So... We're all kinda standing around... waiting for Big Red to send out the goodies. How about some good natured OT chat while we wait?
I’ll start. How about we talk about physics? I’m not a physicist (I’m a mechanical engineer) so I don’t claim to fully understand all these topics (most physicists will acknowledge that they don’t fully understand them either) but I find it mind numbing to try and understand the true nature of the things about us.
Did you know that empty space isn’t really empty?
That even gravity travels at the speed of light?
That an object’s gravity actually impacts how quickly it moves through time?
That time travels slower the faster you are moving?
That you can actually observe events, a long distance away, happening at different points in time just by how quickly you travel towards or away from the event?
That what we can observe in the Universe and what we know is out there based on current models is off? Not by a little, but by a lot. Currently, everything we can see in the Universe only makes up about 4% of what we think is out there.
Let’s just take those in order.
As far as space being empty, it gets complicated quick (these all do really) and has been verified with other experiments, but just take a moment to think through this scenario in your head. Say you are an ice skater, spinning around on one skate. Close your eyes so you no longer can see the reference of the skating rink spinning around you. You pull your arms in tight and pick up rotational speed. You feel centripetal force pulling your arms outward and you know you are spinning. Now imagine we could “magically” remove the sun and other planets and all the things outside and on the earth. Even the rink and the ice under your feet. So you’re spinning in empty space with nothing else around you. You’d still feel yourself spinning, feeling your arms being pulled out away from you, but what are you spinning in relation to? There’s nothing else in the Universe now but you and empty space so what is there that is stationary to reference yourself against? You can still feel that you are spinning because centripetal forces are trying to pull your arms out and the fluid in you ears is telling your brain you are going round and round.. Empty space isn’t empty.
Newton thought that gravity just happened instantly between two objects. That the apple was attracted instantly by the earth and vice-versa, but it isn’t. Nothing in the known Universe travels faster than the speed of light, even gravity. We’ve been told this before in high school, but it can be really mind blowing to fully appreciate the implications of this. Anyone that has spun a ball attached to a string and then let go of it knows that the ball will shoot out in a straight line that is tangent to the circle it was spinning around at the time you let go. This is similar to the Earth and the Sun. The Earth spins around the Sun like the ball around your hand, only it is gravity that keeps the earth going around in a circle. But just as light from the Sun takes 8 minutes to get from the surface to Earth, if the Sun were to suddenly disappear the Earth would still orbit around the point where the Sun was for 8 minutes before heading off in a straight line.
The more massive an object is (or the closer you are to a massive object) the slower time goes. The mass of an object actually slows time around it. Take GPS for example. GPS relies on satellites being positioned in very accurate orbits and sending out extremely accurate signals of what time it is. Basically, signals from different GPS satellites are all broadcast from their respective satellites at the exact same time. The GPS unit calculates your position on the face of the Earth by evaluating how long it took the different signals (all sent from the various satellites at the same time) to get to your position. Ok, so now we know how GPS works, here’s the interesting part. Because the GPS satellites are further away from the massive Earth than we are, time runs faster for them than it does down here! When they developed the GPS system they had to take this time drift into account. If they didn’t, everybody’s GPS units would be incorrectly telling them that they are about 6 miles away from where they actually are.
Similar to time being affected by gravity, time is also affected by the speed an object moves through space. The faster you go, the slower time passes for you. This has been verified by taking two extremely accurate clocks. One stayed on the ground while the other was flown around the world in a high speed jet. When they then compared the two, the clock that stayed on the ground was observed to have gained more time than the one flown about the world. Theoretically, this could be used to allow people to travel (forward) through time.
The direction you are travelling can have an effect on time too. Everyone has learned that light observed from sources very far away is actually light that has been emitted from a long time ago (in some cases as far back as the time close to the beginning of the Universe.) But what is even more hard to comprehend is that you can adjust the “timeframe” of what you see based on how fast you are travelling towards or away from this light source. In short, if you are stationary in space, you will see one time period, if you are travelling towards the distant object at a high rate of speed, you would actually be able to see events occurring distant into the future at that far location. You would literally “fast forward” the view you receive. Alternatively, if you are travelling away from the distant location you would be able to observe a period of time that is distinctly further back in time than you would see if you were stationary. In effect, you can scroll through, forward and backwards, the observed passage of time. Makes you really question the concept of time overall.
As for the last one, physicists are perplexed by what is conveniently labeled, “Dark Matter.” It is a catchy name to something that is quite easy to understand overall, but difficult to truly grasp. Basically, when we allocate all the matter that is visible in the Observable Universe on one side, and we “predict” how much matter there should be based on our understanding of gravity/relativity/particle physics/etc. they don’t equal. In fact, what we can see only amounts to about 4% of what “should” be out there. Yeah, the knee-jerk reaction is to pass it off and say that the models they are using are incorrect. But the thing is, relativity has been shown to be correct time and again, likewise, all experiments ever conducted to verify or disprove the theory of quantum physics have turned out in favor of the theory, at least at the quantum level.
One last comment about the "Observable Universe." Do you know what that really means when physicist use the term? It doesn’t just mean the area around us that we can see with our best telescopes. No, the meaning of the “Observable Universe” is much more bizarre. It is estimated that the Universe is approx 160 billion light years across, but at the same time, the Universe is only about 13.7 billion years old. As such, we can only “observe” light coming at us from a maximum distance of approx. 13.7 billion lightyears in every direction. As such, we can “see” an area of the Universe about 28 billion lightyears across, out of a total width of 160 billion lightyears. So if you assume the Universe is round, we’re only capable of “seeing” approx 3% of it. Even with the best telescopes possible.
The Universe is a strange place.
