Cosmology

VLBA grid system

Artemis13 — Fri, 20 Nov 2009 16:07:09 GMT

The article on the 35 linked radio telescopes that will help establish a new grid system makes the following statement (I am paraphrasing): "the [234] quasars, in spite of their proper motion, appear stationary as seen from earth." I don't understand how this can happen, given the expansion of the universe. What am I missing in my interpretation of this statement?

Question About Virtual Particles

darkmatter4brains — Thu, 13 Aug 2009 15:38:20 GMT

I've always understood that the "virtual" in virtual particles basically comes from the Heisenberg uncertainty principle, specifically the enery-time uncertainty relation - that you can create a particle of energy delta E out of "nothing" and this will not violate the conservation of energy as long as it disappears out of existence in a delta time (2 delta E / hbar). This is what virtual particles are doing all the time in the vacuum right? A particle-antiparticle pair comes into existence and they annihilate themselves before delta t.

Well, doesn't Hawking Radiation have one escaping to infinity and another falling into the black hole. If these guys don't annhilate before time delta t mentioned above, wouldn't they be violating the conservation of energy.

Another thread mentioned grabbing one in the lab - wouldn't this have the same problem.

Or, am I totally getting mixed up here .... it wouldn't be the first time!

Thanks!

Fusion Power

dnatech — Wed, 30 Sep 2009 12:49:10 GMT

Well, in my previous thread in my conjectures (right I hope and think), I listed a book entitled "Sun in a Bottle" written by Charles Seife. I sort of put it out there to buttress my belief that the modern interpretation of particle physics (especially) is wrong. I will start off by quoting a paragraph from the book on pages 105 and 106...it provides a sort-of synopsis:

"The brew did not behave the way scientitst expected it to. It seemed to have a mind of its own, thwarting all attempts to keep it under control. Pinch it or squeeze it or even try to keep it confined in a magnetic trap and it writhed around and ruffled itself in instability after instability. Physicists built bigger and more expensive machines to wrestle the instabilities into submission, but they were failing. As the machines started costing millions and tens of millions of dollars, the scientists were no closer to building a fusion reactor than before; they were just uncovering more and more subtle ways that the plasma fought their will."

The book again: "Sun in a Bottle"; subtitled "The Strange History of Fusion and the Science of Wishful Thinking". Copyright Charles Seife, 2008. First published in 2008 by Viking Penguin.

Deja Vu Theory

Cosmo-David — Thu, 23 Feb 2006 04:23:23 GMT

Something that couple of friends and I have been working on is a theory on Deja Vu. The group is stuck at a dead end, and we need all the help we can possibly get. We would like to recieve lots of feedback on this matter if possible and let me thank you all in advance.

Lets start off with a little background on the matter. A couple of friends and I were sitting at the lunch table at school ( 11th grade) when the topic first came up. We realized that we all had something really big in common... we all frequently have Deja Vu experiences. So we decided to do some testing at my father's lab. We were able to gain access to brain monitors and used them as we slept to monitor brain activity. Many repeated trails were done, since it was quiet unlikely that a person would have deja vu every night. Lukily, we did get at least 10 desired trails. The wierd thing was that brain activity was normal, which ofcourse went against our hypothesis. This later forced us to do things differently and rather talk about the actual experiences...

After consulting with many physcologists, we consulted with each other about our own experiences. We all came to an agreement that these experiences were more like memory flashbacks rather than something you dream about and later having it happen. Then the theory of parallel universes came up, but that didn't quiet fit in. This is what we came up with:

I will do my best to try to simplify it as short as possible, so bear with me. Deja vu is a memory flashback of something that has already happened. Lets say you, sitting by your computer right now, reading this post, were occupying two or more spaces at the same time. According to Albert Einstein, it's possible to occupy two spaces at the same time, but in different dimensions. Our theory is based upon this idea. We suggest that there are other dimensions that we can't percieve, in which we occupy space in. Basically, I am one person in this dimension and I am the same person in another dimension(s). Our idea is that these dimensions have different time scales. So, the next time you have deja vu of something you're almost certain of doing, perhaps you really did do it, hear it, seen it, etc., but in a different dimension.

We are no where near completing this theory, there are many questions that are still unanswered, and hopefully you all could help.

We are having a hard time understanding how the memory of the person in one dimension would leave that dimension and enter another one into the brain of the same person in this dimension. Any ideas?

Thanks in advance,

Dave A., Joseph R., Kyle S., Josh C., James C.

