Astronomy and Cosmology

In the video of Neil Armstrong walking on the moon, the flag is waving.What is the reason behind this?

Correct me if I am wrong, but I think these rocky and metallic meteors are the results of collisions between massive asteroids. They are the fragments that explode outward. So these heavy meteors were originally inside giant asteroids that collided and broke up into pieces, and metallic meteors came from the cores of these giant exploded asteroids. Otherwise, small meteors would be puff balls that easily break up into dust. The puff ball first generation meteors accumulate to form giant asteroids. They never are hard like rock or metal until after they are melted inside giant asteroids. This means the asteroid belt is most composed of broken fragments of ancient gia…

This thread got me wondering. What's with all of the rotation? Is it conservation of angular momentum and the singularity was spinning?

If Earth-like planets were very common, we would have detected a lot of them already from the Kepler Mission. Kepler is watching about 150,000 stars, the vast majority of which are smaller than the Sun. This means the Goldilocks Zone for these smaller stars is closer to the star than in our solar system. This means they should have seen more planets with periods of shorter than one year. They are waiting until they see 3 transits before confirming a planet. There has been plenty of time already to have seen habitable planets around smaller stars, and we haven't seen them. They jump to a wild conclusion that there are 50 Billion planets in our galaxy and if onl…

Can cosmological red-shift have any effect on the physical properties of light? I mean the "redshifted" light we see has a different frequency, wavelength, etc, so could this have any effect on individual photons?

The nuclear fusion inside the sun asmain-sequence star only produces helium now. But, there are heavy elements, evenincluding iron, found in solar spectrum. And the earth contains various heavyelements. Where are these heavy elements come from? Reference viewpoint: The formation of the earth probably camefrom heavy elements condensate of the supernova ejecta of last generation starin the inner orbit of solar system. The age of the earth is 4.6 billion years.Now the sun is a main sequence star, and experienced approximately 4.57 billionyears. There are various heavy elements, including iron, found on the surfacegas of the sun, while the first generation main …

I've looked for figures on the internet but couldn't find any. The sun is ejecting mass into space and I need to know how much hydrogen the sun loses through solar wind and the like. thanks.

Hi so I had a question about telescopes. I was thinking about humans mapping the universe, and I thought about how maybe in the future we will be able to look through telescopes and see every corner of the universe or at least the milky way galaxy. So a question came up because I know that if you look at a star thats far away with your naked eye, you are looking at old light or something. So I had a question about what if you had a powerful telescope that looked upon the surface of a distance star, like really up close, would there still be this time delay? or would we be looking at live action star footage? we could ask the same question about the sun. if we look upon t…

Diracs large number hypothesis postulates some relations among among large numbers that occur in Nature such as the age of the Universe and the inverse strength of Gravity, expressed in certain units. The Wikipedia article: http://en.wikipedia.org/wiki/Dirac_large_numbers_hypothesis Many more references to it can be found by a web search. It isn't a model of the Universe like the Big Bang or Steady State models, but it does offer some guidelines on the building of such models. What do you think its implications are, and what do you think of it in general?

Hi, I am new here and I don't know if I am in the right forum. I have a master in physics and am actually reading the book Gravity of James B. Hartle. I could not answer a question about infinite, homogenous and isotropic models of the universe based on the FRW-metric. This model requires that matter is distributed evenly all over the universe. But since it is a flat infinite model, homogeneity implies that the quantity of matter should be infinite, which cannot be because of Olber's paradox. However, if matter is finite the universe cannot be homogenous at all points. There must be some kind of cloud of matter, beyond which matter starts to rarefy to finally disappear co…

Opening of"Phenomena of the natural parabola" allows you to easily create amirror of any curvature and diameter of hundreds of meters and even a fewkilometers, reflecting the parallel light rays to a point, respectively, with achange in focal length and beam power. In order tostudy the universe through focusing parallel rays of light coming from distantworlds, Hyperboloid St. Valentine's will increase the remote objects a milliontimes, compared with a 6 meter telescope. Simultaneously,the mega telescope gives a ray of sunlight of high-energy, which is in contactwith the substance will cause disintegration of the atoms in the elementaryparticles, it will be much …

If our planet was slung out of solar orbit by a passing star or black hole, what would happen to its atmosphere? With no Sun to warm us, and no life to generate O2 or CO2, would some gases freeze and precipitate out? Would some be slowly lost into space or elsewhere? Would the atmosphere become thick or even solid? Would there be layering of some gases?