I hope I've given you something to think about while we wait.
-Suntan
I’ll start. How about we talk about physics? I’m not a physicist (I’m a mechanical engineer) so I don’t claim to fully understand all these topics (most physicists will acknowledge that they don’t fully understand them either) but I find it mind numbing to try and understand the true nature of the things about us.
Did you know that empty space isn’t really empty?
That even gravity travels at the speed of light?
That an object’s gravity actually impacts how quickly it moves through time?
That time travels slower the faster you are moving?
That you can actually observe events, a long distance away, happening at different points in time just by how quickly you travel towards or away from the event?
That what we can observe in the Universe and what we know is out there based on current models is off? Not by a little, but by a lot. Currently, everything we can see in the Universe only makes up about 4% of what we think is out there.
Let’s just take those in order.
As far as space being empty, it gets complicated quick (these all do really) and has been verified with other experiments, but just take a moment to think through this scenario in your head. Say you are an ice skater, spinning around on one skate. Close your eyes so you no longer can see the reference of the skating rink spinning around you. You pull your arms in tight and pick up rotational speed. You feel centripetal force pulling your arms outward and you know you are spinning. Now imagine we could “magically” remove the sun and other planets and all the things outside and on the earth. Even the rink and the ice under your feet. So you’re spinning in empty space with nothing else around you. You’d still feel yourself spinning, feeling your arms being pulled out away from you, but what are you spinning in relation to? There’s nothing else in the Universe now but you and empty space so what is there that is stationary to reference yourself against? You can still feel that you are spinning because centripetal forces are trying to pull your arms out and the fluid in you ears is telling your brain you are going round and round.. Empty space isn’t empty.
Newton thought that gravity just happened instantly between two objects. That the apple was attracted instantly by the earth and vice-versa, but it isn’t. Nothing in the known Universe travels faster than the speed of light, even gravity. We’ve been told this before in high school, but it can be really mind blowing to fully appreciate the implications of this. Anyone that has spun a ball attached to a string and then let go of it knows that the ball will shoot out in a straight line that is tangent to the circle it was spinning around at the time you let go. This is similar to the Earth and the Sun. The Earth spins around the Sun like the ball around your hand, only it is gravity that keeps the earth going around in a circle. But just as light from the Sun takes 8 minutes to get from the surface to Earth, if the Sun were to suddenly disappear the Earth would still orbit around the point where the Sun was for 8 minutes before heading off in a straight line.
The more massive an object is (or the closer you are to a massive object) the slower time goes. The mass of an object actually slows time around it. Take GPS for example. GPS relies on satellites being positioned in very accurate orbits and sending out extremely accurate signals of what time it is. Basically, signals from different GPS satellites are all broadcast from their respective satellites at the exact same time. The GPS unit calculates your position on the face of the Earth by evaluating how long it took the different signals (all sent from the various satellites at the same time) to get to your position. Ok, so now we know how GPS works, here’s the interesting part. Because the GPS satellites are further away from the massive Earth than we are, time runs faster for them than it does down here! When they developed the GPS system they had to take this time drift into account. If they didn’t, everybody’s GPS units would be incorrectly telling them that they are about 6 miles away from where they actually are.
Similar to time being affected by gravity, time is also affected by the speed an object moves through space. The faster you go, the slower time passes for you. This has been verified by taking two extremely accurate clocks. One stayed on the ground while the other was flown around the world in a high speed jet. When they then compared the two, the clock that stayed on the ground was observed to have gained more time than the one flown about the world. Theoretically, this could be used to allow people to travel (forward) through time.
The direction you are travelling can have an effect on time too. Everyone has learned that light observed from sources very far away is actually light that has been emitted from a long time ago (in some cases as far back as the time close to the beginning of the Universe.) But what is even more hard to comprehend is that you can adjust the “timeframe” of what you see based on how fast you are travelling towards or away from this light source. In short, if you are stationary in space, you will see one time period, if you are travelling towards the distant object at a high rate of speed, you would actually be able to see events occurring distant into the future at that far location. You would literally “fast forward” the view you receive. Alternatively, if you are travelling away from the distant location you would be able to observe a period of time that is distinctly further back in time than you would see if you were stationary. In effect, you can scroll through, forward and backwards, the observed passage of time. Makes you really question the concept of time overall.
As for the last one, physicists are perplexed by what is conveniently labeled, “Dark Matter.” It is a catchy name to something that is quite easy to understand overall, but difficult to truly grasp. Basically, when we allocate all the matter that is visible in the Observable Universe on one side, and we “predict” how much matter there should be based on our understanding of gravity/relativity/particle physics/etc. they don’t equal. In fact, what we can see only amounts to about 4% of what “should” be out there. Yeah, the knee-jerk reaction is to pass it off and say that the models they are using are incorrect. But the thing is, relativity has been shown to be correct time and again, likewise, all experiments ever conducted to verify or disprove the theory of quantum physics have turned out in favor of the theory, at least at the quantum level.
One last comment about the "Observable Universe." Do you know what that really means when physicist use the term? It doesn’t just mean the area around us that we can see with our best telescopes. No, the meaning of the “Observable Universe” is much more bizarre. It is estimated that the Universe is approx 160 billion light years across, but at the same time, the Universe is only about 13.7 billion years old. As such, we can only “observe” light coming at us from a maximum distance of approx. 13.7 billion lightyears in every direction. As such, we can “see” an area of the Universe about 28 billion lightyears across, out of a total width of 160 billion lightyears. So if you assume the Universe is round, we’re only capable of “seeing” approx 3% of it. Even with the best telescopes possible.
The Universe is a strange place.
I hope I've given you something to think about while we wait.
-Suntan
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