Starship Asterisk*

... In detail, I attempted to answer this question last year for Omega Centauri. ... The results were interesting and impressive. ... Imagine looking up and seeing visible stellar densities exceeding the Pleiades everywhere! ... Thanks, alter-ego. I would love to have someone perform this simulatio...

I don't think we have yet thought of any way that, by simple astronomical observation, we could expect to see signs of intelligent life from immense distances. In our own case, humanity has not yet done anything on or around Earth that humanity could see from a distance of over 1000 light years, agr...

This is one beautiful APOD. I was struck by the video that neufer posted. It appears that the coronal mass ejection was accompanied by an opposite ejection as well. Is this common? I wonder about the mechanism of an ejection, and why it would occur on opposite sides of the Sun. What very little I kn...

Of course it's always mis-guided to kill the MESSENGER.

I've seen mention that astronauts are at risk from the Sun's rays, as they are outside of the protective ozone layer and any other radiation-dampening layers. Not having been one, I wonder if it affects their "daily life" in any significant way. For example, staying away from the windows a...

So, if Arnold is coming up on you and he starts to block out the sun, the edge of his shadow across your face is the Terminator's terminator ?

Barely total or barely partial, we may never know. I'm not sure about that. It depends on definitions. Normally, we would ignore the effects of the atmosphere, and simply consider the geometry. That can be done rigorously. I suspect this was actually a total eclipse from a geometrical standpoint, b...

... Has anyone (okay, a group project, unless it's from space) ever observed auroras at both poles simultaneously? Is there any correlation? ... Here's a bit of an answer I found to my own question: http://www.aurorasaurus.org/ . Though currently, they seem focused on the Aurora Borealis, I'm hopin...

What a fantastic aurora shot! Of course one would think of a flag or curtain, but I'm also struck, for the first time ever on viewing an aurora photo, of the relationship to a rainbow! Although the source of the phenomenon is so totally different, one can definitely see a progression here from purpl...

In today's APOD, why does the dark portion of the moon get darker as one approaches the terminator ?

Love this APOD! Also, thanks alter-ego for posting that amazing simulation of the upcoming eclipse.
Perhaps I can beat neufer with a post of:

Of course Merak and Dubhe do not point to Polaris in true 3-D. It would be just too much of a coincidence to hope for. On the other hand, since the distances do increase as one goes from Merak to Dubhe to Polaris (Wikipedia is saying 80 LY, 123 LY, and 433 LY). Then I suppose it is not as far from l...

. . . Also, why are there many fairly straight lines emanating from very near the Caloris Basin's center? Rebound effects after the impact? Those lines are very interesting. They do not all emanate from the center of the crater. The crater has been named Apollodorus , and the overall feature the Pa...

I admit that I while I spend a lot of time in a variety of deserts and have seen a lot of dust devils, all the ones I've seen have been more or less the same color as the dust they're deviling. So, why on a reddish brown planet and on arguably brown soil is that dust devil white? Another factor to ...

One of the links ("local denizen") shows a lot more images. One sequence appears to be an artist's animation, but the others appear to be video made from a sequence of images of this dust devil. If that is correct, the track is faint, but the devil is proceeding down and to the right over ...

This image is great, but the video in the link is more amazing still. As I view the video, it appears that the cloud was stable even as a lot of air moved through the location. It looked much like an eddy in a stream that keeps bubbles floating on top in a stable location even as a great deal of wat...

. . . Which brings up another phenomenon - that the bright crescent appears larger, out of proportion, to the rest of the moon? My wife commented on it the other night. It's more apparent "live" but some photos also seem to appear that way. Wonder why? There is the following : http://blog...

What is the thin dark line extending nearly half way across the image, starting on the left edge and splitting one of the brighter stars as it heads diagonally upwards? A satellite trail I assume, but wondering if anyone knows for sure. Thanks for pointing that out, I would have missed it ! But now...

All's fair in this image !
Especially Venus, with so many radiating lines.

The images are tantalizing, but not nearly as clear and with enough resolution as one would like. Is it significant that there is also a gray region all along that portion of Mars at the same time as the plume is seen at the terminus? Is that a cloud that came from the plumes and then extended very ...

I wonder if an image of the three bodies would be able to show a difference in the phases. I know that even if they all look right in line at some point, Mars will be farther away from and Venus closer to the Sun than the Moon, so they should not have identical crescents. But I wonder how subtle the...

. . . diffraction spikes . . . Occasionally observers use this effect deliberately; I've seen pictures of the faint companion of Sirius where diffraction spikes were added by putting a mask in front of the telescope aperture, moving the scattered light away from the faint companion; and also seen i...

Ahem, something called a DWARF is called Texas-sized??? :ssmile: Sticking to metric units favored by the scientifically inclined, the Wikipedia link on Ceres shows that it has a mean radius of 476 km, so it's diameter is about 952 km. TEXAS, on the other hand is 1,244 km wide (East-West) x 1,270 km...

Dry ice.

. . . REMS Monitoring Station, Planet Mars... Plus 2 C (http://mars.jpl.nasa.gov/msl/mission/instruments/environsensors/rems/) Some of us were just born on the wrong planet... :) Thanks for sharing that. A balmy day on Mars? On the other hand, the low tonight will evidently be about -72 C. :(