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1. ## Limits of the Universe

I agree. When a massive star becomes a black hole it will not become a quasar unless there is still a lot of matter nearby to fall into the hole and create the energy source for the quasar. A young galaxy could have that matter.
2. ## Limits of the Universe

No our galaxy is not a quasar. Imatfaal is correct. Quasars are massive black holes at the center of some galaxies. They are the brightest objects in the universe. Actually they don't seem to exist anymore. They were much more common early on in our universe. Most quasars are so distant they are almost moving away from us at the speed of light (red shift from the expanding universe).
3. ## Distinguishing between acceleration and gravity

Newton did not, could not, predict the movement of the perihelion (even if he had the data collected in the 19 century) but his equations are still extremely accurate IF you consider the ellipse to be moving relative to universe and everything in it. Newton would never have said the orbital ellipse is moving BUT HIS EQUATIONS DO NOT DENY IT.
4. ## Distinguishing between acceleration and gravity

Good discussion Newton's equations are accurate. Here is an exaggerated view of precession of the perihelion of Mercury's orbit: Before Einstein the scientist thought there must be another planet closer to the sun pulling on Mercury. They were so sure that they even named this planet Vulcan (trivia for Star Trek fans) before it was discovered. For the classical physicists the only other explanation would be that the rest of the universe is rotating around the sun making it look like the perihelion is moving. If that were the case then Newton's equations would be extremely accurate. But of course that would mean distant galaxies would be moving faster than the speed of light. It would also defy the notion that the sun did not have a special place in the universe. Then Einstein said this precession of the perihelion is relative. He didn't even have to use any math to show that you could consider the orbit to be perfect ellipse but the movement of the perihelion was relative.
5. ## Distinguishing between acceleration and gravity

No need to think of it as a force? Just becouse Einstein says graity is a spacetime curvature doesn't mean it's not a force. This argument is like saying "a tiger isn't an animal, it's a mammal." There are only four forces in the universe and gravity it one of them. For extra credit what are the other 3? The equations for Newtonian grvity are correct. The issue is not accuracy. The issue is some experiments, such as the precession of the perihelion of Mercury's orbit, can't be explained by classical physics. Einstein says that precession is relative.

7. ## Distinguishing between acceleration and gravity

One reply; Einstein, General Relativity (or is that 2) Gravity is a force. Einstein explained this force as a space-time curvature but that doesn't mean he disproved classical physics as explaining gravity as a force. Newton and Kepler's equations are still accurate. No forces??? How are you falling? In free fall here on Earth you will be accelerating 32 feet per second squared. Every second you will be going 32 feet per second faster than the second before. There must be a force. Gravity is accelerating you. ... and you pushing down with your weight. To every action there is an equal and opposite reaction. So when the earth is pushing up your weight is pushing down. When you are counteracting gravity this is the only time you notice it. Your earlier statement would be more accurate to say you never notice the gravitational force when you are in free fall. THAT's General Relativity. Accelerating motion is relative. Einstein showed gravity and inertia as being 2 manifestations of the same force. If you were in a spaceship accelerating 32 feet per second squared you would experience 1 G of force. You could walk around on the floor of your rocket and think you were on Earth. So as the accelerating rocket pushes against your feet you press back and once again you notice this "gravity" only because there is a force counteracting it. But is this really gravity or inertia? It's relative.
8. ## The maximum number of elements possible in perodic table !!

The higher elements are radioactively unstable. The heavier elements are so unstable they quickly decay. For that reason I don't think there is a definite maximum number of elements. These higher elements were created in laboratories and don't exist in nature.
9. ## Distinguishing between acceleration and gravity

If an object has 1 gram inertial mass it also has 1 gram gravitational mass. So yes these values are always the same. Since they are the same everything falls at the same speed. How do acceleration and gravity produce the same effect? Yes they are both measured in Gs. Gravity can cause acceleration. If I am standing on a bathroom scale it says I weigh 170 pounds. I am not accelerating. If I was in anything free-falling such as an elevator with broken cables or a free falling spaceship (disregard air and other friction) then I am accelerating but no longer pressing on the bathroom scale. If I am standing on the earth I experience gravity because my legs are counteracting gravity (pressing against earth) But if I am free falling and not pressing with my legs then i don't notice gravity. If I am in a spaceship drifting and suddenly press my legs on the side or floor as if jumping I can experience a g force AS I am accelerating. If I turn on the spaceship engines I am pressed in the back of my seat as I am accelerating. If I am not applying any force to counteract gravity or inertial I am floating. I would float in a free falling elevator (even if I was on a huge planet). I would be floating in a spaceship with engines off far from any star or planet.
10. ## As conscious observers, are we moving at the speed of light relative to light?

