Starship Asterisk*

"Nothing can travel faster than the speed of light" is really an oversimplification. The actual rule has to do with causality: the distance in time and space that two events can be separated and still affect one another. There is nothing that says the Universe itself can't expand at a rat...

No, the observable Universe is much larger: about 91 billion ly across. That's because it's been expanding for the entire 13.7 billion years of its existence. I don't understand this. If nothing can travel faster than the speed of light, then something traveling away from the big bang could have go...

I have always wondered why these terrifically distant objects aren't really much farther away at the present. If this cluster is 9 billion LY away, what has it been doing in the 9 billion years since the light left? Assuming (not a good assumption, likely) that it's been receding at a similar pace ...

What's that little blob about a third of the way from the left, near the bottom of the picture? Looks like a flatworm or maybe a small star exploding.

[attachment=0]Little Nova.jpg[/attachment]

Is the reddish hue possibly due to dust blown off from Mars itself? The white streaks from the large crater are intriguing as well. Could that indicate a thin layer of dust or merely ejecta from the impact or ...?

http://apod.nasa.gov/apod/ap070415.html I'm curious about why there are at least 2 groups of RR Lyrae variable stars that appear to be highly synchronized. Could such a group be one star lensed by something inbetween us and them? Could they have formed simultaneously in close proximity and drifted a...

Why does the apparent brightness of the asteroid 2006 VV2 change so dramatically along its tragectory? It's hard to imagine that the exposure varies that much. Does it pass through the Earth's shadow?

But can we really tell if their trajectories are less vertical near the edge of the spot because they just happen to be, or because they initially have less kinetic energy? One things for sure: I should learn more about sunspots. APOD has a lot of very interesting images of solar flare activity. Th...

I found another picture: ftp://eol.jsc.nasa.gov/ESC_large_ISS013_ISS013-E-56495.JPG which shows the same pixel flaw at exactly the same position and here you can see without any contrast enhancements that the contrail-like stripe is running from x = 817 down to 2006! Interesting. The above image ha...

I found the same flaw at the same place on ftp://eol.jsc.nasa.gov/ESC_large_ISS013_ISS013-E-54677.JPG This image also shows the mysterious "contrail" going straight towards the bottom of the picture from the spot at 1137/818. There are more than a few other spots as well. The fact that thi...

It's at pixel 1137/818 (from upper left) in both frames. Seems too much of a coincidence to be external. It is bluish and the intensity is quite different in the 2 frames and the adjacent pixels (reflecting the same object) are also somewhat different so it isn't a single defective pixel. Are there ...

Clearly not a star. My guess is a man-made satellite of some sort. Expanding the pixels shows that it is larger than one pixel and quite "blue" (hence fairly far away).

I am intrigued by the statement in the Oct 25 APOD: "The expanding shell from this explosion now spans 80 light-years and has swept up about 600 Suns worth of mass." How is this "swept up mass" estimated? Is there perhaps a deceleration of the ejected matter that can be observed?...

I too wonder about this assumption. I read the link from the APOD description but it didn't explain the physics of this. Conservation of momentum would require that accretion -decrease-, as opposed to increase, spin. However, I suppose that if the accretion resulted in a tangentially directed releas...