Search found 17420 matches

by Chris Peterson
Tue May 14, 2024 6:10 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The 37 Cluster (2024 May 14)
Replies: 12
Views: 215

Re: APOD: The 37 Cluster (2024 May 14)

Roy wrote: Tue May 14, 2024 6:09 pmLog Age
What about it?
by Chris Peterson
Tue May 14, 2024 6:07 pm
Forum: The Library: Information Desk and Educational Resources
Topic: Why are earthly sunsets never green?
Replies: 24
Views: 16483

Re: Why are earthly sunsets never green?

The color green does not exist outside our human eyes and brains. It is our eyes and brains that "create" the color green. Also then should be the case regarding the sun's green flash, it is an optical phenomenon, as our eyes and brains also create the color green of the sun's green flash...
by Chris Peterson
Tue May 14, 2024 6:00 pm
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: Colors of Twilight vs. Sunset/Sunrise
Replies: 31
Views: 2469

Re: Colors of Twilight vs. Sunset/Sunrise

I wonder if this Wikipedia article on Sky brightness makes sense -- it seems to that there is both direct and indirect sunlight in the sky at twilight -- "Indirectly scattered sunlight comes from ... the atmosphere itself .... the Sun has just set but still illuminates the upper atmosphere dir...
by Chris Peterson
Tue May 14, 2024 5:57 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664 on a Setting Sun (2024 May 13)
Replies: 14
Views: 401

Re: APOD: AR 3664 on a Setting Sun (2024 May 13)

Hopefully someone can clear up some sun confusions for me. Today's APOD shows AR-3664 towards the BOTTOM of the solar disk. That of May 11 showed this cluster to be towards the RIGHT. Does the apparent orientation of the sun shift from day to day? My understanding is that the storms move from left ...
by Chris Peterson
Tue May 14, 2024 3:18 pm
Forum: The Library: Information Desk and Educational Resources
Topic: Why are earthly sunsets never green?
Replies: 24
Views: 16483

Re: Why are earthly sunsets never green?

The color green does not exist outside our human eyes and brains. It is our eyes and brains that "create" the color green. Also then should be the case regarding the sun's green flash, it is an optical phenomenon, as our eyes and brains also create the color green of the sun's green flash...
by Chris Peterson
Tue May 14, 2024 3:13 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The 37 Cluster (2024 May 14)
Replies: 12
Views: 215

Re: APOD: The 37 Cluster (2024 May 14)

Nowhere in the information supplied do they mention the classification or number of the stars in the cluster. Yet the age of the cluster is estimated to be only 11,668,000 years. Curiously short - and no leftover nebular material. About 30 stars. The cluster does lie inside a region of faint nebulo...
by Chris Peterson
Tue May 14, 2024 1:59 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The 37 Cluster (2024 May 14)
Replies: 12
Views: 215

Re: APOD: The 37 Cluster (2024 May 14)

The write-up mentioned that our Sun may have been part of a cluster at one time. Do we know where our sun was born? Was that theoretical cluster here, or did the Sun migrate to here from 'parts unknown'? Do astronomers have any theories of as to where our cluster was? The cluster that the Sun forme...
by Chris Peterson
Tue May 14, 2024 1:25 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: The 37 Cluster (2024 May 14)
Replies: 12
Views: 215

Re: APOD: The 37 Cluster (2024 May 14)

Nowhere in the information supplied do they mention the classification or number of the stars in the cluster. Yet the age of the cluster is estimated to be only 11,668,000 years. Curiously short - and no leftover nebular material. About 30 stars. The cluster does lie inside a region of faint nebulo...
by Chris Peterson
Mon May 13, 2024 10:09 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664 on a Setting Sun (2024 May 13)
Replies: 14
Views: 401

Re: APOD: AR 3664 on a Setting Sun (2024 May 13)

Hopefully someone can clear up some sun confusions for me. Today's APOD shows AR-3664 towards the BOTTOM of the solar disk. That of May 11 showed this cluster to be towards the RIGHT. Does the apparent orientation of the sun shift from day to day? My understanding is that the storms move from left ...
by Chris Peterson
Mon May 13, 2024 7:34 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664 on a Setting Sun (2024 May 13)
Replies: 14
Views: 401

Re: APOD: AR 3664 on a Setting Sun (2024 May 13)

We are getting alot of photoshopped pictures . What do I mean? In this case, a picture of the sunspots superimposed on the sun in a photo in which the sun would be too bright to look at, to cause an artistic view. Photo or portrait? It's an HDR image, composited from several different exposure time...
by Chris Peterson
Mon May 13, 2024 1:44 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664 on a Setting Sun (2024 May 13)
Replies: 14
Views: 401

Re: APOD: AR 3664 on a Setting Sun (2024 May 13)

Rauf wrote: Mon May 13, 2024 8:10 am So is it 3664 or 6443?
AR 3664.
by Chris Peterson
Mon May 13, 2024 4:42 am
Forum: The Asterisk Café: Discuss Anything Astronomy Related
Topic: What did you see in the sky tonight?
Replies: 1303
Views: 1059124

Re: What did you see in the sky tonight?

