries (China, India, Japan, Greece) have completely different systems. Most interesting is that Portugal uses the long scale, while Brazil uses the short scale. That must be confusing...
almost all scientific writing i can find from people in portugal uses the short scale. english formal communication has standardized around the short scale
> All scientific writing in Slovenia uses long scale. I've heard it being used in EU institutions too.
I am able to easily find plenty of Slovenian academics using short scale in their scientific writing. Remember, English is standard for scientific writing and publishing in international journals. I have yet to find a single one using the long-scale, actually.
> observations by cataloging positions and redshifts of billions of galaxies in the next
decade
> and the configuration is stable over billions of years.
> (networks having up to a billion of vertices; there is no limit—except the memory size—on the number of lines
The long scale is common in French, German and Spanish for example. English usually uses the short scale. The scientific community uses SI prefixes, which aren't part of either scale (you don't say a billion joules which is ambiguous, you either say a terajoule for a long-scale billion or a gigajoule for a short-scale one).
My country uses long scale. I've never seen long scale used in English, so I don't think it's ambiguous.
But! When non-native speakers read news, they are not always completely fluent in English, or even aware the short scale exists. This is true even for journalists. I've seen articles written in a serious newspapers where a journalist confused "billion" and "trillion", because they incorrectly translated English "billion" to my language "bilion". Journalists! A cross-cultural mistake not unlike foots vs meters.
So that's one thing to consider if one wants to avoid miscommunication at all cost. I'm not sure if it is important enough to take into account - after all people should know better.
Are those papers in English? Long scale may be translated to short scale if the paper is translated from the original language where long scale is common.
yes, i'm talking about the scientific community - papers are almost exclusively published in english or with an english version. long scale translated to short scale would be a mistranslation, imo
OTOH the phrase “a thousand million” for 10⁹ is not that uncommon.
From what I've seen, in places where billions/trillions are mentioned and it's important that the number is accurately specified, a representation with digits or the exponent of 10 are typically provided.
Died out in English. Not in other languages where long scale was and is used, that hasn't changed at all. I'm not aware of any other language shifting from long scale to short scale (for languages traditionally using long scale).
“Scientifically standard” are the SI prefixes. So, given the ambiguity of what 1 gigastar is (1/1000th of 1 terastar or a really huge star?) one should say “10¹²s of stars” maybe.
A very famous person is very well known for his particular style of enunciating billions. After that, saying any other word is just a wasted chance of having Sagan's voice in their head reading the word.
Hope all of the engineers that struggled to get this mission spacebourne can enjoy!