[HN Gopher] Euclid's First Images
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Euclid's First Images
Author : perihelions
Score : 285 points
Date : 2023-11-07 13:58 UTC (9 hours ago)
(HTM) web link (www.esa.int)
(TXT) w3m dump (www.esa.int)
| Jzush wrote:
| What's up with all the purple dots, why are they all the same
| size?
| xioxox wrote:
| https://twitter.com/akira_doe/status/1721886699863834770
| SiempreViernes wrote:
| Are you referring to what they describe as "ghosts" in the
| image description?
|
| > Another signature of Euclid special optics is the presence of
| a few, very faint and small round regions of a fuzzy blue
| colour. These are normal artefacts of complex optical systems,
| so-called 'optical ghost'; easily identifiable during data
| analysis, they do not cause any problem for the science goals.
| Jzush wrote:
| Ah, yup those are the things I was referring to. They seems a
| little too uniform so it'd make sense that it'd be an optical
| artefact.
| pcrh wrote:
| .... even the smallest dots are huge...
| zoeysmithe wrote:
| I'll never be able to comprehend the idea of "Oh those many
| oblong glowing things in the background that are easy to miss?
| They're all galaxies of their own."
|
| The Perseus cluster contains thousands of galaxies. Every
| little thing in that photo is incomprehensibly large.
| Ringz wrote:
| And what also makes me think again and again is the fact that
| we see their state from 240,000,000 years ago. Some of these
| huge little dots may no longer exist in the form now
| observed.
| dylan604 wrote:
| by the reverse of the incomprehensibly large realization is
| how incomprehensibly small we are. kind of humbling. of all
| of the petty animosity within human civilization, it doesn't
| mount to a hill of beans to the cosmos.
| superposeur wrote:
| Do you know what advantage Euclid offers over Webb?
|
| Also, the Lagrange point is where Webb and some other stuff is
| located -- is it getting crowded up there?
| _Microft wrote:
| JWST is observing the infrared only and has a narrow field of
| view.
|
| Euclid is wide-angle with both visible and infrared
| capabilities.
| superposeur wrote:
| Thanks -- is there a short answer to what can wide angle get
| you?
| anigbrowl wrote:
| Literally what it says - a wider field of vision. Read the
| text on the ESA page.
| mr_mitm wrote:
| Euclid aims at measuring the shape of as many galaxies as
| possible to observe statistical effects that let us draw
| conclusions about the dark matter distribution
| giantrobot wrote:
| A wide angle lets you image something like the Andromeda
| galaxy or nebula all at once in the same frame.
|
| A narrow angle is more "zoomed in" so to image a larger
| structure you'll need a lot of exposures and build a
| mosaic. It takes a lot longer which means you have to
| monopolize the instrument for a long time.
|
| If you want to image large structures like galaxy clusters
| a wide angle telescope is more efficient. Since the
| lifetimes of telescopes are limited (fuel, coolant, etc)
| you want to spend that time getting the most data out of
| the instruments.
| mr_mitm wrote:
| Not that you're wrong, but galaxies in our neighborhood
| aren't really of concern to Euclid. The mission is to
| determine the expansion history of the universe, for
| which we will observe billions of galaxies. The handful
| of galaxies in our local group, which don't contain any
| information about the expansion history anyway, are less
| than a drop in the bucket.
|
| Also, frames can just be stitched together if necessary.
| And Andromeda is larger than the field of vision of
| Euclid.
|
| A large field of vision just helps you cover a large
| amount of sky in a reasonable time frame.
| pixl97 wrote:
| Star/galaxy surveys.
|
| For example there were a bunch of articles recently about
| 'stars disappearing'. That's because we take snapshots of
| wide ranges of the cosmos every once in a while and compare
| them. We can use this to figure out the direction and
| velocity of stars in our own galaxy. And in some cases
| things appear and disappear that are rather unexpected. You
| don't get that from narrow angle photos.
| ajross wrote:
| More data. Euclid is for filling databases with survey data
| covering large-scale structure in the universe. Webb is for
| looking at very small, very distant single objects. Two
| different instruments for two different experiments.
|
| Consider comparing a fancy DSLR with a telephoto lens to a
| night vision security camera. Each does what the other
| can't, and you deploy them for different tasks.
