Astronomy and Cosmology

Hi all. Just wondering if anybody could speculate on the possibility of an earthlike planet orbitting Alpha Centauri A. By Earthlike I simply mean a small rocky planet, not something that has a breathable atmosphere or hospitable temperatures necessarily. I have read that it is not impossible, although because it is a tri-star system it's orbit would be more erratic and prone to bigger fluctuations in temperature and the like. It would also have a far shorter life span than earth because of this, eventually being torn apart. I guess what I'm asking is, is there any reason that such a planet, however inhospitable, could not POSSIBLY exist at the present moment. Any…

This picture records the sun's position in the sky, each two weeks at the same time. Is this picture showing the elliptical path of the sun over a period of a year or is this picture decribing some other aspect of the sun's orbit.

(ps. im norwegian so my spelling might be a bit off ) i started the university (computer science) last year. Outside the classes i have to take we have some optional classes we can take and beeing a hobby science nut i took a basic astronomy class. First i have a problem with how the professor speaks of the big bang theory as undisputed fact. I get how we can speak of certain aspects of astronomy as solved but the origin of the universe ? really ? i havent heard anything about that ( that we solved the mystery ). I mean, i get how we can speak with certainty of how the aurora works, what the athmosphere on the different planets are like, how the sun works etc, be…

Are the rotation curves for the galaxies different for the galaxies near the centers of the cluster compared to the galaxies farther from the cluster center? Are there measurements that give the rotation curves for galaxy clusters? Since the effect of Compton scattering is so tiny, do we currently have the sensitivity and resolution at these low frequencies for the SZ effect to give accurate measurements of the clusters? Can the SZ effect determine a rotation curve for the galaxy clusters? What does the information that we have now from star, galaxy, and black hole formation tell us about the cluster structure and evolution of the clusters? What physical mec…

That dry, dusty moon overhead? Seems it isn't quite as dry as it's long been thought to be. Although you won't find oceans, lakes, or even a shallow puddle on its surface, a team of geologists at the California Institute of Technology (Caltech), working with colleagues at the University of Tennessee, has found structurally bound hydroxyl groups (i.e., water) in a mineral in a lunar rock returned to Earth by the Apollo program. their findings are detailed in the journal Nature. "The moon, which has generally been thought to be devoid of hydrous materials, has water," says John Eiler, the Robert P. Sharp Professor of Geology and professor of geochemistry at Caltech,…

here are three ways to talk about a star’s brightness. We can discuss the apparent magnitude of a star, or how bright it appears when we look at it. We know, however, that stars nearer the earth appear brighter than faraway stars, even though they may not actually be brighter. So, astronomers also talk about the absolute magnitude of stars, or the brightness of a star if the observer were 10 parsecs from it. The third way to measure a star’s brightness is called luminosity. Luminosity is a measure of how much energy a star puts out in comparison to our Sun.

http://news.yahoo.com/s/ap/20100721/ap_on_sc/eu_most_massive_star I see the stars "birth weight" is estimated to have been as much as 320 solar http://www.eso.org/public/news/eso1030/ It has already blown off a considerable amount of its initial mass and its mass is now estimated to be 265 solar. The estimate of luminosity may be lower than what I originally saw in the news. EDIT: The estimate of luminosity (wattage) of "near" 10 million times the sun seems to be OK. Several sources gave it. For me it is a stretch to try to imagine. Thanks to Sisyphus in post #3 for suggesting a way to imagine it---as bright as the sun is to us, but much farther away.

let us put our minds together and design a space station fitting the leading choise in the poll above. lets think of the best way to utulize the Moon for our benefit and try to figure out whats the difficulties of living in space and how to solve them. give me any ideas you have or any tips for our Moon design and ill try to put ut all together. thank you.

4500 years ago builders in ancient Egypt structured the foundation of the pyramids of Saqqara with blocks that had thereon a strange hieroglyphic writing. The writing was known to them at the time - but was subsequently lost, and remained so until 1799 when one of Napoleon Bonaparte's legionaries discovered a basalt tablet (now known as the Rosetta Stone) from which Jean Francois Champollion deciphered the ancient text c1821 -22. It followed that the late Dr. R. O. Faulkner (then of the British Museum, London) translated the hieroglyphic writing and published it in English under the title, The Ancient Egyptian Pyramid Texts. It is therein that the cosmology and t…

Just need some general info on neutron stars, wikipedia's page was a little too advanced and need something a little more basic please. Their compostion, importance in cosmology, and other useful info would help, thanks!

event1 1. A photon is created when object(1) of mass release energy through radiation.. event2 2. The Photon is destroyed when it is absorbed by another object(2) absorption. Between event 1 and event 2 this PHOTON must be accellerated from rest ( WRT object1) resulting in redshift and Decellerated to rest ( WRT object2) resulting in blueshift. This is directly atributable to Gravitation of both objects as i understand it. If the photon does not change its speed i.e always c IN ALL INHERTIAL FRAMES. Would it not make more sense to say that redshift /blueshift. is a result of gravitation , and not the s…

