Janus

Sometimes, I think it's a matter of them feeling that in order to become the "next Einstein", they have to dethrone the existing one; so they develop their "theory" along that vain. It's like they think that science is nothing more than one big game of "King of the Mountain".

Even if the engine stops, the spaceship keeps going at the speed it was traveling when the engine was running. It coasts. With the engine running, the ship accelerates. What the outside observer will measure is that the acceleration of the Ship decreases in such a way that while it gets closer and closer to the speed of light, it never reaches it. BTW, the universe doesn't care what you think is the wrong explanation, it will just continue to behave as it does without needing your permission.

No, because according to the traveler, the distance traveled at 0.99995c is only ~10 light years. The distance between the Earth and distant planet has undergone length contraction due to it's high relative speed to the space ship. It is not just a matter of "perspective". In the space ship frame, the distance really is ~10 light years and his measurement of this distance is no less the "real" distance as the 1000 light years measured by someone on Earth.

That's kind of pointless unless the planet is your actual destination. Let's say I want to get to a planet 1000 ly away, but I need to make the trip in 10 yrs by my time. To do so, I have to get up to ~0.99995c. It will take a given amount of fuel to get up to that speed and a given amount of fuel to slow back down, no matter how far I travel. In other words, if I accelerate up to that speed travel for 1000 ly and slow down at the end, I would use the same fuel as if I accelerated up to the same speed, traveled for 10 ly and then slowed back down. I gain nothing by breaking the trip into smaller legs and refueling after each leg. If anything, I'm making the trip longer because of the extra time needed for the acceleration and deceleration phases of the trip.

Here's the thing, you are talking about intergalactic travel. In order to get to even the nearest galaxy in a single lifetime and stop upon arrival, using the the most efficient rocket drive theorectically possible (photon rocket with antimatter fuel), you would need something like 4.2 million million kg of fuel for every kg of payload delivered. This is not something that can be engineered around.

Let's assume that we are looking down on the space craft and planet from above the orbital plane, and that from our persepective, both are moving to the left. The spacecraft is ahead of the planet by 500,000 km and moving at 3 km/sec relative to the Sun. The planet is moving at 5 km/sec. If we switch to the perspective of someone at rest wtih respect to the planet, we would say that the spacecraft is approaching the planet from the left at 2 km/s. We'll assume that the trajectory of the space craft puts it in a parabolic orbit around the planet. Thus from the respect of the planet, it starts from 500,000 km to the left of the Planet traveling to the right at 2 km/sec. It then falls in towards the planet, whips around it and heads back out, this time going right to left. When it is 500,000 km to the left of the planet it is moving at 2 km/sec to the right. It's speed with respect to the planet hasn't changed, but its direction has. Now go back to the Sun's persepective. It started out moving to the left at 3 km/s which is equal to the 5km/s planet velocity minus the 2 km's spacecraft-planet relative velocity. After swinging around the planet and returning to its starting distance, it is moving at the 5 km/s planet speed plus the 2 km/s spacecraft-planet relative speed. So now it is moving at 7 km/sec to the left relative to the Sun. Of course, this neglects any effect that the swing around had on the planet. In reality, the planet gets a little kick to the right and losses a little orbital velocity in the process, so the final velocity of the spacecraft will be just a smidge under 7 km/s and the planet a bit under 5 km/sec. If the planet is very massive compared to the spacecraft, it results in a very small difference.

As far as B is concerned, he is not moving, A and D are. Also, time dilation is not the only effect to consider. There is also length contraction and the Relativity of simultaneity. As far as A and D are concerned, B. clock runs slow. Which is why it shows less time for the trip than what the clocks at A and D does. As far as B is concerned, his clock runs at normal speed, but the distance between A and D is shorter than it is as as measured by A or D, Thus the trip takes less time. Relativity of simultaneity comes in when any of the above deal with clocks that are separated from each other along the line of motion and are moving with respect to the observer. So for example, if B had clocks at the front and back of his ship that were synchronized according to B, then according to A or D, the clock in the front would read behind the clock in the rear. As far as B was concerned, the clock at D would read ahead of the clock at A. So if I'm at A or D, according to me, the time it takes for light coming from D to travel from front to back of B is less than that for the Light coming from A to travel from back to front. But, since at the moment the light hits the front clock, the rear clock already reads a later time, By the time the light reaches the rear clock, it will read even later. Conversely for light coming from A, when it hits the back of B, the clock at the front reads earlier, So when the light reaches it, it won't read quite as late. The upshot is that if the the light from A hits the back of the Ship when that clock reads 0 sec and hits the front clock when it reads 1 microsecond, then the light coming from D that hits the front clock when it reads 0 sec, will hit the rear clock when it reads 1 microsecond. For B, the same 1 micro second difference in clock readings occur, however according to him, the clocks at the ends of the ship are in sync, so the light actually takes 1 microsecond to cross the ship in both directions and thus travels the same speed in both directions.

