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Euclid's First Images

superposeur
30 replies
23h46m

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
11 replies
23h30m

JWST is observing the infrared only and has a narrow field of view.

Euclid is wide-angle with both visible and infrared capabilities.

superposeur
9 replies
23h27m

Thanks — is there a short answer to what can wide angle get you?

Sharlin
2 replies
19h2m

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" =)

dylan604
1 replies
1h54m

it is a telescope after all, so of course it's going to be scoped in. anyone confusing wide angle photography with a telescope is just not comprehending concepts very well.

Sharlin
0 replies
1h6m

Eh, yes, because this is not an astronomy forum, there may be plenty of people who don't have a good idea of what "wide angle" means in that context. So IMNSHO a clarification was entirely appropriate, and thinking otherwise is rather arrogant. I didn't mean that "wide angle" would mean something like a 24mm camera lens, but more that it's much more narrow than even long telephoto focal lengths like 200mm or 400mm or even 600mm!

Especially given that this is a survey mission whose purpose is to image large parts of the sky, it could be entirely plausible to a layman that its angle of view were much wider than 0.7 degrees!

giantrobot
1 replies
23h18m

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
0 replies
22h54m

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
0 replies
22h20m

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.

mr_mitm
0 replies
23h25m

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

anigbrowl
0 replies
23h25m

Literally what it says - a wider field of vision. Read the text on the ESA page.

ajross
0 replies
19h43m

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.

PlutoIsAPlanet
0 replies
21h56m

How's the Nancy Grace Roman Space Telescope compare to Euclid?

pkaye
5 replies
19h24m

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/

dakr
4 replies
17h44m

Back when 10TB was enough space for the entire Sloan survey, Vera Rubin Observatory was expected to produce 1TB every night. They dug a trench up into the mountains to lay a fiber optic cable specifically (and only) for Vera Rubin.

OldGuyInTheClub
3 replies
17h18m

Not to quibble but it is an even more mindboggling 15TB/night.

https://www.ipac.caltech.edu/project/rubin

dakr
1 replies
16h45m

Haha, it must be inflation. Back when I was involved the 1TB number was the one being thrown around. Thanks for posting that link. IPAC is really doing well for themselves with all the new projects they're hosting.

OldGuyInTheClub
0 replies
14h15m

That must be it! A few years ago, an old high school chum who works on the Rubin also mentioned the 15TB number. I neglected to ask if that was raw FPA output that would be processed down to smaller sizes or sent as-is. The project has been going for a while so maybe the technology to do it became practical in the interim? Whatever they do send, it is still an astronomical amount of data. I'll show myself out.

ahazred8ta
0 replies
11h6m

Lsst.org is now saying 20TB, or ~ 60 Petabytes for the whole run.

giantrobot
4 replies
23h24m

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
3 replies
23h17m

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
2 replies
22h31m

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
1 replies
22h19m
giantrobot
0 replies
20h26m

Good find, I was looking for a similar (or maybe that) image for illustration. It's a good description and illustration of Lagrange orbits.

sbierwagen
2 replies
20h39m

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.

superposeur
1 replies
14h47m

Thanks and great diagram — I’d imagined a tiny orbit around L2, not one the size of the entire earth!

sbierwagen
0 replies
12h43m

The diagram does not make this clear at all, but the big circle is the orbit of the Moon. The Earth is only 12,756 km in diameter, and the tick marks are 200,000 km apart. If drawn to scale on that diagram, it would be 2.7 pixels wide.

dylan604
0 replies
21h49m

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.

dakr
0 replies
23h10m

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
0 replies
22h56m

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...

Anotheroneagain
0 replies
10h44m

It images a large patch of sky in 600megapixels at once. It's an overwhelmingly more valuable telescope by how much it gathers at once, JWST only captures a tiny dot, in similar resolution.

sergiotapia
19 replies
23h13m

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.

thriftwy
4 replies
21h49m

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
3 replies
21h46m

Relatively in the total lifetime of the Earth, there are theories that Earth possibly is a second generation planet within Sol's lifetime.

thriftwy
2 replies
20h11m

What happened to the first one? Where did they go and how old were they?

sph
1 replies
6h35m

Maybe crashed together (see Theia) and the entire evidence of their ultra-high technological society lies in a molten state 2500 km below in the Earth's mantle and encased in solid rock a few hundred km below the surface of the Moon.

thriftwy
0 replies
5h42m

Ultra-high technological society will be all over the solar system.

namanyayg
4 replies
22h37m

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.

tekla
0 replies
20h1m

Dark Matter based life is probably impossible. Dark matter doesn't interact with electromagnetism so have fun with that.

pixl97
0 replies
22h16m

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
0 replies
20h43m

> 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.

mr_mitm
0 replies
22h31m

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

sheepscreek
3 replies
22h55m

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
1 replies
22h26m

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
0 replies
20h43m

Also we have pretty strong evidence that, at least in the observable part of the universe, almost all visible matter is regular matter.

