As

 

I was saying a lil bit ago...

"People..."

JWST’s “most distant galaxies” might be fooling us all JWST has seen more distant galaxies than any other observatory, ever. But many candidates for "most distant of all" are likely impostors.

"If all of these ultra-distant galaxy candidates were real, we’d have too many of them too early, forcing us to rethink how galaxies begin forming within the Universe. But we might be fooling ourselves completely, and we won’t know for sure with only our current data. Here’s why.

"There’s a tremendous difference between the light that a distant galaxy emits and the light that arrives at our eyes after journeying for billions of light-years across the Universe. That initially emitted light gets affected by everything that interacts with it along its journey, including:

light-blocking neutral matter,

hot gas and plasma that scatters and disperses that light,

growing and shrinking clumps of matter that change the gravitational potential in the region where the light is propagating,

and the expansion of the Universe, that stretches the wavelength of any light that travels through it."

"This simplified animation shows how light redshifts and how distances between unbound objects change over time in the expanding Universe. As distances between objects are not constant as time goes on, the expanding Universe does not possess time-translation invariance, and a consequence of this is that energy is not conserved on a cosmic scale. Progressively more distant objects become visible as long-ago emitted light, in transit for billions of years, begins to arrive at our eyes for the first time. This remains true even in a dark energy-rich Universe."

"Even though the laws of physics — from the quantum physics that governs electrons, atoms, and ions to the thermal and stellar physics that governs stars and galaxies — are the same everywhere throughout the Universe, objects at different distances won’t appear the same way when you observe them. The environments they’re in, as well as the environments they must pass through on their way to our eyes and instruments, alter that light irrevocably. If we want to understand and discover what’s out there, we need to be able to not only observe the most distant light possible, but to reconstruct what that light was like when it was first emitted so long ago.

"When you see an object that’s redder in color than the typical, nearby objects we observe in our vicinity, there are many possible reasons why it might appear red. It could be full of intrinsically red stars. It could be extremely dusty, where light-blocking material obscures the shorter-wavelength light. But one fascinating possibility that must be considered is that it’s red because the expansion of the Universe shifted that light, emitted at much shorter wavelengths, to the long wavelengths we now observe."

"One of the keys to unlocking our understanding of our cosmos, as well as our place within it, came about in the 20th century when we discovered the expansion of the Universe. 

(It means the universe had a beginning, and as matter and energy dont create themselves? It means "something" outside of itself must have set the events in motion that led to it's existence. I wonder what that "something" was or could have been or is?)

"The fabric of space itself is like a ball of leavening dough, and the galaxies within it are like raisins sprinkled throughout it. As dough leavens, it expands, and all of the raisins mutually get farther apart from one another. From the perspective of any individual raisin — or of any observer located within a galaxy — the other raisins (galaxies) move away from it, with more distant raisins (galaxies) receding more quickly, and the light traveling from one to the other experiencing a greater shift in its wavelength than the ones found more nearby."

"It should come as no surprise to anyone that, even in its very first science observation that was released, the JWST found a large number of extremely red objects. But just because you see something that’s red doesn’t mean it’s an ultra-distant galaxy. There are many signals that can fool you:

galaxies where all of the hot, blue, massive stars have died, but the redder stars remain,

galaxies that are rich in dust grains of small, common sizes, which are efficient at blocking the bluer light but are transparent to redder light,

or galaxies that exist along a line-of-sight that scatters away or blocks the bluer wavelengths of light passing through them, while leaving the red ones behind."

"This is the problem with the most basic of astronomical techniques that allow you to measure the color of an object or set of objects: photometry. Just as humans have three types of cones in our eyes — sensitive to red, green, and blue — our telescopes have multiple filters on them, sensitive to different wavelength ranges of light. When you see that the shorter wavelength ranges show no light, and then longer wavelength ranges beyond a certain threshold show lots of light, you’ve got an excellent candidate for an ultra-distant galaxy."

"How do you confirm the distance to an object whose light appears extremely red?

That’s where the technique of spectroscopy comes into play."

(They haven't done that yet with all the "candidates" that JWST has recently found.)

Spectroscopy

"But among those objects, there were a number that stood out from the rest. In particular, 87 of those points of light were seen to be extraordinarily red, with no light at all visible in the shortest-wavelength JWST photometric filters. This is why they’re treated as candidate ultra-distant galaxies."

"But being a candidate is only part of the game; you have to gather the critical, spectroscopic data if you want to answer the all-important question of, “How many of them are real?” In other words, how many of them aren’t just “candidates” for being ultra-distant galaxies but are actually ultra-distant galaxies, rather than impostor objects that exist at lower redshifts? Is it all of them? Most of them? Some of them? Or only a few?"

"In research presented at the 241st meeting of the American Astronomical Society, Professor Haojing Yan made a strong case that many of these galaxies likely were ultra-distant objects, and that astronomers and astrophysicists might be forced to rethink the early birth, growth, and evolution of galaxies if that’s the case. 

(Not the entire Big Bang)

He was so confident in the quality of the photometric data and what it suggested, that he was willing to bet a very large beer that more than 50% of these galaxy candidates would wind up being spectroscopically confirmed, and that our ideas about the population, abundance, and properties of these many galaxies would demand a cosmic rethink of how they formed so early on."

(Again, not the entire big bang theory.)

"This almost-perfectly-aligned image composite shows the first JWST deep field’s view of the core of cluster SMACS 0723 and contrasts it with the older Hubble view. The JWST image of galaxy cluster SMACS 0723 is the first full-color, multiwavelength science image taken by the JWST. It is the deepest image ever taken of the ultra-distant Universe, with 87 ultra-distant galaxy candidates identified within it. They await spectroscopic follow-up and confirmation."

"Without the critical data, all of this is simply speculation. The quest is not to determine whether someone’s hunch is correct or not, it’s to understand and measure the true nature of these objects, finding out which ones are ultra-distant galaxies, which ones are less-distant interlopers, and to understand what the false positive rate is and what determines it. But you can’t draw any definitive conclusions at all without spectroscopy; for the non-astronomers out there, you should trust a photometric measurement of redshift about as much as you trust a purported photo of the Loch Ness Monster to reveal the truth about its nature."

"But without the critical spectroscopic data on these galaxies — enabling a measurement of the false positive rate from photometric candidates — we have no way of knowing whether a few of these galaxies, many of them, most of them, or even nearly all of them are less-distant impostors, tricking our inexperienced eyes into thinking they’re more distant than they are. In the meantime, as exciting as the possibility is that our cosmic story might need a rethink, we have to keep in mind that JWST’s alleged “most distant galaxies” might be fooling us all."

(Things have a way of not being what we think they are, think I remember somebody talking about that not to long ago.)