Yea.. bring it on.. I know where this would lead us to!.. ... but anything for science..

I absolutely love this thread.I'm into Physics but can't answer for some reason.

As SLS has said,time will make this a VERY messy thread.

  I am pleased to see the response  ....

When are discussing gravity, momentum and intertia....Time anyways become an integral part of it..... so  ..... lets put some thoughts about time too.......

Ok.. just to kick start it..

Lets say we have two perfectly matched atomic clock... ticking in perfect resonance. Note that these two clocks are at Earth. Now, if we transport one of this clock to the moon.. Do you think the clock will still run perfectly matched?

No

The clock on the moon will run slower due to the gravitational time dilation, lower the influence of gravity slower time passes 

To dial it a notch higher.
How much time will it take for you to travel to a star say five light years away if your space ship is traveling at the speed of light.
Assuming traveling at the speed of time is possible

SLS got it... but its the other way round. The clock on the moon will run faster due to lower gravity/mass of the moon.

I wonder how gravity or the mass of an object influences time.

The GPS satilites have clocks compensated so that it matches with the time on the surface of the earth.. without the time compenstation there will be like 4 (or 6??) miles cumulative difference in the GPS location you wish to go.. Isn't physics interesting?

Do post some weird questions.. I am sure there are lot more members here with such questions.

Oh yes, its the other way round.
About the GPS satilites, wont that be due to dilation due to relative velocity or may be both
ps: see my question posted above your response

Quote from: SunLikeStar on June 02, 2011, 05:16:59 PM
The clock on the moon will run slower due to the gravitational time dilation, lower the influence of gravity slower time passes 

That is wrong. Greater the influence of gravity slower the time. Time nearly stops near a blackhole. Thats the theory

Quote from: SunLikeStar on June 02, 2011, 05:22:28 PM
To dial it a notch higher.
How much time will it take for you to travel to a star say five light years away if your space ship is traveling at the speed of light.
Assuming traveling at the speed of time is possible

5 years.

There are more questions with baffling answers.. I have a few..

1, Why are planets spherical in shape.. why not a cube?

2, This may be a bit too much... but just for our imaginative minds : What is infinity?... there a quite a handful of mathematicans who have gone mad thinking about it.... see the documentry named - "Dangerous Knowledge" in youtube.

3, This is another thing I could not explain to myself.. Why do we need earth connection for mains power supply.. I know its for saftey but if we do not earth the neutral line at the power plant we will not get a shock.. unless we touch both the conductors (line and neutral)... A good professor of mine once convienced me but I kind of forgot what he said over time.

4, Now, something on airplanes... If you see videos of sonic boon created by aircrafts.. you would see the plane moving at a speed which is not too high compared to some RC airplanes.. but still it manages to create a sonic wake.. I have seen RC planes doing much higher speeds (for my eyes) but they don't make sonic wake.. What deceives our (my) eyes??

-Ismail

Quote from: SunLikeStar on June 02, 2011, 05:22:28 PM
To dial it a notch higher.
How much time will it take for you to travel to a star say five light years away if your space ship is traveling at the speed of light.
Assuming traveling at the speed of time is possible

Most stars that we look at night sky are millions, if not, billions of light years away.. So, the light that you see from the star today have started their journey millions of years before.. May be even before the evolution of man or existance of life... It could be that a star that we see today has already died and we are just seeing the light it had produced when it was alive...

Everything and i mean everything is related to time even the answer to the first post is about time. IF asinghatiya makes a hovering vessel (which is not affected by any outer force) and wait 24 hours he will be at same place again. so its all about time.

Quote from: SunLikeStar on June 02, 2011, 05:22:28 PM
To dial it a notch higher.
How much time will it take for you to travel to a star say five light years away if your space ship is traveling at the speed of light.
Assuming traveling at the speed of time is possible

Please do not even assume as one can not travel at speed of light because of time constraint. all kinds matter & energy etc etc. known to man will cease to exist before reaching at c. in other words only light can travel at c. if someone reaches at c or beyond,  he can time travel ( one way only no going back). so in the end everything is related to time.

Another interesting question that my brother asked...

Imagine you are inside a car running at 60Km/hr... there is a bug inside the car and it flew from the rear window to the wind screen.. Lets say the bug's forward speed is 3Km/hr.. So, does it mean that the bug has flown faster than the car (@63Km/hr)? Can it do 63Km/hr outside the car?

Quote from: kartikmadhira on June 02, 2011, 03:13:24 PM
Man are u sick?World is not only made of of machines!!damn it!these days humans are so narrow minded!!.U dont like birds, the greenery and evrethng?oh gosh its bcoz of people like u by which our earth is changing and yeah..concrete jungles too!change ur mind snehal!otherwise nature will take its own stuff!.nd i never meant watching animal stuff i said might ships, megastructures stuff like that!oops forgot time warp..its my fav!

