Search found 7 matches

by GoatGuy
Sat Feb 17, 2024 5:01 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Meteor over the Bay of Naples (2024 Feb 17)
Replies: 18
Views: 7896

Re: APOD: Meteor over the Bay of Naples (2024 Feb 17)

Lovely shot. I was wondering how big such a meteor could be. Various sources say things like 'less than a centimeter' and 'millimeters or so'. I guess so. Then I decided to use the other "can be brighter than Venus" to work some Excel magic, to figure out how big a bit-o-dust it might have...
by GoatGuy
Tue Nov 21, 2023 4:30 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Fleming's Triangular Wisp (2023 Nov 21)
Replies: 12
Views: 10972

Re: APOD: Fleming's Triangular Wisp (2023 Nov 21)

It was … for a minute … a head-scratcher: how exactly does 6 times visual 'size' of Luna (0.5°) correspond to 30 light years, given 2400 LY distance. Upon closer reading, it became more apparent. The Veil Nebula is (((6 × 0.5°) ÷ 360) × (2π)) × 2400 LY = 125 LY in total span. The Wisp is only a frac...
by GoatGuy
Sun Nov 19, 2023 5:38 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Space Station, Solar Prominences, Sun (2023 Nov 19)
Replies: 12
Views: 11639

Re: APOD: Space Station, Solar Prominences, Sun (2023 Nov 19)

What a marvelous image! Thank you. Being an incurable mathemaholic, I asked myself " I wonder what the actual solar face transit time is, from someplace more-or-less underneath (Sea level)" . Doesn't require that much math, (and no … cheαting by way of Google isn't the point), but it does ...
by GoatGuy
Sat Dec 31, 2022 2:56 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Moon over Makemake (2022 Dec 31)
Replies: 13
Views: 3110

Re: APOD: Moon over Makemake (2022 Dec 31)

It is worth noting that even 50× further from Sol, the surface isn't anywhere near the temperature of the Cosmic Background radiation, either. Since temperature in kelvin is proportional to radiation to the ¼th power, we can pretty easily estimate from Earth's statistics alone. Earth receives about ...
by GoatGuy
Mon Sep 24, 2018 8:05 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Rover 1A Hops on Asteroid Ryugu (2018 Sep 24)
Replies: 23
Views: 4398

Re: APOD: Rover 1A Hops on Asteroid Ryugu (2018 Sep 24)

Well… it is pretty interesting to do a few calculations regarding Ryugu's mass, surface gravity, height of hops, and all that. Doing a Google search, one finds a couple of key things about Ryugu: • M → Mass of 4.5×10¹¹ kg • R → Radius of 490 m • P → Rotational period of 7.67 hr Using G₀ of 6.66×10⁻¹...
by GoatGuy
Mon Apr 08, 2013 4:40 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: A Redshift Lookup Table for our Universe (2013 Apr 08)
Replies: 36
Views: 6939

Re: APOD: A Redshift Lookup Table for our Universe (2013 Apr

Sorry to bother about what may have a trivial answer, But what's up with the 1" scale and the kpc scales? Seems like (for the 1") 8.7 is the magic number, around which there's a kind of strange symmetry. I would have thought that there's a linear distance-size relationship. Obviously, ther...
by GoatGuy
Wed Feb 02, 2005 5:45 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD 'Meteor Wiggling'
Replies: 4
Views: 4751

APOD 'Meteor Wiggling'

In an email I sent to the moderator, I questioned whether the 'wiggle' in the apparant motion of the APOD meteor was a result of a high-frequency vibration in the camera-system, and also whether a walnut-sized meteor is going to even move in a cycloid enough [say 1 foot?] to be visible 25 to 50 kilo...