Astronomy and Cosmology

Okay, there probably is a simple answer, but as we know the Earth orbits around the Sun. So, why does it orbit? I know it is partly because it is in the Sun's gravitational field but what gave it the momentum to start orbiting? When a satellite is launched, it needs some initial momentum to push the satellite around the Earth after it escapes the atmosphere. So is this proof that anything with an orbit has had some initial momentum at some point in time, proving the big bang?

Are there any theorys as to the origins of galactic black holes? Could it have been an explosion of a super duperly humungus and ancient super nova?

I have read a couple of previous posts about this, but have wondered if the supposed graviton, if responsible for gravity, could be actually faster than light. My reasoning for this is that if light can't escape a black hole but gravity can, does that not make gravity faster than light?

So, NASA released this amazing topographical map of the far side of the moon, based on images from the Lunar Reconnaissance Orbiter (LRO): (Source: http://www.nasa.gov/mission_pages/LRO/news/lro-topo.html) But this got me thinking. On Earth we define 0-elevation as sea-level. Anything below is negative, anything above is positive. But there's no sea on the moon, or liquid water -- where's the 0-elevation defined, then? Why is this map showing negative elevation values? It just peaqued my curiosity, wasn't entirely sure. Thanks, ~mooey

Would Earth actually burn up if Jupiter were to emit the same powerful source of light as the Sun? Why or why not?

So there's this asteroid called Sylvia. (It's primarily known for having two moons, Remus and Romulus, but that's beside the point.) Sylvia rotates about once every 18661 seconds, sidereally; and her mean radius is about 286 kilometers. That means that, at her equator, assuming approximate sphericity (obviously a big assumption, but that's also beside the point), she rotates at about 96.3 meters per second. But, assuming an object of negligible mass could revolve around her at a non-eccentric distance of exactly her mean radius (again, implausible, but let's not get hung up on that), that object would have an orbital period of (286000^3/(1.478*10^19)/(6.67428*10^…

(realizing that the Physics does not allow for it) "If Jupiter had the same mass it has now but was undergoing nuclear reactions of such a level that it was shining just as bright as our sun, what would that do to our life here on Earth?” All I am asking you to do is to identify ONE thing that would change BUT you must also tell why it would change. Remember – we orbit the sun because of its excessive mass and the mass of Jupiter in this thought problem is NOT to change.

What do you guys think would happen if this was possible? If Jupiter had the same mass it has now but was undergoing nuclear reactions of such a level that it was shining just as bright as our sun, what would that do to our life here on Earth?”

According to John Archibald Wheeler (Journey into Gravity & Space-time): matter tells space-time how to curve; and, curved space-time tells matter how to move Now, beginning about 7 Gya, galaxies had 'clumped' together; and, evacuated inter-galactic deep-space; so that they stopped accreting new, fresh, primordial gas. Thus, galaxy growth has stalled; galaxies today have 10x less gas than 5 Gya; and, galaxies are forming stars 10-30x less rapidly, than 5 Gya (ABC AU 2011). So, if, beginning about 7 Gya, inter-galactic 'voids' had been largely evacuated; and, if local matter-density determines local space-time curvature; then, c.7 Gya, would not most of…

First of all i dont have much knowledge of string theory. String Theory talks about 11-Dimensions. On the other hand all the things or object to which human can observe are 3D and for more details 1 for time, even this too make sense. But according to string theory all the dimensions more than (3+1) are infinitesimal. OK now consider a any mathematical function, f(x,y,z) which when plotted, you can see it in 3D and if you wanna see it more from that than you can zoom up to the limit of your computer performance, memory than also you'll not be available to see any further dimensions. This is not only the case with computer but in real paper and pencil al…

The way I see it, all the time, wherever we look, we are looking into the past. So if you look through a telescope and something that was 10 light years away, then exactly what your seeing would have happened 10 years ago. So while your looking at your computer right now, you are actually seeing the past but on a extremely small scale. Would this be correct?

Since meeting extraterrestrials is unlikely to happen I wonder if just communicating with them would be worthwhile. What I'm trying to determine is if any useful information could be passed between the two civilisations and since all they know about each other is what they are told how much information would they share? Is the search for extraterrestrial life of any value?

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In a previous discussion "Stellar cores - how hot really?" it was mentioned that during the one second in which a Type II supernova creates half the elements heavier then iron, the temperature reaches about FIVE Billion Kelvin. Then a poster said something about a neutron star (at its' core I suppose) the temperature may reach about ONE Trillion Kelvin. Baric: "Temperature is a measure of the average speed of the particles contained within the sample being measured. At some early point after the Big Bang you are no longer dealing with particles so the notion of temperature doesn't apply, at least in a traditional sense. "Also, neutron stars start out at about…

This article suggests that the cosmilogical constant varies, in a smooth manner, relative to the direction of their survey. http://www.dailygalaxy.com/my_weblog/2011/11/stunning-new-stunning-study-of-300-galaxies-shows-some-regions-of-universe-not-fine-tuned-for-life.html#more I think variences do exist but, because they explain this as a smoot transition, I'd say that the light traveling through fields of relativity that exist in our very own galaxy obscurrs the test results.

