Sombrero Galaxy dazzles in new James Webb image | Hacker News Reader

Sombrero Galaxy dazzles in new James Webb image

science.nasa.gov

119 pointsnixass44 comments

Probably personal taste, but I still like Hubble's image more, really gives the disk some depth, as opposed to the flatter MIRI image.

Quick link to Hubble image:

https://science.nasa.gov/mission/hubble/science/explore-the-...

It is interesting seeing past the central portion to see the complete rings on the back side. In the MIRI image, it looks like a special FX shot from some scifi where the explosion happens on a plane rather than a sphere.

There's also https://webbtelescope.org/contents/media/videos/2024/137/01J... which shows Spitzer, Webb, Hubble with rotating images at the same image size.

i got nerd sniped and did the same thing myself. i could not find a way to blend the two images together that did anything interesting that the separate images did not do on their own. looks like they came to the same conclusion.

I thought the same about an old-vs-new comparison of the classic Pillars of Creation image, though on a second look they are both stunning in their own ways.

https://webbtelescope.org/contents/media/images/2022/052/01G...

The superposition and comparison of both images (exhibit B) is incredible how they got each background star exactly in the same place

How long did it take you to check the positions of all starts? :D

If you jigger the slider fast enough, persistence of vision will give you the answer pretty quickly.

You know the story about IR cameras that can see through clothes, it is mostly a myth but there is some truth to it as some clothes are transparent in infrared.

Same idea here, with the deeper IR Webb operates on, you get to see the galaxy "naked", which is great if you want to study its anatomy. But not everyone enjoys seeing naked galaxies.

In the sibling photo in the index is a comparison of Hubble vs Webb.

Hubble is very brown-y, and Webb is much more blue.

But these are false colors, and they capture different light. It has to be an artistic decision to make it blue, vs brown, so does anyone here know the rationale? Is it to distinguish the different provenance? Is the color shift indicative of the captured spectrum difference? Is it a convention of the sensor? Is it a 2020s fad?

https://webbtelescope.org/contents/media/images/2024/137/01J...

The relevant part being near the bottom:

> These images are a composite of separate exposures acquired by the James Webb Space Telescope using the MIRI instrument. Several filters were used to sample wide wavelength ranges. The color results from assigning different hues (colors) to each monochromatic (grayscale) image associated with an individual filter. In this case, the assigned colors are: Blue: F770W, Green: F1130W, Red: F1280W.

Chasing some numbers up, it looks like they've made the wavelengths around 20 times shorter to bring the picture into the visible spectrum.

I'd like to see some everyday objects as well as planets in our solar system in these same frequency ranges and color assignments for comparison.

Webb uses mid-infrared to capture the image. I'm not sure if they then assign colors arbitrarily.

Hubble uses visible light and I prefer this image from an artistic standpoint as it seems to capture depth better.

It's not arbitrary. They assign colours in order based on wavelength, so the shortest wavelengths will be bluer and the longest wavelengths will be redder.

Makes sense. Thank you

mid near infrared vs visible light. one of the big bets with webb is that visible isn't the ideal spectrum to target. it's fantastic from a research standpoint but the pictures may seem less pleasing vs hubbles.

I looked up Triangulum on a lark, and learned:

"Unlike the Milky Way and Andromeda galaxies, the Triangulum Galaxy does not appear to have a supermassive black hole at its center. This may be because the mass of a galaxy's central supermassive black hole correlates with the size of the galaxy's central bulge, and unlike the Milky Way and Andromeda, the Triangulum Galaxy is a pure disk galaxy with no bulge."

Triangulum is a spiral galaxy in our local group, perhaps bound to Andromeda or us.

https://en.wikipedia.org/wiki/Triangulum_Galaxy

What was the impetus of you looking up Triangulum?

I was curious how much closer it was than the Sombrero (about 10x).

I thought I missed something in TFA. It's interesting to see how a post can make different readers spin off into various random trains of thought.

A fun game would be to make a post like yours and then find the fewest degrees of Kevin Bacon to get back to TFA.

