Astronomy and Cosmology

hello my dear science fellas, many questions have been tangled my mind since quite a time.here it goes: take a rope and swing it or keep swirling it for days together, you will see wear and tear in it, but why does earth see wear and tear though it revolves and rotates at moderately high speed and have keep doing it for years together. and even earth faces air friction due to the atmosphere around it. any help here??

Hello everyone I don't want to waste anybodies time so I will get straight to the point. I have been working through a book written by Peter Duffett-Smith called Practical Astronomy with your calculator (Third Edition). I am writing a computer program based on the algorithms detailed in this book. Unfortunately I have now run into a problem. Is there anybody on this forum that is familiar with this book? If so, perhaps I could detail my problem and maybe you could help. If not, sorry for wasting peoples time. Many thanks Nikki

I appologize in advance if this topic has been discussed before in this forum. If it has, I have not encountered it. A "dedicated enemy of Einstein and Relativity Theory" - whom I believe some of you already know, his name is Tsolkas - has recently claimed to have explained the precission of Mercury's perihelion by the fact that the sun itself orbits around the barycentre of the solar system. He claims that nobody else, from Leverrier to nowdays, did ever take into account this fact, and that "all astronomers before...him ("Tsolkas Magnus") always considered the solar system's barycentre as essentially identical with that of the sun"! It would be a waste of time t…

im not sure if this has ever been though about before, but i was doing some thinking about where everything came from, and i was wondering what if there was a law saying that there can not be nothing, so upon the being of nothing, the universe will create something out of nothing to fill that space. Im not sure if it makes sense i just know that people have never been able to have a space truly filled with nothing, and i just though that seemed relevant.

Consider a perfect (diamond) crystal lattice of carbon. Incident neutrinos would "alchemize" the C --> N. And, the N would induce defects, in the crystal lattice, which could be detected, e.g. w/ STEMs. Thus, could you not create a "solid state" neutrino detector, and simply expose it to some neutrino source; wait a while; then come back and "count the defects", divide by the detection time, and so have a neutrino detector ??

A naked-eye observer who tracks the rise and set position of the moon on the horizon will see that for half a "month" the position moves farther south each day and then for another half "month" moves farther north each day. How long is this "month"?

Please ponder the following "beta-decay" reaction: [math]p^{+} + \bar{\nu}_e \rightarrow n^0 + e^{+}[/math] So, if you propelled a powerful beam, of anti-neutrinos [math]\bar{\nu}_e[/math], into a star, then would you convert protons to neutrons? And, then, would those neutrons not fuse, with remaining protons, ultimately into helium nuclei?? So, could you not "stimulate" fusion, inside stars, and produce powerful "pulses" of helium production, i.e. generating an artificially-induced super-novae explosion (possibly powered by positron-electron annihilations too) ??

Could it be like a gas existing in a state below absolute zero? I undestand scientists are mapping dark matter using it's light bending properties. I was wondering if neutrinos past through without bending. And/or protons and/or quarks.

Hello, I have been using this online converter that stops at the year 2011 but mostly 2012. Here:http://www.exploratorium.edu/ronh/age/ I have been asking my friends and they have seen the same thing. I enter birth dates to check ages on other worlds and etc, then I noticed it froze after a birth date of the year 2011 or 2012.. As I know there are many people here with an outstanding credibility and good reputation, I am sure you can give me some knowledge as to what is going on here.. I have also been seen in many astronomical programs including my own that the sun is placed in every "other" constellation. Example when it should be in Saggitarius it i…

According to String Theory, all matter is composed of vibrating "strings". What are the size and dimensions of a string? I suppose they are 2 dimensional with no thickness, only length, as the name implies. How long would the string be in Planck Lengths? (A Planck length is approx 10^-20 of the diameter of a proton.)

possibilities: if you were going to travel to the past and visit yourself in lets say new year's 2005. you would see yourself before you even travel back in time because in the future you time traveled back to yourself so for the traveler you see yourself when you were younger and to the person who has not traveled[ which is still you] would see you as an older self. Impossibilities: if you wanted to pass away deliberately [A.K.A suicidal person] a different way than usual lets say you travel back in time 10 minutes then you drown your past self that would not be possible because you died 10 minutes earlier so you would not have a chance to go back in time[ even …

This astronomy/ cosmology news article seems appropriate for this forum to discuss. Strange New "Species" of Ultra-Red Galaxy Discovered http://www.scienceda...11201125358.htm] We can discuss mainstream interpretations of these galaxy observations on this thread or discuss alternative interpretations/ speculations Here.

