Astronomy and Cosmology

Hi everybody, I would like to ask your opinion about some results from my solar sistem simulator. First, let me explain the method I used. I started with the classical N-Body problem and wrote the equations of motions in the usual form: [math]\frac{d^{2}\textbf{r}_{i}}{dt^{2}}=G\sum\frac{m_{j}}{r^{3}_{ij}}(\textbf{r}_{j}-\textbf{r}_{i})[/math] where, of course, the sum is valid for j = 1,..,N and j not equal to i. To semplify the implementation I integrate the equations of motion in the inertial reference frame centered on the Sun, being the initial conditions for velocity and position given by the JPL ephemerides software HORIZONS (even if my final target is to …

has anyone here actually Done this at all? It`s a project of mine that Ive been working on for some time, in both aquiring data and apparatus, along with experimentation. does anyone know what is the best color filter(s) to use and does this filter go on the Main front lens (closest to the sun) or between the telescope eyepiece and the cam lens, or both even? I`ll be using color film, cross processed to B&W, so the use of red filters is fine. the film type is 100ISO, so the image grain will take being enlarged quite nicely.

From http://spaceweather.com/ I thought that might interest some of you. I wonder what caused that brightening... Any idea ? May be the comet fragmented ...

Why gravity is always atractive. Why there is no repulsion?

ok so I just bought of that and I was wondering if such theory was already proposed or if its just a ridiculous idea. Basicaly its on what was there before the big bang. We know that when star dies it usually implodes then explodes. Now what if we think of a black hole as a star. It does emit gamma rays which is basicaly a high energy light. And I basicaly acts like a star. And some stars become black holes which can be thought of as the next step in the evolution of the star rather then its death. Now what if the black holes have some point if "critical mass" where it acts the same as the star? It explodes. Wouldnt that mean that all the elements which got abso…

I just read in science illustrated that scientists have found a "hole" in the universe. To be more specific its a patch of the universe that has nothing in it, the WMAP satellite found a large patch that is cold and supposedly has no galaxies in it. It is about 1 billion light years in diameter. If their calculations are correct than it would upset the current big bang theory. One theory is that early on in the universes life there was a quantam fluctuation that left an "imprint" in the structure of the universe, which we would see as that void. Another theory is that the universe is not homogenous but is fractal. And finally the third theory set forth in the article is t…

Are antimatters present anywhere in the universe. And is it really possible to create antimatters in Earth. P.S. I came to know of this when I read the book "Angels and Demons" Can anybody please help me Thank you

Well, the Orion project is being delayed due to budget cuts. I watched a German story about it that said when the Shuttle is retired there will be a five year gap before a U.S. spacecraft becomes available to service the ISS. NASA plans on using ‘commercial’ capacity. My backyard catapult is at their service. http://www.space.com/news/070301_orion_delay.html

I'm trying to get an accurate representation of the moon's orbit around the earth. It seems as though it is commonly characterized as going "round and round" the earth. I was under the impression that the moon kind of swerves in and out of the orbital path of the earth. I guess my question is, what is the path of the moons orbit around the sun? Is it a series of "loopty loops" or is it a wavy line?

Firstly, I'd like to apologize if I've posted this in the wrong section, as I wasn't sure if it belonged in Relativity, Quantum Theory, Modern/Theoretical Physics, or here in Astronomy and Cosmology; my question really relates to all these topics in one way or another. Anyway, on to the meat of my query: As I understand, "Hawking Radiation" is a result of the meeting between Heisenberg's Uncertainty Principle and the incredible gravity at and around the event horizon of a black hole; as a particle-antiparticle pair "pops" into existence, one of these particles is sucked into the hole and the other, in turn, is cannoned off into space, (thus the radiation) rather t…

Does anyone know any current materials used in spacecraft that are meant to block or absorb this? What materials DO absorb or block this? Besides led. I can think of water, right? I ask because for my science fair I want to design a small-scale spacecraft model with some kind of material that will block/absorb radiation. Also, what about creating a small-scale magnetosphere? Is that possible? Because wouldn't that block the ionizing raditaion from the spacecraft? How can you make one? No this is not trying to get homework answers that's why I didn't put it there. I am just brainstorming for a project months ahead of time. =] Any ideas about how to g…

Just found this... http://physicsworld.com/cws/article/news/35368;jsessionid=48833536D0AA1CF3FDDE27AE83B7112D from the Physicsworld article... Not sure if this means the death of measuring expansion via the Type Ia Supernovae technique, but this is certainly good news.

