Starship Asterisk*

I wonder why after I clicked Show in YouTube I was presented with a view defaulted to 480 pixel height video and had to go through options to see 1080 pixel height original video Hmm, I get a 720p (1024x720) video resolution when I click on the link. I would think the default resolution is set by t...

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...

The result looks like so: https://www.youtube.com/watch?v=1MYJhsjX-C4 Thanks johnny, I had to strip a channel parameter off my url in order to get it to work. FYI, this URL also works properly in the [youtube][/youtube] tags: https://www.youtube.com/watch?v=1MYJhsjX-C4?si=zsBn6ckJw_SLulZa

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...

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 ...

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 time from the Sun and the extreme improbability of it NOT being so. The flares and ejectio...

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 group, and are responsible for th...

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...

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...

Sunspot groups remind me of random Life patterns (as in Conway's cellular automaton "Game of Life"). Here's an illustrative example I just created with the very excellent "Golly" app: https://asterisk.apod.com/download/file.php?id=49682&t=1 But the location of sunspots on th...

Sunspot groups remind me of random Life patterns (as in Conway's cellular automaton "Game of Life"). Here's an illustrative example I just created with the very excellent "Golly" app: sunspot group life pattern.jpg And hey, the Sun's atmosphere is even partitioned into "cell...

Does a pair of BHs have to lose any of its total mass-energy to merge? Can the two BHs just get closer (losing potenial energy and gaining kinetic energy) and then merge in a central collision? It seems to me that a straight line collision would involve minimum of going around and radiating away on...

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 accelerating mass generates gravitational waves ("acceleration" can...

In the mundane world, gravitational potential energy gets converted to kinetic energy, gets converted to gravitational waves all the time. Like when you drop a rock. But it takes something as massive as merging black holes or neutron stars to produce strong enough gravitational waves for our existi...

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...

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...

I don't think the quote is a good description at all. A black hole is an entity which is sufficiently dense that there is a region around it (bounded by the event horizon... which itself isn't a physical thing) where the escape velocity is greater than c. Really, that's all. Every visual aspect of ...

Photons are just packets of energy. Presumably the energy is converted to its mass form once a photon falls into a black hole. The black hole keeps its energy; it doesn't keep its "light". That implies a cool idea! All the photons of every star in the sky that reach a black hole are conti...

There's far too much here for me to understand, but I'll ask this question: what's the difference between the event horizon and the photons sphere, and why it the photon sphere 50% larger than the event horizon? At least that's what I'm seeing at Wikipedia: A photon sphere [1] or photon circle [2] i...

From the link posted just above: "You can roughly think of a black hole as a star that traps all of its light" . I like the " its " light. We normally read that "even light" can't escape a black hole, but saying "its" own light makes me wonder further. For in...

Nice to see the diamonds of the two rings on diametrically opposite sides through the center, as god intended. (Yeah, I know Chris has pointed out that it might not appear like this in other totality locations.)

A black hole's "gravitational effect" is determined by its mass. The event horizon isn't a real thing, just a boundary that defines where light can't escape. It really has little physical meaning. We're talking here about stellar mass black holes interacting with stars . That is, objects ...

The mass of the black hole doesn't matter, except to the extent that it's a factor in determining the orbit. Whether it hits the star depends on whether its orbit intersects the interior of the star. This is basically no different than two stars passing by each other, except in the case of the blac...

The tidal force of a black hole, because it is so small, is also small. Something doesn't feel tidal distortion around a black hole until it's about to fall in. (And with supermassive black holes, after it's fallen past the event horizon.) I edited my post with more queries... The mass of the black...

The 3ATs are certainly an advantage for us who keep on looking for new pictures of the infinity of the Cosmos. It is also fascinating that our beautiful Earth will not be destroyed but only be transformed into a New Earth just like other planets like Mars to be terraformed. Well, your title certain...