Last night I tried to photograph the aurora with my DSLR with little success. My wife took these with her IPhone. image_123650291 (1)a.JPG image_123650291 (2)a.JPG image_123650291a.JPG With my eye it was not very apparent but her cell phone captured quite a different scene. :? Is aurora photography...
by Chris Peterson
Sun May 12, 2024 4:27 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Red Aurora over Poland (2024 May 12)
Replies: 13
Views: 350

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

It works but only if the youtube url is of a specific format, namely like this: https://www.youtube.com/watch?v=1MYJhsjX-C4 And you need to use the right tags: [youtube][/youtube] The result looks like so: https://www.youtube.com/watch?v=1MYJhsjX-C4 I wonder why after I clicked Show in YouTube I wa...
by Chris Peterson
Sun May 12, 2024 1:53 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 845

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

Is this image, its quality and the gesture to publish it, a huge joke? From time to time APOD editions pop into my view, last time I left some abrasive comments was for the photoshoped solar eclipse-moon-something. I literally shoot better (read: much better, link below to our forum) images during ...
by Chris Peterson
Sun May 12, 2024 12:17 am
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 845

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

And where were they? Is it ever possible to link a specific sunspot group with an aurora? The four CMEs in the last days, and the new one today, all came from this group, and are responsible for the current auroral activity. Ok. Is the cause and effect indisputable? I guess so simply due to travel ...
by Chris Peterson
Sat May 11, 2024 9:34 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 845

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

Ok, where are the sunspots? 😊 Wrong question. Cause and effect. Where were the sunspots a couple of days ago? That's what mattered! And where were they? Is it ever possible to link a specific sunspot group with an aurora? The four CMEs in the last days, and the new one today, all came from this gro...
by Chris Peterson
Sat May 11, 2024 7:41 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 845

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

Pretty good here in central Colorado, 38°N, despite it being pretty cloudy. This is an allsky video from late twilight to 1:30am when it completely clouded over. https://vimeo.com/945334892 Last image below was taken pointing very high, with the Big Dipper in the frame. _ E7_48521p.jpg E7_48527p.jp...
by Chris Peterson
Sat May 11, 2024 7:33 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 845

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

Pretty good here in central Colorado, 38°N, despite it being pretty cloudy. This is an allsky video from late twilight to 1:30am when it completely clouded over. https://vimeo.com/945334892 Last image below was taken pointing very high, with the Big Dipper in the frame. _ E7_48521p.jpg E7_48527p.jpg...
by Chris Peterson
Sat May 11, 2024 6:17 pm
Forum: Open Space: Discuss Anything
Topic: Weather!
Replies: 2868
Views: 996775

Re: Weather!

How can evolution favor an organism's death? In the big picture, no species can evolve for long if the old versions aren't eliminated. You need reproduction for adaptation and evolution, and you can't have reproduction without death in any system with limited resources. OK, let's say that hypotheti...
by Chris Peterson
Sat May 11, 2024 6:08 pm
Forum: Open Space: Discuss Anything
Topic: Weather!
Replies: 2868
Views: 996775

Re: Weather!

Yes, but why a tree can't live forever? I mean, some have been living for more than a millennia. Why this tree can't live that long? DNA gets damaged over time, toxins accumulate over time. Some pest, parasite, or disease will eventually win. And evolution doesn't favor organisms that don't die and...
by Chris Peterson
Sat May 11, 2024 2:54 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: AR 3664: Giant Sunspot Group (2024 May 11)
Replies: 25
Views: 845

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

Earth is sweeping up “particles” - charged, by the way - from solar flares. What charged particle? Electrons & protons - electricity. Now we get to see if it sis another Carrington event. My thought is: probably not, because there are a lot more wires and a lot more grounds than there were in 1...
by Chris Peterson
Fri May 10, 2024 11:08 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 830

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 Chris Peterson
Fri May 10, 2024 6:33 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 830

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

Can you clear up that statement for me? Any missing words for example? I don't think there are any missing words. When a mass is allowed to move in a gravitational field, its velocity increases, which represents a conversion of gravitational potential energy to kinetic energy. Right? And any accele...
by Chris Peterson
Fri May 10, 2024 6:25 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 830

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

Kinetic energy can get converted into gravitational energy? In the mundane world, kinetic energy clearly can get converted into heat (a bullet hitting a steel plate for example), but does it also get converted to GWs (however miniscule an amount that might result in)? In the mundane world, gravitat...
by Chris Peterson
Fri May 10, 2024 6:06 pm
Forum: The Bridge: Discuss an Astronomy Picture of the Day
Topic: APOD: Simulation: Two Black Holes Merge (2024 May 10)
Replies: 21
Views: 830

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...