Search found 1563 matches

by JohnD
Wed May 31, 2023 3:58 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: A Disk Galaxy Forms (2023 May 31)
Replies: 20
Views: 4464

Re: APOD: Simulation: A Disk Galaxy Forms (2023 May 31)

What a sparse explanation to this most involved and involving video! Ok, it starts at "Redshift 12", which is how long ago? And ends at "Redshift 0", but no scale or mete is shown. But several do appear with no explanation; "LogM* which increases, "SFR" in "M....
by JohnD
Sun May 28, 2023 10:12 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Ida and Dactyl: Asteroid and Moon (2023 May 28)
Replies: 11
Views: 2473

Re: APOD: Ida and Dactyl: Asteroid and Moon (2023 May 28)

Ida's shape appears to be a long way from spherical, while Dactyl is very round!
How stable will the latter's orbit be, when the gravity field around Ida must vary around it?
John
by JohnD
Mon May 22, 2023 2:52 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Supernova Discovered in Nearby M101... (2023 May 22)
Replies: 36
Views: 17194

Re: APOD: Supernova Discovered in Nearby M101... (2023 May 22)

So much for the Zwicky, if it didn't notice a Super Nova!

Hooray for the human eye, and Koichi Itagaki!
John
by JohnD
Mon Apr 24, 2023 2:25 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Medulla Nebula Supernova Remnant (2023 Apr 24)
Replies: 8
Views: 2439

Re: APOD: The Medulla Nebula Supernova Remnant (2023 Apr 24)

Kidney_glomerulus,_light_micrograph.jpg
Whoever named this "The Medulla" was sadly lacking in anatomy! While it looks nothing like a medulla, it closely resembles the Glomerulus, the primary filtration apparatus in the mammalian kidney.

John
by JohnD
Thu Jan 19, 2023 10:04 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Replies: 31
Views: 8409

Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

johnnydeep wrote: Wed Jan 18, 2023 8:23 pm
JohnD wrote: Wed Jan 18, 2023 5:05 pm Spectral lines?
Was that in answer to my second question above?
Yes, Johnny. That's a guess, no doubt Chris could confirm or tell us how.
John
by JohnD
Wed Jan 18, 2023 3:56 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)
Replies: 31
Views: 8409

Re: APOD: MACS0647: Gravitational Lensing of... (2023 Jan 18)

Gosh! That is most impressive, not just of the Webb's capability, but of the astronomers' (Larson, Hsiao? There's no credit for the pic) dedication in searching the image. To my eye there are signs of lensing, especially on the left with 'smeared' galaxies, but to search for and find THREE images of...
by JohnD
Fri Jan 06, 2023 11:53 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Moon O'Clock 2022 (2023 Jan 06)
Replies: 9
Views: 2397

Re: APOD: Moon O'Clock 2022 (2023 Jan 06)

Aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaargh! Not more of this falsely nominative Full Moon stuff! Might as well name them 'Haircut Moon', 'Pancake Moon' (February) or 'Mother in Law Moon' (That's when she visits). These names have nothing to do with the seas...
by JohnD
Thu Jan 05, 2023 9:22 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Messier 45: The Daughters of Atlas... (2023 Jan 05)
Replies: 24
Views: 4435

Re: APOD: Messier 45: The Daughters of Atlas... (2023 Jan 05)

Ann,
You give us two pics of the Pleiades, one with "suppressed stars", but there seems to be no congruence in the nebulae either. They could be pics of two different objects. What am I missing?

John
by JohnD
Sat Dec 24, 2022 10:35 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Comet 2022 E3 (ZTF) (2022 Dec 24)
Replies: 7
Views: 2698

Re: APOD: Comet 2022 E3 (ZTF) (2022 Dec 24)

No.1 Grandson used his Xmas present from last year, a 'NASA' telescope (about 50mm) to look at the recent full moon, and got very excited.

Would this comet be too ambitious a target for an 8 year old?
by JohnD
Sun Dec 11, 2022 2:52 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Io in True Color (2022 Dec 11)
Replies: 12
Views: 2549

Re: APOD: Io in True Color (2022 Dec 11)

Luke Jerram is an English installation artist - his works have included the Museum of the Moon: Museum of the Moon Priory.jpg And Gaia, Gaia Earth Priory.jpg Both have been seen around the world, including at the Lancaster Priory. Huis latest work, Mars, is on tour. Mars Luke Jerram.jpeg What a good...
by JohnD
Fri Dec 09, 2022 10:58 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Mars Rises above the Lunar Limb (2022 Dec 09)
Replies: 15
Views: 5503

Re: APOD: Mars Rises above the Lunar Limb (2022 Dec 09)

Quote, Ann: "Of course the size difference is a consequence of the Moon's great proximity to the Earth."