Black holes - cold spots - in Space

J.Gordon — Wed, 07 Oct 2009 16:32:11 GMT

G'morning all, I have been wondering. Perhaps a few souls out there are familiar with the BEC , the Bose-Einstein Condensate. In short the BEC experiment a is group of atoms, normally rubidium atoms entraped by weak- commonly obtained diode lasers. Tossed about and confined be these lazer like bingo balls in a box. And over time slowly, ever so slowly the temperature is reduced to - well temperatures unknown in nature. Eventually an attempt was made to 'shoot' light thru these now quite frozen atoms - and true to Einstein and Mr. Bose predictions - the light does 'not' pass thru..... light cannot escape. Hmm. Well perhaps these gravity well monsters we've all heard about. Black Holes, have something in common with what we now know is possible demonstrated by the BEC experiment. Perhaps Black Holes are quite cold.................. Just wondering. thanks for your time.

Cosmology: A linkage between Geology and The Galaxy

morbas — Sat, 22 Nov 2008 02:30:24 GMT

Paleoclimate: Oligocene Epoch and P-Tr Boundary

Could a galactic in plane quasar precession be causal to the central bar and galactic arms? The Oligocene temperature notch may be ‘a smoking gun’. The Oligocene was an epoch of few new fauna speciation, which indicates a global environment detrimental to diversity. The loss of Heliosphere shielding and exposure to Gamma Ray and X-ray could cause global cloud cover cooling. The Heliosphere can be reduced by the impact of high velocity interstellar material with a density range of kilo particles per cubic centimeter (Frisch, 2007). VLA galactic mapping (Georgelin, 1976) shows the origins of each arm approximately along the extended Galactic Bar axis. Quasar black hole 3C321 (NASA, 2007) emits a relativistic beam to a 20,000ly distant galaxy, causing star formation. For a central bar angular recession rate from Sol of 0.86(0.1) degree per million years also aligned to the Oligocene (33.5Ma), puts present angle of the central bar at 29 degrees lead relative to Sol (JPL indicates 32 degrees) and a central bar Sol interception interval of 210M-years. In coincidence, Sol is known to have a 64M-year oscillation about the galactic plane. A sinusoidal with a period of 64M-years has a 0.9 z-axis of 51.7 degrees (9.2M-years). So, to first order we see a 10M-year Sol dwell time at each of the 90% z-axis north and south apogees. Sol is presently rising north through the galactic plane at about 50/250^th maximum z-axis height. The Oligocene (33.5Ma) was then in the galactic plane region. The 220M-year Planetay Equidistant Rupture (PER, (Kvet, 1991) hits the Oligocene (33.5Ma) the P-Tr (251Ma). Also, a sinusoidal 64 M-year wave aligned to the galactic plane crossing (Sol, 5 Ma), and the P-Tr 251Ma approximates to 3.4 cycles of 64M-years. At the Permian Triassic extinction, Sol was in the 10M-year northern apogee region. The 220M-year also intercepts the middle Ordovician Epoch before leaving the entire Phanerozoic Era, a coincidental central plane position would indicate a galactic resonance. All the remaining eight Phanerozoic Geologic Periods have a collective 70M-year period to a standard deviation of 9M-years. If these correspond to arm intercepts then the Oligocene, Permian and Ordovician end dates are in intra-arm voids. The Permian intra-arm position compounded by a z-axis apogee would be in a region of extreme minimal Galactic shielding against an approaching Virgo Cluster extra-galactic bow shock. There is one more caveat, the P-Tr position would be between minor arm (Crux-Scutum) and a spur arm (unnamed), further exasperating earth’s celestial Gamma-Ray exposure.

morbas

Castaic, California 91384

The Spiral Structure of Our Galaxy Determined from Hii Regions ; Georgelin 1976
Complete Periodical Geological Time Table; Kvet, 1991
Astronomy and Astrophysics 351,506-618(1999).
Solar Journey: The Significance of our galactic environment for the heliosphere earth ; Frisch, 2007, Springer.
Melott, Liebermann, University of Kansas, 10 Jan 2007. The American Physical Society Abstracts et.al. Melott and Lieberman analysis of minimal bio-diversity correspondence to z axis apogee.
NASA Announces Discovery of Assault by a Black Hole; Evans, 2007.

Proximal Check: 360 degrees at 0.85 degrees per M-year with six arms yields a 70.6M-year arm to arm interception. ((360 degrees /(0.855 degrees/M-year))/6 arms =70.2M-year per arm.