Look, in order to get to Mercury you have to shed a fair portion of the Earth's orbital speed. Just firing your engines in a direction opposing the Earth's orbital direction isn't going to do it unless you make a large enough change in ytour speed. Anything less just puts you in an eliptical orbit which has a perihelion further from the Sun than Mercury is. In order to get your trajectory to intersect with Mercury's orbit you have to get your orbital speed at Earth orbit distance down to, at most, 22 km/s, which means you have to change your velocity by ~8 km/sec. As you fall in towards the Sun you will pick up speed and by the time you reach Mercury's orbit, you will be moving at 57 km/sec. Mercury's orbital speed is 48 km/s. So in order to safely rendevous with it ( and not just slam into it at high speed) you are going to have to shed 9 km/sec. This puts the total velocity change needed 17 km/sec. And this doesn't even take into account what it would take to lower yourself to the surface. In order to leave the solar system completely from Earth orbit requries a velocity change of only 12.4 km/sec. As to what a 17 km/sec velocity change means in terms of fuel: If we assume a exhaust velocity of 4500 m/s (about as good as you'll get with a chemical rocket), it works out that you'll need ~43 kg of fuel for every kg of payload you want to get to Mercury. If you want to land, this jumps up to 116. If you want to include a return trip, you are now talking 13750 kg of fuel for every kg that you land on Mercury and return to Earth orbit. Basically, the ratio of fuel to payload varies by the power of the total speed change divided by the exhaust speed of your rocket. If the velocity change doubles, the mass ratio increases by a power of 2.

Just to add to the last response. What the sound box of the guitar does is increase the amount of energy transfered from string to air. A string alone doesn't do this very well, so it doesn't sound very loud. By adding the sound box we can increase the volume we hear. But this comes at a price. The extra energy transfered to the air comes at the expense of the vibration of the string. The sound box also dampens out the vibration faster. You end up with a louder sound, but for a shorter duration and the total energy transfer is the same.

There is no controversy. The electrons carries the energy but they do it as an electromagnetic wave. An analogy: You have a tube filled with rubber balls. You push on the rubber ball at one end and almost immediately the ball on the other end moves. Your pushing on the first ball starts a compression wave that moves through the tube at the speed of sound that reaches the other end long before the ball you pushed gets there. The balls carry the energy as a compression wave.

Quantum mechanics does not recognize any fixed background. In fact, Quantum Electrodynamics represents the fusion of Quantum Mechanics and SR and it is one of the most successful theories in terms of prediction vs. observation. Also, I should point out that this thread is in the "Speculations" forum, not the Trash can. The Trash can is a subforum of the Speculations forum and is under that heading near the top of the page. You have to actually click on "Trash can" in order to enter it.

Even if one accepts that it would only take a 2° change in trajectory, this change would have to take place at perihelion. Perihelion for comet Ison is 1.86 million km at which point it will be moving at a speed of 378717 m/s. To deflect it by 2° would require a delta v of 13217 m/s. The highest exhaust velocities achieved by steam rockets specifically designed to be efficient as possible is 1911 m/s. So, assuming perfect conditions, we can use the rocket equation to determine just how much of the comet would have to be converted to steam and ejected in order to generate the needed delta v. That equation is [tex] M/m = e^{\frac{\Delta v}{v_e}} -1[/tex] Ve is the steam exhaust speed. This gives an answer of M/m = 1008 Meaning that Comet Ison would have to convert ~99.9% of it mass to steam in order to deflect the remaining 0.1% the required 2°. Keep in mind, that this assumes a properly designed pressure chamber and nozzle. In the case of a comet, such would have be formed from the comet substance itself, which means the comet would break up and the rocket action would cease after it had only generated a small fraction of the needed delta v. Considering how easy it was to debunk this part of the argument, I calling bogus on the idea that this claim originated from an actual scientific institution.

