Airbrush

Thanks for the answers to my question above. So basically, the reasons Barak Obama announced the killing of Bin Laden was because the operation was messy, we invaded Pakistani territory without telling them, and we assumed that the info would get out rapidly anyhow.

Here is a question I never heard asked. What good was it to immediately announce Osama Bin Laden's death? Why not keep it a secret and use the info gathered at his compound to track down and kill or capture other Al Qaeda leaders BEFORE they could find out by looking at the newpaper headlines "Bin Laden Killed"? Then they all scattered and we missed a golden opportunity.

If the entire universe really was smaller than a proton when it started expanding, and it has been expending at a finite rate. Even if explansion during inflation was a number of times faster than light speed, the expansion rate was a finite number. Then how can it reach an infinite size in a finite period of time? Therefore, it appear that the size of the universe is finite.

Watch some science series such as "The Universe" "How the Universe Works" or "Wonders of the Universe". Do you have cable TV? Science channel often has astronomy programs.

They don't know and openly admit that. But dark energy does not make the universe expand, it only accelerates the expansion from the Big Bang.

85% of stars are red dwarfs. Even stars that are much larger than red dwarfs, such as our sun, cannot explode. So I will go out on a limb and stay probably over 95% of stars you see in our galaxy will never explode. Also, not all stars you see in the sky are as old as you think. In other galaxies we detect gamma ray bursts almost every day. But that is because there are so many galaxies.

The theory is that black holes evaporate by Hawking Radiation. Just before it disappears it explodes. This can only be seen by us to happen to very tiny, primordial black holes, because stellar black holes will take Googols of years to evaporate to that degree, and the universe has only been around for less than 14 Billion years.

"What exactly is gravity?" Gravity is the curvature of space caused by matter.

Expansion is from the Big Bang, the acceleration of expansion is currently explained by dark energy. Dark matter has nothing to do with it, nor does gravity. Gravity and dark matter work against expansion. Dark energy does not "use" gravity.

Certainly all black holes must spin, because stars spin, and even if the star is slowly spinning, when it collapses into a black hole any spin will be immensely increased, like the spinning ice skater bringing their arms in. They relatively quickly lose energy and lose spin, but will always be spinning some. But black holes are there and if they vanished gravitationally then they wouldn't exist, and yet they are still there. If your theory was correct, there would be fewer black holes. "Rotating black holes are formed in the gravitational collapse of a massive spinning star or from the collapse of a collection of stars or gas with a total non-zero angular momentum. As most stars rotate it is expected that most black holes in nature are rotating black holes. In late 2006, astronomers reported estimates of the spin rates of black holes in the Astrophysical Journal. A black hole in the Milky Way, GRS 1915+105, may rotate 1,150 times per second, approaching the theoretical upper limit. "A rotating black hole can produce large amounts of energy at the expense of its rotational energy. This happens through the Penrose process in the black hole's ergosphere, an area just outside its event horizon. In that case a rotating black hole gradually reduces to a Schwarzschild black hole, the minimum configuration from which no further energy can be extracted, although the Kerr black hole's rotation velocity will never quite reach zero." http://en.wikipedia.org/wiki/Rotating_black_hole

In this senario, everything will have evaporated into a state of maximum entropy, empty space with low energy photons flying around at the speed of light? So will their energy not be destroyed but rather extremely rarified, to the point of a few photons per cubic Billion light years? What if there is a Big Rip, will the same happen?

Outside our Virgo Supercluster there is hardly any lateral motion. All other superclusters are moving away from us. I suppose the method they use to measure galactic rotation could also be used to measure lateral motion of galaxies within our supercluster. Anyone know how they measure galactic rotation speed?

I was watching an episode of "Wonders of the Universe", or something like that, on the Science Channel. As I recall Brian described the universe far into the future, in very deep time, after all the stars have burned out as black dwarfs, and even after all black holes have evaporated. In fact, all matter will have evaporated, and all that will remain is something like dead photons. I am not clear on this. What will remain? Do photons die, or lose their energy, so they are dark, and yet they still exist? How can anything have no mass and no energy, and yet exist?