| Sharlin wrote:
| Should also note that "wide angle" is very much relative
| and in this case means "about the apparent size of a full
| Moon in the sky" - so vastly different from what a
| photographer would mean by "wide angle" =)
| PlutoIsAPlanet wrote:
| How's the Nancy Grace Roman Space Telescope compare to
| Euclid?
| giantrobot wrote:
| Euclid has visible imager and near-infrared spectrometer and
| photometer. Webb is all infrared. So they have non-overlapping
| missions even when observing the same structures and objects.
|
| Also space is very large. The L2 orbit is gigantic and the
| probes are teeny tiny in relation. So it's hardly crowded in
| any sense.
| flockonus wrote:
| I'm sure crowded is far off, but it's still interesting to
| think how they interfere with each other's instrumentations
| (given the field of vision is immense in comparison to their
| size), is there some type of space control traffic involved?
| giantrobot wrote:
| The L2 point is about 1.5 million kilometers from Earth.
| The various probes like Webb and Euclid orbit _around_ that
| point at (IIRC) about a million kilometers. The various
| probes in that orbit will effectively never interfere with
| each others instruments.
|
| As for coordination, at that orbit, it's going to likely be
| the individual agencies coordinating with one another.
| Every probe/satellite launch gets COSPAR IDs and other
| tracking IDs through various national and international
| agencies.
| jjgreen wrote:
| More on L2 orbits https://webbtelescope.org/contents/medi
| a/images/01F4STZH25YJ...
| giantrobot wrote:
| Good find, I was looking for a similar (or maybe that)
| image for illustration. It's a good description and
| illustration of Lagrange orbits.
| dakr wrote:
| It's not really about one being better than the other, just
| that they're designed for different purposes. Euclid is a
| survey telescope built to research dark matter, for which it
| has a large field of view so that it can build up a picture of
| the entire sky in all directions. JWST is focused more on
| investigating the early universe, for which it has a much
| larger primary mirror (gather more light), but has a lot of
| other capabilities as well.
|
| Euclid has a much smaller primary mirror, and its spectroscopy
| capabilities are limited compared to JWST (it doesn't need all
| the same bells and whistles). It also can't observe as far into
| the infrared as well as Webb. However, as stated, it has a wide
| field of view and enough photometric color and spectroscopic
| resolution to do it's main job of measuring galaxy shapes and
| positions and their redshifts in support of investigating dark
| matter.
| chpatrick wrote:
| Space is big. Really big. You just won't believe how vastly
| hugely mind-bogglingly big it is. I mean, you may think it's a
| long way down the road to the chemist, but that's just peanuts
| to space. Listen...
| dylan604 wrote:
| the word point used with Lagrange is bit misleading if you're
| thinking of it as an actual point. The satellites at a Lagrange
| "point" are actually orbiting the point like it is a NULL
| pointer in a 3D app (if you have familiarity with that
| concept). Also, space is big.
| sbierwagen wrote:
| What advantage does a flatbed scanner have over a polaroid
| camera? They both capture light, but with different optics and
| for different purposes.
|
| Copy and pasting a previous comment:
| https://news.ycombinator.com/item?id=36558940
|
| Euclid is a deep sky survey space telescope. Like many space
| telescopes, it's designed to run cold (-140C) to extend viewing
| into infrared bands ground telescopes can't access. Being a sky
| survey instrument, it has a wider field of view than Webb, 0.5
| square degrees versus 0.0025 sq deg.
|
| It's something of a follow-on to ESA's Gaia astrometry space
| telescope, which surveyed the entire sky out to visual
| magnitude 20 and in 320-1000 nm light, while Euclid will
| specifically examine the 15,000 square degrees of the sky the
| Milky Way doesn't cover, out to magnitude 24.5 and in 550-2000
| nm light. Both dimmer and more redshifted. (Fun fact: both Gaia
| and Euclid are made largely out of silicon carbide, including
| the optical bench and mirrors, which has become a ESA
| specialty.)
|
| For another comparison, the first Sloan sky survey (using a
| 2.5m ground based telescope much bigger than Euclid) took 5
| years to image 8,000 square degrees down to magnitude 22.2 and
| only out to 893 nm. Again, Euclid can see objects dimmer and
| more redshifted.
