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Where did you read that? Obtaining a stable orbit is pretty simple. Lift the object out of the bulk of the atmosphere and give it a horizontal velocity somewhere between 17,500 and 24,700 miles per hour. Achieving a precise orbit is a bit more taxing. Where did you read that? Rocket science is not all that exact a science -- at least not the thrust (typical variance from expected thrust is 2 to 10 percent, depending on the thruster), or the delta V (typical variance from expected performance is a percent or so). This is one of reasons why spacecraft control systems are so hideously complex. How did you read that into the link I provided? There were no changes in how they create trajectories. They didn't complicate the launch. That launch was quite simple compared to modern ones. They just didn't know the initial trajectory all that well. The vehicle gave slightly better performance than nominal. Suppose Hoagland was right, that there is a fifty year old secret. Our allies and our enemies would also have to be in on the secret or they would not be able to have satellites orbiting the Earth the way we do. I would have to have been informed of that secret to do my jobs. Tens of thousands of others like me would have to have been informed of it as well -- and that includes students from all over the world. Somebody would have spilled the beans long ago. There is no secret. Hoagland is just lying (again).

It's not. It explains nothing. Baloney. Many of us has said that it explains nothing. We, on the other hand have asked you to explain - How uncharged objects fall. - How moons can orbit planets. - To state exactly where on the electric universe you perceive yourself. You have not said one word with regard to these questions. Baloney. Science has a very good understanding of how the sun formed. Science has an excellent understanding of the energy source that ultimately makes the sun shines. Science has a very, very good understanding of what will become of the sun. Science has a fairly good understanding of the solar dynamo. This last is from Alfven. There are a few open questions. There's the angular momentum problem in the formation of stars and solar systems. Coronal heating is another. Just because there are open questions does not invalidate the whole. Huh? That is a false argument. Nobody says it does. The fact is, there are four forces, not one. Electromagnetism does not explain how stars form, why stars form galaxies, why stars shine.

We've had some incredible crackpots come through here who not only claimed to have PhDs but in fact do have PhDs. One claimed that physicists from Newton on have gravity all wrong. That "gravitational force is equal to the product of the acceleration times the area of a circle with radius equal to the semimajor axis of revolution (F = a . A) is the correct interpretation of Kepler's third law." This in turn means that the gravitational force on the surface of the Moon is at least 68.71% that of Earth's. Ergo, we didn't land on the Moon. Another claimed that everything did gyre and gimble in the wabe. Or something like that. Actually something more like "I <–> denergyre (denergon) <–> ombregyre (ombron) <–> photogyre (photon) <–> electrogyre (electron) <–> hydroxygyre (hydroxyon) <–> carbogyre (carbyon)<–> phosphogyre (phosphon) <–> ribogyre (ribon) <–> aminogyre (aminon) <–> deoxyogyre (deoxyon) <–> cellulogyre (cellulon) <–> organogyre (organon) <–> envirogyre (environ) <–> visigyre (visuon) <–> phonogyre (phonon) <–> linguigyre (linguon) <–> symbogyre (symbon) <–> numerogyre (numeron) <–> econogyre (econon)<–> lapoligyre (lapolon) <–> geniugyre (geniuon) <–> I".

Incorrect. Dr Rocket is correct. The identity relationship is reflexive by definition. Oh really. Perhaps you should tell us what you think then. What set, what axioms, and what definition of equality are you using that makes you think that "it's not what you think"?

That 2.5% error in Δv (change in velocity) was very small considering the capabilities of those times. That vehicle had no inertial navigation system, no onboard computer, no GPS. It used solid rocket upper stages rather than liquid. Nowadays rockets are launched into orbit with liquid upper stages so that the rockets can be turned off when the desired Δv is attained. Modern vehicles have elaborate inertial navigation systems to assess the Δv and to control the vehicle. As an example, here's the planned mission timeline for the rendezvous and capture of the Japanese H2 Transfer Vehicle: http://spaceflightnow.com/h2b/htv1/090902missiontimeline.html. Notice the complex sequence of burns used to make this rendezvous and capture happen.