Thought I would present an abstract of the research I have been at...following the Galactic Geologic Interval Theory posted in the Astronomy Archives. Perhaps I will hear from the web friends that participated in that fun expedition?

Overlay of JPL optical galactic map with Georgelin Astron & Astrophys 49,57-79(1976). VLA Hydrogen Mapping.

Diametric mirrored Georgelin overlay on NASA/JPL artists Galaxy Map. Overlay is black, spur arms are added in gray, as well as the gray labels. JPL places the Central Bar at a 32 degree to Sol. Sol is on the orange orbital path in the Orion Arm. Author has maintained naming convention, joining the Norma-Cygnus label based on a diametric structure, JPL has renamed the Scutum to Scutum-Centaurus. Notice: origins of all the arms are along the central bar vector line.

Dark Matter

Joep229 — Tue, 15 Sep 2009 15:04:39 GMT

Can someone educate me about why the rotational speed of objects in outer reaches of galaxies infers or implies that there must be invisible matter far beyond the edge of the visible matter? Is it possible that this uniform rotation is due to some effect of the central black hole that we do not understand?

Observing first clear sky

porcupinehill — Wed, 04 Nov 2009 04:09:59 GMT

According to Partridge "3K: The Cosmic Background Radiation" , the solar system is in motion relative to the CMB. The motion (to account for the dopplar shift required to create the CMB dipole anistrophy) is 360km/s +/- 20km/s roughly in the direction of constellations Leo and Crater. This works out to .0012c.

To stay honest to SR and the prevailing cosmological model, this velocity is relative to the ionized plasma that originally emitted the CMB photons ~350,000 years after the BB.

Thought experiment:

Jump in your ACME starship (equipped with ion drive but without the turbo-warp option) and start accelerating toward Leo and Crater. The original blue shift of the CMB dipole is enhanced. Accelerate more and the apparent temperature of the radiation increases well above 3K in the direction of acceleration (and dops toward 0K in the opposite direction). Continue this acceleration until the temperature of the cmb on the nose of the starship is 3000K (roughly the temperature of the original plasma).

The CMB will now be largely in the visible spectrum in a small circle in the original direction of acceleration. You are now very close to c relative to Earth. In fact Earth and the nearby galaxies have contracted by the lorentz factor and nearly disappeared. The prevailing feature of the universe around you is a bright spot on the nose.

So... are you now observing the primordial plasma cloud as it existed 13 billion years ago?. Is it in focus? Is this a direct observation of the universe right after the BB?

Up & Running

jodoak — Thu, 29 Oct 2009 19:34:35 GMT

The Large Hadron Collider is up and running.

http://www.foxnews.com/story/0,2933,570326,00.html

From Stringgene: A BB discussion

Stringgene — Sun, 18 Oct 2009 06:58:40 GMT

Heavy Elements and the Solar System Origin

brooksquest — Wed, 14 Oct 2009 01:23:16 GMT

Elements heavier than iron are created only in supernova explosions. This means that in the galactic neighborhood where our Solar System now resides, there were in the past at least one (perhaps more) supernova explosions that gave us the heavy elements found in the terestrials and in other parts of the solar system.

Is there any evidence, gas, radiation etc... leftover from the supernova that gave us our home planet? Is it common for supernova leftovers to reincarnate as solar systems? The solar system is believed to have started out as a large gas cloud, gravity, rotation etc... Was the cloud a supernova remnant? I wonder how many supernova it would take to generate all the heavier elements in our solar system?

Could the CMB be leftover radiation from the supernova that gave us our planet?

Just some thoughts. Jeff have you read any on this subject?

Cheers,

Seeing the Big Bang?

AstroTime — Wed, 15 Apr 2009 06:13:01 GMT

Hi everyone,

Well, as we all know, light takes awhile to travel in space. Looking in the sky is like looking in the past. The furthest thing we can see (from what I know) is the Cosmic Microwave Background radiation which was said to be created 400,000 years after the Big Bang. My question is, if one day, we will be able to see the light/gas (through instruments) from the Big Bang. Of course not in our lifetime but it should'nt be that much longer away due to the visibility of the CMBR, relatively speaking.

Or is it never going to come into view because we where a part of it?

Explaining the theory

Dj1 — Mon, 21 Sep 2009 13:29:36 GMT

Hi, I read the comments on my theory about the black hole and dark energy ... Regarding the grammar… I used Google translator and ... In any case, I accept the criticism. I will correct that now.