Please explain. Actually I don't think you are speculating. I think you are misunderstanding physics. In 1887 Mikchelson and Morley set out to find out the absolute speed of Earth. They knew light traveled at 186,000 miles per second so they performed experiments to see how fast light was traveling relative to Earth. (actually they were comparing the speed of light coming from different directions) Their experiments showed that the Earth was not moving. They showed that light always passed by Earth exactly as if we were standing still. This was very confusing since they knew the Earth was spinning on its axis and the earth was in orbit around the sun and the sun was moving in the galaxy. Then Einstein Showed that, although motion and speed is relative, the speed of light is always absolute. Light will always pass up the fastest spaceship as if it's standing still.
11. ## As conscious observers, are we moving at the speed of light relative to light?

If you are talking about E=MC² This is not talking about our speed relative to light. Energy = Mass X Speed of light squared That means if mass is converted to energy (such as a nuclear explosion) that the energy resulting is equal to the mass times the speed of light squared. In other words there is a LOT of energy in a little mass.
12. ## ﻿Are we overpopulated?

I made this thread a poll because I knew that, even if everyone was looking at the same data, some would say we're very overpopulated and some would say the Earth can sustain much more people. When Mother Teresa was asked about overpopulation she said "how could there be too many people? That's like saying there are too many flowers." No the environment is not allowed to change at all. If the environment does change then it is overpopulation. If the population of deer in a area becomes so high that they eat up most of the vegetation then that is overpopulation. In such areas you can see just how high the deer can reach because all the leaves below a certain height on the brush and trees are all eaten by the deer. Just because the deer can survive doesn't mean they are not overpopulated. By everyone's definition (except Danijel Gorupec's) once the environment is impacted then it is overpopulation. A species does not start to die off from lack of resources until the very late stages of overpopulation.
13. ## As conscious observers, are we moving at the speed of light relative to light?

Speeds and motion are relative. Except for the speed of light. No matter how fast a spaceship is traveling light will always pass it up exactly as if it's standing still.
14. ## ﻿Are we overpopulated?

First off I love meat. A nice big steak is my favorite food. Secondly we have canines for a reason, were are meant to eat meat. We're omnivores. We need big factory farms because we are overpopulated. If a large percentage of the population were to become vegans we wouldn't release the cattle and pigs to roam the wild, we would simply produce less livestock. We have complete control over their population. Sure we raise the cows and pigs just long enough to be killed for food but I believe it's better for the animals to have a short life than to never have lived at all.
15. ## ﻿Are we overpopulated?

We are overpopulated and it's evident because of the degree that we disrupt the environment. We have to all be ecological with our resources because of our overpopulation. And if we have to become vegetarians then we are most certainly overpopulated. We are omnivores. We have taken over most of the fertile land as farmland. Environmental deterioration is part of the definition of overpopulation. http://www.merriam-webster.com/dictionary/overpopulation Straining available resources is also part of the definition http://dictionary.reference.com/browse/overpopulation
16. ## ﻿Are we overpopulated?

oh no I didn't mean we should all go back to hunters and gatherers. I only meant we could hunt if we want or kill livestock. I don't like the idea of our population being so high that we have to resort to raising meat in such tight confines as artificial meat factories. So if wolfs grew in population that they were killing up all the deer, all the racoons, the beavers and otters. They would not be overpopulated? They would continue to exterminate other life forms but never be overpopulated until they kill off all their food. Once they start to die off because they killed off their food, only then, during their demise would you consider them overpopulated? Colonization of other planets is still very far off. I believe we are already very much over populated. Did you guys vote? from the looks of the responses everyone but kindheart seems to think we are not at all overpopulated. But the poll says everyone agrees with me that we are already over populated.
17. ## ﻿Are we overpopulated?

