Starship Asterisk*

the interesting illusion about today's Astronomy Picture of the Day of the Eagle Nebula is that our brains see the blue as a hole in the dark clouds showing sky behind. But the sky in space is black, not blue. The blue is also a cloud, at about the same distance at the others. Indeed, even though i...

johnnydeep wrote: ↑Fri Aug 12, 2022 7:49 pm There are those big "skeletal" DOBs that could be played with without disassembling them:
https://www.cloudynights.com/uploads/mo ... _thumb.jpg

Yes, if you could play with one of those, that ought to do it!

Thanks! That almost makes sense to me but I can't quite convince myself how far away things would look to an off axis observer looking at the mirror from a short distance as in this APOD. I'd think that you would see a more continuously varying stretching of images across the surface than what we s...

There's lots to wonder about in this beautiful image. To the upper left of the blue patch, is a red and milky white shape that looks like a solar prominence, or a two-thirds of a doughnut. It must be at least 5 light years in diameter. As I look at it, I think it is actually spherical, and the only ...

Alright, what's the cause of the blurriness in the reflection we see in top half of the mirror? all streaks are parallel and close ones are of the same length. They must be long-exposure stars' tracks. Why some part of the sky in the mirror show longer star tracks, I don't understand Capture.JPG Th...

Ah, thanks for the labelling.

I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around? I'm not persuaded by the study that produced the theory that some of the tracks were made by boulders bouncing along. One w...

I wonder why Nasa doesn;t use the same technology as Facebook to produce stereo or 3-D pictures. How many people have an old set of red and blue paper spectacles lying around? Phobos again! I really like the 3D model at the APOD caption's link: asteroid-like moon's . (Scroll down to the second imag...

johnnydeep wrote: ↑Fri Aug 05, 2022 12:12 pm

MarkBour wrote: ↑Fri Aug 05, 2022 5:12 am

Chris Peterson wrote: ↑Thu Aug 04, 2022 1:42 am ... The Universe is made for algae.

How about whales?

Yes, whales are made for algae too

Chris Peterson wrote: ↑Thu Aug 04, 2022 1:42 am ... The Universe is made for algae.

How about whales?

Amazing view. Not many folks will have seen that ! I've always wondered how did they calculate the dynamics of rising off the moons surface and catching up/docking with the lunar orbiter. There would only be a small margin of error for that to succeed ?. And a large possibility of missing ?? If the...

Beautiful sight! And the "captured this view" link gives a video of the auroras that is incredible. Nice work by astronomer Ian Griffin, using a new auroral camera on SOFIA, so I guess this was actually part of the observing mission, enjoying the aurora. In the video, one can see a faint r...

As the primary intent here is aesthetic, it would make sense to remove the fiducials (which could certainly be helpful in producing the panorama, but serve no purpose in the final image, are distracting, and are trivially removed). _ a11pan1040226lftsm_nofids.jpg Yes, this scene on Selene is much m...

But is it not true that the spin of a proto-disk is blocking gravitational collapses, and after some spin is shed to evaporating (i.e. partially to kicked-out clumps in the plane of the disk and partially to a pair of conical jets from every new star or a large planet), what finally forms is spinni...

As to Saturn spinning fast, I know that it and Jupiter are similar, with Jupiter spinning even faster. A basic idea would be that they got it from their accretion and formation process. That's consistent with your suggestion, that angular momentum comes from what has fallen inward. This one effect ...

Saturn's moonlets in the rings are small in radius even doubled with their ridges so their spinning up by the rings' differential rotation would be tiny. They should migrate to Saturn faster than the rings' particles, too. Not sure they live long enough to spin up before they crash into Saturn. Sat...

I like the blob nearly at the bottom, a little right of center:
It probably already has a name.
If not, I'd propose calling it the Anglerfish Galaxy Group

Got to show you perhaps the most beautiful picture I have seen, fittingly called "The Blue Universe" by Japanese photographer Hiroki Kondo: ... Amazing, isn't it? Sigh! Sometimes we can see heaven on Earth. Or - wait! I take that back! Sometimes we can really see that the Earth is the hea...

Capture1.png I'm just looking at this image from the Wikipedia "Roche Limit" page and thinking about it intuitively ( https://en.wikipedia.org/wiki/Roche_limit ) As the object approaches the Roche limit, its inner chunks are wanting to orbit angularly more rapidly than the rest, and its o...

Ann wrote: ↑Sun Jul 10, 2022 3:25 pm ... There is no such thing as "absolute color", but there are such things as "absolute wavelengths".

Ann, just in good fun -- or to be another thorn in your side --

Ahh, Mr. Doppler, that's an interesting phenomenon ...

I wonder, if, as it approaches its Roche limit, will it perhaps begin to rotate? Why would it? Once it starts to break up the individual pieces will assume their own rotations, with the total angular momentum conserved, of course. Capture1.png I'm just looking at this image from the Wikipedia "...

and the explanation about the name of the mountain (in Italian : Sella del Diavolo) is not the good one. See Wikipedia italian : https://it.wikipedia.org/wiki/Sella_del_Diavolo I fail to see the problem. The Italian Wikipedia page says the same thing, that the structure is named for its resemblance...

I missed answering this part. As the description states, the dashed lines are extended exposure times so that the sun trails instead of just forming a dot. The intermittent dark regions within trails are clouds blocking the sun. Thanks for this and your prior response, but I still don't get it. Wer...

I wonder, if, as it approaches its Roche limit, will it perhaps begin to rotate?

A wonderful and opportune composition! We discussed this once years ago. It was clear that you'd need different exposures to show all of the planets at once (for reasons Chris posted above). But I wondered if such an alignment was possible more than once in a person's lifetime. It's not as tightly a...