Been reading A Brief History of Time, and I have a few questions I want to sort out. Hawking talks about the event horizon and says a few things that I think I've read right: 1. The event horizon is a set of events that it is impossible to escape to a large distance from. 2. The event horizon forms the boundary of the black hole, and is formed by the rays of light that nearly escape the black hole, but not quite. 3. These light rays must be parallel, otherwise they would eventually touch and cause each other to fall into the black hole. 4. Due to the way time works within a black hole, this cannot happen as then they wouldn't be able to be at the event horizon. 5. T…

I think black hole isn't hole it is solid,very dense round sphere ,because the more dense it is more gravity it has,so the light can't escape or reflect from the surface

can wormholes be the same as black holes as we all know a wormhole takes us a shortcut but what if black holes are just wery long sucking wormholes post what you think about it and also i wonder how the black holes are so small yet so powerful

These last years, the search for extrasolar planets has been successful. To date, the astronomers have detected more than 400 extrasolar planets. Among these 400 planets, only ten have been discovered by their own light. There is perhaps a phenomenon which could facilitate this search for extrasolar planets. The astronomer Michael Mumma and his team have discovered in 1981 (*) a natural laser emission produced by the Martian upper atmosphere. This very fine emission ray centered on 10,33 µm is due to carbon dioxide, majority component of the Martian atmosphere. This natural laser emission has been not only confirmed by other teams but another natural laser has …

When an object emits light, we can see it. _when the objects moves away at some speed, we observe light coming at us at constant speed = C. _when the object moves away at speed less than C, we observe light at C. _when the object moves away at C, we observe light at C (because C is constant) _when an (hypothetical) object moves away at speed faster than C (?), we must observe (I suppose) light coming at C, because C is constant. So I suppose that even when an object like a galaxy is receding from us at speed faster than C, we are observing the light coming from this object traveling at C. Independently of any "space expansion". Or, in other word: a…

Basically, my christian friend gave me a religious/science book (because I'm a terrible atheist, ya know ) called "The Science of God" where he tries to show that if you look at the creation of the universe from a point in the big bang that it appears to have lasted six days, while on Earth it will have been 15 billion years. [MATH]\frac{15 billion}{10^{12}}[/MATH] : [MATH]\frac{x*365}{1}[/MATH] It is a ratio showing the 15 billion year old earth (I thought it was 13.7 billion years?) over the temperature at the end of the particle era ([MATH]10^{12}[/MATH] k, the whole thing started at [MATH]10^{15}[/MATH] k though). X*365 turns out to equal 5.47 days. His reaso…

I would like to hear other peoples hypothesis on pre big bang space, and the future of our universe, also if the universe is infinite or finite. Can't hurt to hear new theories!

As far as I've understood, the whole supernova process starts with that the core is collapsing when the gravitational force is grater than the electron degeneracy pressure. This collapse happens in a very brief amount of time, and it reach to a sudden halt when the neutron-pressure and the weak force is holding back gravity for collapsing even further. Apparently it is this "halt" which is triggering the outer layers to explode. My question is how do the core and the outer layers interract? Is it particles which is carrying the kinetic energy from the core to the outer layers?

Hello everyone. I've been a member for a while now, but have never posted a new thread. I guess I wasn't sure what kind of a response I'd get. But here goes. I am a physics enthusiast with no formal teaching/training. I have ready many books on the subject ranging from Quantum physics to Cosmology to Information science, etc. Anyway, I had some thoughts that I'm sure are thoroughly flawed, but was curious if you could help sort them out for me. Hopefully I can convey the idea properly, but unfortunately this might be long. Bare with me if you can. Don't be to hard on me, I'm a novice. Thanks in advance. The idea is based on the idea that as objects appr…

I was looking around the NASA website and came across a flash they did comparing the two telescopes. Being that Webb is infrared, what do you guys hope that it will find that Hubble couldn't?

How do we define a Singularity? How big does it have to be? How small? What shape? Did our world actually begin as something less than the size of a pin point of light? While I believe our universe was the instantaneous transitional phase of a singularity into becoming matter, could "it" have possibly been billions of miles in diameter at the time? American Heritage, definitions of: SINGULARITY 1. The quality or condition of being singular. 2. A trait marking one as distinct from others; a peculiarity. 3. Something uncommon or unusual. 4. Astrophysics: A point in space-time at which gravitational forces cause matter to have infinite density and infinitesimal vo…

Let's think. Supposedly, you'll never detect a black hole visually. It doesn't let anything -- including light -- escape. So all we'd see is a black patch of space. Yet also, if an object were to fall towards a black hole, we'd perceive it as eternally "frozen" on its journey due to relativity. Therefore, shouldn't a black hole appear as a messy, cluttered ball in space? Due to the accumulated multitudes of cosmic debris that should be "frozen" on all the edges of a black hole.

Is the big bang the beggening of time provable. I think we just can't calculate with our human instriments exactualy how time got started. Or even if it did have a start. Someone please unconfuse me here. If that's even posible.

http://arxiv.org/abs/1006.2799 "On 15 June 2010 the Kepler Mission released data on all but 400 of the ~156,000 planetary target stars to the public. At the time of this publication, 706 targets from this first data set have viable exoplanet candidates with sizes as small as that of the Earth to larger than that of Jupiter. Here we give the identity and characteristics of 306 of the 706 targets. The released targets include 5 candidate multi-planet systems. Data for the remaining 400 targets with planetary candidates will be released in February 2011." In the past exoplanets have been detected by watching the to-and-fro wobble of stars. Kepler spacecraft detec…