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The universe as we know it.
- Thread starter thelorax
- Start date
really enjoying the ten-ish part series on history channel right now. parallel universes really blew my mind. the fact that there really is no "universe" right now only "multi-verses" is really blowing my mind. also, the fact that the system that contains the multiverses is in, is infinite - and that eventually if you keep going through space you will eventually meet your parallel self.
the space time special was also great. im currently trying to hack the google algorithm hoping that when i do i will discover the meaning of life.
the space time special was also great. im currently trying to hack the google algorithm hoping that when i do i will discover the meaning of life.
Cool video, but i think it zooms out too fast to get a good idea of the scale of things.
I like this image, certainly makes you feel small. (scroll to the right to see it all)
I like this image, certainly makes you feel small. (scroll to the right to see it all)
Great vid. I love this stuff. It fascinates the hell out of me and if I had been better at math, I probably would have been an astrophysicist or something related. For those of you who haven't read Hawkings "A Briefer History of Time" and you're into this space shit, check it out. It will give you a fairly easy to understand background on a lot of the basics like general & special relativity, blackholes, creation of the universe etc.
Here's another perspective of how small we are from the book.
"We can see about five thousand stars from Earth, only about .0001 percent of all the stars in just our own galaxy, the Milky Way. The Milky Way itself is but one of more than a hundred billion galaxies we can see using modern telescopes - and each galaxy contains on average some one hundred billion stars. If a star were a grain of salt, you could fit all the stars visible to the naked eye on a teaspoon, but all the stars in the universe would fill a ball more than 8 miles wide"
Here's another perspective of how small we are from the book.
"We can see about five thousand stars from Earth, only about .0001 percent of all the stars in just our own galaxy, the Milky Way. The Milky Way itself is but one of more than a hundred billion galaxies we can see using modern telescopes - and each galaxy contains on average some one hundred billion stars. If a star were a grain of salt, you could fit all the stars visible to the naked eye on a teaspoon, but all the stars in the universe would fill a ball more than 8 miles wide"
I happen to be an astrophysicist. Feel free to ask interesting questions.
You should also understand that anything that is recent research (anything past early 20th century), entire quantum theory, for example, is just a theory. A well proven one, but nothing more. Especially when the discovery channel talks about stuff like multiverses. That is a theory that is currently being explored by a couple dozen scientists, but you will never know whats up. They claim that black holes could be the gates to new universes being created, and Im not saying they are right or wrong, all Im saying is that its not possible to prove. Most of modern physics research is just forming theories around thin evidence.
The first concept that is hard to grasp for anyone who doesnt learn this from first principles is the way how light behaves. Everyone knows that the speed of light is a physical speed limit, and that light always travels at that speed. But when you get into special relativity, you will learn cool stuff.
Heres a question for you:
Assuming two space ships, 1 light year apart. Both travelling at a speed close to the speed of light. Lets say 99% of the speed of light, in the same direction (this is a difficult statement to make, because the concept of direction as we know it really only holds under certain conditions). The space ship that is "behind" fires a laser, because theyve got some beef. Laser is light. How long does it take for the laser to reach the other space ship? You dont need a calculator to answer this question.
Knowing the answer to question one, how long would it take for a laser fired by the space ship in front to reach the other one?
You should also understand that anything that is recent research (anything past early 20th century), entire quantum theory, for example, is just a theory. A well proven one, but nothing more. Especially when the discovery channel talks about stuff like multiverses. That is a theory that is currently being explored by a couple dozen scientists, but you will never know whats up. They claim that black holes could be the gates to new universes being created, and Im not saying they are right or wrong, all Im saying is that its not possible to prove. Most of modern physics research is just forming theories around thin evidence.
The first concept that is hard to grasp for anyone who doesnt learn this from first principles is the way how light behaves. Everyone knows that the speed of light is a physical speed limit, and that light always travels at that speed. But when you get into special relativity, you will learn cool stuff.
Heres a question for you:
Assuming two space ships, 1 light year apart. Both travelling at a speed close to the speed of light. Lets say 99% of the speed of light, in the same direction (this is a difficult statement to make, because the concept of direction as we know it really only holds under certain conditions). The space ship that is "behind" fires a laser, because theyve got some beef. Laser is light. How long does it take for the laser to reach the other space ship? You dont need a calculator to answer this question.
Knowing the answer to question one, how long would it take for a laser fired by the space ship in front to reach the other one?
Ok.
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I guess you could call that an interesting question. I'd call it poor English skills, but hey, that's just me.
I guess
A local dish that is similar to ravioli
keep in mind that it isnt specified in which rest frame the velocity is being measured because its not important. Both questions would lead to the same answer.
Never or a really long time?
If fighter jets shot bows and arrows instead of missiles, it would look like the arrows were just dropping from the sky. The only boost the arrow would get at all would be the kinetic energy from the physical movement of the jet itself, which it would very quickly lose.
I would imagine its quite the same in this scenario, except the major wind and air resistance is replaced by the speed limit of light. It's not the same resistance of course, the laser just simply doesn't get a boost from kinetic energy because there is no more speed to gain.
Or, didn't see the second question in reverse. Answer #2 would be instantly wouldn't it?
I like your reasoning, but you make two mistakes.
1. the arrow is boosted by its own kinetic energy. Its velocity is equal to that of the fighter jet. Kinetic energy is a function of velocity: E=mv²/2
You are right, comparing the kinetic energy it has while not being fired is almost the same as after its being fired, so the image you draw is correct.
2. Light is fundamentally different from the objects you compare it to. Your reasoning doesnt apply. Light is massless, it doesnt get pulled by gravity (only by general relativity effects, which we are neglecting and wouldnt apply in this situation anyway). Light always travels at the same speed, regardless of the objects you compare it to.
1 light year is the distance light travels in a year.
99 years?
(1 year apart x 1/99th speed)
Disclaimer: I fully admit I suck at all things mathematical.
(1 year apart x 1/99th speed)
Disclaimer: I fully admit I suck at all things mathematical.
Classically, at least your train of thought would be correct, but we are trying to learn about special relativity. What is the fundamental statement of special relativity? Its E=mc², but that doesnt help you because you dont have the knowledge to apply it to the problem. Keep in mind that light travels at the same speed for every (possible) observer.
I got the answer for you:-
You've got to be kidding me. I've been further even more decided to use even go need to do look more as anyone can. Can you really be far even as decided half as much to use go wish for that? My guess is that when one really been far even as decided once to use even go want, it is then that he has really been far even as decided to use even go want to do look more like. It's just common sense.
btw great video