|
| These press photos are of large, interesting objects, like
| nebulae and nearby galaxies. Amusingly enough, though, for
| Euclid's mission these are _obstructions,_ which are getting in
| the way of all the dim smudges in the background that it 's
| actually supposed to be capturing. A cloud passing in front of
| a mountain you're trying to take a picture of. We'll either
| need to send another telescope a thousand light years away to
| image them, or wait thousands more for Sol to travel along its
| orbit in the Milky Way and move them out of the way.
|
| >Also, the Lagrange point is where Webb and some other stuff is
| located -- is it getting crowded up there?
|
| For stability reasons, spacecraft orbit around L2 rather than
| sitting at its center. Here's a diagram of JWST's orbit:
| https://i.stack.imgur.com/sBH2i.png It's a bent ellipse that's
| 1.6 million km in length along the long axis, considerably
| larger than the orbit of the moon. You could put three million
| telescopes on that orbit and they'd each be a kilometer apart.
| pkaye wrote:
| Euclid is a survey telescope so closer to the Nancy Grace Roman
| telescope which might be sent out around 2027.
|
| https://www.nasa.gov/missions/roman-space-telescope/nasas-ro...
|
| There is also another earth based sky survey telescope, the
| Vera Rubin Observatory up next year. That one is kind of
| interesting because it will produce a massive amount of data
| with data processing to detect if an object in the sky changed
| brightness or position over time and send out alerts to
| scientists or anyone else interested.
|
| https://www.lsst.org/
| aaroninsf wrote:
| 2/5 too many nearfield stars, would not travel through cosmos
| again
| twic wrote:
| Damn the Solar System. Bad light; planets too distant; pestered
| with comets; feeble contrivance; could make a better myself.
|
| -- Francis Jeffery
| sergiotapia wrote:
| At this point there has to be other civilizations out there
| right? There's just too many systems for us to be the only ones.
| sheepscreek wrote:
| Either that or as Elon once said, maybe life is just that
| special. I would still love for someone to do a Bayesian
| analysis of finding life on a planet/in a galaxy. It sounds
| pretty crazy when I say it out loud. We're staring into
| infinity essentially.
|
| So yeah, life must be out there. But maybe "there" is very very
| far. Possibly many million light years away. In other words, in
| a universe with billions of galaxies containing billions of
| stars, life is likely not very plentiful. I imagine
| encountering any element besides H/He is usually a discovery
| (more so if the element is higher up in the periodic order,
| such as the ones needed for our kind of life).
|
| Then again, there is so much we don't know. Like dark matter
| (anti-proton/electron/neutron/*). Maybe there is life that
| exists in anti-everything - (anti-carbon, etc). It won't be
| very good if we ever encounter them (our carbon based bodies
| and anti-carbon based one will collapse on encounter, emanating
| a staggering amount of energy).
| ladams wrote:
| A minor correction: anti-matter is actually regular matter.
| We understand it quite well, and are even able to create
| anti-atoms in the lab. On the other hand, dark matter is much
| more poorly understood: essentially the only evidence we have
| for its existence are observations of "weird" gravitational
| effects in the universe.
| hwayne wrote:
| Also we have pretty strong evidence that, at least in the
| observable part of the universe, almost all visible matter
| is regular matter.
| input_sh wrote:
| Personally I consider life outside of the planet to 100% be a
| thing.
|
| Intelligent life? Probably, if there's life it's bound to
| happen some percentage of the time.
|
| Intelligent life that has mastered exploring space enough that
| we could theoretically communicate with each other if we both
| looked at the right spot? I'm less convinced, but it's
| impossible to say with the sample size of 1.
|
| Intelligent, spaceflight capable civilisation that's close
| enough that we could ever make an actual, physical contact
| without the trip lasting generations? Unlikely.
| p_j_w wrote:
| > I consider life outside of the planet to 100% be a thing.
|
| Show your math?
| dylan604 wrote:
| Is partial credit available for showing work even if the
| incorrect answer was derived?
| mr_mitm wrote:
| A seductive thought, but without knowing the probability for
| life, this question simply has no answer. We only know that
| 0<p_life<1, so maybe the probability is even more unimaginably
| smaller than the number of galaxies is large. It could be
| 10^-50, who knows.
| namanyayg wrote:
| Rather than just carbon-based organisms confined to rocky
| planets, I am more interested in the possibility of how life
| might look outside of that viewpoint.
