Starship Asterisk*

I truly enjoyed the spelling exposition on the use of the "u" in vario(u)s words in the English language. As a Brit I tend to object to some substitions of "f" instead of "ph", for example in the word "sulfur." On the other hand, with the huge contribution to ...

A very interesting image. Despite the comment that by chance co-central impact craters might occur, for no justifiable reason I verge towards the alternative idea that the secondary ring is the result of an upwelling resulting from the primary impact.

http://apod.nasa.gov/apod/ap091007.html

The post also refers to the "Moon close to the horizon" illusion, which makes people think that the Moon appears larger than when it is high in the sky. An easy way to show that the illusion is not fact is to stretch ones arm out so that one's thumbnail is visible. The angular size of one'...

There are certainly unstable regions within the rings- that's why the structure is so complex, with its gaps and density variations. It seems perfectly reasonable that right at boundaries between stable and unstable zones you should see odd effects, such as the frills you mention. I don't see how t...

My only beef would be that sometimes too many of the links go to 'Wikipedia', which as we all know can be subject to questionable editing..... On the whole, however, Wikipedia is an extremely good source for scientific information. I'd trust its science articles over what you would find in an edite...

I wish to thank Chris Peterson, of the Cloudbait Observatory, for his explanatory observations, which I find most valuable. There is, however, a further comment I would like to make on the stability in the long term of the ring system around Saturn. As has been noted in at least one previous APOD co...

My understanding (shored-up by last night's repeat of The Universe) is that orbital mechanics sufficiently explain why the particles keep from coaslescing. The particles at different distances from the planet simply orbit at different speeds. I've always wanted to see a time lapse of the rings to m...

I find this magnificent composite photograph extremely difficult to interpret. I presume that the ring system and the accompanying shepherd moonlets are coplanar, so that at equinox they contribute a single dark line of shadow on the upper Saturnian cloud layer. Underneath what I interpret as this l...

One interesting factor about this stunning picture is that, since the Sun is so distant from Neptune and therefore has a much smaller angular diameter than our half a degree, each of the moons produces a total solar eclipse on the top of the Neptune's cloud layer. For historical reasons, the term &...

One interesting factor about this stunning picture is that, since the Sun is so distant from Neptune and therefore has a much smaller angular diameter than our half a degree, each of the moons produces a total solar eclipse on the top of the Neptune's cloud layer.