Astronomy and Cosmology

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?

Image source ... Here we report the detection of a dark-matter filament connecting the two main components of the Abell 222/223 supercluster system from its weak gravitational lensing signal, both in a non-parametric mass reconstruction and in parametric model fits. This filament is coincident with an overdensity of galaxies10, 13 and diffuse, soft-X-ray emission4, and contributes a mass comparable to that of an additional galaxy cluster to the total mass of the supercluster. By combining this result with X-ray observations4, we can place an upper limit of 0.09 on the hot gas fraction (the mass of X-ray-emitting gas divided by the total mass) in the filament. http…

If the universe is dozens of orders of magnitude larger than the observable universe would it be reasonable to question homogeneity and isotropy? (My guess is that this would conflict with the theory that undergirds inflation in the first place.) What is the smallest actual size of the cosmological horizon allowed if we assume the inflationary epoch? Thanks, people.

Do we have evidence of completely void and empty space? Can someone please show and explain to me the mathematical proof that shows us gravitational boundary (the distance a gravitational field extends to) is infinite?

Since watching the newest Rover land on Mars I have thought again about what it would take to terraform Mars. Terraforming Mars has some good ideas, yet I don't know what would be the most practical at this time. I had thought about forcing a Chemical reaction in the atmosphere could be one way. What I was thinking is Finding a way to Split the CO2 into something else. One possibility could be to force a massive H2O reaction in the Atmosphere. I Was thinking maybe 10 Megagams of Hydrogen and 5 Megagrams of Oxygen would be a good start. Seeing as I have do not have a formal science background I do not know what would happen or even if this would do anything. I do…

Despite Jupiter rotating very quickly in one direction what causes the alternating counter rotating bands of clouds, because if Jupiter is rotating so fast wouldn't all the cloud bands rotate in the same direction? Thanks

What can Curiosity do that Sojourner, Spirit, and Opportunity could not do? And if you could put it into plain language that would be appreciated. People are wondering what 2 Billion dollars can accomplish, the science folks should be differentiating Curiosity from her predecessors. She doesn't depend upon solar panels that can stop functioning when they get totally covered by the nasty, attractive Mars-dust.

Can somebody explain to me why the universe is expanding? Or maybe just some speculations to why it's expanding. Putting the explanation in layman's terms would also be helpful. Thanks!

Has anybody got an insight on weather this is possible?: If two black holes of a similar size were attracted to each others gravitational pull, would the effect on the light absorbed by each black hole be negated for any period of time? If so, what would we gain from this knowledge? I read somewhere recently that if a human was able to reach a large black hole, one which is large enough to have its effects on passing its event horizon were slowed way down, then that human would be able to see everything that ever has or ever will be sucked into the black hole, including things from the beginning of the universe, because of the speed you are travelling and its effe…

I'm just a casual pedestrian layperson to science. Subscribing to Scientific American is about the depth of my interest. But I'm fascinated with this exhibit that physically demonstrates the presence of cosmic particles, in real time! Not just a theoretical subjective notion that I wonder when science will overturn it, but actual particles that are landing 2 feet from me after passing through feet of concrete supports located just above this underground exhibit! I got to thinking, it would be fantastic to make it directional (3 dimensional). The thought just occurred to me last night in my sleep so for all I know the exhibit does show direction but I didn'…

Hi everyone, can anyone help me for Sessile drop fomula, from young's equation.... maybe subtance of exam will help me to undestanding Sessile drop more further. thanks,

Does the The XENON Dark Matter Project give evidences of dark matter? http://xenon.astro.c...100_Experiment/ Xenon100 has just reported another null result: http://blogs.discove...r-still-hiding/

Hello, I'm very busy on thinking if multiple universes are real or if we are the only universe. If they would be real wouldt if even be possible to get there or wouldn't your body be able to handle it. These are many question but there are different theories about black hole's. Some say they will lead to somewhere else in our universe and a theory says that they end in another universe. i have spend alot of time on thinking about this topic. Is there anyone that have an opinion on this?

Just recently started getting into reading and learning about the creation. makeup, size, etc. of the universe. Regarding expansion, I think I understand the raisins in the dough theory (that the space between objects is expanding). My question is, under this expample, is there not a limit to the distance the space between objects can expand. If you pull the dough far enough it will break apart, a ballon will pop. Although I know nothing about physics and cosmology, under the "dough" example, I would think the expansion of space could only go so far. Please enlighten me. Thank you.

I am new here. I apologize if this is a ridiculous question. Dammit Jim, I'm a lawyer, not a scientist (perhaps a reference more relatable in this forum ). If the nearest galaxy is about 2.5 million light years away, is it crazy to think that our solar system and galaxy is the only thing and all other galaxies and stars have died out since what we see is an appearance from so long ago. Or is there other evidence that these other galaxies and stars still are in existence, etc. Does that make sense?

If 83% of all matter is Dark Matter, then why aren't our bodies,and everything on earth, and in our Solar System, 83% Dark matter? IOW, why does current mainline theory posit that Dark Matter is only observable at galactic distances? If Dark Matter responds to gravity, then why is itdistributed so unevenly? My conception is that it is because most of space is empty,and the matter density of our Solar System, and Earth, is much higher than thatof galactic space, and Dark Matter is actually distributed somewhat uniformly.

In the Big Bang was created matter and energy out of nothing. It is assumed that currently the amount of energy+matter is constant, and that expands isotropically...only by the spacing of matter between them? Then... at what moment after the Big-Bang was stabilized the amount of matter and energy in the universe?

Only using red shift phenomena, can we learn the distance from the supernova ?

Im not a PHD or scientist but after many discussions i still have no way of overcoming the mind boggle that is put simply, is - Where is the universe ? In much the same way as this lad in the state of reflection staring up at the stars, everything and everyone is 'somewhere' and has a physical place of existence. Often the debate turns into a debate about infinity etc etc. This, i can understand but everything has to have a place of existence to actually exist and surely the infinity explanation just decays into a 'cop out' much the same as God is everywhere. what are the thoughts of other users? regards Nelson

I have 2 theories on how the Big Bang could have happened, and I want you to show my flaws and what you think about the Big Bang/How the Universe was created, and what energy created it. Theory no.1: There was a previous universe and it came to its end and died out but when it died it made a supernova type affect (The Big Bang) and created our universe. Theory no.2: There was two universes/multi universes the expanded so much that they collided and mad a mass explosion (The Big Bang) and created our universe. Please say what you think about them, any of there flaws how likely they are and your own theory.

How can we earthlings sitting out somewhere in the universe still see light from the very young universe. It makes no sense and is not as easy to answer as some might think?

Q: How would the universe be different if π = 3? There are sometimes questions about physical constants changing, and those questions make sense because there’s no real reason for the constants to be what they are. But π is mathematically derivable; it kinda needs to be what it is. You can’t, through the power of reason alone, figure out what the gravitational constant or the speed of light are, but you can figure out what π is. But lets try think about it anyway, mathematics will be put on its head, planetary orbiting will alter etc?