Starship Asterisk*

I don't understand the relationship between North and East in the "complementary annotated image." Is it just an ordinary optical inversion? I thought these things were corrected as a matter of course.

Fortunately...humanity is advanced enough to have a spacecraft that can see the rings during equinox from the side.

So that's an earmark of how advanced humanity is: coulda fooled me.

Beautiful picture of the Shuttle and the Hubble Telescope against an almost perfectly bald and smooth Sun - there is a small spot around 7 o'clock from the Shuttle. Is the Sun unusually quiet for this part of its cycle (or not)?

The wave of star formation following a collision I can understand, but by what mechanism is the middle of a galaxy emptied?

The caption explains: "This newly released raw image shows at least one type of false artifact, however, as seeming chains of craters are not so evident in other concurrently released images of the same region." How are they false artifacts? They are all different lengths and slightly curv...

This isn't material ejected from the star. It's interstellar material being pushed outward by the radiation pressure and stellar wind. This occurs at the heliopause. In the direction of motion, the build-up is usually greatest, creating a bow shock, but that is not the case here, apparently because...

"But measurements have shown the [Wolf-Rayet] star is not really moving directly toward the bright edge." Wouldn't it be reasonable to assume that the star was moving away from the direction in which it had ejected the most material, as a simple consequence of action-reaction?

But but guys, that helicoid-looking cloud is really interesting! Is this a well-known phenomenon?

Is that a helicoid cloud in the right half of the photo?

My friend was inspired to write this poem after seeing Monday's APOD. If any lawyers are lurking, I have Blad Hansen's permission to post it. =============================== Prayer For New Physics ... by grace of Parity and Mind's photo-electric, virtual clarity..... We pray for fields where are no ...

The visual impact of this photo is fantastic, combining the eeriness of Piranesi's Carceri with the sharp, symmetrical perspective of some modern action comics.

"Visible on the hot and barren planet are many craters, many appeared to be less shallow than similarly sized craters on the Moon. The comparatively high gravity of Mercury helps flatten tall structures like high crater walls." I don't understand. If the crater walls are flattened, would't...

It has struck my slow mind that the APOD picture is labelled IMG_2287.jpg in McVay's gallery, whereas the darker picture is labelled IMG_2288.jpg. While it isn't 100 percent certain, chances are the lighter picture was taken before the darker one, in which case both would have been after sunset - an...

Now, I'll hazard a guess that it's another aurora that was caught in the image, and it just so happens to bear an uncanny resemblance to a comet. As others have postulated, if it were an actual comet, we'd have heard/read about it on the many other space/astronomy websites that are out there. And b...

If you click on the link to Lance McVay's site in the APOD page, and then click on "Night Photography", you will find in the (terrific!) gallery two pictures of the same scene, both dated 4 October 2007. One of them is the one we have all just seen; the other is slightly darker and presuma...

Okay, a "false dawn" isn't a dawn by self-definition, so "false dawn" is obviously a metaphorical term applied to a phenomenon. Yet the phrase "Once considered a false dawn" implies that people who used the term were misguided. Surely the phenomenon was just called a fa...

Like many other words, it ["believe"] has different meanings in different contexts. I don't see it as a problem, except that the lay public doesn't usually understand what it means in the context of science. Scientists "believe" something when good theories support it. This beli...

I guess it depends on what you mean by "observable". By your definition, perhaps you don't believe in electrons, quarks, or even other galaxies. These are all observed indirectly. Likewise for the geometry of the Universe. That, in a nutshell, is the problem of the 21st century. How do we...

SmartAZ wrote:I guess I understand the 4D universe concept as well as anybody, which is to say zero equals zero.

When I asked him about higher dimensions in his last year at Princeton, Emil Artin told me that visualizing space up to six dimensions was "Easy! After that it is difficult."

I'm not sure "matter" is what banged at the big one, at least not immediately, but the question is interesting. Where are all the cosmologists? We want opinions!

Yes it's beautiful. But despite what APOD and Wikipedia say, it should be Serpentis Cauda (and Serpentis Caput).

That is a splendid time-lapse image of the lunar eclipse. If the shots were really taken at 4-minute intervals, the picture can give students an idea of what a degree looks like in the sky. But the great discovery, for me, was Yuichi Takasaka's website (just click on his name under the APOD pic). Th...

I understand encounters between galaxies - even head-on collisions - involve such tenuous structures that anyone living on a planet in one of the galaxies wouldn't notice anything special was happening. But there is contact between dust and molecular clouds, fields, and so forth. So on reading about...

When I looked at the picture of the hydrocarbon sea on Titan, I reached for a tissue and wiped my monitor because I thought there was a track of dust across the screen left over from a previous cleaning. But no: it's a very straight, though fuzzy, line crossing the sea at about 7 degrees (counterclo...

So it's been a week. No astronomy question I have asked before has gone so long unanswered. If my question is stupid or formally unanswerable you can say so, my morale is high today.