Search found 1068 matches

by VictorBorun
Mon Jun 10, 2024 6:31 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)
Replies: 27
Views: 838

Re: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)

2 What momentum is not being conserved? This isn't a planetary nebula, it is a shock front created by winds coming off a star. Does a CME from the Sun require a matching one from the opposite hemisphere to conserve any momentum? my guess was that the nose is a dissipating track of massive fast-movin...
by VictorBorun
Mon Jun 10, 2024 3:57 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)
Replies: 27
Views: 838

Re: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)

An anti-nose or a few ones are needed to conserve the total momentum without an invisible party What momentum is not being conserved? This isn't a planetary nebula, it is a shock front created by winds coming off a star. Does a CME from the Sun require a matching one from the opposite hemisphere to...
by VictorBorun
Mon Jun 10, 2024 11:39 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)
Replies: 27
Views: 838

Re: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)

Not sure quite what structure you're referring to here. Why would you expect one? the bumpy surface covered by a pale smooth veil: https://asterisk.apod.com/download/file.php?id=49820 An anti-nose or a few ones are needed to conserve the total momentum without an invisible party That kind of struct...
by VictorBorun
Mon Jun 10, 2024 7:13 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)
Replies: 27
Views: 838

Re: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)

Your image isn't about color, but about structure. Ann talking about the structure, I wonder why there seems to be a smooth pale cover about 1 ly above bumpy and solid surface (though it's hard vacuum for a laboratory)? Not sure quite what structure you're referring to here. And why the Nose has no...
by VictorBorun
Sun Jun 09, 2024 1:51 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)
Replies: 27
Views: 838

Re: APOD: SH2-308: The Dolphin Head Nebula (2024 Jun 07)

Ann wrote: Sat Jun 08, 2024 5:56 pm Your image isn't about color, but about structure.
Ann
talking about the structure, I wonder why there seems to be a smooth pale cover about 1 ly above bumpy and solid surface (though it's hard vacuum for a laboratory)?
And why the Nose has no anti-nose feature at 4 or 5 o'clock
by VictorBorun
Tue May 28, 2024 10:52 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: M78 from the Euclid Space Telescope (2024 May 24)
Replies: 10
Views: 822

Re: APOD: M78 from the Euclid Space Telescope (2024 May 24)

Blue star light does not make purple reflection nebulas! 🤬 Ann The info on the ESA site says The blue, green, red channels capture the Universe seen by Euclid around the wavelength 0.7, 1.1, and 1.7 micron respectively. This gives Euclid a distinctive colour palette: hot stars have a white-blue hue...
by VictorBorun
Sun May 26, 2024 6:12 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: M78 from the Euclid Space Telescope (2024 May 24)
Replies: 10
Views: 822

Re: APOD: M78 from the Euclid Space Telescope (2024 May 24)

Blue star light does not make purple reflection nebulas! 🤬 Ann The info on the ESA site says The blue, green, red channels capture the Universe seen by Euclid around the wavelength 0.7, 1.1, and 1.7 micron respectively. This gives Euclid a distinctive colour palette: hot stars have a white-blue hue...
by VictorBorun
Sun May 12, 2024 3:46 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Red Aurora over Poland (2024 May 12)
Replies: 13
Views: 681

Re: APOD: Red Aurora over Poland (2024 May 12)

Amazing display on Friday night from Cornwall in the South-West of the UK. The pillars were bright rapidly changing, in subtle greens, purples and occasionally blue. Didn't know where to look at times, there were some bright transient features due South. Brightest display here for over 20 years I b...
by VictorBorun
Sat May 11, 2024 7:05 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 1350

Re: APOD: AR 3664: Giant Sunspot Group (2024 May 11)

the location of sunspots on the Sun is not random. https://www.rmg.co.uk/sites/default/files/styles/large_no_alt/public/2022-08/A%20Year%20in%20the%20Sun%20by%20Soumyadeep%20Mukherjee%20-%20Astronomy%20Photographer%20of%20the%20Year%202022%20Our%20Sun.jpg?itok=Y-_vrDSh Ann seems rather like one of ...
by VictorBorun
Sat May 11, 2024 12:42 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 1116

Re: APOD: Simulation: Two Black Holes Merge (2024 May 10)

Neither black hole lost mass. The individual precursor black holes merged to form a new black hole, and it has a higher mass than either of the precursors. The total mass difference reflects the conversion of gravitational potential energy (as the two precursors got closer) into kinetic energy, and...
by VictorBorun
Fri May 10, 2024 11:01 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 1116

Re: APOD: Simulation: Two Black Holes Merge (2024 May 10)

Hello everybody, I have a question about the BHs' masses. I imagined that nothing could escape from a BH (except perhaps by Hawking radiation) but it seems that part of the mass of a couple of merging BHs is radiated as GW. I suspect that the energy emitted as GW comes from the kinetic/gravitationa...
by VictorBorun
Fri May 10, 2024 7:19 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 1116

Re: APOD: Simulation: Two Black Holes Merge (2024 May 10)

While the bare physics have to be right, and the simulation flawless, I was underwhelmed by the video - surely such an event will be accompanied by more fireworks, with accretion disks and jets exploding? And thank you to Ann for telling me of the "Final Parsec Problem". I found this: &qu...
by VictorBorun
Fri May 10, 2024 6:32 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Galaxy, the Jet, and a Famous... (2024 May 09)
Replies: 3
Views: 540