As planets migrate toward their sun, what changes do they undergo? Do they: shrink or expand; heat up or cool off; get gassier or wetter or dryer; get more radioactive or less radioactive; get brighter or darker; move higher or lower; spin faster or slower; tilt forwards or backwards? Is it a different tale for a gas giant, a terrestrial planet, and an asteroid belt? Or is it the same for each? I want the story at the peak of the bell curve, please.

Hi everybody! I am new of the forum and I would like to ask you an opinion. I am setting a high precision simulator for the Earth - Moon system and I am integrating the equations of motion in the ECI reference frame (the earth centered inertial). I also have a spacecraft moving in the vicinity of one collinear lagrangian point and I know its state vector (position and velocity) in the synodic reference frame, that is a reference frame having origin in the earth-moon center of mass, x axis in the direction from the earth to the moon (hence, rotating in the eci frame) and z axis normal to the moon's orbital plane a y axis to form a right hand frame. Now I have to open point…

http://www.nytimes.com/2008/08/01/science/space/01mars.html?_r=1&oref=slogin there were various signs suggestive of water noticed earlier but this is still a first in some sense water vapor evolved from soil heated to zero Celsius an earlier sample released water vapor when heated to higher temperature, indicating that, instead of simple water ice, there was water chemically locked in the minerals (the minerals had to be partially broken down to release the water) now it is clearly demonstrated that the latest sample scoop of soil did contain simple water ice. it looked like there were chunks of ice present before, but until now there was no chemi…

this is being reported as an explosion which was intermediate between a supernova collapse (say to form a neutron star) and the more powerful event called a Gammaray Burst (GRB), or sometimes a hypernova. http://www.sciam.com/article.cfm?id=supernova-2008d-missing-link&sc=rss the SciAm article calls it a "missing link" Some models of GRB involve collapse to form a black hole. I dont know enough to evaluate how appropriate it is to say missing link. I guess the hope is that studying the event will reveal something about what causes GRB. There definitely are at least two different classes of powerful explosions---SN and GRB and there are different typ…

As the Sun is loosing something like 400 million tonnes a second in mass it must therefore be getting smaller. As it gets smaller its gravitational influence on the planets must therefore be lessening. Is it therefore reasonable to say that as the Sun gets smaller the planets are very slowly drifting further and further away?

Im doing a project at the moment involving using redshift data measured photometrically. This is opposed to redshift data that is measured spectroscopically. Could anyone outline the main differences between photometric redshift and spectroscopic redshift? Also, the photometric redshift measurements are obtained using different methods. There's a Neural Network based 'empirical' method and there are template based methods. Some of these template based methods are Bayesian. Can anyone explain what this all means? I have to write a paper up which explains how the methods are different, but the explanations need to be as concise as possible (A sentence or two for eac…

Hi, Please can anyone let me know if there is an accurate computer model of the solar system that I can explore, or if possibly there is a way for me to build one? Also, is there an existing place in the world(!) where people can explore physics concepts using computer models? Thank you.

Dous the hypothesis of "every galaxy got it's own black hole" cancel out he hypothesis of there is mass missing so there is dark matter? Or can they coexist?

is it something to do with light 'blurring' (diffusing?) as it passes through the atmosphere at an angle?

I've heard that there is a lack of consensus about whether Pluto should be considered a planet or not when compared to other similar bodies, and that outer ring planets and inner ring planets also have nothing in common to both fall under the same definition of "planet". What about a system where planets are categorised based on the thickness of their atmospheres? Either by the depth to/from the core or by percentage of radius that is their atmosphere. For example, you could say that Planet X is a gas giant with a 1000Km thick atmosphere with a small iron core, or you could say that Planet X has a ratio of 90% atmosphere to 10% solid core, etc. Compared to…

1. why do they form spirals ? 2. why do they attact each other ? 3. what happens when they collide?

Could stunting star formation have any impact on the expansion of the universe? Like say you cut down star formation at some certain time by say 50% of what is estimated or known would such have any noticeable impact on the expansion of the universe?

This is a question that puzzles me. I take it that Near Earth Objects such as Comets or Asteroids that are on a trajectory that will hit the Earth can be detected well in advance of hitting us. However, does the technology yet exist to deflect a dangerous asteroid? For example, if an asteroid was over 1km in diameter, do we have any chance for survival? Views and opinions welcome.