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Astronomers just discovered the farthest object in the known universe
- onlyrealcuzzo 5y agoIs there a physical limit to the resolution we can get from such absurdly large distances? And if so - is there an equation?
- all2 5y agoI vaguely recall that image resolution is a function of total photons inbound, distance to the object being observed, and effective sensor size. The photon density (assuming the source is not a point source) varies over the distance to the observed object, which will place a theoretical limit on resolution. The other half is sensor size, ie, can we catch enough photons to make sense of what's emitting/reflecting them? I haven't touched optics in a long time, though.
- andreareina 5y agoIt's proportional to the aperture diameter and inversely proportional to the wavelength. That's why they needed telescopes that spanned the globe for that image of a black hole. More photons does get you shorter exposure times (and therefore better temporal resolution, fair enough). JWST by the way is able to resolve at this theoretical limit, which is just wild.
- gizmo686 5y agoThe theoretical limit for resolution comes from diffraction. It is a function of the wavelength of light being observed, and the size of the telescope. This is measured by the Rayleigh criterion For a telescope with a circular apeture, the resolution is given by aproximatly R ~ 1.22 λ/D where: * λ is the wavelength * D is the diameter * 1.22 is the first zero of the intensity function for the Airy Disk
- astroH 5y agoA lot of the work on distant galaxies is not being done with gravitational lensing. The idea is that you use massive objects in the foreground, like galaxy clusters, to focus light from the background. Depending on orientation, we can get magnifications of more than 10,000. There was a recent press release of such an example. So in principle, our telescopes combined with gravitational lenses can resolve almost all of the relevant detail we would want of a galaxy if the orientation is correct. It rarely is of course but there are a few examples so such strong lenses.
- Archelaos 5y agoLayperson's question: The article talks about "a possible galaxy that exists some 13.5 billion light-years from Earth". But isn't that just the light traveling distance, and the object should actually be much further away due to the expansion of the universe?
- simonh 5y agoWell spotted yes, by now that object will be about 45 bn ly away. The light reaching us from it has only traversed 13.5 bn ly though.
- sdeframond 5y agoDefine "now" https://en.m.wikipedia.org/wiki/Relativity_of_simultaneity https://en.m.wikipedia.org/wiki/Relativity_of_simultaneity
- simonh 5y agoWhile that’s a problem in theory, to moderate accuracy it’s not a practical issue. Most objects in the universe are roughly at rest relative to the cosmic background radiation (in other words they don’t see it as Doppler shifted in any particular direction), so we can use that as a common frame of reference. When we’re talking about ballpark integer billions of years, or even to a few decimal places, that’s easily good enough.
- uoaei 5y agoAccuracy? "Now" is an inaccurate (nonsensical, actually) concept except in extremely local conditions.
- simonh 5y agoIt's perfectly sensible given a common frame of reference, which we have thanks to the CMB. Frames of reference aren't local. We have clocks and can measure time on them just fine, and 'now' is just a time on a clock.
- lil_dispaches 5y ago
- marginalia_nu 5y agoThat's not even wrong.
- lil_dispaches 5y agoYet "physicists" are staring deeper into the paradox with the notion that the image is perfectly logical.
- 0des 5y agoCan one of the people down voting this please explain why?
- lil_dispaches 5y agoI wish. This is my fifth heretical account. They all end up in the ghostbin thanks to anonymous downvotes. Yet I have never cursed, sworn, or made any false allegations, only drawn out it very precise terms what I consider to be the case. It's b/c this is a money forum when you get down to it, not really a hacker forum, and this is last place that is really going to shake the alter. Disrupting business is just business, nothing radical about it.
- deleted 5y ago[deleted]
- thro1 5y ago"The Big Bang is the diffraction of logic around the perimeter of the lens on the universe we call Quantum Physics." ??? (I just don't want to lose this opinion.)