Gosh, Ann, you make it so much clearer than with Ted and Dougal!
https://www.youtube.com/watch?v=MMiKyfd6hA0
by JohnD
Thu Dec 01, 2022 9:04 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Artemis 1: Flight Day 13 (2022 Dec 01)
Replies: 16
Views: 3966

Re: APOD: Artemis 1: Flight Day 13 (2022 Dec 01)

And all captained by Shaun the Sheep! But of course, Shaun, for all his uniform and zero-gravity training, cannot pilot the sheep - sorry, ship. Which brings to mind the original design of the Mercury capsules, that had no windows and nothing for the 'pilot' to do, being wholly ground controlled. Fa...
by JohnD
Thu Nov 17, 2022 10:15 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Planet Earth from Orion (2022 Nov 17)
Replies: 23
Views: 13556

Re: APOD: Planet Earth from Orion (2022 Nov 17)

Please, APOD, Artemis 1 is NOT uncrewed! On board is one of ESA's fully trained and experienced astronauts, Shaun the Sheep! Here he is undergoing zero-g training, and with some of the launch team: Shaun zero-g.jpg Shaun launch team.jpg His trainers and Aardman are very proud of Shaun's achievement!...
by JohnD
Wed Sep 28, 2022 9:32 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)
Replies: 12
Views: 2965

Re: APOD: A Furious Sky over Mount Shasta (2022 Sep 28)

Yes, a stunning picture, but more highly processed than McDonald's cheese! As the blurb describes, the sky and mountain had to be imaged separately and combined to justify the spurious title, as it shows something a human eye could never see. Observations that our eyes cannot see are commonplace, bu...
by JohnD
Mon Sep 12, 2022 3:26 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Red Sprite Lightning over the Czech... (2022 Sep 12)
Replies: 16
Views: 3661

Re: APOD: Red Sprite Lightning over the Czech... (2022 Sep 12)

10% light speed? Wow! A quick Google finds that to be 67 MILLION mph. They are ionised gas, in the upper atmosphere, so not very dense. Can anyone estimate their mass? Because to accelerate from zero to that, even for a millisecond, must use a heck of a lot of energy, even for a packet of thin gas!...
by JohnD
Mon Sep 12, 2022 12:20 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Red Sprite Lightning over the Czech... (2022 Sep 12)
Replies: 16
Views: 3661

Re: APOD: Red Sprite Lightning over the Czech... (2022 Sep 12)

10% light speed? Wow! A quick Google finds that to be 67 MILLION mph. They are ionised gas, in the upper atmosphere, so not very dense. Can anyone estimate their mass? Because to accelerate from zero to that, even for a millisecond, must use a heck of a lot of energy, even for a packet of thin gas! ...
by JohnD
Wed Aug 31, 2022 5:25 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Siccar Point on Mars (2022 Aug 31)
Replies: 26
Views: 7762

Re: APOD: Siccar Point on Mars (2022 Aug 31)

"Curiosity continues to explore Gale crater on Mars, looking for clues of ancient life. Simultaneously, 2300 kilometers away, its sister rover Perseverance explores Jezero crater"
Surely "daughter" rover? Perseverance is another generation, even if it has the family look!
John
by JohnD
Sun Aug 21, 2022 9:58 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The Spinning Pulsar of the Crab Nebula (2022 Aug 21)
Replies: 15
Views: 4301

Re: APOD: The Spinning Pulsar of the Crab Nebula (2022 Aug 21)

Again, have I discovered, and am suffering from, an acquirable form of colour blindness? Quote blurb, " The featured picture combines visible light from the Hubble Space Telescope in purple, X-ray light from the Chandra X-ray Observatory in blue, and infrared light from the Spitzer Space Telesc...
by JohnD
Sun Aug 14, 2022 9:15 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: 4000 Exoplanets (2022 Aug 14)
Replies: 26
Views: 11943

Re: APOD: 4000 Exoplanets (2022 Aug 14)

Strange choice of indicator colours, or have I discovered an acquirable cause of colour blindness? The "purple" and "pink" look to be different shades of flesh colour. "Orange" comes through as faded beige. I can see the crop of "green" planets, all on the gal...
by JohnD
Wed Jul 20, 2022 11:17 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jupiter and Ring in Infrared from Webb (2022 Jul 20)
Replies: 42
Views: 28168

Re: APOD: Jupiter and Ring in Infrared from Webb (2022 Jul 20)

....That the Great Red Spot is hotter than anything else on Jupiter might be expected - it's a welling up from deeper layers. ... Comment to the picture: " In the image warmer areas appear bright, including four large hot spots that appear in a row just north of the equator. South of the equat...
by JohnD
Wed Jul 20, 2022 9:16 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Jupiter and Ring in Infrared from Webb (2022 Jul 20)
Replies: 42
Views: 28168

Re: APOD: Jupiter and Ring in Infrared from Webb (2022 Jul 20)

That the Great Red Spot is hotter than anything else on Jupiter might be expected - it's a welling up from deeper layers. But why are the Poles hotter?
John
by JohnD
Fri Jul 15, 2022 9:50 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Lubovna Full Moon (2022 Jul 15)
Replies: 4
Views: 1845

Re: APOD: Lubovna Full Moon (2022 Jul 15)

Full Moon! Old middle European castle! It's pitchforks, burning torches, wood stakes and garlic time!
Yummy.