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# Agen

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## Posts posted by Agen

1. ### A serious issue with space exploration

The greatest observed redshift are on the order of z=7, which corresponds to a distance of about 4 billion parsecs, a few thousand times the radius of the Local Group. Hubble’s law, which is widely believed to give accurate estimates at all distances in the observed universe, gives a recessional velocity for such a very distant body of about

$v = D H_0 = 3.9 \,\mbox{Gpc} \cdot 70 \,\mbox{km/s/Mpc} = 273000000 \,\mbox{m/s} = 0 .91 \,\mbox{c}$

, corresponding to a time dilation factor of about $\sqrt{1-0.91^2} \dot= 0.41$.

Thanks! That was pretty much the answer I was looking for.

2. ### A serious issue with space exploration

Interesting. So the time dilation effect in our local group of galaxies is not that notable.

How about distant galaxies then? Those, which have a relative velocity of near c to us. Wouldn't exploring those be a problem?

3. ### A serious issue with space exploration

Hello!

I have been thinking about space exploration and have come across an interesting problem. I haven't seen anyone mention this before, bu here it goes:

The biggest problem right now with traveling to other stars/galaxies is the light speed gap. We cannot even come close to light speed at this time. An alternative that is frequently proposed is using wormholes or shortcuts in space-time.

Ok, lets assume that we have the technology to create wormholes and we could use them to transport ships to other galaxies in an instant. Here is were I came across jet another problem. If we send a ship to another galaxy, lets not forget that other galaxies are moving away from is (the expanding universe) and may of them are doing so at great velocities in reference to us. Wouldn't this cause time dilation between the ship and home and as a result one would age more than the other or something to that regard?

Time is not constant, so this would make establishing a universal "empire" impossible it seems. Or what would you say?

4. ### Probability and infinity

But you didn't like that. Why?

Because I was talking about absolute zero. You where talking about close to zero. They are two different things.

and you where adding parameters from this universe to this question for no apparent reason.

5. ### Probability and infinity

So basically what you are saying is that this is an impossible scenario and cannot be answered?

6. ### Probability and infinity

There is no right answer to this question, because you have proposed an impossibility. An infinitely large number of anything means a real number (any real number) divided by zero. As soon as you divide by zero you throw away all logic. Basically, the question is meaningless.

ok, so where exactly do I divide by zero?

The equation is: 1 / ∞ x 100 = 0.(0) x 100 = 0.(0) = 0

7. ### Probability and infinity

I think the view is that a countable infinity, such as that in post 1, gives an infinitely small probability but an uncountable infinity gives a probability of zero.

ughaibu, could you please define "countable infinity" and "uncountable infinity" and compare the two. I don't seem to understand what you mean by them.

8. ### Probability and infinity

I think your logic is pretty flawed - it's basically stating that winning the lottery is impossible. Yet we know it isn't.

Are you kidding me? The lottery has odds with finite numbers. It's not like there are infinity amount of tickets and only one wins.:esmoking:

I don't really understand what you are trying to say. There are a couple of unknowns - like what is the "right" product out of the infinity?

Just 1 unit is right, the rest infinity are wrongs.

If there are an "infinity of products", what are the odds that there would be an infinite amount of products that look so similar to the "right" product that you can't distinguish them?

That is totally irrelevant. You have all the information you need.

"As you know, 0.000....=0" is not a true statement, either.

How so?

Is that close enough to zero for ya??? :eek2:

I gave you the parameters of a universe (with infinity objects, 1 is "right"). There is no need to put any parameters from our own universe to this equation.

9. ### Probability and infinity

Hi !

Let's say that there is an infinity amount of objects and only one of those objects is the "right" one. What would be the chances of the "right" one being picked?

Looking at this mathematically I would say it's ZERO. Because the chances are 1 to infinity of the right "right" choice being made. The way I came to this conclusion is this way:

Lets say there are 2 objects and only 1 is right. Obviously the probability is 50%. In the case of 10 objects the probability would decrease to 10%. With 10 000 it would be 0.01%, because 1 / 10000 x 100 = 0.01. As we can see the probability is nearing to 0. Now lets put infinity to the formula. It would seem that 0.000... will keep repeating forever and as you know 0.000...=0. Therefore there would be a zero chance of choosing the "right" object.

Now a lot of people have a problem with this saying: "But there still is a chance because the "right" one exists."

Any ideas?

10. ### Is mass also relative?

We can never know exactly what happens in any event. :confused:

hehe.. I love this argument.

I could respond to that with this: We can never know if we can ever know exactly happens in any event... and we can never know if that is true either.

Wouldn't you agree? :confused:

11. ### Is mass also relative?

So basically we don't know exactly what happens in these extreme events jet?

Well that's quite understandable, as physics are not 100% accurate jet.

12. ### Is mass also relative?

Okay, now moving on. If an object is moving fast enough will its mass turn so large that is collapses into a black hole?

The problem that I see here is that for the stationary observer the objects mass will be large enough to turn into a black hole (assuming this happens) but to another (something moving at half the speed of the primary object) it will not.

13. ### Is mass also relative?

If I am not mistaking the faster an object is going the higher it's mass will become, but this has to be relative to something right? If two objects are going at 0.8 c in the same direction they don't see the other moving at all, so their perception of the other mass should remain the same, right? However to a stationary observer both of the moving objects masses would increase?

