Astronomy and Cosmology

1. Where is the sun in its ecliptic when it is the hottest period in the northen hemisphere? 2. Take a look at the picture I upoloaded. Why is the time that the sun is at the meridian again 12:30 rather at at noon? How do you explain the wave shape of the curve? I'd think that it's because the discrepancies between the sidereal day and the apparent solar day, I don't know if it is the answer

Hi The high redshift supernovao survey came out with a supprising result: the expansion of the universe is accelerating. The first explaination proposed is that there should be an unknowed force that drive that acceleration, and cosmologist called it drak energy. I have an other explaination using only relativity. Let me exposed the principles and observations on withch I base my reasonning. 1- Time slowing down in a gravity well. This is experimentally verified by many method. One of it involve and radiation emiter situated above a detector: the radiation is blue shifted. 2- The large scale structure of the universe is like a foam: a web of galaxies and galaxy clust…

Dear Friends First of all ,I would like to thank you for your interest and time. Please ,I would be very grateful if you send our message here to all our members in all Forums,Universities and asking some scientists to share me to publish some series books in Universe,Astrophysi cs,NewTheories of dimentions and Strings. I am asking Prof.KAKU from USA,and Prof.Hawking from U.K for this matter. I would appreciate it if you would please pass my deeply greetings along to all astro scientists who look towards to share us with this global works. With sincere gratitude and all the love we have. Dr.Prof.Salem Al AbdulRahman leadassessor1@ yahoo.com FIEFF.FIEE…

when we talk about a black hole as being infinitely dense, is that not a figure of speech for "very very dense more than any other object we know of yet?" if it was really TRULY infinitely dense, would not the event horizon match the outer boundaries of the universe?

according to relativity, objects warp space time with their gravity, some like black holes to an immense degree. as they travel through space, they are moving from one point to another, thus new and different spacetime is distorted, while the original spacetime they occupied is left without any more gravitational force acting on it from that object. is there spacetime damage in regions subjected to immense gravity that we can observe, and if so, does it heal itself after the object has passed into new spacetime and moved away from the original point?

http://www.science.psu.edu/alert/Bojowald6-2007.htm he's making the rounds of major international conferences now his article on "Before the Big Bang" will be in the July issue of Nature Physics online and then in the August hardcopy issue. the press release (above link) goes into quite a lot of detail, but it would still be a good idea to try to get ahold of the actual article

Dr Steinn Sigurðsson (Penn State) has been reporting findings announced at the Confererence on Extreme Solar Systems on his blog Speculation of another Neptune in the Solar System at the Conference of Extreme Solar Systems, Santorinibut amongst all the interesting discoveries is this idea raised by planetary dynamicist Dr Ed Thommes: Now this could really be quite fascinating. I recall reading that the mass of all TNOs, SDOs, and LPCs added up together cannot be more than a few Mearths at best. A far cry from the predicted 10-30 Mearths postulated to have existed in those nether regions i.e. the Edgeworth-Kuiper Belt (EKB), Scattered Disk (SD) in the …

When I was doing some research, I found a theory that the universe which we know is actually only the surface of the entire universe as a hypersphere. Something then occured to me; if the universe really is a hypersphere, what keeps it from collapsing? I think it is pretty safe to assume that the universe does not have a solid shell surrounding it that allows it to keep is't form. I came up with two possible explanations, maybe both of them are correct. 1) The interior of the universe contains massive volumes of negative energy. This could theoretically explain why the universe isn't collapsing because since negative energy is repelled by gravity as opposed to attract…

I was a physics major 35 years ago (they didn't even know what quasars were and black holes were exotic theories). I've recently been reading my tail off here and 100 other Google hits on cosmology. I've completed a couple of relativity tutorials, and done the math on Hubble's Parameter and topics relating to it. And still ... I must be missing something fundamental. I can't figure out why increasingly distant objects should have increasing redshift (assuming that this is the appearance of receding velocity). In Newtonian terms, this would mean that distant objects have had more time to accelerate, but I'm cool with an isotropic universe, so there are no "dista…

Hi, i'm new on this forum, so I thought a bit of the kind of thing that interests me might be appropriate. I penned this a couple of years ago on a bitingly cold Christmas night. Christmas on the Doorstep I look above to velvet sky amid the Winter night, Orion rising through the dark, Rigel blue and bright. I see Hunter’s sword where misty birthing stars shine clear, And glowering Betelgeuse, dimly red, marks the dark months of the year. In aged bloated body, the giant’s embers glowing low, Self devoured, consumed within, ashes choking now, The time will come, the spark will fade, pressures no more to be borne, And the giant will blaze in his…

I understand that it is not possible for light to escape a black hole because the escape velocity is higher than the speed of light, which it cannot achieve of course. But if you are, for an instant, just inside the event horizon, say a millameter, then light shone out WILL cross the event horizon, albeit perhaps to only a millameter or so outside it. I say this because a craft may not have sufficient velocity to escape the earth's gravity, but launched upwards it WILL go up for some distance before falling to earth. So could you not have a chain of devices, a camera on the first. The camera takes a photo inside the event horizon, sends the data out to the next de…