The problem here is that you are trying to show Einstein wrong without actually knowing what Einstein said. For instance, in your analogy, you imply that your time slowing down should compensate for the slowing down of the your reception of the Earth signal. Einstein never predicted this. For one, the classical Doppler shift would be found by [math]\frac{1+V_r}{1+V_s}[/math] Where Vr is the velocity of the receiver and Vs the velocity of the source, and both are measured as fractions of the speed of light. In the case of traveling away from the Earth, we Assume Vs = 0. Vr would be negative, so we get 1+Vs Time dilation is found by [math]\frac{1}{\sqrt{1-V^2}}[/math] where V is the relative velocity between ship and Earth (as a fraction of c). There are nowhere near reciprocal. In fact, what Einstein says you'll see is Relativistic Doppler shift: [math]\sqrt{\frac{1-V}{1+V}}[/math] Where V is positive while moving away. The point is that you get the same answer no matter who you consider as moving. All that matters is the relative velocity between source and receiver. Someone on the ship sees the same thing whether he is moving between Earth and Moon or he is still and it is the Earth and Moon that is moving. For him the speed at which the signal travels relative to himself is the same from both transmitters, it is changing distances that causes the Doppler effect. Another problem with your scenerio is that you have a ship going from Earth to Moon at near lightspeed, and watching an 1 hr long broadcast. The Moon is only 1.28 light sec from the Earth, so the ship would get there in under 1 sec. So, in fact, he would only see a fraction of the show. Keeping that in mind, Here is what happens according to Einstein with the ship traveling at 0.99c First seen by the Earth-Moon frame: Assuming that the shows start at the moment the ship passes Earth: It takes 1.293 secs for the ship to reach the Moon. Since it takes 1.28 sec for the light to reach the Moon, the ship will have seen 0.1293 sec of the show. Since time dilation would have the Ship time run at a rate of 1/7, 0.1847 sec passes for the ship clock. Thus he sees 0.1293 sec of show in 0.1847 sec. In other words, he sees that show run at 0.7 speed. The ship will not start receiving the Moon transmission unitl the ship meets the incoming tranmission. This happens after 0.64 sec (Earth time). The ship will see 1.293 sec of the show during the remaining 0.653 sec of the trip (earth time). With a time dilation of 1/7, this means the start of the show reaches the ship when its clock reads 0.0914 sec, So he will see 1.293 sec of the show in 0.0933 sec. He will see the show run at 14 speed. Now as seen by the ship: It takes 0.1847 sec to reach the Moon (Because due to length contraction, the distance between Earth and Moon is 0.1829 light sec.) By the relativistic Doppler shift equation, he would see the Earth signal at a rate of 0.7 and see 0.1293 sec of the show. ( exactly what the Earth frame predicts) He starts receiving the Moon transmission at 0.914 sec by his clock and see it at a Doppler shift rate of 14, seeing 1.293 sec of the show during the remainder of the trip. Again, this agrees with what the Earth expects. There is no disagreement nor contradiction, even though the Earth assumed that both signals traveled at c with respect to itself and the ship assumes that the signals travel at c with respect to itself. Here's the bottom line: there are no contradictions in Relativity, if you think you've found one, you have misunderstood something or made a mistake. Now this is not to say that Relativity can never be shown to be wrong, but instead, it can not be shown wrong by the way you tried. No analogy or thought experiment by itself can disprove Relativity. In order to do that, you would have to provide an example from the real world that does not agree with Relativity's prediction. IOW, if Relativty predicts given results for an experiment, and the actual experiment gives different results, then you have a case. But you are not going to do it with arguments on a forum.

Use a sextant and a good watch to compare positions before take-off and after landing.

You need to look at the actual formula of how the speed of sound is effected by the density. An increase in density drives the speed of sound down not up. Consider this, Lead is denser than iron, but the speed of sound in Iron is greater. In fact, wood is even less dense than lead and has a higher speed of sound.

For photons, energy is found by [math]E = \frac{hc}{\lambda}[/math] where h is Planck's constant and lambda is the wavelength. The general formula for both zero and non-zero rest mass objects is [math]E = \sqrt{m_o^2c^4+p^2c^2}[/math] Where [math]m_o[/math] is the rest mass. For light [math]p= \frac{h}{\lambda}[/math] and the rest mass is zero. When one talks about light being massless, it is its rest mass that is 0.

It would gain energy, and in doing so increase it's frequency and shorten its wavelength. It's speed however would remain unchanged.

No. Dark matter tends to form halos around galaxies and galaxy clusters. If the aether was dark matter, then light wouldn't traverse the regions where there isn't DM, but we see through these "gaps" just fine.