Preface: While this may be destined for the "speculation" bin... I am trying to learn ... not teach. I am trying to validate my understanding, or lack there of, by paraphrasing, using colloquialisms, and analogy. It’s extremely likely the ideas here have already been thoroughly discussed, but I wasn’t able to find them because I didn’t use the same words. Everyone who has idly played with an empty Masson jar will understand. The jar is empty and presumably has no pressure or vacuum within. If you push down on the middle of the lid it buckles down. When you remove your finger it pops back up with a pleasant metallic pop. (well… pleasant until your three year old …

Question from an amateur Is the fact that the speed of light is independent of ots source just a fact of reality proven by observation or does relativity offer a reason for this fact.

And movement in a magnetic field creates electrical currents, so maybe your theories are wrong as everything seems to radiate energy. The Earth both speeds up and slows down in its orbit around the Sun, it gains energy and uses energy to keep its orbit. http://farside.ph.ut...res/node73.html These are standard cosmology math for charged particles. The universe is made up of 99% of a charged medium. http://www.nasa.gov/...atmosphere.html So any movement of a conducting material in a magnetic field creates electrical charge. http://farside.ph.ut...res/node85.html http://www.astronomy...40-5474af1661a3 But it will all get sorted out soon when the NASA mission…

Hi During the core collapse of a massive star does spacetime stretch ? Is it possible that because of that stretching, some particle get catch in a wave and accelerate to faster than light ? I know relativity prohibit that matter be accelerated faster than light, but when we consider distant galaxies they look like going faster than light because of the space expansion. Is it possible that something similar happen on a smaler scale in supernova explosion ? Thanks

Alright, I know Planet X is a bunch of conspiracy BS, but, if it was real, would it make sense that it could be made of dark matter and that's why we can't see it?

The advocators of Darwin'stheory of evolution discover that it is difficult for normal evolution ratealone to form the species diversity now. What factor(s) accelerated the originof life and species diversity? Reference viewpoints: Novae,especially supernovae, would generate high energy cosmic rays that would impacton acceleration of creature DNA gene mutation during this period, thus createlots of new species. The best supernova rate estimate we can offerindicates that one or more supernova explosions are likely to have occurredwithin 10 pc or so of the Earth during the Phanerozoic era, i.e., during thelast 570 million years since the sudden biological …

A hypothetical situation that has bugged me recently: A small spacecraft full of air at 1:1 compression ratio with that of Earth's atmosphere suspended within a bubble of the vacuum of space appear instantly in our atmosphere. When the air rushes in to fill the void, is the craft lost from the change in pressure? Would the craft survive if it was contained within a bubble of atmosphere, and suddenly appeared in a vacuum, or would the sudden decompression rip it apart?

The Origin of the Universe Through decades of research on dark matter and dark energy, people beginto realize the mass and energy exchange relationship among the universe andmultiverse. And what is the essence of "Big Bang"?

If scientists confirm their existence to a high level of confidence and can assign specific characteristics to them such that they become mainstream and generally accepted, will their names be changed or will they always be called such?

Below i will give you a description of my exoplanet Mass .226 earths, density 5.72 g/cm3, radius .60 earths, surface gravity is .63 earths It has 1 moon that has 5% the mass of the main world orbiting 250,000 miles above the surface. It orbits a sun like star, same luminosity and mass every 385 days at 1.05 au, eccentricity is .02 The average surface temperaturer is 300 Kelvin It has 75% water and 25% land, the crust ranges from 5-30 miles thick The salinity of the oceans are 5-7% with a mean depth of 18,000 feet The atmospheric composition is 70% nitrogen, 20% oxygen, 5% xenon, 3% carbon dioxide, 1% water vapor and the rest methane, argon, carbon monoxide, neo…

I was going through the latest dark matter papers (and others) below and I wondered, if you had accidentally used the reduced Compton wavelength instead of the Compton wavelength, could you just divide your mass by 2 * Pi to get the correct answer? http://en.wikipedia....pton_wavelength http://www.ras.org.u...for-dark-matter The main workings of this paper are described in the second paper. http://arxiv.org/abs/1205.4033 This paper does not mention Compton wavelength although the final equation (28) contains 2 * Pi. http://phys.org/news...sun.html#ajTabs 3 equations, 11, 12 and 13 contain 4*Pi. Just to clarify the question, if I unknowingly use a r…

If Dark Energy is pushing everything apart in the universe then how is it that Galaxies are on a collision course with each other? Even Andromeda and milky way are said to be on a collision course with each other.

Does anyone know how many neutron stars, magnetars, pulsars, white dwarfs and blackholes have been discovered so far in the universe?