The Pre-Akashic records


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The Pre-Akashic records

Created:
Sun Jun 07, 09 6:37 AM
Karma:
168 Points
Number Of Entries:
22
Number Of Replies:
6


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New Ion engine could speed up space travel


[ Category: Physics ]

Excerpt:

Source: gizmag.com

Quote:
The problem with traditional rockets is that they’re terribly inefficient. About 90% of a mission’s initial weight is fuel, most of which is burned up escaping earth’s gravitational pull. After that, a traditional rocket could only slowly coast to Mars. Very slowly. Scientists describe rocket efficiency in terms of specific impulse, which is a rough measure of how fast fuel is ejected out of the back of the rocket. A chemical rocket has a relatively low specific impulse of 450 seconds - in other words, it gets one pound of thrust from one pound of fuel for 450 seconds.

Chang-Diaz’s prototype, however, promises specific impulses as high as 15,000 seconds. How? Well, his rocket doesn’t achieve propulsion by combusting fuel but, rather, by superheating atoms to create and expel a plasma plume.


What is the Casimir Effect?


[ Category: Physics ]

Source:Math.ucr.edu

Quote:
The Casimir effect is a small attractive force that acts between two close parallel uncharged conducting plates. It is due to quantum vacuum fluctuations of the electromagnetic field.

The effect was predicted by the Dutch physicist Hendrick Casimir in 1948. According to the quantum theory, the vacuum contains virtual particles which are in a continuous state of fluctuation. Casimir realised that between two plates, only those virtual photons whose wavelengths fit a whole number of times into the gap should be counted when calculating the vacuum energy. The energy density decreases as the plates are moved closer, which implies that there is a small force drawing them together.


An excerpt of Carl Sagan explaing the 4th dimension


[ Category: Physics ]


Which is better if you are in an inevitable head on colli...


[ Category: Physics ]

Okay, so here is a question that all drivers in a head-on collision face: Is it better, when one is faced with an inevitable crash, to speed into the collision or slow down?

The answer is slow-down. maybe even go in reverse if possible. The formula for momentum is m*v + m*v= M*v +m*v, where m is equal the mass of the objects in kilograms, and v is the velocity of the cars. The equal sign simply states that the momentum is conserved throughout the whole affair. Another equation for momentum is F*t, where t is the time. Now, by speeding into the crash, one is increasing the amount of momentum. The equation suggests that by speeding, one could negate momentum and prevent a force. Sadly, this is not the case.

Let's say that we were in one of the cars. Now to us in that car, are we the ones that are moving? Or is it the world moving around us? In this case, we are the ones that are stationary. Therefore, the velocity of our car would be the world moving in the opposite direction. Since the other car is moving faster than this to our perspective, we would add our velocity to the opposite car's velocity. Therefore the force would be higher the faster we go for it would be m(v1+v2)=f*t.

Also, let's look at f*t. While this is a formula for momentum, it is known as the impulse formula, which is a way of measuring how much time a force is applied. Now, by speeding up, one is actually decreasing the time constant for the F*t equation. Due to the law of conservation, to compensate for this, the force would have to increase considerably. Conversely, by slowing down, time constant increases and the force would have to lower, or it would break physics.

Any questions?


From Newton to Einstein : A video about gravity


[ Category: Physics ]


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