==quote Baez latest TWF== * In 1.1 billion years the Sun will become 10% brighter than now, and the Earth's atmosphere will dry out. * In 3 billion years the Andromeda Galaxy will collide with our galaxy. Many solar systems will be destroyed. * In 3.5 billion years the Sun will become 40% brighter than today. If the Earth is still orbiting the sun, its oceans will evaporate. * In 5.4 billion years from now the Sun's core will run out of hydrogen. It will enter its first red giant phase, becoming 1.6 times bigger and 2.2 times brighter than today. * In 6.5 billion years from now the Sun will become a full-fledged red giant, 170 times bi…

Do you think simple life is common in the Universe? The vast, vast majority of the history of life on Earth was comprised of prokaryotic cells accomplishing very little other than releasing free oxygen into the atmosphere. Perhaps life is common in the Universe, but most life cannot jump to the eukaryotic or multicellular stage. Or, maybe these fragile lifeforms are continuously wiped out by simple changes in the climate or chemical make-up of the oceans. The tiny minority reaching a more complex stage would have to deal with the occasional extinction event. Possibly asteroid strikes, GRBs, are major volcanic activity are more common on other developing wo…

Hi All, Some news are being transmitted now, that the cosomological constant, these time in the Universe, is passing through an abrupt change in value. Have anyone have any idea about that? Thanks in advance.

When looking at the universe on a large scale, we see galaxies moving away from us proportional to distance. This is due to expansion. What I'm wondering is... disregarding expansion, is there a lot of motion in the universe? Or is everything pretty static.

i am totaly bored so any1 wana talk some cosmos stuff?

The article http://www.midwestbusiness.com/news/viewnews.asp?newsletterID=17347 talks about major solar storms that happen about every 100 years. The article focuses on satellites, but what would happen to fiber-optics and copper wiring? If telegraph wires actually exploded from a storm in 1859, what would happen to all of the utility wires we have now?

Blackholes are just transfer points of matter. Lets imagine the "big bang" was the result of the formation of a black hole in another universe. From a central, infinitely small point, an explosion of matter streams out, and our universe is born. On the other side a black hole is formed from in a massive collapse of matter, into, and through the center of the blackhole,this immediately opens up the process of our new universes expansion. So our universe is live and expanding, taking in a steady flow of matter as it expands. This would mean there could be potentially an unimaginable amount of universes, all branching from a previous, and maybe the oldest of the universes s…

They are talking about Hubble's successor at http://news.bbc.co.uk/1/hi/world/americas/6645179.stm , which will "enable us to look further back towards the beginning of the universe." Surely, the limits to "how far back we can look" start fizzling out at a time when the universe is already quite old, though I suppose that doesn't count for parts of the universe that spread out in the opposite direction from this presumed central focal point of the Big Bang, wherever that may have occurred. Taking this into consideration, it would still be rather old stars that we would see moving into the other direction and have very little relation to the "beginning of the univers…

Just wanted to share this article from Physicsweb... http://physicsweb.org/articles/world/20/6/4/1 Although the main focus is on the detection of gravitational waves, it also serves as a concise summary of some of the key successes in the field of physics, and future areas of research.

The idea that the universe has a beginning and end seems too difficult to comprehend. It raises the questions "what caused the beginning?" and "what will happen after the end?" I can't understand why an unlimited amount of time would pass, and then the universe suddenly forms and expands, and then an unlimited amount of time passes again. I think the fact that the universe exists must be a law of physics. The universe must exist, just like any other law must be true. I believe that the universe is a never ending cycle. It has a phase of compression, it expands, and then compresses again. Given what we know about the universe, this is the only explanation that is…

Wikipedia lacks an article about black hole entropy, so I'm going to try and work it out for myself. I want you guys to help me by correcting mistakes and answering questions. It is my understanding that "entropy" is quantum mechanics talk for "information/description." So basically, when Stephen Hawking came up with the famous equation of S = (c^3*k*A)/(4*h*G), (h is actually read "h-bar," but I don't know how to type the real letter) he combined all the possible information of a black hole into one value, which he assigned the capital letter S. The units for the variables are thus: c^3=m^3/s^3, since c is the speed of light and thus is a velocity. k=J/K, or Jo…

It is generally accepted among astronomers that the heart of a black hole, the singularity, is an infinitely small geometric point, of infinit gravity and infinite density. It is derived through theoretical physics that at this singularity, space and time come to a screetching hault, and everything that reaches it is crushed out of existence. Or is it? Aproximately a century ago, Albert Einstein suggested in the theory of relativity that the force of gravity acted, not on objects, but on spacetime, curving it, and objects and energy just follow the curved path. So, by that logic, if the singularity is of infinite gravity, then spacetime must be infinitely dis…

the title says it all, Tomorrow May 31`st we will have our Second full moon this month lets hope it`s a clear sky so that we can see this, it`s quite a rare event, one might say it only happens once in a Blue Moon

Don't let the title mislead you. Yes, I know the information paradox is a dead controversy, but what I'm about to ask relates to how it could have been such a big deal in the first place. For those who don't know, the information paradox was a theory that was proposed in the 1970's by Stephen Hawking where he hypothesised that during the life of a black hole, the black hole wold suck up matter and energy, and then, at its death, said matter and energy would unexplicably disappear. It's called the INFORMATION paradox instead of the matter-energy paradox or something to that affect because these particles and energy contain information, so if this paradox were true, i…