If this is true then I have a question concerning of this and back holes, but lets leave it at this for the moment.

14. ### What is E/mc2?

E=mc2

is like

8=4x2

8 / 4x2 = 8/8=1

mhmh...:shrug:

15. ### Can something move faster than light?

Riper, of course it would take place in space. If it was started on Earth it would move out of the atmosphere in a very-very short time.

In a vacume I don't think it matters how fast you are going to damage the moving object, because there are no obstacles in your way to damage it.

And controllability is not the same thing in space, because balance (like on the road) is not a issue there and there is no wind resistance to deal with.

16. ### Growing nerves

As far as I know this has not been 100% accomplished jet, but will be a very important part in medicine.

So the question is what progress are we having on this matter. Will we see people recovering from severe spinal nerve root damages and other nerve related issues in the coming 10 years or so?

I myself have bad eyesight because of this. Wearing glasses wont help me all the way, because the main problem is in the nerves of my eyes, or so I was told.

17. ### Self driving cars ?

So I have heard that there are some prototypes out already. Cars that are basically able to drive by themselves, but still not quite ready jet. So the question is when will this be available to the public (in a decent price range). This is important for me, because I don't think I can get a license because of my eyesight.

18. ### 3 Word Conversation!!

and really big

19. ### Time dilation does not make sense to me.

Well actually there have been successful tests on this, but the difference was recorded in only mere nanoseconds. Still it's a difference.

Here is a test to prove it:

Now if anyone knows someone that has tested this but using something faster than just an airplane. Something more like a shuttle?

And I myself am also interested in finding out the fastest we have gotten something to move that can carry passengers. I would assume a rocket in orbit. (how fast does a rocket move in orbit anyway?)

20. ### Time dilation does not make sense to me.

Very informative, thank you. I'll try to get my mind around this.

21. ### Time dilation does not make sense to me.

Ok, so lets say I am on the rock and the ship is moving past me at close to c jet again. So lets say that it takes Derrick 5 minutes to move from point A to point B. So I am on the rock and as soon as he bypasses point A I start to read. When he reaches point B I stop and what do you know - I am on page 15, because I had 5 minutes to read, but Derrick is still on page 2, because of time dilation. Well.. now I am on the ship and Derrick on the rock. Let's do it again. I pass point A and start to read. Finally after 5 minutes I reach point B (because as I mentioned before it takes 5 minutes for the ship to move from point A to point :shade: and I seem to be on page 15, but Derrick on the rock is still on page 2, because in reference to me he was the one speeding and his time was flowing slower.

So the problem here is: When the ship reached point B, how can Derrick on the rock still be on page 2 and me on the ship on page 15, while if I was on the rock and the ship reached point B I would be on page 15 and he still on page 2?

22. ### Time dilation does not make sense to me.

So according to relativity the faster an object is moving relative to another object - the slower the moving objects time flows relative to the stationary object. This is called time dilation.

Well lets say I am on a rock in space and there is a space ship flying by me near the speed of light. We both are reading a book for about 5 minutes. Lets say that in that 5 minutes I can read 15 pages of the book. The guy in the space ship also reads 15 pages in 5 minutes. But because of him moving that fast if I look at him - his time will be flowing slower, so I would be able to read the 15 pages in the given 5 minutes while he will be at... let say the 2-nd page after 5 minutes. So the conclusion would be that I read 15 pages in 5 minutes, while he read only 2, because of him moving so fast. But now lets switch paces. I am now on the ship and that guy... err... Derrick is now on the rock. So I am moving close to c past him, but from my perspective he is the one speeding and reading slower. So after the 5 minutes of reading on the ship I will be on page 15, while he still is on page 2. Nope... does not make sense at all...

And btw if I look at a speeding object I will see it "living" in slow motion. Well let's say that the speeding object is looking back at me - shouldn't he see the opposite - me "living" very fast? No he because relative to him I am the one speeding and in slow motion, but how can both observers see the other one in slow motion? One must see the other moving very fast for the other to see one moving very slow for this to make sense... but according to time dilation and relativity, there actually won't be anyone anyone "living" very fast.

Very-very confusing.

23. ### Virtual reality physics.

What you are describing is not the "ordinary way" as I meant it. The simulation is not allowed to manipulate you physically in such a way. It's only allowed to show you the light from the screen and the sound waves from the speakers.

If you where to add the "trip" so you could create a time dilation effect then it's not the "ordinary way" anymore. Then its more like adding a moving/vibrating chair to the monitor, speaker, mouse, keyboard or/and joystick for a more realistic effect. But in the "ordinary way" anything other than a monitor, speaker, mouse, keyboard or/and joystick are not allowed.

So in this case relativity can't be 100% added to the simulation now can it.

24. ### What happen to the mater who go through black hole

I think he is just trying "win" me by outsmarting me with random knowledge.

This would be a similar situation: "Man A beats man B at a 500 m sprint. Therefore man A is better than man B, but man B wants to get even and walks up to man A and asks him random questions about the string theory. Man A gets silent and as a result man B is satisfied and walks away smiling and thinking that now he is better.

Classical.

25. ### What happen to the mater who go through black hole

Interesting...

Ok back to the topic then, before this gets out of hand. :eek2:

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