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Posted on: did time begin?
at 11/25/2009 12:48pm

I suppose this topic is somewhat philosophical, but it appears that time begain when the universe begain - at the big ... more(+)

XairstrikeXD wrote:i want to know if time ever began. i read somewhere that time has no begening or end. if so would it still have to begin somewhere like the X and Y axis on a graph beggining at an origin?

I suppose this topic is somewhat philosophical, but it appears that time begain when the universe begain - at the big bang. close(-)

Posted on: Who wants to do FTL now?
at 11/25/2009 12:07pm

Good question.

First the universe is expanding faster than light without the dark energy. Dark energy is only ... more(+)

Solifugae wrote:If Dark Energy can expand space faster than light travels, if we could produce it, couldn't we use it for FTL travel?

Good question.

First the universe is expanding faster than light without the dark energy. Dark energy is only theorized to explain the acceleration of the expansion.

Dark energy or any expansion does not allow you to get closer to another celestial body it has to do with space expanding not movement through space.

Lastly the expansion of space is very tiny. It is so small you cannot measure it except over huge distances.

As an example imagine a huge rubber band that is expanding a rate of 1 cm per meter per hour, that is, if you make 2 marks on the rubberband 1 meter apart after 1 hour the marks would go from 100 cm to 101 cm apart. I think you'd agree this would be pretty a pretty small change. But here is the point of the expansion, if the rubberband was from here to mars the ends of the rubberband would be moving way from each other at about 500,000 km/hr. close(-)

Posted on: Traveling at Speed of Light?
at 11/25/2009 9:05am

measure the speed of light as having the same velocity. more(+)

XairstrikeXD wrote:i dont understand. how is it possible for time to pass differently on earth. if the universe is expanding at a constant rate i can see how the trip would take a little less than 100 light if it is expanding towards you but i still dont understand how time flows differently?

It is possible because time is not absolute. Our everyday experiences tell us that time is constant but it is not. Time dialation does not really have anything to do with the expansion of the universe.

What is at the heart of time dialation is that the speed of light is constant relative to any observer no matter what their velocity is. This site has a little graphic that shows why time is measured differently by individuals moving at different velocities. Keep in mind that everyone will always measure the speed of light as having the same velocity. close(-)

Posted on: Traveling at Speed of Light?
at 11/24/2009 9:48pm

Yeah, there are all sorts of implications if you travel close to the speed of light. Even though the speed of light is ... more(+)

Solifugae wrote:

Jerromy wrote:Excellent link, Speedfreek. Crazily complex to factor in the resistance one would encounter travelling near c...

That's the worst part about relativity. If I understand this correctly, if you were traveling at many .9 decimal places ahead of 99%c, and the outside time is faster in relation to you. Then as you take a year to cross the galaxy, besides from photons and cosmic rays, you will hit atoms every now and then. If you hit 1000 Hydrogen atoms per year (in reality it would be a lot more I'd think), but as your year passes, thousands do for the frames of the atoms, then don't you actually up the rate at which you are getting hit, even more than just caused by the speed increase itself? You are being hit by millions of atoms instead of 1000s. Never mind all those horrible subatomic particles.

Besides the energy needed to power it, the craft would need to be made out of some impossible material which passes through everything like a ghost, but that's a story for the unexplained.

Seems like we'll be stuck to taking 10s of thousands of years to colonize the local stars.

Yeah, there are all sorts of implications if you travel close to the speed of light. Even though the speed of light is constant no matter how fast you are going, the energy of the photons does change. If you are traveling towards a star very close to the speed of light the photons in the visible range of light can be blue shifted all the way to hard gamma rays. Luckily, I guess, gamma rays that are 'chasing' you will be red shifted to a less dangerous energies. close(-)

Posted on: Bulgarian Academy Scientists "in Touch with A...
at 11/24/2009 3:42pm

The story states that the 'institute' is in communication with the aliens by reading crop circles. more(+)

The story states that the 'institute' is in communication with the aliens by reading crop circles.
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