It doesn't take much expertise to know that anything and everything that Richard Hoagland says is 100% excrement. He lies, sells a book, someone debunks his lies. He lies again, sells another book, makes some paid appearances, someone debunks his lies. He never recants his lies. He does this over and over and over again. He preys upon the gullible. This is my field of expertise, and no, I don't need to prove it to you. If you don't believe me, perhaps you'll believe this. http://www.thespacereview.com/article/1224/1

SHM = simple harmonic motion. SFN = ScienceForums.net Avirup-Croocked Scientist, what work have you done on this problem? This is essentially a homework problem. You need to show some work before we can help you.

The melting temperature of iron is 2800 °F at one atmosphere of pressure. That does not mean that the melting point is 2800 °F at the center of the Earth. In almost all substances (water is a marked exception), the melting point increases with increased pressure.

It only explains that with immense amounts of hand waving. It does not explain coronal heating in a scientific manner. The electric universe crowd not only rejects gravitation, they also reject the concept of fusion being the ultimate source of a star's energy. They are completely nuts. I agree with that wholeheartedly.

No. He. Didn't. That link you gave was to an article by Richard Hoagland. Hoagland is either an absolute nut or a very canny charlatan, or perhaps both. The electric universe crackpots look almost legit in comparison to Hoagland's nutty writings. Over fifty nations have put satellites into orbit, about nine of them with their own launch vehicles, the others using one of those nine countries / associations of countries to put satellites into orbit. The United States has a program that lets colleges put microsatellites (cubesats) into orbit. If Hoagland was right, somebody would have blabbed. There is nothing to blab. Rather than focusing your time and energy on crackpot sites, I suggest that you spend your time and energy learning some real science.

The entire Earth became hotter than the melting point of iron shortly after the Earth formed. The iron core formed after this melt. This differentiation of the Earth resulted in even more warming. The iron core was entirely molten when it first formed. The Earth's core froze (and is freezing) as the Earth cooled. When the solid core first formed is not known. It was perhaps somewhere between four billion years ago (half a billion years after the formation of the liquid core) to only two billion years ago.

Sure it can. Some teachers encourage curiosity. They like kids who ask those nasty questions. Even one such teacher can make a huge difference in a student's ultimate outcome. Other teachers discourage curiosity, or rather, the education system as a whole discourages it. With the extreme focus on standardized tests, school administers encourage teachers to teach the test and nothing else lest they lose their jobs or lose funding. Teachers teach the test lest they lose their jobs. Anything that impedes students doing well on the standardized tests, and that anything includes fostering curiosity.

So try being objective yourself. What open problems does this electric universe concept explain? Even more importantly, what solved problems does this electric universe concept explain? The former question is important because explaining open questions is exactly what new hypotheses are supposed to do. Otherwise, why bother? The latter question is important because any new theory must explain those phenomena that are already well explained by science. A new concept that fails in this regard is a big step backwards, not forwards. For example, relativity and quantum mechanics had to explain not only how classical physics was wrong, they also had to explain why classical physics was so very good in the domain where classical physics was applicable. It would be nice to know where you fit on the electric universe / plasma cosmology / plasma astrophysics spectrum. Which of these best describe your point of view: There is no such thing as gravity, or the weak interaction or the strong interaction. Electromagnetism is the one and only interaction. Gravitation exists and explains why apples fall, but it does not explain why satellites orbit planets, planets orbit a star, etc. Gravitation exists and is the dominant force between planets and satellites, stars and planets, but it plays a lesser role at the galactic scale. Electromagnetism is the dominant force at galactic scales and larger. Gravitation exists and is the dominant force at the scale of solar systems and larger. However, the weak and strong force are needed to explain what happens at the very core of a star, and electromagnetism is needed to explain electromagnetic phenomena. Electromagnetism may also play a secondary role in the formation of galaxies and stars. Gravitation exists and is essentially the only force at the scale of solar systems and larger. Some in the electric universe crowd apparently espouse option #1. It is nonsense, so utterly nonsensical that the word nonsense barely applies. Option #2 is almost as bad. Even option #3 is still nonsense. Option #5 is the parodized version of cosmology presented by proponents of electric universe nonsense. It too is nonsense, but nobody worth their salt disputes that electromagnetism plays some role. It is however secondary to gravitation for the most part.