- ericmay 5y ago
- SkyMarshal 5y agoKey sections: "The researchers discovered HD1 in data collected over 1,200 hours of observation time using the Subaru Telescope, the VISTA Telescope, the U.K. Infrared Telescope and the Spitzer Space Telescope. They were particularly looking at redshift, a phenomenon in which light waves stretch out or become redder as an object moves away from the observer. In this case, the redshift suggested HD1 was extremely distant. The researchers found that the red wavelengths were the equivalent to a galaxy located 13.5 billion light-years away. HD1 also seems to be growing at a feverish rate — about 100 stars each year, or at least 10 times the rate predicted for starburst galaxies that are known to produce stars at an extraordinarily high pace. These stars were also more massive, brighter (in ultraviolet wavelengths) and hotter than younger stars, the researchers found. As such, HD1 could be home to the universe's very first stars, called Population III stars; if that identity is verified, this would be the first observation of this type of star, the researchers said. There's also the possibility that HD1 is a supermassive black hole with a mass of about 100 million times that of the sun." Also a paper on it: https://arxiv.org/abs/2201.00823 https://arxiv.org/abs/2201.00823
- thanatos519 5y agoI can't wait for JWST to look over there!
- 8bitsrule 5y agoPaper sez: z ∼ 13
- BurningFrog 5y agoHow do they count the number of new stars? I mean, it's way too far away to see individual stars.
- keithnz 5y agono, due to gravitational lensing, you can see stars. For a straightforward break down, see Dr Becky, https://www.youtube.com/watch?v=VChgsXbIgdw https://www.youtube.com/watch?v=VChgsXbIgdw
- karmakaze 5y agoWould it be more accurate to say 'oldest' since it's not there as we're seeing it now? I suppose it's all the same in space-time. But what we study about it is more in relation to the time of the light rather than the place, so 'oldest' has a more relevant connotation.
- rich_sasha 5y agoWe have also seen very old objects closer by. The Methuselah star is estimated to be 13.7 billion years, in fact by some estimates older than the universe (which is clearly somewhat problematic). It is a mere 190 light years away.
- all2 5y agoSo the calculated age of the star is wrong (ie, our observations are correct and our underlying theories about how stars age is wrong), OR our observations are incorrect. The former is a far more interesting case, IMO.
- rich_sasha 5y agoOne thing that is unusual about the star relative to our regular experience is how little “metals” it contains (in astrophysics metals are any elements heavier than helium). Metals heavier than iron are only created in supernovae, lighter metals still only get created in stars. Either way, if it was created a few 1e8 years after Big Bang, there weren’t many of those going around. Now, most of our models for stellar evolution are calibrated to stars we see, which have plenty of metals in them. Whereas this one doesn’t so our models could be off.
- karmakaze 5y agoThis is a different sense of 'old' as in "What is its age?" That's a vague question unless there's no change. e.g. Ship of Theseus or stepping in the same river twice. The image (information) of Methuselah we see is 190 years old. Saying farthest vs oldest disambiguates. Unrelated observation: everything travels through spacetime at the speed of light. It's not a speed limit, it's the only speed. If you're not travelling through space then you're travelling through a purely time-line at c. Really makes one wonder how much time we casually waste.
- crate_barre 5y agoIf it’s only 500 million years from the Big Bang, is it possible we could capture a picture of the Big Bang?
- hotpotamus 5y agoWe cannot because light could not travel through the early universe. That took half a million years or so and the light from then has now redshifted into microwaves and has been imaged in great detail.
- crate_barre 5y agoSo if we saw something older than this thing (roughly), would that fundamentally disprove the Big Bang?
- hotpotamus 5y agoMy understanding of the current state of the science is that there are many theories of the early state of the universe and early star formation but not a lot of definitive proof for any of it. However, the Big Bang is quite sound and as a rough theory has been well established since Hubble (the astronomer, not the namesake telescope) started measuring red shifts of galaxies. They actually have found stars that appear older than the universe, but the it's mostly believed that that's a problem with estimates of star age. All that said, there is plenty of research to be done from all angles.
- sdeframond 5y agoThe closest we have from that is the cosmic microwave background I believe. Here's the picture https://www.esa.int/var/esa/storage/images/esa_multimedia/images/2013/03/planck_cmb/12583930-4-eng-GB/Planck_CMB_pillars.jpg https://www.esa.int/var/esa/storage/images/esa_multimedia/im...
- zoom6628 5y agoShare this with your kids! Just showed the timeline picture to family to explain to them when we see something distant it is light crossing a chasm. As someone who was really into astronomy as a kid, field by interest from father and grandfather, this announcement is really exciting.