Starship Asterisk*

How did they count the 2 million galaxies in the image? Did they count in a small square and extrapolate to the rest of the image? No, they actually counted them individually. Astronomical images are routinely analyzed with special software tools that extract a list of all objects, and which can di...

A stupid question perhaps - but the center star of "the Belt" has a blue dot in the center of the corona. None of the other stars has that. Is it because the star is so much brighter that it's burned in, or because there is a fortuitous eclipse happening, or am I missing the point? It is ...

What are the three vertical lines? I don't think they could be satalite tracks due to the position of the STEREO A spacecraft that took the picture. Are they artifacts from the camera? They look like blooming artifacts. These result from electrons bleeding along CCD columns from oversaturated pixel...

I think the sky in that photo is orange from the setting sun in the western sky, which means that the sun is in front of the camera, so what's shinning on the moon to make it full? When you are facing a full Moon, the Sun is behind you. If you think that a sunset (or sunrise) can't make the opposit...

Chris Peterson: Thank you for a reasonably clear and explanatory response. I have only done a little work with optics, I know my understanding is minimal. Why do they have to be point sources? Or is that just a relative term? Why do you say a gravitational lens is so different from an ordinary one?...

Suppose there were a neutron star, or maybe even a black hole somewhere near the visual center of that group. Then, suppose there may be some other objects between us and that thing. Wouldn't an observer see something much like that? No. Gravitational lensing doesn't produce point sources. Opticall...

I find this very interesting, if this cosmic radiation is deflected around us by our planets magnetic field(protecting us from being burnt to oblivion, but also putting on a spectacular light show in the northern regions of our planet),I always wonder, is it possible to harness this tremendous powe...

According to a wiki entry on the topic it can happen both during spring and autumn, signots. In spring it happens after the evening twilight while in autumn it happens before the morning twilight. From a dark site it is visible year round. It's simply more prominent near the equinoxes. The bottom i...

Think of ALL the smaller objects that are so heavily cratered, but they have very little gravity to cause the hyper velocity speeds. The gravity of an object doesn't determine the collision speed, but the minimum collision speed. The dynamics of the all the objects in the Solar System mean that col...

craterchains wrote:uh huh, , , :roll: explain Hyperion then, , FOCLMAO :P

Explain what?

Personaly I think these craters, for the most part, are caused by weapons. You're joking, right? The craters are just exactly as you would expect for high velocity collisions, which are the only kind of collisions possible on a body with any significant gravitational field. Very little of the origi...

“Explosion-like” only if there is something to make it explosive, impact is just that, an impact. There's nothing wrong with calling it an explosion- that's what a high speed impact produces. An explosion is just a rapid release of energy; it doesn't matter if the cause is chemical, nuclear, or kin...

sniezynka wrote:Anyone have more photos of this event?

http://spaceweather.com/meteors/gallery_01sep07.htm
http://www.cloudbait.com/science/aurigid2007.html

Bodies of water are not necessary for a triple rainbow. I have observed the phenomenom in the desert of Arizona on Hwy 89 between Tuba City and Paige. No, but each rainbow needs a light source behind the observer and in line with its center. Usually there's only one source, the Sun, so to have mult...

There's no reason that the workings of the Universe have to make sense to us on some intuitive level. One of the axioms of science is that if the axioms are not true we can't know anything. You may be correct, but if you are then the universe runs on magic and/or religion and there is no point in p...

Ok, let's say we had a big bang when time and matter came into existence. What was before that? The question is meaningless, because no time means no "before". Ok, so what caused the big bang? I don't think anybody is ready to give up cause and effect, because that would mean magic was in...

Can someone explain why the periferial stars are streaked away from the center ant the central stars are not streaked? Most likely this is caused by a combination of poor tracking (or no tracking) and field rotation. You get field rotation when you don't use a mount that rotates with the sky. It lo...

I once saw an amazing atmospheric display of sun halos while skiing at Alta one sunny day. I realize this phenomena has to do with ice crystals in the air lined up in a certain way, but the patterns looked similar in that there were reverse arcs among other bizarre rainbow patterns. Could there hav...

My point is that it is impossible for the visible lake in the left front to be the source, as it is not in line. Lets ask the photgrapher to turn around, so we can see the lake behind him. That's true. But the lake to the left of the camera is where the reflection is coming from (the Sun is behind ...

I think the second set of rainbows is caused by reflection off part of the lake behind the camera. This must be the case, as rainbows can only be observed when in-line with the light rays. As we can assume that the reflecting surface of the lake is horizontal, the only surfaces which can be candita...

The correct, anatomical name for your thumb is 'pollux'. But you call it a thumb. A surgeon would too, though they would use 'pollucis' (of the thumb) of the muscles that move the thumb. But thumb doesn't also carry a meaning that is otherwise contrary to modern medicine. If the term had been inven...

I think that scorpio is allowable since it IS a zodiacle constellation Of course, it's a matter of opinion whether Scorpio is an allowable synonym for Scorpius . But it shouldn't be based on the fact that the constellation is Zodiacal. Zodiacal just means that it is one of the twelve (really thirte...

I regularly have to correct people when they call me an astrologer instead of astronomer, and now APOD decides to call the constellation Scorpius by its astrological name, Scorpio . What were you thinking? (I know that Scorpio is sometimes considered synonymous with Scorpius , but it goes against as...

That, in a nutshell, is the problem of the 21st century. How do we know to "believe" in quarks but not in the secret military programs of small dictatorial regimes? In brief, how do we handle the verb "believe"? Like many other words, it has different meanings in different conte...

It will be different stars from Canada. Only a little bit: the difference is under 3°; the Moon stayed in Aquarius. Yes, but the pictures are oriented with respect to the horizon. So what's above the Moon in Canada is below it in Antarctica. The stars seen above the Moon are in completely different...