What you are missing is that that thing that we call a "foot" varies quite a bit across species. There are three basic forms. A ballerina walking on the very tips of her toes is analogous to how horses, cows, and antelopes move. Only the very tips of their toes of these unguligrade animals touch the ground. A horse's hooves: Those are the equivalent of our toenails. A person walking on tiptoes (but not the very tips of the toes) is analogous to how dogs, cats, and birds move. Those digitigrade animals stand on their digits. The equivalent of the ankle in both unguligrade and digitigrade animals is well off the ground. Some people see this as a backwards knee. It's not. Those animals have knees that are much higher up the leg. Humans, opossums, bears, and raccoons are plantigrades. We walk with our heels on the ground. This stance a bit awkward and slow compared to the other two stances.

Imagine that you're outside on clear, calm day and you hear the sound of a far-off passenger jet up in the sky. You look in the sky in the direction the sound appears to be coming from. There's no jet there! Did the plane disappear? Of course not. If you listen for a while the source of the sound appears to be moving. You can see the jet by looking well in front of the source of the sound. Now that you can see the jet, you can hear that there is no sound coming from where you see the jet. The sound is coming from well behind the jet. On a clear, calm day you can see and hear a jet that is 13 miles (21 kilometers) away. For such a distance, the sound you are hearing now is the sound that the jet emitted over a minute ago. You are hearing what was, not what is. You are hearing into the past. You only hear the sound from one spot, not two or three or more. You are hearing the jet from where it was a minute ago. The sound from where it was 90 seconds ago: You heard that 30 seconds ago. That sound has already gone past. The sound from where it was 30 seconds ago, or where it is now: You haven't heard that yet. Those sound waves are still en route to you. You will hear those sounds when they reach you.

Yes, it is. Pressure is essentially the weight of all of the mass above the point in question. So even though gravitational force goes to zero at the center of some object, the pressure goes to a maximum at the center.

The net gravitational force is zero. The pressure, however, is immense. A hollow region as mentioned in the original post couldn't exist because of the immense pressure.

Newton's crackpottery was crackpottery back in Newton's day. He was cracked by the standards of his own time, particularly with regard to his fascination with the occult and his religious views.

You forgot Newton, who was arguably the smartest physicist of all times. He was also completely and utterly cracked. I would venture that most good scientists have, and almost all the great ones had, more than a tinge of crackpottery to their thinking. We remember those great scientists for their good ideas. That they also had some completely cracked ideas, well, that goes with the territory. Perhaps, perhaps not. The crackpot fanbois love Tesla for some reason. He does not rank up there with the crackpots those fanbois should be looking to such as Newton, Einstein, Dirac, .... Those words are not yours. You should have given proper attribution. That said, the only places you'll find these words is at crackpot fanboi sites. Didn't your mama, or your wife, or your daughter tell you not to believe everything you read on the internet? Those words are nonsense, of course. They sad thing is that there is no way to disprove them. There are no secret papers. That doesn't stop the conspiracy nuts.

It's important to distinguish between plasma cosmology and the electric universe "theory". Plasma cosmology is a bit fringy. Electric universe is pure crap. Unlike that electric universe nonsense, plasma cosmologists don't claim that gravitation doesn't exist. What they do claim is that their science has been given short shrift. With regard to star formation, there are some aspects of plasma astrophysics that may provide answers to some open questions such as the angular momentum problem. (The Sun has almost all of the mass of the solar system, about 99.9% of it. The Sun has very little of the angular momentum of the solar system, less than 1% of it. Why is that?) The currently accepted mechanism is magnetic breaking, so obviously an electromagnetic phenomenon. Magnetic breaking isn't really plasma cosmology, however. It's plasma astrophysics. Once the star does form you aren't going to be able to explain what's going on inside it without plasma physics. That again however is not plasma cosmology. It's plasma physics. On a galactic scale, there are fewer open questions to which plasma cosmology provides even a clue of an answer. There several concepts from plasma cosmologists that have been falsified at this scale. On an even grander scale, its gravitation that provides the answers. There are no answers from plasma cosmology.

You've got it backwards. It's your version that is kind of scary. Your version requires outfitting an entire galaxy with an Alcubierre-style drive, with the galaxy coming to a stop now and then to refuel. What we would see would be the galaxy during those refueling stops (which would presumably entail the consumption of an entire galactic cluster; Alcubierre drives require a preposterous amount of energy). Fortunately we don't see anything of the sort. There are rare cases where astronomers do see multiple images of the same galaxy. It's called gravitational lensing. That gravitational lensing is very different from what you are proposing.