|
| For example, how about interplanetary scale lifeforms akin to
| boltzmann brains, where each analogue to a human neural impulse
| takes minutes or even days to zoom across empty space?
|
| What about dark-matter based life? If dark matter composes of
| 95% of our universe, could there be a whole different set of
| dark matter based physics, life, and technology, where the
| intelligent dark-matterians speculate about the mysterious 5%
| of the universe which interacts with these strange oscillating
| electric and magnetic fields?
|
| I know it's unlikely and that given our sample size of n=1 we
| can only be confident about organic lifeforms, and it's our
| best bet to search for similar life -- but I like to imagine
| that thousands (millions?) of years in the future when we find
| other kinds of life, it'll be obvious to everyone that life
| exists in all possible ways and they'll laugh at us 21st
| century folks for believing that just carbon could self
| replicate and think.
| mr_mitm wrote:
| One of the defining properties of dark matter is that it
| interacts only weakly at most, or else we would see an
| entirely different distribution. Ordinary matter can
| dissipate heat because of electromagnetic interaction and
| thus collapse into galaxies. Dark matter can't, so it only
| forms diffuse, homogeneous halos.
|
| The idea of "dark chemistry", whole not whacky enough to be
| immediately discarded, is highly exotic.
|
| https://www.space.com/21508-dark-matter-atoms-disks.html
| pixl97 wrote:
| Lots of people try to jump on the "silicon based life isn't
| possible", but even on that I take a different viewpoint.
|
| As we are watching AI with concern on our own planet, what if
| that is a common bootstrap. Carbon based life creates
| silicon/metallic 'life'. And if that is possible, who knows
| what that would bootstrap itself into in the future.
| ordu wrote:
| _> the intelligent dark-matterians speculate about the
| mysterious 5% of the universe which interacts with these
| strange oscillating electric and magnetic fields?_
|
| They would have a hard time figuring out the existence of
| electic and magnetic fields. They wouldn't feel them. And
| their devices wouldn't feel them.
|
| They would be able to notice 5% of mass by gravitational
| interactions only. They wouldn't be able to see how magnetic
| fields reconnect on a surface of a star and conclude that it
| means there is some unknown field at work.
|
| So to think, they probably have their own dark versions of
| magnetic and electric fields.
| tekla wrote:
| Dark Matter based life is probably impossible. Dark matter
| doesn't interact with electromagnetism so have fun with that.
| BurningFrog wrote:
| True, but maybe we just happen to be first?
|
| That would explain why we don't see anyone else.
| thriftwy wrote:
| It is quite possible that we are one of the first ones. The
| universe as we know it is rather new. Our planet exists for a
| significant chunk of its total lifetime, and it needed heavier
| elements to be produced before it could coalesce.
|
| The universe is expected to be teeming with purposeful matter
| eventually.
| dylan604 wrote:
| Relatively in the total lifetime of the Earth, there are
| theories that Earth possibly is a second generation planet
| within Sol's lifetime.
| thriftwy wrote:
| What happened to the first one? Where did they go and how
| old were they?
| h1fra wrote:
| I started saying "this image is so noisy" but all the dots are
| actually stars, it's incredible!
| taylorlapeyre wrote:
| They aren't stars, they're galaxies!
| mr_mitm wrote:
| Depends on which picture you're looking at
| dylan604 wrote:
| Depends on which dots you're looking at
| ySteeK wrote:
| Depends on which post u are refering it
| gwerbret wrote:
| Since the article is low on details about Euclid [0]:
|
| > The objective of the Euclid mission is to better understand
| dark energy and dark matter by accurately measuring the
| accelerating expansion of the universe.
|
| > Euclid will [...] measure the redshift of galaxies out to a
| value of 2, which is equivalent to seeing back 10 billion years
| into the past.
|
| > During its nominal mission, which will last at least six years,
| Euclid will observe about 15,000 deg2 (4.6 sr), about a third of
| the sky, focusing on the extragalactic sky (the sky facing away
| from the Milky Way).
|
| > About 10 billion astronomical sources will be observed by
| Euclid, of which one billion will be used for weak lensing (to
| have their gravitational shear measured) with a precision 50
| times more accurate than is possible today using ground-based
| telescopes.
|
| > After Russia withdrew in 2022 from the Soyuz-planned launch of
| Euclid, the ESA reassigned it to a SpaceX Falcon 9 launch
| vehicle, which launched on 1 July 2023.
