Starship Asterisk*

This thread from February 23, 2024 , contained a lot of discussion about the Vela supernova remnant. I'll refer you to that thread instead of reiterating things that were said there. Still, before I go, let's take a look at today's APOD and compare it with the picture of the Pencil Nebula that is l...

Peter, I think you are right that the anti-twilight sky phenomenon, the Belt of Venus, can make the sky take on hints of a purple color. Ann Ann, I was following up on hints of a purple color and the anti-twilight sky phenomenon, the Belt of Venus, and I came across "afterglow," at the mo...

You may also know the great Deep Sky Collective: Carl Björk - @Palmito, Thomas Bähnck - newhorizonobs (instagram), Oliver Carter - @Oliver Carter, Sascha Frei - @Usernamealreadytaken, Jake Gentillon - @jake_g, Richard Hall - @Richard, Tino Heuberger - @RononDex, Jason Jacks - @jmdl101, Travis Lectu...

There is, in the upper right part of the Webb image, something that looks like a globular cluster and which is completely invisible in the Hubble image. Impressive. Alex Interesting… not even the enlarged Hubble image is sharp or detailed enough for me to notice any individual clusters, especially ...

Okay! I've given this some more thought. It is clear that the Flying Fox is not quite comparable to Hanny's Voorwerp: https://live.staticflickr.com/65535/53649398282_fcceba3d87_b.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Hannys_voorwerp.jpg/330px-Hannys_voorwerp.jpg Let's omside...

Okay! I've given this some more thought. It is clear that the Flying Fox is not quite comparable to Hanny's Voorwerp: https://live.staticflickr.com/65535/53649398282_fcceba3d87_b.jpg https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Hannys_voorwerp.jpg/330px-Hannys_voorwerp.jpg Let's conside...

https://live.staticflickr.com/65535/53650491518_730c75c2c7_b.jpg Thanks, Jac, you know I love your images! :D 😀 🥳 A flying fox of plasma without a galaxy inside, eh? That reminds me of Hanny's Voorwerp. https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Hannys_voorwerp.jpg/330px-Hannys_voorw...

This is kind of fun, an animated version of what we see in today's APOD. Frames are 30 seconds apart. (Might have to click on it to see the animation... depends on your browser.) _ prom_stack.gif Indeed, that's kind of fun, Chris. I must admit that the hydrogen alpha-bright lower right limb turns i...

Consider this image, which is exposed for the prominences, not the outer corona. _ https://asterisk.apod.com/download/file.php?id=49462&t=1 https://asterisk.apod.com/download/file.php?id=49463&t=1 Ann Which illustrates what I discussed elsewhere. "Color" is not just hue, but hue a...

When I zoom in the APOD I do see the "pink" as intense red indeed; could the impression (shared by many it seems) of having seen pink instead simply come from a residual fraction of white light blending in with the deep red? Consider this image, which is exposed for the prominences, not t...

I saw this eclipse and the bright pink prominences were stunning, and it got me reading about H alpha emission. And after some reading, I feel betrayed by every "H alpha" filtered photo of the sun I have seen. Because the prominences appeared obviously PINK to human eyes, doesn't that mea...

Very true... but possibly excepting flowers! The color of the petals of pink/red/blue/purple flowers is created by a class of molecules called anthocyanins, and the actual color can vary across that range, determined primarily by pH. So really, there is no "natural" or "real" co...

Peter, you wrote about the purple color of the upper sky. As I said, I have never observed purple color in the sky, except on those rare occasions when pink clouds at sunset or sunrise momentarily seem to take on a purplish-pink hue. Otherwise, I've never seen it. Ann, thanks for putting me in the ...

I think that if you see a color photo whose color balance seems surprising, chances are that it is the picture that is different, not the natural phenomenon that has taken on a strange hue. Very true... but possibly excepting flowers! The color of the petals of pink/red/blue/purple flowers is creat...

Yes, that is a possible explanation, but I wonder if there could be something else at play here, namely the camera itself. If I enlarge your second photo (by Thanakrit), the dark lunar disk is significally smaller than the sun disk, as displayed before or after the eclipse. I don’t think so. Bear i...

Why is there a small dark spot in the middle of the sun (that isn't there to see)? I have seen this curious phenomenon in some of my own amateur photos (taken during other eclipses). My guess is that "the small dark spot in the middle of the sun" is the lunar disk. The bright ring around ...

Does this mean that the release of gas from the parent body of Pons-Brooks is "episodic"? Like a series of little explosions? Ann It probably depends on the exact chemical composition, the physical structure of the material and how long each surface is in the full glare of the sun as the ...

Very interesting to see the changing ion tail of Comet Pons-Brooks!


Does this mean that the release of gas from the parent body of Pons-Brooks is "episodic"? Like a series of little explosions?

Ann

Mount Etna in Italy is the most active volcano in Europe. Since April 3, 2024, it has been blowing smoke rings in the air! https://www.youtube.com/watch?v=md7hRFrngk8 The reason seems to be that there is a new vent on Mount Etna that is almost perfectly circular in shape. As gas is being released fr...

I don't see the scientific lesson here about the unwinding. Although you can't see it on the APOD main page, if you click on the larger screen version for it you can see double. The rectangle is divided into two double portions, the left and right sides are with with the identical star formations i...

Am I the only one who thinks there is a similarity between today's APOD and yesterday's? https://apod.nasa.gov/apod/image/2404/M51Unwound_crop600.jpg https://apod.nasa.gov/apod/image/2404/CoronaGraph_1024.jpg Well, I'm nodding good-bye to yesterday's solar corona to concentrate on today's M51. Being...

I suppose the Sun has no meaningfully permanent longitude map that would allow these two coronal un-wrappings to be matched up. Which makes sense since the Sun is just a ball of plasma! But I gather that the rotational north-south pole line should remain the same long term. Or does it? I know the r...

It looks gorgeous! :D https://apod.nasa.gov/apod/image/2404/CoronaGraph_1024.jpg It is such a beautiful, otherworldly (that's right!!!) image. Thanks to Peter Ward for producing it. I can tell from the picture that, indeed, the solar corona behaves differently during solar minimums and solar maximum...

Says ChatGPT: The radioactive decay of nickel-56 (⁵⁶Ni) typically proceeds through electron capture, where one of the atom's inner shell electrons is captured by the nucleus, resulting in the transformation of a proton into a neutron. This process converts the nucleus into iron-56 (⁵⁶Fe) through th...

Yes, Pons-Brooks is a nice comet! :D https://apod.nasa.gov/apod/image/2404/12P_Pons_Brooks_2024_03_30_JuneLake_DEBartlett1024.jpg APOD 4 April 2024 annotated.png I still find it very interesting that Pons-Brooks is so "gassy", even though it has (or so I think) visited the vicinity of the ...