Re: APOD: The Galaxy, the Jet, and a Famous... (2024 May 09)

I wonder how to tell Wiki to edit all ly to kly at the right side of this infographics from 15 April 2021 about the companions to the Event Horizon Telescope's April 2017 campaign:
Image
by VictorBorun
Mon May 06, 2024 7:44 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Black Hole Disrupts a Passing Star (2024 May 05)
Replies: 29
Views: 1131

Re: APOD: A Black Hole Disrupts a Passing Star (2024 May 05)

The singularity is small (infinitesimal) but isn't the BH's "size" and hence the gravitational effect - and collision window - determined by how large the event horizon is? A black hole's "gravitational effect" is determined by its mass. The event horizon isn't a real thing, jus...
by VictorBorun
Mon May 06, 2024 5:24 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Black Hole Disrupts a Passing Star (2024 May 05)
Replies: 29
Views: 1131

Re: APOD: A Black Hole Disrupts a Passing Star (2024 May 05)

IMHO this APOD means that the star is going away moving the other way than suggested in the comments above. The accretion disk has been dark but now there is a bright trail through it; we can't see the disk in this pic, just the glowing trail through it. What makes me think that the exit is broad ha...
by VictorBorun
Sat May 04, 2024 8:33 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: 3 ATs (2024 May 04)
Replies: 5
Views: 432

Re: APOD: 3 ATs (2024 May 04)

I searched in vain on the ESO site for an annotated overall map of the VLTI facility but came up empty. But google was my friend. Sadly though, the - much! - smaller R2D2-like ATs on their tracks aren't labeled, but are clear to see in the lower parts of the photo: https://www.eso.org/sci/facilitie...
by VictorBorun
Sat May 04, 2024 1:44 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: GK Per: Nova and Planetary Nebula (2024 Apr 30)
Replies: 16
Views: 1367

Re: APOD: GK Per: Nova and Planetary Nebula (2024 Apr 30)

Once again a masterpiece! Congratulations to the Deep Sky Collective team. Be sure to click twice on the image to see the Nova up close, gorgeous object! I like cosmic dandelions too! ...and when you overlay older images (e.g. from Hubble) you can clearly see how the nova is developing... https://l...
by VictorBorun
Fri May 03, 2024 10:53 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)
Replies: 34
Views: 1973

Re: APOD: M100: A Grand Design Spiral Galaxy (2024 May 02)

I just told you that I don't necessarily always trust Wikipedia, but now I'm going to quote Wikipedia anyway to back up my claim that there are two bars in NGC 1365: And I can see the bars of NGC 1365. :wink: Ann Is there even a definition of a "bar" based on something other than mere app...
by VictorBorun
Thu May 02, 2024 6:58 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: IC 1795: The Fishhead Nebula (2024 May 01)
Replies: 24
Views: 1345

Re: APOD: IC 1795: The Fishhead Nebula (2024 May 01)

I still find the area very exciting even in IR. https://live.staticflickr.com/65535/53692377213_263792ee09_b.jpg jac berne (SSDS/GLIMPSE) https://live.staticflickr.com/65535/53691271482_756c52c430_b.jpg jac berne (SSDS/SPITZER) I wonder why does SSDS fish have a collar (just like APOD fish does) an...
by VictorBorun
Wed May 01, 2024 8:12 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: IC 1795: The Fishhead Nebula (2024 May 01)
Replies: 24
Views: 1345

Re: APOD: IC 1795: The Fishhead Nebula (2024 May 01)

In context from a wider field of view image at one of the links in the text: fish head, heart, and soul nebulas.jpg I still find the area very exciting even in IR. https://live.staticflickr.com/65535/53692377213_263792ee09_b.jpg jac berne (SSDS/GLIMPSE) https://live.staticflickr.com/65535/536912714...
by VictorBorun
Wed May 01, 2024 5:37 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: IC 1795: The Fishhead Nebula (2024 May 01)
Replies: 24
Views: 1345

Re: APOD: IC 1795: The Fishhead Nebula (2024 May 01)

I think, regardless of the observer's distance to the object, its width, in light-years, is static. I.E. Q:"How tall is Snowman?" A: 2 meters Q: I've doubled my viewing distance from Snowman; now how tall is Snowman? A: 2 meters But in order to determine that the snowman is 2 meters high,...
by VictorBorun
Wed May 01, 2024 3:59 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Regulus and the Dwarf Galaxy (2024 Apr 26)
Replies: 18
Views: 1379

Re: APOD: Regulus and the Dwarf Galaxy (2024 Apr 26)

Ah. It's a shame these diagrams don't all use the same standard scales. Well, personally I prefer to use Gaia data. these are standardized and used in the same way for many analyzes. Here are 25 April 2018 Gaia — More than four million stars within five thousand light-years from the Sun 10 August 2...
by VictorBorun
Mon Apr 29, 2024 12:12 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Regulus and the Dwarf Galaxy (2024 Apr 26)
Replies: 18
Views: 1379

Re: APOD: Regulus and the Dwarf Galaxy (2024 Apr 26)

Exactly. Which reasonably suggests that they have entirely different formation processes. The HR diagram of the Milky Way..jpgThe HR diagram of the Milky Way-.jpg https://asterisk.apod.com/download/file.php?id=49545&mode=view Cool! Nice work. Well I am not sure. Maybe fitting the temperature sc...