8bitsrule
0 replies
15h22m

maybe life is just that special.

It appears from spectra that the chemical elements produced by stars are the same everywhere. If so, then the possibility of material life exists everywhere in the universe ... where conditions permit. It's down to the presence and concentrations of the various elements, the temperature and stability of some fluid medium that can bring the endless potential combinations into contact, and a lot of time. (Calculating the odds is an exercise left for the student.)

input_sh
2 replies
22h51m

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
1 replies
20h44m

I consider life outside of the planet to 100% be a thing.

Show your math?

dylan604
0 replies
19h23m

Is partial credit available for showing work even if the incorrect answer was derived?

mr_mitm
0 replies
22h50m

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.

BurningFrog
0 replies
22h2m

True, but maybe we just happen to be first?

That would explain why we don't see anyone else.

semireg
18 replies
22h32m

"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.

dylan604
13 replies
19h31m

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
12 replies
19h20m

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...

p-e-w
7 replies
14h8m

Six hundred thousand dollars for a 1m telescope? That's a crazy price tag. What's the expensive part here? That's the price of 10 upper-tier cars. Is it so insanely difficult to make that mirror, or are they just gouging because they have little or no competition?

dylan604
4 replies
13h32m

That's like asking why a Ferrari costs so much, it's just a car. There's a big difference from a mass produced car with automated processes compared to a product that is pretty much one offs and are made by hand. Pretty much every industry has the equivalent mass produced vs hand made. Leica makes camera lenses for the masses, but they also have a very expensive line of lenses that they only start the hand made process when you're check clears. Clothing, homes, etc all have versions of it.

So unless you can tell me that you've hand ground a telescope mirror of any size to have direct knowledge of the experience, I'd suggest taking a look at the process while considering the size of the mirror discussed. Even the base and the trusses for the assembly will have required design time and iterating through changes. Not sure why this seems so strange compared to all of the other things in life with "accepted" price tags.

gosub100
1 replies
4h19m

Your answer is basically "it's expensive because other high end things are expensive, too!". Thats not what the GP was asking. Also a Ferrari is a bizarre comparison. Telescope has about 10 or less moving parts. Ferrari has hundreds, maybe thousands.

A real answer to this would be to break it down by materials vs labor. Not shaming them for being curious and then saying it's high end.

dylan604
0 replies
2h57m

If you think a telescope has 10 or less moving parts, you don’t know what your talking about.

baq
1 replies
7h17m

Spot on, for a concrete example check this one out - there's a slight chance these are mass produced

https://www.usa.canon.com/shop/p/rf1200mm-f8-l-is-usm-lens

but the f5.6 version... doesn't seem to be:

https://www.the-digital-picture.com/Reviews/Canon-EF-1200mm-...

dylan604
0 replies
2h1m

https://www.usa.canon.com/shop/p/rf1200mm-f8-l-is-usm-lens

"Minimum focus distance of Approx. 14.1 ft. / 4.3 m. "

Which is conveniently able to be measured by taking the distance from the camera mount to the end of the lens, then doubling it! However, at least this is "affordable" enough to have a price listed. The Leica lenses I was referring to has the "oh boy, this is going to be expensive" infamous Find a Dealer button. Also, it's a set of 11 lenses, and for nearly double the price, they add in a few more wide angles and a few more telephoto lenses to the kit.

https://www.leitz-cine.com/product/summicron-c

gosub100
1 replies
4h22m

It's a huge piece of very pure glass, that has a precise uniform shape down to the nanometers scale. Another thing that I learned is they are first ground to a spherical shape, then a parabolic. It's a very time consuming process, although I don't have exact data.

Someone
0 replies
52m

And it’s time consuming partly because so few are made.

I guess the unit price could come down by 90% or more if you were to order a million of them, and could convince a manufacturer that you’re good for the money.

(And you may get something that’s superior, for example because they figure out that, at a million copies, extra money spent improving the software for adaptive optics can be more than made up by making the hardware a bit less rigid)

We’re spoilt by the amazing efficiencies of mass manufacturing.

braydenm
1 replies
15h44m

For those looking for something large but still a little bit more realistic, for <$3k you can have a 0.4m telescope on your backyard.

https://hubble-optics.com/UL16.html

dylan604
0 replies
14h23m

The astronomy campus I used to make regular visits to had a pair of 36" Dobs. They were tall enough that you would need a ladder of some sort to reach the eyepiece depending on the position. I only got to view with my eyes, but they were impressive compared to my 6". I always wanted to try imaging from one of those. The same place also had a pair similar to the link you provided, only, they were set up to be a stereoscopic viewing. I never got that experience though as nobody ever wanted to go through the painful alignment process. People have come up with some interesting ideas on how to view the sky

sjackso
0 replies
11h17m

Ah, yes-- but if you shop around, you can find a telescope of that aperture for less. Here's one for a mere $132k!

https://explorescientificusa.com/collections/optiques-fullum...

dcormier
0 replies
19h3m

adds to Christmas list

Sharlin
1 replies
19h7m

There are about 41,000 square degrees in a sphere, so it would take roughly 82,000 of Euclid's 0.7°x0.7° exposures to image the entire sky. (The plan is to image one third or so.)

mr_mitm
0 replies
10h2m

The rest is obscured by the milky way, for anyone wondering.

twic
0 replies
21h22m

Oh, so it's a Samsung?

d--b
0 replies
8h11m

Very nice, it’s one of the only image that gives some feeling about how much stuff there is in the universe.

pcrh
5 replies
1d1h

.... even the smallest dots are huge...

zoeysmithe
4 replies
1d

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.

mbivert
1 replies
18h13m

Every little thing in that photo is incomprehensibly large.