@ kartik .U misunderstood i am not telling that don't love nature ,don't interact with them,dont watch shows regarding it.But don't forget that u cant live without science too .U have to  interact nature as well as science so that you could live a better life.If you are so concerned about nature then for god sake dont watch Tv,Don't drink cold water from refrigerators ,don't run your pulsar bikes,take some action regarding it,plant trees.
If you do all these then you don't have the right to say that.
In this 21th century u need both nature and science TO LIVE. 

So now next we come to watching shows. Lets take an example .
Suppose there is a show telling us what to do when snake bikes or people are sharing their experiences of snake bites. So i watched that show and i know how to save myself.And you watched alien stuff and mega structures(suppose .... dont take it wrong) then you wont be able to do so.
Actually... different views of different person.BUT U CANT PROVE ME WRONG.If yes then tell me.....

Yes it is true that watching things that we have never seen before is interesting .dat again depends on u and ur interest.I have no objection.And i also dont have the right to say that yes dont watch that show.But yes the thing u said of sickness....u can guess it urself

Quote from: izmile on June 02, 2011, 07:08:30 PM
Most stars that we look at night sky are millions, if not, billions of light years away..

Alpha centauri is ~4.5 light years away from us.

Quote from: izmile on June 02, 2011, 07:04:22 PM
5 years.

The journey would be instantaneousness and will take no time. There is a very nice thread about this on the physics forum.

Quote from: CrazyPilot on June 02, 2011, 07:15:04 PM
one can not travel at speed of light because of time constraint.
PS- Lets waste some more time reading this thread.

I said assume. And I did not understand you PS note, can you please elaborate 

Quote from: izmile on June 02, 2011, 07:39:57 PM
Imagine you are inside a car running at 60Km/hr... there is a bug inside the car and it flew from the rear window to the wind screen.. Lets say the bug's forward speed is 3Km/hr.. So, does it mean that the bug has flown faster than the car (@63Km/hr)? Can it do 63Km/hr outside the car?

For the observer inside the car the bugs speed is 3Km/hr and for the observer outside the car the bugs speed is 63km/hr. Speed is perceived because as time is relative speed is also relative.

Quote from: snehal50samarpit on June 02, 2011, 02:58:11 PM
Their is one called airship (lighter than air vehicle ) amazing. Run on hydrogen or helium.
Only drawback for those is time.

But ur question is good.I am too confused that what is the need of aeroplanes when we can travel anywhere on earth within 24 hrs.
Maybe the wind is villain.

guys are we going to invent something?

yes snehal wind is the willion. Its not only the earth, but atmosphere too which moves along..

But its possible in space, just remember the geostationary satellites, which has to be mechanically given the initial momomentum, in direction of earth to focuss at same time on earth..,

if not, it will see the whole world within 24 hrs as you said  

Quote from: izmile on June 02, 2011, 07:39:57 PM
Another interesting question that my brother asked...

Imagine you are inside a car running at 60Km/hr... there is a bug inside the car and it flew from the rear window to the wind screen.. Lets say the bug's forward speed is 3Km/hr.. So, does it mean that the bug has flown faster than the car (@63Km/hr)? Can it do 63Km/hr outside the car?

Well, the orbital speed of the earth averages about 29.8 km/s (107000 km/h). So, if one moves at 3 km/h it doesn't mean they're moving at 107003 km/h, it's all about relative velocity. When the bug is on the rear window of a car moving at 60 km/h, it too has a speed of 60 km/h and a momentum because of that speed which it can use to go to the front pane.
Again, if it hovers for too long, it will gain a relative speed w.r.t the car. This case is similar to the one in the first post.  

Quote from: izmile on June 02, 2011, 07:39:57 PM
... Can it do 63Km/hr outside the car?

No, not even if the bug in question is a 'dragonfly' (which are the fastest and have been clocked at a speed of 35 miles an hour) 

Quote from: SunLikeStar on June 02, 2011, 09:15:22 PM
The journey would be instantaneousness and will take no time. There is a very nice thread about this on the physics forum.

Yes. You are right. For the traveller it would be almost instantaneous because time slows down at the speed of light.. but for the observer in earth it would be 5 years.

I could not find convincing answer of Time stopping or going back to past... that would create a lot of unexplainable paradoxes.

Quote from: Swapnil on June 02, 2011, 09:42:51 PM
Again, if it hovers for too long, it will gain a relative speed w.r.t the car. This case is similar to the one in the first post.   

Even if it hovers for a long time, it will still fly at 60Km/hr (for the observer outside)... This is because the air column inside the car is also moving at 60Km/hr and it carries the bug forward and it dosen't need to flap its wing harder than just hovering outside the car.

