Astronomy and Cosmology

hello was wondering about pluto maner of orbiting its own moon , and its orbit concerning the planet neptune. could it be possible pluto when originally forming was beginning to be drawn in to neptune as a distant moon. at the same time charon was as well. however charon instead began to orbit pluto and the extra moment caused a slingshot effect that caused both bodies out and away, though still in and orbit that draws it close to neptune on return. -strange thoughts- mr d

Using Newton's 3rd Law, we can calculate the total galactic mass within the orbit of an object if we know the rotational velocity of the object and it's distance from the galactic centre. Apparently this is done routinely and the results indicate there must be a huge halo of dark matter extending well beyond the halo of visible galactic matter. My question is: The "distance" in Newton's 3rd Law is the semi-major axis. When we establish the distance of an object from the galactic centre, how do we know that distance is also the semi-major axis? Could not the object in question have an orbit that brings it much closer to the galactic centre than it is "now". In …

Hello, I'm currently working on a small educational program that illustrates how planets orbit the sun. I'm learning the neccesary math, physics and programming on the fly, which is very interestng but also quite frustrating! I hope you might help me with some problems... When working with orbital mechanics (or celest mechanics) You often use the gravitational constant G and the total mass of the system M, beeing very close to just the mass of the sun. This have caused me a grat deal of worry: G is 6.673e-11 N*m^2/kg^2 and Msun is 1.989e+30 kg, but when I use these values my formulas go amok. Just yesterday I found out that the two constants are often combned in …

there is a controversy about this picture http://ipac.jpl.nasa.gov/media_images/ssc2005-22a_medium.jpg discussed e.g. here: http://www.badastronomy.com/bablog/?p=206 It is from the Spitzer Space Telescope. the bottom half is labeled Infrared Background Light from First Stars the splotches in the foreground are where they masked out brighter objects in order to get the way-redshifted background. infra-red heat patterns in what looks like otherwise empty sky they published in Nature journal, this week http://arxiv.org/abs/astro-ph/0511105 but it isnt settled yet that the pattern they see really is the first starlight. If it is, it would be very redshif…

Copernicus skull was found according to this news item http://news.yahoo.com/s/ap/20051104/ap_on_re_eu/poland_copernicus and a forensic reconstruction made, using the scull, and compared with a contemporary portrait http://zdjecia.astronomia.pl/wiadomosci/kkgp/kkgp.jpg the portrait they had to compare with was actually a self-portrait that Copernicus did himself----does anyone have a a link to the self-portrait? I don't and would like to see it

this is to stop the tangent in the parallel universe thread. the big bang was not the beginning of the universe. it says nothing of what banged, why it banged, how it banged, or where it came from. all it says is that at one point in universal history there was a rapid expansion from an extremely dense state. at this point, physics breaks down at the singularity, so right now we can't know much more than what i just said.

http://mars-news.de/life/spherules/:confused:

I've frequently seen what appear to be rays of light passing through gaps in clouds. These always diverge fron the sun's position. But since the sun is so far away it's effectively a point source so what makes the rays not parallel?

Lets say that one day on mercury is 2 earth years (i think this is right, but if its not, it doesnt really matter) If you traveled to mercury, would one day FEEL like 2 years, or would it feel like one day? this may be a stupid question, but please no flaming.

http://uanews.opi.arizona.edu/cgi-bin/WebObjects/UANews.woa/wa/MainStoryDetails?ArticleID=6522 http://www.space.com/businesstechnology/050831_phoenix_tech.html I just wanna know what you guys think. Do you guys think phoenix will find any signs of life under the surface of Mars?? Do you think there will be any significant contributations made after it studies the ice caps?? Thanks for your opinions!!!!

I heard that our solar system has its frequency and the frequency is the same with the frequency of the human's brain. Is it tru?

The other day I was having a conversation with a staunch creationist about the big bang theory. He stated that it is his personal belief that the universe reached it's present size in less than 10,000 years. He also claims that the universe is no longer expanding, we're just seeing old light. Finally, he says that there is no way we could tell the difference between an expansion that took place rapidly over the course of a few thousand years and a continuous, long-term (billions of years) expansion. Now, I'm inclined to say that something in the red-shift would tip us off to a rapid expansion. But this is way out of my arena. I'm just curious to see what our resident cosm…

I am going to introduce a new theory for rapid star formation from seed stars. Nuclear fusion is an highly exothermic reaction. Although gravity may be required to induce the original primal fusion, the question becomes, is gravity still needed to help sustain this highly exothermic reaction that wants to proceed forward? It is sort of like needing a match to start a fire, but once the fire is lit because it is highly exothermic the fire becomes self perpetuating if fuel is nearby. The fire will pull in the air that it needs to keep going. Here is the theory, after gravity induced fusion in the earliest seed stars, the strong self sustaining exothermic potential call…

This may be a repost , sorry. I read that the black holes can 'evaporate' by shooting off some radiation and other stuff. If anyone has heard of this please let me know. By evaporating, they eventually will become nothing, because they will lose all their mass by 'evaporating' or shooting off stuff like radiation and other things. well my quetsion is.. if 'nothing' not even light can escape, how can black holes evaporate? how can even radiation get away or anything else. thanks guys/girls.