Could you build a big "cargo-net", of metal cables, to create a radio-reflective "rigging", which could be adjusted, similar to the sails of ships ?? For, if suspension bridges can be built, with vaguely similar "riggings", of metal cables, spanning distances of many km; then one could plausibly build radio "net" antennae many miles across. And, such a "rigging" of cable "netting" could be adjusted, to reshape the "net", and thereby steer the aperture.

I read not long ago a couple of articles about water vapor in space trapping radiation resulting in star formation. I was wondering if/or when a sun sized star ignited if the outward flow of preasure could cause some of the escaping water vapor to become liquid? and if so could this liquid water cool down plasma enough to cause it to reform into dust?

Does plasma ever turn into dust? Hey stop laughing, there's no supid questions right?

If bosons tend (slightly) to "inclusively" associate (even as fermions tend (strongly) to "exclusively" dissociate); then, if, along some earth-bound sight-line, some foreground object were to "add its (new) light to" older, already earth-bound light, from background objects; then, might not all those "over-lapping" photons tend to "bosonically cluster" ??? Could such a "photon clustering" phenomena help infer redshifts, of foreground objects ???

Nuclear Star Clusters resemble massive Globular Clusters, residing in the cores of small galaxies (Ho. Galaxy Formation & Evolution). NSCs, in low-mass galaxies, are associated with surface-brightness 'cusps', having 'disky' isophotes, and evidencing weak rotation. High-mass galaxies tend to host SMBHs, instead of NSCs (Mason. Astrophysics Update 2, p.180). According to 'Hierarchical Structure Formation', small proto-galaxies merge, to make larger galaxies. And, in 'wet' gas-rich galaxy mergers, gas gets 'funneled' to the center of the system, whereat NSCs would reside. Perhaps, then, when small, gas-rich proto-galaxies merge, gas gets funneled to the center, env…

http://arxiv.org/abs/0907.3432 This is a 39 page article that delves into a dozen or so different answers to the Fermi question/paradox that have been proposed over the past half century. The author is a Belgrade astronomer/SETI expert/future generalist. He seems to know a lot and reason carefully, like a credible academic. Well, that's my first impression. Maybe you can find some flaws, if so please let the rest of us know where you think he is wrong. I don't think he has any preferred answer, he compares and weighs them all. Maybe he ends up throwing out some as relatively improbable, and narrowing down to the ones he thinks are better. But on the whole it…

In our galaxy, stars form from within Giant Molecular Clouds (GMCs), of cold molecular hydrogen (H2), characterized by densities of 10-18km/m3; and, temperatures of 10K. GMCs, which "are not gravitationally bound", may be compressed by the surrounding, hot-but-diffuse, Inter-Stellar Medium (ISM). Collapse/compression continues, until the cloud becomes opaque to its own thermal radiation emissions, at densities of 10-10-10-9km/m3; and, temperatures of a few hundred Kelvins. Note, that densities increase by nearly nine orders-of-magnitude; whereas, temperatures increase by only one-and-a-half orders of magnitude, i.e. the clouds contract nearly semi-iso-thermally. On…

Why do some star-planet systems are so compact like Kepler11 ?

Does anyone know of an entertaining source of information of the stars near our solar system (<50 lightyears)? I am looking for more information... and it's just for my own entertainment. No project, no work, no urgent questions, just a desire to learn more, while at the same time too lazy to chew through the dry information or poorly written websites and books. I have already found a nice atlas of the solar neighborhood, which 3D pictures of our neighborhood within 12.5, 50 and 250 lightyears, and quite a bit of additional information. I think is pretty awesome, although I personally would want to make that thing a rotating 3D model where you can seamlessly zoom …

With Hobson's notation: H=(da/dt)/a dH/dt = ((d2a/dt2)/a) - ((da/dt)/a)2 If ((d2a/dt2)/a) is negative, (dH/dt) is certainly negative. But if ((d2a/dt2)/a) is positive, (dH/dt) can be positive or negative. What is your interpretation?

Are there, or is it possible that clouds or regions in space can drop hundreds of degrees below absolut zero?

What is the exact calculation of Particle horizon in Lemaître model? Does it exist? Is it finite or infinite? Can anyone calculate that integral? Thanks

If space-time "sags" under the influence, of massive objects: and if matter "grips" space-time, so as to "curl space-time up", i.e. induce positive "contractile" curvature (Wheeler. Journey into Gravity & Spacetime); then might relativistically-dense black-holes be able to "curl the fabric of space-time all the way around", and "pinch off" (vaguely resembling a rain-drop) ??