Starship Asterisk*

<<"Now, here is the really neat part: all objects accelerate to the Earth at exactly the same rate given the same distance from the Earths center. In other words, even the Moon is accelerating towards the Earth at a rate that is appropriate for its distance from the Earth's center! If another ...

I was thinking that since the moons are traveling at Jupiter's velocity around the sun that they would tend to move away from the sun's gravity due to their lower mass reaching relative escape velocity. When the mass of the orbiting body is much less than the mass of the central body, mass can be i...

We know what gravity can do, but! we do not know what gravity is. What gravity is may be a meaningless question. It is defined by what it does, and that we understand very well. Indeed, under GR, what gravity actually is happens to be well understood as a distortion of spacetime. So it's very likel...

When was the last time "non-baryonic particles" were needed to explain an observed phenomenon? Has any non-baryonic matter ever been observed else where in our universe? That dark matter exists is virtually certain. And current theory (well supported by observation) strongly favors non-ba...

Chances are that our lack of knowledge is a greater suspect. Our history of science clearly supports this conclusion. I would argue that our history of science, with respect to fundamental physical laws, shows that we have seldom been wrong. Once the process of understanding nature was approached s...

harry wrote:Now! don't you think that definition is a bit odd?

No. It seems quite reasonable, and is accepted by 100% of the scientific community. The definitions are based solidly on observation, not on theory.

Please explain the difference btween Dark Matter and dark energy. Dark matter is material (matter <g>) that is invisible (has little or no interaction with electromagnetic radiation) but exhibits obvious gravitational effects on normal matter. Its existence is widely accepted due to close correspon...

G'day Chris Upto this date I have not seen one person, being all read up. If you are, than please explain to me the formation of Neutron Stars and the transition to ultra dense plasma matter that has a trapping horizon. That's a separate discussion. All I asked is that if you disagree with somethin...

harry wrote:G'day from the land of ozzzzz

My point is that you need to read up on the topic.

Thats up to you.

Okay. I'm all read up. My previous observations remain unchanged.

G'day Chris Your statement tells me that you need to read up... Sorry, I fail to see the relevance of any of these citations to your speculations about dark matter. If you have a point to make, you need to present your argument and provide a specific citation that supports it. If you feel that some...

What about if all the dark matter and dark energy was in the form of degerate matter found in ultra dense plasma matter located in compact stars such as Neutron Stars, quark stars and dark stars (black holes). First of all, the only things dark matter and dark energy have in common are the word &qu...

There is also a good chance that we have gravity wrong once again and there is no "unkown matter". :oops: I think there's only a very small chance we got gravity that wrong. We see many different types of evidence, both near and far, that gravity behaves the way GR predicts. Dark matter i...

There are four fuzzy areas in the picture, top and bottom near the center and top and bottom further right. What is the cause of these areas. Since they are placed top and bottom it seems to me that they are likely to be artifacts rather than of astronomical significance. Does anyone out there know...

What is it? Nobody knows for sure. Dark matter is currently defined in terms of its properties, particularly its mass. That definition doesn't require that much be known about its other physical properties. Beyond its observable behavior, there are a number of theories about more specific propertie...

The exposure for the stars must have been long enough for the camera to need to move, or trails would be visible. So how is that there are no stars seen 'through' the edges of the stone arch, only recorded during a brief flash?John Aesthetically, I find this image quite ugly. And part of the reason...

What does this mean? What is dark matter by their definition? No one knows or defined dark matter. Dark matter is well defined, as the property or material responsible for a number of effects that are observable (so far) anomalous gravitational effects on visible matter. There are various theories ...

I woke up at about 4am (mountain time) to let the dog out. While standing in the backyard I couldnt help noticing something strange in the sky. It appeared to be a "bigger than average" size star, very, very bright. It was blinking/twinkling and changing colors. Almost certainly you were ...

Re: lunar ranging. Can someone provide a calculated or estimated value for how much higher the intensity of the light received would be (per unit surface) if the detector were near the center of the returning beam ? Just estimating, but I'd say there's little difference. The beam has lost coherency...

Hi all, Just a complaint about the text under the APOD for today. It says that " Today is an equinox, a date when day and night are equal. ". This is NOT correct. If the Earth did not have an atmosphere, it would be correct. It would be wrong even in the absence of an atmosphere, because ...

http://arxiv.org/abs/astro-ph/0702671 Do Black Holes End up as Quark Stars ? What part really is non scientific? My assessment of the paper is that the author is not a crackpot (quite a few self-published cosmologists are), but that the paper is weak. That's because some important arguments are bas...

Gee, I guess if someone has a good idea they have to give it to someone else to write-up, as they are excluded from being considered due to lack of membership within the clique of acceptable people. Science is a process of consensus. Radical new ideas occasionally alter mainstream thinking, but for...

I came across this link: http://arxiv.org/abs/astro-ph/0702671 How to evaluate a paper like this: It is self-published, with no peer review; The author has no peer reviewed publication history; The author self-published, in close succession, three papers covering nearly identical subject matter; Th...

I am curious… Does anybody know why the moon is situated the way it is? By that I mean that its orbit is tilted about 5 degrees from the ecliptic with the earth tilted roughly 23 degrees in its rotation to the ecliptic. Everything in the Solar System (inside the Oort Cloud) is largely on the plane ...

Black holes are only visible when they're eating. That's not really true. Black holes only produce photons when something falls into them, so if you limit "visible" to that, I'd agree. But they also have the same sort of properties that normal matter has, in that they can be charged or ha...

Could dark matter possibly be clouds of extremely small black holes? Atomic particle sized black holes would not interact with normal matter except for gravity. Furthermore, the cloud should be invisible. Why do you say this? Black holes interact normally with matter: they can have an electric char...