Distance is obviously a measurement between 2 different locations, which can be subatomic, as you proposed, but also between ANY 2 objects in different locations. Ok, here you go.....there.....you want to see me prove nothing again?

Ok, here is my proof. You cannot divide by zero. Just kidding. Since "nothing" is such a loded term in this context, I'd like to see someone prove nothing. "Nothing does exist. It exists between the nucleous of an atom and the electron." I like this explanation. However, the deeper we probe matter, the more complicated it gets. Maybe there is something between a nucleus and the lowest energy electron shell, we just haven't discovered it yet.

"Could dark matter be nothing; literally?" Do you know the meaning of the word "literally"? My dictionary says "in a basic or strict sense". How can literally nothing have gravitational lensing and other effects? The word "nothing" is often used loosely or figuratively in cosmological discussions. But literally nothing is a preposterous proposition. Where can this literal nothing exist? Between the singularity and event horizon of a black hole? Or when did it exist? Before the big bang? Please tell me more about this literal nothing.

Just because something may seem like nothing does not prove literal nothingness. Is outer space nothingness? No, there are atoms there, even in the middle of the great voids, there are atoms. There are also virtual particle pair popping in and out of empty space. Where do they come from? Prove literal nothingness.

"nothing; literally" is an impossibility.

Why is it all or nothing when it comes to closing tax loopholes? Keep the home mortgage interest deduction, but put a limit on it. Duuuhhhhhh! So the average American takes a loan of $100,000 to $300,000, for example, to buy a home. For bigger loans for rich people, only allow the interest deduction for a $300,000 loan.

Good idea. Build the spaceship so robust and streamlined that it will penetrate and pass through objects.

I was watching Stephen Hawkings "Into the Universe" the episode about time travel. He said travel into the past is unlikely because of the "Grandfather Paradox", and using wormholes is also unlikely because of "feedback". However the most likely option is traveling at such a high speed that time dilation becomes a major factor. But traveling at such high speeds, like 90% light speed or higher, seems too dangerous. How do you dodge a pebble when you are traveling so fast? Also the faster you are moving, the more massive your spaceship is, so the more energy it takes to make any change in velocity. It seems impossible to fly around objects, which will probably destroy your spaceship. As my signature says "How do you dodge a bullet" at such high speeds? Or are they confident that interstellar space is so empty that you will probably not run into anything?

Alpha, I admire your courage to discuss this in English which is obviously not your first language. May I ask what your first language is? Hydrogen has various densities depending upon the pressure. Deep inside of Jupiter the Hydrogen is very heavy and dense from high pressure. It even becomes like a liquid with high temperatures and metallic. "Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, although helium only comprises about a tenth of the number of molecules. It may also have a rocky core of heavier elements." http://en.wikipedia.org/wiki/Jupiter

I think the velocity is simply directly proportional to the distance. Distant superclusters that are twice as far away as a nearby supercluster will be receding at twice the speed.

There are small localized holes in the Ozone layer, over Antarctica and over the Atlantic Ocean off the coast of Brazil. This is common knowledge and not a subject of debate among scientists. These holes will not cause the atmosphere to "scatter out to space" because gravity holds the atmosphere.

"Why do you insist about a theory that water had been vaporized from the Earth and later on new water had been delivered by comets and asteroids?" Because in recent programs I have seen on TV, with findings from 2010, the experts best guess is that the early Earth was baked dry by its' molten state from the late heavy bombardment, which lasted for 10s or 100s of Million years. Even though most of the water had baked away from the planet, there could still remain traces of the original liquid water as old as 4.4 Billion years, which you refer to. The vast amount of water on Earth now can only be explained as having been delivered over the past several Billion years by asteroids and comets. And if these were plastering the Earth with water, they would do the same to the Moon and Mars. Why do you so quickly reject the best guesses by the experts?