Might it be that in galaxies without a blackhole at the center, civilizations could be much older in that galaxy compared to galaxies like ours?

At a rough 10 trillion kms = 1 light year, Sombrero galaxy is 31.1 million light years away, 1 quadrillion kms = 100 light years, 1 quintillion kms = 100,000 light years, 100 quintillion km = 10 million light years, so basically we are looking at an object 300 quintillion kms away At this fraction of light speed 0.99999999999999999999 to the person inside the spaceship only 1.6 days will pass. But to a person on earth, it would be 31.1 million light years. Crazy eh?

Not hugely crazy, it's a function that asymptotically approaches infinity.

If you want crazy effects, IIRC the relativistic time dilation factor is also the temperature dilation factor, which means at that speed the cosmic microwave background radiation will cause positron-electron pair production in the hull of the spaceship, to a depth that is dependent on how effectively it blocks extremely hard gamna rays — like, if you're in a space suit, it will be throughout your entire body because neither the suit nor your bones are particularly opaque at that energy level.

Tip: Click on an image and scroll down for options of higher resolutions.

https://stsci-opo.org/STScI-01JCGMTFA7D07SQHJX5VWCY29J.png

Unrelated- but exists there a fast forward- projected position of the sky- as it would be actually toady? Like a rendered simulation without a million year timelag?

These are the photos of the galaxy as it is as of our today. There is not a fixed, absolute "today".

Just Wonderful. Though it looks a bit less like a sombrero this time. Might need to think about changing the name.

The Frisbee Ring Galaxy?

I wonder why galaxies tend to be shaped like a disc rather than a ball. Doesn't really make sense to me.

It sort of does to me - disks made up of concentric orbits are have no intersections, and so collisions are less likely. In a ball, debris would have different directional vectors that would eventually collide with one another. The disk is the stable evolution of that state.

I believe it's not that collisions (and gravitational interactions) don't happen when it's in a disk, but the galaxy as a whole has an overall rotational momentum about some axis, and collisions within the galaxy can't change that. This means that it can flatten along the axis, but it can't shrink in the perpendicular plane.

If everything were twice as close to the axis (as gravity would like it to be), it would need to be moving twice as fast to conserve rotational momentum, but that's faster than the velocity of a circular orbit at the new radius (assuming everything was in a circular orbits to begin with).

The same principle is why almost everything in the solar system approximately lies within a plane.

Because galaxies spin. A spinning ball will compress into a disc after a while. The parts which are close to the axis just fall into the middle and some amount of friction slows them down until they stay close to the plane.

If you started with a galaxy that is a nearly uniform ball, the gas and bodies near the equator would attract the gas and bodies that are further out.

Those further out would tend to collapse towards the equator and eventually that initial ball would become more disk shaped.

Then there is this explanation refering to the conservation of angular momentum: https://van.physics.illinois.edu/ask/listing/18318

Elliptical galaxies are ball-shaped.

https://en.wikipedia.org/wiki/Elliptical_galaxy

I’m gonna be the grumpy old man here, but this is a marketing page. If there’s science going on here, it’s not even mentioned. Instead it’s all artist’s visualisations of infra-red data of an unusual galaxy. Is the galaxy of any scientific interest? I have no idea from the article whatsoever.

It's a pop sci article. It shows off advances in our imaging capabilities and hopefully inspires a little wonder about the universe. I believe the intended takeaway is something like "neat! We can see a lot of stuff going on in infrared that's hard to see in the visible spectrum". The rendering of other wavelengths as red, blue, and green pixels is a very standard scientific visualization method for multispectral imaging, and the article makes it clear what choices they make to do so.

I see what you did there :-)

Spelled out for those who don't: 'sombrero' is Spanish for hat.

All galaxies are just space explosions

No, they are not.

You're thinking of a nebula. That’s the remnants of a supernova. A galaxy is an unimaginably large collection of stars. A nebula is still quite large, but several orders of magnitude smaller than a galaxy.

instead of being "explosions", galaxies appear to be closer to a condensate between bubbles of ... well .. much less.

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