Quote from: izmile on June 02, 2011, 10:47:56 PM
I could not find convincing answer of Time stopping or going back to past... that would create a lot of unexplainable paradoxes.

Actually majority of physicists (including Steven Hawking) believe that travelling to the past is impossible. The theory is still based on lots of assumption, while travel to the future via time dilation has been proved, like the atomic clock experiment you pointed out earlier.

Quote from: asinghatiya on June 02, 2011, 04:11:24 PM
BTW good question to snehal50  ,,,he need to spent his today's night to answer this.......

Man Yes u were right it took me night to think about it at my level.

Quote from: CrazyPilot on June 02, 2011, 02:58:11 PM
snehal50 one question for u. If the Earth stopped rotating, would time stand still?

Sir currently I am studying in +2 and I am not expert on this and also not good in physics ..here is the answer of my level and maybe it is  wrong.
If the Earth will stop its motion then that means half the night and half the day always.
We measure tym by rotation of Earth and not by clock. Ghari ek jariya hai tym btane ka . If not so ,I would have taken out batteries of clock

If earth stops then yes time stops for us  coz w say that time is passing by when we see position of earth related to sun or moon or other stars .So I will say Time Stops For Me  and not for aliens when Earth stops its motion coz this is night or day for me .
But there is no use of saying that coz Earth will never stop!!
Even if Earth stops its environment will be in motion (Sir Newton's law) and it will take away everything with it and no life will sustain.(Suppose we are Siting in a car at 1000 km/hr speed .we will be comfortable in that speed also But if suddenly car stops then we will be thrown out .(Maybe car phaar ke bahar nikal jaye.)
In this case car is our environment and we are its inhabitants and in large view all the topmost surface of Earth ,layers of Earth and all its inhabitant (including us)  are its inhabitants and environment is our environment.So life will end within one sec.
I am wrong then please correct me.
Another thing related time is related to BLACK HOLE .accding to scientist we know that black hole is nothing but dark energy which pulls everything inside it and time in there slows in real (imagine it takes ½ an hour for a pen to fall from our hand).
That is another tym and another wrld. Scientist also say that we can travel in future wid the help of black holeand also travel backwards.But I am unable to understand that  hows is dat possible?
When an object falls in a black hplrr  o o soruy 30 sec left at café .wil continu nxt tym sory.

This is a reasonable question. I had a question inn Time travel . my question was " Consider that we are launching a space shuttle that travels to the speed of light. Then by Time Dilation, time inside the space ship will be longer than that of ground station.Won't it cause a disturbance in their communication? For eg. If the space shuttle travels for a day,it would be just a day inside the space shuttle but in the ground station it might be a couple of months. That brings out a confusion between the shuttle crew and ground crew. Is this possible or not?"

I had contacted NASA and got answer for that.The answer was relevant.
"hanks for your question. Yes, you are correct that communications would be very difficult!

First, I should point out that the space ship could never quite reach the speed of light. According to Special Relativity the total energy of an object increases as its speed increases and approaches infinity as the object's speed approaches the speed of light. This means that it would take an infinite amount of energy to accelerate an object to the speed of light.

So, we'll assume the space shuttle is traveling away from Earth at near the speed of light. From the perspective of the ground station on Earth, time would appear to pass more slowly on the space shuttle. Their radio signal still reaches us at the speed of light (albeit with a doppler shifted frequency) but we perceive their transmissions to lengthen.

But what about the signal we send to the space shuttle? From their reference it is the ground station that is traveling away at nearly the speed of light. So they record the signal from the ground station slowing down! Both communications are slowed down relative to the perspective of those who are receiving them.

How is it that both clocks slow down? This is the "Twin Paradox" (explained here: http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970701a2.html). If at some point the space shuttle were to return to Earth to compare communications with the ground station, then they would change their inertial reference frame (ie, change course). This requires an acceleration that leads to its own effect on how communications are perceived by the observers on both the shuttle and ground station. It's during this acceleration that General Relativity come into play, causing the total time experience by the shuttle to be less than that on the ground station (assuming it's the shuttle that changes course).

This isn't just a thought experiment. GPS satellite signals need to take into account the relativistic effects to correctly determine positions, as explained in detail here:
http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html

In short, the orbital velocity has the effect of making the GPS clock tick slower (relative to us). But there is also a much stronger General relativistic effect from the GPS satellite being higher in the Earth's gravitational potential than us on the ground, that makes the GPS clock appear to tick much faster. The net effect is that the GPS satellite clocks appear to tick faster than our ground clocks (but both are important)."

You can contact and ask your question here: http://imagine.gsfc.nasa.gov/docs/ask_astro/ask_an_astronomer.html