Posted on 07/18/2024 1:17:05 PM PDT by Red Badger
JWST deep field vs hubble
This region of space, viewed first iconically by Hubble and later by JWST, shows an animation that switches between the two. Both images still have fundamental limitations, as they were acquired from within our inner Solar System, where the presence of zodiacal light influences the noise floor of our instruments, and cannot easily be removed.Credit: NASA, ESA, CSA, STScI, Christina Williams (NSF’s NOIRLab), Sandro Tacchella (Cambridge), Michael Maseda (UW-Madison); Processing: Joseph DePasquale (STScI); Animation: E. Siegel
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KEY TAKEAWAYS:
* The darkest night skies, both from Earth as well as from interplanetary space, aren’t completely dark, as sunlight reflected off of tiny particles always generates light pollution.
* However, by traveling billions of miles away from the Sun, this pollutive zodiacal light can be left behind, enabling astronomers to measure how dark the depths of intergalactic space truly is.
* In a stunning find from New Horizons, they overturn a previous study that suggested a “cosmic optical background” existed atop the light from known galaxies. Deep space truly appears to be completely dark.
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Share Deep space really is completely dark, New Horizons shows on LinkedIn Four years ago, astronomers had a spectacular realization for a new type of science they could perform: they could, at long last, search for the presence (or absence) of a cosmic optical background. We have a theory about where light comes from in the Universe:
* we have the leftover light from the Big Bang, now shifted into microwave portions of the spectrum,
* we have the light generated from stars, thought to be distributed inside galaxies, galaxy groups and clusters, as well as a few stars and star clusters in the intracluster medium,
* we have the light reflected off of neutral clouds of matter, and we have the light generated by heated matter, which generates a cosmic infrared background.
In theory, the only “cosmic optical background” that ought to be there is the light generated from stars, which should be confined to within galaxies and larger bound collections of matter, plus a little bit of additional reflected light from within those same structures. But from Earth and even from the space within our Solar System, we cannot conduct these measurements; there’s too much “stray light” from sunlight reflecting off of tiny particles in interplanetary space to find true darkness.
But there are five spacecraft that have traveled far enough away from Earth — Voyager 1 and 2, Pioneer 10 and 11, and New Horizons — that all of that stray light, known as zodiacal light, is finally faint enough that they can answer questions about the darkness of deep space. Although the first four don’t have the right tools to make those critical measurements, New Horizons does, and is still fully operational to boot. After a careful analysis by the New Horizons team, here’s what we’ve learned about the cosmic optical background.
A portion of a JWST deep-field image, shown with the Hubble observations as its counterpart. Within the JWST field are a significant number of objects not seen by Hubble, showcasing JWST’s ability to reveal what Hubble could not, thanks predominantly to its longer-wavelength capabilities. All of the light produced by stars, black holes, and excited atoms contributes to the cosmic optical background, but excess light beyond that would present a cosmic puzzle.
Credit: NASA, ESA, CSA, STScI, Christina Williams (NSF’s NOIRLab), Sandro Tacchella (Cambridge), Michael Maseda (UW-Madison); Processing: Joseph DePasquale (STScI); Animation: E. Siegel
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Imagine that you were around at the start of the hot Big Bang, and you were able — from an omniscient point of view — to watch the history of the Universe unfold. Initially, you’d find that the Universe was completely illuminated. An incredibly dense and energetic bath of particles, antiparticles, and radiation, including photons, persisted everywhere and in all directions, with energies easily reaching and exceeding those of optical wavelengths. Over time, however, the Universe expands and cools, and the light within it sees its wavelength stretch, reducing its energy and transforming it from ultraviolet to optical to infrared and even longer, lower-wavelength energies. As the Universe cools by a large enough amount, neutral atoms form.
But then a new source of light arises. Once neutral atoms form, the matter in the Universe begins to gravitationally contract, drawing matter into the densest regions of all and causing streams of gas to intersect. As these gas clouds collapse and fragment, their innermost densities increase, trapping heat as they contract down farther and farther, until a critical threshold is crossed, and stars form. Those stars once again begin lighting up the Universe with optical (visible) light, and by the time we arrive at the present day, more than 13 billion years later, we expect that more than two sextillion stars have formed, distributed in galaxies, groups of galaxies, clusters of galaxies, and even grander structures.
[MUCH MORE INFO, PICS AND CHARTS AT LINK]...............................
What is the Speed of Dark?..........................
Matter of fact, it’s all dark.
WONDERFUL thread, Red.
It’s called the “black” of space for a reason.
I know I’m mad; I’ve always been mad.
I don’t know. I was really drunk at the time.
It simply depends on where the observer is.
Interesting article.
-c
Dark is the absence of any thing that can be accreted and thus has no speed
In other breaking news scientists discover water is wet
Heck I knew a kid that so fast he could flick off the light switch, run across the room, and jump in the sack before it got dark.
Hmmm...
It’s only dark if you cannot see the superluminal, massive, tachyons...
At least that’s what I read the other day...
The Solar System is 20,000 light years from the edge of our galaxy. Voyager 1 , the furthest man man object ever, is not even past one light day out . Nowhere near Intergalactic Space.
If it’s dark, wouldn’t they be TACHY-OFFS?...............
True, but it can ‘see’ it...................
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