Hi, Why do the 9 planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto) orbit around the Sun? If the reason is due to the fact that the Sun has the biggest mass, why wouldn't the planets get attracted toward the center of the sun, instead of orbiting around the Sun elliptically? Furthermore, since Jupiter has a bigger mass than Earth, why is it farther away from the Sun than Earth?

New research published in the IOP's journal of Classical and Quantum Gravity shows that primordial black holes did not die out - they formed stable gravitational bound states called Holeums in the aftermath of the Big Bang - which form haloes around galaxies today, and are an important constituent of dark matter. An isolated black hole is subject to the evaporation of its mass due to the Hawking radiation caused by the vacuum fluctuations in its vicinity. This would seem to rule out the possibility of formation of bound states of primordial black holes. There are two conditions which need to be satisfied for a black hole to evaporate due to Hawking radiation: (a) …

I would to raise a little controversay. Data has appeared that shows the existance of galaxies, which formed and were making starts less than a billions years into the evolution of the universe. Our sun is posulated to have taken maybe a long as that to reach something close to its modern state. But in this case, whole galaxies, stars and all, form in less than 1Billions years from t=0, during extreme conditions of temp and velocity. The question I have is, are any of the current cosmology models able to accommodate this data? The theories that can not accommodate this data, do they need to go back to the old drawing board or are they grandfathered in?

Imagine if you have a gigantic circular space station that is tethered with numerous space elevators, is concentric with the earth and spans the entire geocentric orbit (I think A.C.Clarke played with this idea in one of his early works). My question is, at what altitude would it need to be tethered to provide 1g of centrifugal force in the "roof" of the space station, so that people can walk around up there in a normal way?

Im doing a bit of research on lunar landscape, and I was wondering if anyone had access to a good lunar map, specifically displaying the lunar far side ("dark side" of the moon), and more specifically with labels for named locations? As always, all help is appreciated. Thanks

Can the speed of light & gravity have various velocitys? The reason I ask is a brighter light, faster than a dimmer one? & is a stronger force of gravity faster than a weaker force? some argue that darkness is the abscence of light, but if that is so; is light the abscence of dark? or maybe they're equal relatively speaking? your thoughts?...us.2u

If an object is receeding because of spacetime expansion, is the redshift we measure because of spacetime expansion, and not necessarily the object's relative velocity? In other words, is the stretching of space what changes light's wavelength? If so, shouldn't receeding galaxies have two redshifts: One from the expansion of space that the light is travelling through, and one because the expanding space is carrying the object away?

http://wyslijwiadomosc.pl

I would like to propose a fun conceptual model that can readily explain all the observational universe. Picture is we created a house of mirrors. We position the mirrors at various long distances so that the light reflected between all the mirrors takes various amounts of time to return to us. The time delay and the reflections of time delay would allow one to see the step by step history of their visit in the house of mirrors reflected back to them at the same time real time events are being reflected. If we also allow our house of mirrors to expand with a uniforn velocty from center, each reflection will be red shifted and the more times the light is reflected bac…

http://www.cerncourier.com/main/article/45/8/8 General relativity versus exotic dark matter Determinations of the rotation speed of stars in galaxies (galactic rotation curves) based on the assumption that Newtonian gravity is a good approximation have led to the inference that a large amount of dark matter must be present - more than can be accounted for by non-luminous baryonic matter. While there are plenty of attractive theoretical candidates for the additional dark matter, such as a lightest supersymmetric particle (LSP), it is also interesting to look into the details of the calculations that suggest the need for such exotica. Now F I Cooperstock and S Tieu …

My idea is that the singularity was of the 4th dimension only at t=0. Space is infinate and eternal in the three spacial dimensions, it is the 4th dimension of time that began at the big bang. The 3D infinate was an infinate scalar field and it is useful to consider it an infinate Higg's field (although not neccessarily). Unlike m-brane theory I propose that there was only one infinate brane that was entirely homogenous with no dynamics or gravitational gradiant....a 3D infinate t=0. The Big Bang event was not an expansion of a super condense state of mass, it was a decay of the infinate scalar field into a matter/anti-matter quantum soup. The decay like the "ba…