Well, I was thinking the otherday about the huge amount of light bending around the galaxie like a googilian googilian tiny little electro magnetic fibers. And how some percenage of each ray transfers through the galactic time dialation where it bends and twists around the inner felds of relativity. Amoung the cloud of thoughts I realized that the light going around the time distortion field probably spins the time dialation field. And that there is probably an atmsmasphere of electro magnetic clouds that build up and disapate similar to cloud formations on earth. Especeally towards the outer edge. And that this model suggests that if the clouds become turbu…

If dark matter is clumping at the center of galaxies that will form super massive black holes. Does dark matter interact with the black hole or its gravity?

Hi, I had a look at the Bell Island boom incident and I think it is very interesting and there are a lot of different theories. Personally, I think it was a solar flare which radiated plasma energy, causing electronic disruption, electrocuting animals, blasting holes in the ground, a huge BOOM, and an unexplained ball of light. I would really like to hear some of your theories and views on my theory ( I know it's extremely vague but I'm don't know very much about solar flares and plasma energy. Here are some links: http://en.wikipedia.org/wiki/Bell_Island http://www.stopdirectedenergyweapons.freeservers.com/ http://en.wikipedia.org/wiki/Bell_Island http://www.rum…

How hot are stellar cores really? The Sun's has a core temperature of about 15 million Kelvin but what if a star is 500 or even 1000 times more massive than the sun? What would its core temperature be then? How do you calculate this? Although it's very obvious to me that no electronic component and nothing solid can survive in these temperatures but I would still like to know.

Are there credible theorys out there that suggest that lightning /or some percentage thereof/ is the result of cosmic rays cruzing through the atmosphere? I've read that a bolt of lightning can produce anti matter in high altitudes. It seems reasonable to me that it should take no more energy than this to create matter, like maybe hydrogen from energy. Of course the hydrogen would probably explode from the heat. I guess the waste byproduct of hydrogen would have to be left behind.

Hi guys, I wondered if anyone on here has watched nassim Haramein's latest vid on his award winning paper regarding his theories on physics. I am keen in talking about all aspects of life, philosophy and new up and comming theories. I have been reading alot of Tao the last couple of years amongst other ancient scrips regarding knowledge, i find it amazing the our ancestors talk about physics in their own way. Nassim is more than aware of this and it shows in his work, he is a person that likes to think outside of the box as do i, i understand its not eveyones view but i will glad to hear what you have to say on Black Whole as i value your oppinion and will take on boa…

Hi everyone I'm sorry but I think I posted in the wrong forum! I'm not sure where this question should go but it's probably not an astronomy question Hello all. I've been reading about Hawking Radiation. My interest is mainly in science fiction so please excuse the wild and wacky hypothetical question, but I'm wondering if it's valid or plausible. My understanding is our ability to create high energy particles is continuing to increase every year, culminating with the Large Hadron Collider in recent history. Surely future particle accelerators will be able to create even more energetic particles, until one day we produce a collider so powerful it could potentially g…

http://en.wikipedia.org/wiki/Pascual_Jordan Is Pascual Jordan so unpublicized because he joined the Nazi Party like tens of millions of Germans in his time, or because his theory says a singularity is not needed to create the Universe as presented in the widely accredited Big Bang? "A star can be made out of nothing at all because at point of zero volume its negative gravitational energy precisely cancels out its positive mass energy." Jordan. Furthermore, are Jordans 'quantum fluctuations' by which he said matter is created merely the addition of tiny bits of Time to the tiny bits of Space as presented in Loop Quantum Gravity?

Howdy, I've got a few questions about whatever it is within which "the universe" appears... Is there a distinction between the "universe" and "space"? I see the two terms used interchangeably quite a lot. If the universe is the definition of "space"... then what is the formal scientific name of what the universe is expanding "into" or "out of"? Is the term "universe" just a convenience used to describe patterns and processes of energy/movement taking place within space? If this is the case, then is there any reason why there wouldn't be other, even many universes? Simple, please...I realize there really isn't any boundaries to the universe, and that …

Whenscientists say that 90% percent of the matter in the universe cannot be seen,have they factored in black holes? Even if we have to guess at the # of blackholes and the mass they contain on average, surely that’s been calculated somewhereright? Any links to articles with these calcs would be awesome.