The world's best scientists claim that "something" exploded in a "big bang" and that our universe is the result of that explosion. Using the best equipment they calculated that the universe should cease to expand. By this calculation it should begin to shrink and gather , attracted by the strength of gravity of celestial bodies in it. However, they were surprised when they discovered that the universe is still expanding and even accelerating. Scientists also claim that there are two main forces in the universe, dark matter that holds the universe together and dark energy, which expands the universe.

This is my theory about that:

First, to claim that the object that exploded in the "big bang" was the only one in the universe at that moment is not reasonable. We should at least consider the possibility that other celestial bodies existed at the time

Second, if we have to guess which kind of object exploded in the "big bang", the best candidate would be a black hole, because all we know about the universe points to that, but this theory is already known.

Third, most of the celestial objects in the universe, especially black holes are surrounded by other celestial objects. And therefore, if they explode, their remains will be surrounded by these celestial objects.

Fourth, when something explodes, usually all that remains is just a cloud of dust, which contains small particles of the exploded object. So, if we have a cloud of dust at the place where the black hole or some other object used to be, surrounded by space objects of normal size, perhaps the entire galaxy of such objects, what behavior can we expect from that cloud of dust? I think that the small particles that make that cloud of dust would be attracted by the huge mass of those surrounding objects. Despite the mutual attraction of particles within the cloud, it would eventually be ripped a part by gravity pull of those massive objects.

Fifth, when the object moves, it must be either pushed or pulled. If some force is pushing the object, then that force must be faster than that object . In the universe, it would mean that the inner layer mast expand faster, or at least in the same speed, than the outer layer, in order to push it away. This is not the case. On the contrary, the outer layer expands and accelerates faster than the inner layer. This can happen only if some external force is expanding the universe by pulling it apart.

I think that my theory is no less logical than the existing theories. And if it is correct, then we will have the explanation for dark matter, dark energy and expanding of the universe.

P.S. This is only a theory. For me theory is the assumption that exists between , "proven to be theoretically impossible" and "proven true".

That is all, bye people.

The LHC Still having problems with the magnets.

Primordial — Mon, 10 Aug 2009 16:18:42 GMT

Looks like problems with electrical supply connections to the magnets. They may not run with full power for about another year.

The big bang and the expanding universe

Buckzumoff — Tue, 25 Mar 2008 00:57:28 GMT

I read an article by Jerrold G Thacker called re inventing the universe. It talks about how we all assume the universe is expanding because of the red shift of the light spectrum of distant galaxies. Noting that nothing actually has been proven and just educated speculation on astronomers part. He goes on to say that astronomers use the doppler effect as proof of the red shift and not taking into effect the great amounts of gravitational effect on the light spectrum over the vast distances that the light has to travel. He uses the Shapiro effect as the reason for the red shift. Is there anyone else looking into this mans ideas or are we just going to assume that everything we are told is a fact without exploring any other options. Is there any other studies into this Shapiro effect theory that Mr. Thacker has presented

Black Stars not Black Holes

Iggle — Fri, 25 Sep 2009 12:45:34 GMT

There is an interesting article in Scientific American about quantum effects making black holes virtually impossible to form. They argue for the existence of bodies without an event horizon and yet still dense enough to cause many of the effects associated with the concept of a black hole. As an amateur, I always find it interesting when one finds that there is still serious scientific debate about concepts that the popular press implies are settled.

Scientific American

Our observable universe is not 30 to 38 billion light years in distance.

Dusty_Matter — Sat, 27 Jun 2009 03:17:57 GMT

While perusing the August 2009 issue of Astronomy magazine, I came across a one page article who’s topic was on the edges of our universe. In it, was the idea that the limit of our observable universe is roughly to about 38 billion light years in radius from us. This is wrong.

In the article the author mentions a galaxy named A1689-zD1, who’s light took 13 billion years to reach us. In other words, we can glimpse a galaxy as it was 13 billion years ago. Now, 13 billion years ago A1689... was only 3.35 billion light years away from us, however because of the expansion of the universe it now lies about 30 billion light years away. This is true.

