Starship Asterisk*

Can anyone explain why the edges of the Moon's shadow on the Earth are so blurry, while the outline of Io's shadow on Jupiter is so sharp? For a shadow, the umbra is the area from which you cannot see any of the source, and the penumbra is the area where you can see part of the source. The smaller ...

Thanks to all of you who looked at my post! Please let me know -- no one wants to reply to my question because: 1. It is a such difficult question, impossible, I've asked a question that has stumped all viewers! (unlikely!) 2. On the contrary, my question is quite idiotic and incomprehensible, the ...

I guess we may compare the dark patch of the eclipse with the reflection of the Sun on the uneclipsed Earth. https://apod.nasa.gov/apod/image/2403/eclipse99_mir_960.jpg https://imageio.forbes.com/blogs-images/startswithabang/files/2017/07/1-JEBc5QHgI9adkVph6TDC1w.jpg?format=jpg&width=1440 Here c...

Yeah, the shadow of the Moon looks cool when seen from space. :yes: (Or at least from orbit.) :wink: https://apod.nasa.gov/apod/image/2403/eclipse99_mir_960.jpg https://planetary.s3.amazonaws.com/web/assets/pictures/_2400x1997_crop_center-center_82_line/VGER-40-JUPITER-BLOG__Figure_C.jpg.webp Can an...

The tidal tail of NGC 3628 is currently minding its own business, and it doesn't care about M66! While I get where you're trying to go with this, that's completely the wrong way to think of it! The tidal tail, like the body it has been drawn from, is in orbit around M66. It "cares" about ...

Astronomers explore stellar populations of an extremely metal-poor dwarf galaxy phys.org | 2024 March 21 https://scx1.b-cdn.net/csz/news/800a/2024/astronomers-explore-st.jpg Using the James Webb Space Telescope, astronomers have conducted near- and mid-infrared observations of an extremely metal-po...

Also take a look at an amazing picture of the 300,000 light-year-long tidal tail of NGC 3628! :shock: https://asterisk.apod.com/download/file.php?id=49354&mode=view Tidal tail of NGC 3628. Credit: Mark Hanson. Thanks for highlighting this Ann. It took me a while to realise that the tidal tail o...

I'm staying out of the Tycho catalog discussion, but let me say that, on second thought, foreground star HD 98388 couldn't have been a Milky Way globular cluster seen in the same part of the sky as the Leo Trio. Why not? It's because it's too small. I checked the angular size of M65, and its angular...

Ok, what's the prominent, yet unmentioned thing in the upper left quadrant? Is it just a local globular cluster? And an aside: to the posters of these APODs: I really wish that instead of having to laboriously refer back and forth between the image and text descriptions such as "upper right&qu...

At this time of year, when spring is in the air or at least in the sky in the northern hemisphere , it is of course very suitable to greet the new season with the most iconic galaxies of spring, the Leo Triplet. While extreme saturation may serve to emphasize certain features, and therefore has som...

At this time of year, when spring is in the air or at least in the sky in the northern hemisphere , it is of course very suitable to greet the new season with the most iconic galaxies of spring, the Leo Triplet. APOD 21 March 2024 annotated.png The Leo Trio. Image Credit & Copyright: Steve Canni...

ThanX Ann ...for your wonderful comments and suggestions. What is interesting to me is that the Hubble image only shows a section, but the galaxy is larger. Actually, to me this looks more than a merger of three arachnids - definitely very unusual. As far as the colors of the background galaxies ar...

Yes, I like it! :D The colors are so deep and rich that they almost remind me of a 19th century landscape painting! https://apod.nasa.gov/apod/image/2403/Ngc4438_Selby_2068.jpg https://smarthistory.org/wp-content/uploads/2019/10/17011649438_fc837e27a6_o-870x600.jpg So yes, I could almost frame this ...

18.03.2024 HST: The Spider (and not its web) NASA/ESA | Original release 2024 March 18 https://cdn.esahubble.org/archives/images/screen/potw2412a.jpg This gauzy-looking celestial body is UGC 5829, an irregular galaxy that lies about 30 million light-years away. Despite there not being many observat...

And somewhat related to the concept of front/back is this recent different take on Sagan's Pale Blue Dot in XKCD - https://xkcd.com/2906/ https://imgs.xkcd.com/comics/earth_2x.png Okay, enlighten me, Johnny. When did Carl Sagan mess up the low Earth orbit reentry burn? Ann 'Tis a pretty funny joke,...

But the "front" or "back" doesn't change depending on orientation. Only "up" and "down" do. Front or back is determined by distance from us! Guess so. But you can get a little dizzy out there. https://miro.medium.com/v2/resize:fit:1400/0*10_MijtSraShS7ee Ann ...

Amazing amazing!!

Is that red stuff hydrogen alpha? Chris?

Ann

To me, it seems exactly the reverse: the old yellow stars are clearly in front of the starburst areas! And who am I to say what is up or down or in front of or behind in the Universe? :wink: Ann But the "front" or "back" doesn't change depending on orientation. Only "up&quo...

Unfortunately, I, the Galaxy Girl, don't have too much to say about today's APOD ... But I do find it fascinating that the starbursting part of NGC 7714 appears to be placed in front of the old yellow part of the galaxy. Almost as if the the starburst came loose and flew away from the staid old sta...

ThanX Ann I don't think the star formations are peeling off. For me, this impression only arises because the APOD shown is a bit too dark. ...I also find the active radio galaxy (QSO B2333+019) in the background (orange circle) exciting. But I haven't found out how far away it actually is because t...

Unfortunately, I, the Galaxy Girl, don't have too much to say about today's APOD https://apod.nasa.gov/apod/image/2403/Ngc7714_HubblePohl_1080.jpg https://bigthink.com/wp-content/uploads/2022/04/Arp_147.jpg?resize=768,633 But I do find it fascinating that the starbursting part of NGC 7714 appears to...

With that pair of bluish and goldish stars straight beneath it almost looks like a galaxy sitting on top of Albireo , lovely effect! For the context of that apt reference, see: Albireo /ælˈbɪrioʊ/[19] is a double star designated Beta Cygni (β Cygni, abbreviated Beta Cyg, β Cyg). Beta Cygni is about...

Image133k_n1055_1024[1].jpg Portrait of NGC 1055 Image Credit & Copyright: Dave Doctor I like this APOD, but I'm a bit critical, too. A very good thing is that NGC 1055 gets highlighted in the first place. This galactic denizen of Cetus is hardly one of those galaxies that gets too much limelig...

Is it at all unusual that the ionization should appear to be so spherical? I assume whatever gas cloud the star is embedded in is not spherical and that the gas likely extends invisibly and asymmetrically all around that star. But I guess the ionization power only extends so far... Interesting ques...

Thanks for the correction, Chris. However, seeing that the HII region is compact, I'd still say that it's highly likely that the ionizing star is the central one. After all, what other compact HII regions are known where the ionizing star or stars are located at the periphery of the nebula? Ann Oh,...