And that's just a small portion of what we can perceive, as humans. It's mindblowing; daily concerns are so trivial in comparison. It's so sad we can't see the night sky clearly anymore, that must have been fantastic, especially with an understanding of what those little specks of light are. Probably more fulfilling than watching screens.

chrsw
0 replies
13h30m

Maybe we had to think our problems were important so we can surivive. I get your point though, we're due to revisit our priorities. Especailly as science continues to show us what's possible, and what's at stake. Turns out the universe is bigger than anyone imagined and we're probably not going to be visited by Little Green Men any time soon eager to tell us the meaning life, the universe and everything in between.

dylan604
0 replies
21h43m

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.

Ringz
0 replies
22h25m

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.

h1fra
5 replies
22h50m

I started saying "this image is so noisy" but all the dots are actually stars, it's incredible!

taylorlapeyre
4 replies
22h45m

They aren't stars, they're galaxies!

mr_mitm
2 replies
22h43m

Depends on which picture you're looking at

dylan604
1 replies
21h48m

Depends on which dots you're looking at

ySteeK
0 replies
20h53m

Depends on which post u are refering it

adonovan
0 replies
12h51m

It blew my mind when I realized that all but about a dozen of the points of light that you can see at night with the naked eye are actual stars... but nearly every point of light in the Hubble deep field is a galaxy of 10^8 stars.

nologic01
3 replies
22h41m

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 :-)

dylan604
0 replies
19h24m

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.

_a_a_a_
0 replies
22h25m

go on....

SushiHippie
0 replies
22h27m
Jzush
3 replies
1d1h

What's up with all the purple dots, why are they all the same size?

SiempreViernes
1 replies
1d1h

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
0 replies
20h58m

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.

xioxox
0 replies
1d1h
thread_id
2 replies
15h38m

I never cease to be blown away by images of the Perseus cluster - planet earth is but a tiny spec in one solar system in an enormous spiral galaxy. In this single image there are scores of galaxies.

“It’s hard to talk about the Cosmos without using big numbers. I said “billion” many times on the Cosmos television series, which was seen by a great many people. But I never said “billions and billions.” For one thing, it’s too imprecise. How many billions are “billions and billions”? A few billion? Twenty billion? A hundred billion? “Billions and billions” is pretty vague. When we reconfigured and updated the series, I checked—and sure enough, I never said it.” ― Carl Sagan, Billions & Billions: Thoughts on Life & Death at the Brink of the Millennium

euroderf
0 replies
7h18m

Perhaps somebody misquoted him saying "billions of billions" ?

ahazred8ta
0 replies
11h18m

The running gag was "we'll travel through billions and billions of cubic kilometers of star-stuff".

gwerbret
2 replies
22h41m

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

jacquesm
0 replies
21h41m

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.

Ringz
0 replies
22h36m

Thanx!

deanCommie
2 replies
19h15m

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?

venice_benice
0 replies
6h8m

Euclid's website has some nice explainers­ – for example, https://www.euclid-ec.org/public/core-science – which mentions using two methods:

- “weak gravitational lensing” with the visible light instrument (which has higher resolution than the IR one) to measure very precisely the shapes of galaxies, to enable a statistical study of distortions in their shapes, caused by weak lensing due to dark matter (and regular matter which they can observe “directly”)

- “galaxy clustering” with the near IR instrument to calculate distances to the galaxies (via their redshift) which they can use to map out 3D distribution of galaxies and compare to simulations for example (there is a nice figure on this page: https://www.euclid-ec.org/euclid-core-science showing a few surveys and simulations)

There is more information on their blog here as well: https://www.euclid-ec.org/blog

The images here are simply first light images (i doubt the horsehead nebula or globular clusters are part of the core science of Euclid); more images and spectra will be taken in the coming years to do the actual core science (which will require a lot more data)

mkesper
0 replies
17h37m

These are first demonstration images. Euclid had a hard start but now it's ready to be used.

aaroninsf
1 replies
23h20m

2/5 too many nearfield stars, would not travel through cosmos again

twic
0 replies
21h19m

Damn the Solar System. Bad light; planets too distant; pestered with comets; feeble contrivance; could make a better myself.

-- Francis Jeffery

taway1237
0 replies
19h33m

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).