Starship Asterisk*

And yet... there is a medium in space, and sound does travel through it. All those fantastic nebula and SNR remnant images we see on this forum look as they do because of the passage of sound through them. That is the primary mechanism that forms their structure. The Moon makes a sound that carries...

red sprites[/url] may start as 100-meter balls of ionized air that shoot down from about 80-km high at 10 percent the speed of light As Chris and Art point out it is the ionization charge that moves at 0.1c, not the ionized air molecules themselves. Consider the orientation of the linear features o...

If those small blue galaxies are satellites of M 109, then they aredominated by stars that are much younger than the stars that dominate M 109. The mass-to-ligt ratio is much higher for old yellow stars than for young blue ones: in other words, you get a lot of "oomph" for the mass of you...

http://apod.nasa.gov/apod/calendar/S_130301.jpg Colors of Mercury Mercury's large, circular, tan colored feature known as the Caloris basin was created by an impacting comet or asteroid during the solar system's early years . The ancient basin was subsequently flooded with lava from volcanic activi...

I noticed that the sun appears to be tracing a curved path. I wonder if that is due to the use of a wide-angle lens? Or was the camera moved during totality? The path prior to totality seems somewhat straight, and after totality also somewhat straight, although less-so, so that in replacing the cam...

potoole wrote:Can someone provide a sense of scale? I'm guessing this shot is about the diameter of the Earth, is that about right?

And how fast are these clouds moving?

"The polar ice deposits imaged by Earth-based radar are in yellow." When I first saw the image I had assumed that the radar that discovered the ice in craters at the north pole of Mercury was "Messenger-based", not "Earth-based". I wonder how an Earth-based radar could ...

I cannot help but think of this little bit of verse when seeing an image of Jupiter and Io: http://www.baltastro.org/AstroPoetry.html#JupiterAndTen :-D I agree. "Jupiter and Ten" sounds considerably more frustratingly fascinating than "Jupiter and Io" (Jupiter and IO?) Ann Remin...

I noticed that the sun appears to be tracing a curved path. I wonder if that is due to the use of a wide-angle lens? Or was the camera moved during totality? The path prior to totality seems somewhat straight, and after totality also somewhat straight, although less-so, so that in replacing the came...

Check out the APOD's of May 5, 2006 and May 23, 2008. Can someone tell me how it is that "climate change" on Jupiter occurs without humans present? Or are there Jovian SUV's floating around in that hostile atmosphere? Of course not all climate change is due to human causes. However, when ...

Human global warming is already having a strong & noticeable impact on warming our cold Arctic region (as predicted). The arctic is warming, but so too are the tropics. I sumbit that the difference in the rates of warming between them is the issue here regarding increasing or decreasing winds.....

one defining point of a Black Hole is...it shrinks down to a Singularity. A Star is not a singularity as far as I know. :---[===]* I for one don't buy into the suposed singularity of black holes. But I'm no specialist. I'm not saying they aren't real, something is definitley there, but I don't thin...

In this image (and others too) some stars appear not as points of light but show an extent, as if they are large enough to subtend an angle. I believe that Rigel's diameter is around .7 AU or roughly 11 light minutes. Given that the Witch Head Nebula in the image is estimated to be 50 light years ac...

I have seen so many pictures of star trails. (This is a nice one.) I, who have no real equipment, would like to do something a little different. That would be to take an extended time lapse photo of the NCP, but have the camera fixed (adjusted by tracking motor) to reduce the stars to just mere poi...

A perturbation mechanism that turns many orbiting Oort bodies into (virtually angular momentum dead ) comets but one that doesn't (at the same time) scatter the vast majority of Oort bodies out into interstellar space is the mystery :!: I fear you may be thinking that a highly eccentric orbit (such...

134 m/s is not a tiny delta-V :!: But that isn't the delta-V required to put a distant Oort body into a parabolic orbit. Yes it is. No, it's not... Given an object in a circular orbit, ANY delta-V will result in an either an elliptical or parabolic (if the change is great enough to exceed excape ve...

... This lack of Sun caused winter . ... This abundance of Sun caused summer . ... No doubt the duty cycle of the sun is important in causing winter and summer, but also important is the difference in angle of incidence of sunlight. In the winter, not only is the sun visible for less time each day,...

Strange name, Glenelg. It is the same backwards. There must be a story behind this. A Ray Bradbury story? From http://www.nasa.gov/mission_pages/msl/multimedia/pia16065b.html : The science team thought the name Glenelg was appropriate because, if Curiosity traveled there, it would visit the area tw...

REST ASSURED: The universe is infinite. Thanks for the assurance. But you can probably tell that I'm not all that assured. Finite but unbounded is the generally accepted belief. Just as the 2-dimensional surface of a sphere is finite in area (but has no end or boundary), the 3-dimensional volume of...

REST ASSURED: The universe is infinite. Thanks for the assurance. But you can probably tell that I'm not all that assured. Finite but unbounded is the generally accepted belief. Just as the 2-dimensional surface of a sphere is finite in area (but has no end or boundary), the 3-dimensional volume of...

The skeptic poses a complex question of how, even given billions of years, a single cell could develop into a complicated human body that thinks and feels. In my view the leap from no cells to one cell is greater than the leap from one cell to a human. But that doesn't prevent me from believing tha...

Guest76 wrote: The only way it could be inevitable is if the universe is infinite, and then you could say, 'life had to happen somewhere, and we're it'. But the universe does not seem to be infinite. How do you know that the universe isn't infinite? Ann I believe that the current view is that the u...

Researchers write book using DNA By Hristio Boytchev, Washington Post: August 19 Researchers have encoded a full book in DNA, the largest amount of information stored on the biological medium yet. Think that's good? Leonard Adleman (The A in RSA) has used DNA (and related chemical processes) to enc...

Lessee, shoot a 4-ton 9-ft high x 14-ft diameter over 350 million miles, then drop a one-ton semi-autonomous nuclear-powered ATV on target in working condition 13.8 light-minutes away? No problem. What's even more amazing: http://www.nasa.gov/images/content/673734main_PIA15978-43_516-387.jpg Curios...

So all the big planets in our solar system - Jupiter, Saturn, Uranus and Neptune - have rings. I wonder: Are all the rings equatorial ? They certainly seem so from all the images I've seen of the rings of Saturn and the banding of the clouds... Further, all the rings seem to be in the same plane. I ...