If it took 13 billion years for the light to now reach us, from a galaxy that was only 3.35 billion light years away from us in distance, that would mean that that light is extremely stretched. (red-shifted)

If the universe is 13.7 billion years old, and now A1689... Is 30 billion light years away from us, if we subtract 3.35 billion light years from that distance and average out that galaxies speed of recession from us, how fast is that galaxy’s average speed of recession from us? The answer is almost twice the speed of light. 30 - 3.35 = 26.65

26.65/13.7 = 1.945

How can we observe something that’s average speed is almost twice the speed of light? And as an object gets farther and farther away from us their speed of recession increases due to the expansion of the universe. In other words A1689... Is really traveling at more than twice the speed of light from us, now. How can they say then, that our observable universe is roughly 30 to 38 billion light years in distance? It’s not.

Looking out in distance is also looking back in time, and we can only see so far back into time. About 13 billion years or so.

It’s like taking a photo of a bird in flight. And then six months from that time, you pull out the photo show it to a friend, and say. “That bird is now thousands of mile away, and so because of this photo, I can now see over a thousand miles in the direction that that bird flew in.”

The Hubble Ultra Deep Field shows lots of little baby galaxies. These galaxies are now well over 20 billion light years away. Do you think they stayed little baby galaxies? They never merged, or collided, shrank in numbers, and grew in size? Is the photo of A1689... From 13 billion years ago still a current photo? Because that galaxy (which has certainly changed in over 13 billion years time) is now 30 billion light years away, is it justifiable to say that we can now observe things 30 billion light years away? Can we see objects that are receding from us at twice the speed of light or greater? The answer is no.

While distances can be confusing, we can only see as far back in time as about 13 billion years ago. That severely limits our observational horizons. We cannot see those ancient distant objects where they reside today, and their light will now never reach us. Our observable universe is limited by time, and speed of recession, and nothing is going to change that.

The author then said something about the “great attractor” being beyond our visible universe. He says “many astronomers think this…” As far as the “great attractor” is concerned, it is not located outside of our observable universe, especially if you are saying that the horizon to our observable universe is at least 30 billion light years away. In fact it lies much closer than even 13 billion light years away. It is thought to be in the region of the Shapely Supercluster. All less than even a billion light years away. I can’t help but wonder, just how “many astronomers” think it’s beyond our visible universe?

I am also beginning to wonder if the writer of these articles is really doing his own writing.

Semi-classical musings

dnatech — Mon, 27 Jul 2009 05:52:57 GMT

I don't propose a complete re-write of theories based on observations...but what has seemed to work pretty well is quantum mechanics. However, I find it troublesome that there seems to be no answer to some reasons concerning subjects such as why there is such a thing as charge or the Pauli Exclusion Principle and others for example (if it is necessary...apparently people involved in the science are wondering why such things occur) . Sometimes I just want to throw some ideas or musings out there to see if the stick in my mind or others. I too have reservations, just as Einstein did about the IDEA of quantum mechanics...however it has been pretty successful.

I have posted before under the posting of Graviton Configurations. It was fanciful, but why not? I believe that there has been things overlooked and by positing again I hope to provide some deeper thought on the broad subject of Cosmology. Something I have thought of include the idea of maybe there are different types of space...space which by common speculation is absolutely nothing at all. If there is truth to that, then what if you have multiples of absolutely nothing. I can conjecture this as a term in my head: Absolutely Nothing. It is something like conjecturing something like "Beyond Infinity"...it is there. I live in a Universe where I can actually place that...I can term it. Why should I be able to term Absolute Nothing in multiple terms...why should I even have the ability to conceive of this?

As you recall, I said that gravitons are configured. Spin quantities ARE additive. I posited that there are three different types of space: Positive, Negative, and Null. I posited that there are two momentum axes. I positied that there is a charge axis. I posited that in positive space the only particles in existence or is absolutely necessary are two electrons...each one of them thermally displaced from each other from our perspective. Electrons ONLY see another electron...everything else in this Universe is another electron.

There are Apparent and Non-apparent aspects to this Universe from my mind to yours. I do have personal faith in what I post here and other places. There is something missing in my mind's eye in the totality of what has been said up to this point by all. This missing element from all this can be laid in my opinion is the concept of Superconductivity. In my opinion, Quantum Mechanics has skipped the application of this non-apparent superconductivity. In fact, I believe there are several non-apparent superconductivity arrays in this Universe. I believe this goes a long way in explaining the Whys that quantum physicists have ignored. Simply put, quantum mechanics IS the tracking of non-apparent supercondutivity.