|
| > In total, nine Science Data Centres spread over countries of
| the Euclid Consortium will process more than 170 petabytes of raw
| input images over at least 6 years
|
| > The telecommunications system is capable of transferring 850
| gigabits per day. It uses the Ka band and CCSDS File Delivery
| Protocol to send scientific data at a rate of 55 megabits per
| second during the allocated period of 4 hours per day to the 35 m
| dish Cebreros ground station in Spain, when the telescope is
| above the horizon. Euclid has an onboard storage capacity of at
| least 300 GB.
|
| [0]: https://en.wikipedia.org/wiki/Euclid_%28spacecraft
| Ringz wrote:
| Thanx!
| jacquesm wrote:
| > The telecommunications system is capable of transferring 850
| gigabits per day. It uses the Ka band and CCSDS File Delivery
| Protocol to send scientific data at a rate of 55 megabits per
| second during the allocated period of 4 hours per day to the 35
| m dish Cebreros ground station in Spain, when the telescope is
| above the horizon.
|
| To put this feat in perspective: it can be a pretty difficult
| job to install working WiFi in a warehouse a few hundred meters
| on a side. And the transfer rate at that distance is really
| mind boggling.
| nologic01 wrote:
| Is there some sort of citizen science we could engage-in with
| these datasets? When zooming in on Euclid's view of the Perseus
| cluster of galaxies I see some very strange stuff :-)
| SushiHippie wrote:
| Do you maybe mean this?
|
| https://news.ycombinator.com/item?id=38177815
| _a_a_a_ wrote:
| go on....
| dylan604 wrote:
| A popular citizen science is writing a classic hacker script
| with wget/curl to download all of the images and then stack
| them together. Numerous comets have been found this way as the
| comet will be the only thing moving once all of the images are
| aligned. I guess it doesn't have to be a comet, as asteroids
| and Planet X could be found this way as well. If the dot
| changes course/speed in your research, it could be Aliens!!!!
|
| The fun thing is that when a group gets scope time, it's
| typically for a specific purpose so the images are initially
| studied specifically for that purpose. It's possible there's
| more treasure in those images beyond the original intent that
| just needs more time being studied or added to other
| imagery/collections that come together to reveal something.
|
| So depending on what you might be interested in, you can find
| all of the images from every scope imaginable of the same
| object to do some fun stuff, or you could find a time series
| from one scope that might reveal something.
| semireg wrote:
| "This figure shows an overlay of an image of the Moon on top of
| an image of the sky recorded simultaneously by the 36 detectors
| of Euclid's VIS instrument."
|
| https://www.esa.int/ESA_Multimedia/Images/2023/11/Euclid_s_w...
|
| Worth a click.
| twic wrote:
| Oh, so it's a Samsung?
| dylan604 wrote:
| I have a wide field telescope at home that yields a similar
| field of view when I image the moon. Too bad my scope doesn't
| have the same imaging abilities as this. I'm guessing a few
| more 0s and a couple additional commas added to the price tag
| helps.
| hn8305823 wrote:
| Euclid has a 1.2m primary mirror. For $600k you can have a 1m
| telescope in your backyard. You will still have to deal with
| the atmosphere, clouds, and Moon, however. Especially clouds.
|
| https://planewave.com/product/pw1000-1-meter-observatory-
| sys...
| dcormier wrote:
| _adds to Christmas list_
| Sharlin wrote:
| There are about 41,000 square degrees in a sphere, so it would
| take roughly 81,000 of Euclid's 0.7degx0.7deg exposures to
| image the entire sky. (The plan is to image one third or so.)
| taway1237 wrote:
| >Astronomers demonstrated that galaxy clusters like Perseus can
| only have formed if dark matter is present in the Universe.
|
| Any MOND people here to comment what they think about Euclid? I
| always enjoy reading MOND speculation here on HN (even though I
| don't know enough to have an informed opinion myself).
| deanCommie wrote:
| Not sure I'm understanding how to match the images here against
| Euclid's stated purpose "to investigate how dark matter and dark
| energy have made our Universe look like it does today."
|
| How is the data being presented here helping us investigate dark
| matter/energy, which is not in the data?
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(page generated 2023-11-07 23:00 UTC)