I would try it but petri dish meat, that's just not right. I care about the life on this planet but I also firmly believe in the natural food chain. Let's go out and kill our own meals. I am firmly against killing off wolfs and other animals that are a threat to our livestock, us and our safety. I live in the mountains of SW Colorado. We have wolfs, bear and mountain lions here. They may be scary but I eagerly hope to see these animals when I am out. They aren't too much of a threat since none of them consider us thier prey. but they are still far from being safe animals. If i gave the impression that I care so much about animal life that I am a vegan that's far from the truth.
18. ## ﻿Are we overpopulated?

Yea, we are happier than ever. So what? So we are the most important animal? The heck with all other species? I'm looking over the members that have responded to this thread. I really don't know you guys but I'll go out on a limb and say most of you are humans. If I could get some more deer, bear and maybe even wolfs to chime in I bet we would get more responses saying humans are crowding out wildlife and animals the world over. The other animals need a chance. And they need us to give them a chance. We could kill off any animal that inconveniences us. Wow, by that standard no other animal has overpopulated the world (maybe a local area). By that standard humans could populate the whole world as one big city and grow our food in laboratories (such as the petri dish meat posted earlier) Like what was talked about in this thread: http://www.scienceforums.net/topic/57972-do-we-need-so-many-other-animals-on-earth/
19. ## Distinguishing between acceleration and gravity

Gravity can be shown to pull on anything with mass. Magnetism only affects some metals. Acceleration is not a force, it's the result when a force is applied. That was my point earlier. That I think it's more accurate to say inertia and gravity are the same (so says Einstien). Acceleration and gravity are not the same.
20. ## ﻿Are we overpopulated?

You can see where we are. If you have read my posts you can guess where I think our population should be. This chart shows why I don't think there is a practical solution to our over population.
21. ## The Official JOKES SECTION :)

These gun laws are getting ridiculous. The last time I went to the sporting goods store and was ready to pay for my purchase of ammo the clerk told me "Strip down facing me". Well, I did just as she instructed. As the screeching was dieing down i realized that she was talking about my credit card. Is it just me or do they need to be more clear with those instructions? I guess it hardly matters now. I was told I have to conduct my shopping elsewhere in the future.
22. ## ﻿Are we overpopulated?

Phi for All, what you are talking about is ZPG or decreasing the population a bit but since my opinion is the earth is over a thousand times overpopulated that's why I don't think there is a practical solution.
23. ## ﻿Are we overpopulated?

Overpopulation is a problem that has no practical solution. I hate to complain about things without a solution but I'm afraid that's what I'm doing.
24. ## ﻿Are we overpopulated?

I think it is all about the numbers. You may think we can populate the Earth all we want as long as we use the resources wisely. I think that is managing an extremely overpopulated Earth. I think we are overpopulated by a factor of thousands or 10's of thousands. There is no other animal that has taken over the landscape as much as humans. Sure you can find local areas where deer are overpopulated but not over the whole world like the humans are. The overpopulation that humans experience is not found with any other large animal. But it does happen with smaller organisms such as bacteria, algae and yeast. Long ago before people learned how to keep food sterile and fresh they could not enjoy grape juice unless it was freshly crushed from grapes that were just picked. Within a couple days natural yeast would infect the juice. The yeast would eat the sugars and produce alcohol. The alcohol is their waste. Grape juice would turn to wine within a couple weeks. Bacteria would also infect the juice so this uncared for wine would also be sour. Within a few weeks the yeast would eat up all their food (sugar) and be swimming in their own waste (alcohol). At that point the yeast would die by the millions. This is the point that I think we humans are at. We humans live in cities of hundreds of thousands or millions. We can not get food in those densities EXCEPT for bringing our technologies into the problem. We can truck and transport food from the farmlands to the cities. If we had zero technologies our cities would die up just like the overpopulated yeast. Even if we migrated to the farmland and distributed our population over the fertile land we would not be able to sustain our population without technology. If we had to have our food so close that each of us had to walk out to our field and pick our own food. Or if we had to go out and kill our own animals most of our population would die off. There are lots of fertile land that can support lots of people but there is also a lot of very dry lands. Earth could not support our population without our technologies.