Thoughts on black holes and big bangs

Joep229 — Fri, 11 Sep 2009 23:00:18 GMT

I read this headline today and it started me thinking. "University of Hawaii astronomer finds giant galaxy hosting the most distant supermassive black hole" "The black hole contains at least a billion times as much matter as does our Sun." This galaxy is 12.8 billion light years away and had that much mass 12.8 billion years ago. I wonder how large and massive this black hole is right now and. I think I read that it is theorized that for some unknown reason there are an inordinate number of supermassive black holes in early galaxies. The gravity fields of supermassive black holes must be many times (millions?) the diameter of their visible galaxies. I wonder if in these areas of the universe where galaxies were closer and clumped together as seen in WMAP (Light and clumps in the WMAP picture is from only 379,000 years after the Big Bang), possibly because of the gravitational influence of their super massive black holes, and despite the fact that the universe is expanding, after many billions of years the interracting masses could reach a threshhold where they start gravitationally falling towards each other. The Oort cloud is thought to be 3 light years from the sun and is also thought to be the edge of the sun's gravitational influence. Imagine the distance of the gravitational influence of a supermassive black hole say 5 billion times more massive than the sun? What if the clumped areas eventually collapse into individual supermassive black holes and they then eventually combine to form a stupendously, unbelieveably supermassive black hole and when eventually some threshhold of mass is reached - BANG! a new universe is born right inside the existing universe. The new universe also develops clumpy areas which also eventually condense, and BANG again, over and over. Maybe our 13.7 billion year old universe is just a miniscule little sub-universe that was the result of one of these BANGS somewhere inside the original one (if there was an 'original' one). Just a thought. Any comments? Obviously, I'm not a cosmologist, just curious.

What are the "other" 8 dimensions? (was: READ)

oMulveYo — Thu, 10 Sep 2009 02:34:40 GMT

so me and my friend are having an intellectual conversation regarding the dimension, jeff what are the supposed dimensions? like i know we can comprehend 3... but what are the other 8? this no one may know but ive had no luck on google searches so i figured i would ask on this forum for a straight answer thanks!

Extreme Matter

lynxcat — Thu, 02 Mar 2006 06:15:31 GMT

You know how they say that white dwarf and neutron star stuff is super dence because of the stars gravity... Well, I've always wondered if you could bring some of it back here on Earth, would it still stay super dence or would it expand back out to it's normal density once it was no longer in a strong gravity field? Sort of like a sponge that you compressed with your hands and then let it go.

They should have an Ask Astro section in the forum!

New Cosmology 101 video series

Karri Ferron — Wed, 19 Aug 2009 19:28:18 GMT

I just wanted to make everyone aware of a new video series Associate Editor Liz Kruesi is working on. The series is called Cosmology 101, and each video provides an overview of a different concept in the field. So far, she's produced two installments:

The Big Bang

Dark Matter

The Big Bang video is available to anyone, while the Dark Matter piece is available to registered members of Astronomy.com. Registration on Astronomy.com is free and easy, although if you are posting on the Forums, you've obviously already registered.

Enjoy!

largest HST imaging data set now available!!!

acs-gc — Sun, 05 Jul 2009 19:14:03 GMT

Hi,

I am currently working at the Jet Propulsion Laboratory in Pasadena as an astronomer and have some fun links to share with everyone. I have done extensive research with the Hubble Space Telescope and have provided a website to allow the public to have access to this data set. please take a look and let me know what you think.

http://www.ugastro.berkeley.edu/~rgriffit/Morphologies/

as well as my personal website

http://isi19.ssl.berkeley.edu/~rogerg/My_site/Welcome.html

and a youtube site with a bunch of fun astronomy videos I made

http://www.youtube.com/user/ganguskan8

cheers,

Crashing comets not likely the cause of Earth's mass extinctions...other thoughts

jenshadus — Sat, 08 Aug 2009 23:42:42 GMT

This was an interesting article. I was a geology major; so I still stay updated with that. I had just watched a special about methane gas in the ocean floor and it being a possible contributor to the various extinctions attributed to comets. The methane theory may prove to be more probable considering the recent history of deaths by methane erupting from lakes in africa. But then, who is to say that at least one time a comet didn't kill dinasours.

Existence of Gravity...

de_oppresso_liber — Sat, 25 Jul 2009 18:29:19 GMT

Hello all, I've been doing some research and did some thinking... Why is it that Gravity cannot be proven? I mean, we know how it works and we know what it is, yet we cannot prove it. Maybe I'm wrong on this, but can anyone shed some light on it?