This forum does allow speculative posts. Just take a look at the speculations section. At some point those who maintain the site will demand that those speculators put up or shut up. That is their right; they own the site. We don't. Other forums do not allow speculative posts at all. That too is their right. It is those who own a web site who get to decide what is allowed and what isn't. Regarding the nonsense you just posted, right now on this forum there is an active discussion on whether it would be ethical to terraform a planet orbiting a star that will explode a couple of million years later. That discussion is quite OK here even though we don't know how to go to other stars or know how to terraform planets. Oh please. Enough with the over the top, oh woe is me rhetoric. If you don't like this discussion forum, or some other one, start your own discussion forum. It's easy. Do that and you'll get to set the rules, but you'll also have to pay the bills.

I'll leave your last question unanswered. As far as the electric universe "theory" goes, it is nonsense. Galaxies orbit each other, stars orbit about the galaxies that host them and in some cases orbit one another, planets orbit stars, moons orbit planets. The only way this makes sense is if everything is attracted to everything else. The electric universe nonsense cannot explain this. Gravitation does.

I feel your pain. One problem here is that giving a solid clue as to "how they know it" requires a basic understanding of the underlying science. People only start getting that basic understanding in the first year of a graduate program. Another problem with many of those popular science programs is that they often overstate things as fact. How are you to know that what you just saw on a TV show presented as fact is in fact they a highly conjectural consequence of one of but many interpretations of quantum physics? (Note that no interpretation of QM of has yet been successfully merged with general relativity.) I'm writing here of the "physics as mystical woo" nonsense presented on shows that feature the likes of Sean Carroll, Brian Cox, Brian Greene, or Michio Kaku as commentators. A noted exception is Neil deGrasse Tyson. He's usually pretty good on distinguishing conjectural from mainstream science. When you see some of this "physics as mystical woo" nonsense and yell at the TV "HOW to they know that? They can't know that to be fact!": You are absolutely right. This mysticizing of physics, astronomy, and cosmology and intermingling fact, conjecture, and fiction as one in my opinion does more harm than good. In this case the case is extremely strong that this is true. Scientists have a fairly good understanding of what goes on inside stars, of how stars are born, how they change as they age, and how they ultimately die. It took quite a bit of work to come up with this understanding. Theoretical physicists, experimental physicists, and astronomers contributed to the effort. Even geologists and biologists played a role. Physicists scoffed when geologists and biologists first started coming up with numbers in the billions of years for the age of the Earth. That evidence from geology and biology was incontrovertible. It forced physicists and astronomers to reevaluate their theories. The current theory is quite deep and is very consistent with all of these multiple lines of evidence.

Ethical (or unethical) to whom: They future human inhabitants of those planets, or to the life that already exists on those planets? With regard to the latter question, I've raised the specter of the unethical nature of terraforming elsewhere; see this post, for example. I'm far from the only one who is concerned with the ethics of terraforming. Terraforming a planet that already harbors life is anathema to many. Even to some in NASA and other space agencies. NASA does have an Office of Planetary Protection (http://planetaryprotection.nasa.gov/). One of their goals is to ensure that if alien life is encountered, it isn't brought back to Earth. Another is to ensure that Earth life isn't brought to other planets that are potentially capable of harboring life. With regard to the first question, I suspect your premise is incorrect, at least with regard to massive giants. Red giants don't blow up (they in a sense have already "blown up"). Their death is one of slow attrition. It is the massive stars that "blow up". My guess: Massive stars do not have a habitable zone. The current definition of the habitable zone is one dimensional. It looks at temperature only. It doesn't look at harmful radiation or solar winds, for example. Blue giants emit considerable amounts of ultraviolet light and even into the x rays. They also spit out incredible amounts of gas in the form of solar winds. The high radiation and the intense solar winds would quickly strip a planet of its atmosphere. I see an even bigger problem with your premise: Why would we terraform at all? Assuming we ever do develop that level of technology, I'd bet that we would leave the planets behind. Why would we go back down into a gravity well, even just to visit, let alone live there permanently?