But this one's worth more: http://www.ebay.com/itm/Star-Trek-Classic-Enterprise-1991-Hallmark-Christmas-Ornament-MINT-BOX-UNUSED-/360522277132#vi-content I used to have two of them. They were in such demand when they came out that you had to be put on a waiting list for a chance to get one. I signed up at two stores to double my chances and got lucky at both. I finally sold them few years back. The next year they came out with the shuttecraft Gallileo. In order to not be got short on stock again, Hallmark produced tons of them. (I remember walking by a stack of them in a Hallmark that year).

I have now idea what you mean by "approaching frame" and "escaping frame". But simultaneity in different frames can be demonstrated like this: Imagine you have two clocks, they are set to the same reading and designed to start running when a light flash reaches them. You originate a flash form a point hlafway between them. To anyone at rest with respect to the clocks, events unfold like this: The light exapnads outward from the origin at c, and strikes both clocks at the same instant. the clocks start and from that moment on always read the same time. One thing of importance here is that is does not matter whether or not the source of this flash is moving with respect to the clocks or not, all that matters is that it is halfway between the two clocks when it produces the flash. Now consider the same flash and clocks according to someone moving with respect to the clocks. Events now unfold like this: The light still originates at a point halfway between the two clocks and expands outward at c. However the two clocks no longer maintain the same distance from the origin. (again, it does not matter as what the velocity of the source is with respect the clocks or to the observer) As a result, the light strikes one clock before it strikes the other and one clock starts running before the other. As a result, both clocks will read different times once they are both running with the clock on the right lagging behind the clock on the left. Thus according to someone at rest with respect to the clocks, the running clocks are in sync, and according to someone moving with respect to the clocks, they are not. The events of the clocks reading 1:00 are simultaneous in one frame, but not simultaneous in the other.

Here's what I assume you mean: A muon which is at rest with respect to the Earth is formed at the surface of the Earth at the same time as a fast moving (with respect to the Earth) is formed in the Upper atmosphere. According to the Earth frame, the first Muon decays before the second muon can reach it. However, if time dilation is reciprocal, then according the frame of the second muon, it should reach the surface of the Earth before the first muon decays. Thus if the first muon is in the path of the second, they should collide in according to one frame but not the other. The problem here is not the reciprocal nature of time dilation but the phrase "at the same time". "At the same time" does not mean the same in both frames. If the first and second Muon are formed at the same time in the Earth frame, They are not formed at the same time according to the frame of the second muon, according to it, the first muon formed well before the second muon does. So far before that it's expends it longer life time before they can meet. If instead, they form at the same time in the second Muon frame, then according to the Earth frame, the first Muon forms well after the second Muon, and thus lives to meet the second Muon. In either situation both frames agree as to whether or not the Muons meet each other, they just don't agree on the order of the creation of each Muon. This is the Relativity of Simultaneity. Just about any time someone comes up with what they think is a contradiction in Relativity, it is because they neglected this effect.

Something to keep in mind is that a part of the driving force for evolution is change in environment. Without it, the rate of evolution is very slow. In an environment that has not changed in 2.6 billion years, you are likely to see little evolution.

If you put a mirror on the White dot, then what the left part will show is the light coming straight down, hitting the white dot and then retracing its path straight up and returning to the source. The right side (according the white dot) has the light coming in a an angle from the right, bouncing off at an angle to the left, and intercepting the yellow dot as it travels to the left.

The stay at home and traveler cannot both see the light coming from a direction of 90 degrees to the direction of travel. The traveler will see pulses coming from some angle in front of him due to the aberration of light. He also will see the pulses blue-shifted by a factor of gamma. Thus, if the Stay at home twin sees 365,000 pulses in one year at a rate of 1000 pulse per day while the traveler travels out and back at 0.866c, the traveler will see 365,000 pulses in 1/2 year at a rate of 2000 pulses a day.

Actually, it is the curvature of Space-time. This is where the analogy breaks down. We show it as a two dimensional space curved into a third spatial dimension because that's how we can visualize Non-Euclidean geometry. In reality, there is no extra spatial dimension, it's that the rules of geometry in "curved space-time" are based on different postulates than those in Euclidean geometry (which decribes flat space=time). The thing about geodesics are that they are the shortest path between two points. If you follow the a gridline from the point it enters curved space until it leaves, you will find that it is not the shortest path between those points. the shortest path is a curve that intesects the gridline at these two points, at an angle. Light always follows the shortest path. Light following the gridline in flat space-time will follow the geodesic that is parallel to its path upon entering curved spacetime. That geodesic will lead to a point in flat space-time, from which the light will continue on in flat space-time, in a different direction than it entered as seen from flat-space time.