19 replies to this topic

[Waspie_Dwarf]

Quote

Seven years ago, astronomers boggled when they found the first runaway star flying out of our Galaxy at a speed of 1.5 million miles per hour. The discovery intrigued theorists, who wondered: If a star can get tossed outward at such an extreme velocity, could the same thing happen to planets?

New research shows that the answer is yes.Not only do runaway planets exist, but some of them zoom through space at a few percent of the speed of light - up to 30 million miles per hour.

"These warp-speed planets would be some of the fastest objects in our Galaxy.

Read more...

Edited by Waspie_Dwarf, 09 June 2012 - 02:24 PM.
Added tags

[JayMark]

Quite facinating!

"Other than subatomic particles, I don't know of anything leaving our galaxy as fast [...]" added lead author Idan Ginsburg of Dartmouth College.

That was quite indeed one of the first thing I thought.

Isn't it a good example of what was arleady theorised about using a black hole to propel crafts at these kind of velocities? Wasen't it Hawking who thought about this?

[Taun]

That means a hypervelocity planet would only take about 782,000 years to get from our Solar system to Alpha Centauri (if my math is right)... That's still insanely faster than we could do it...

Edit: my bad... re-did my math and it seems it's only 88 years... oops...

Edited by Taun, 23 March 2012 - 03:04 PM.

[JayMark]

Taun, on 23 March 2012 - 02:59 PM, said:

Edit: my bad... re-did my math and it seems it's only 88 years... oops...

Just blame it on the calculator.  

[Taun]

JayMark, on 23 March 2012 - 05:58 PM, said:

Just blame it on the calculator.  

Nah it was me...  I did it in Excel and squirreled up the formula...

[PsiSeeker]

Taun, on 23 March 2012 - 02:59 PM, said:

That means a hypervelocity planet would only take about 782,000 years to get from our Solar system to Alpha Centauri (if my math is right)... That's still insanely faster than we could do it...

Edit: my bad... re-did my math and it seems it's only 88 years... oops...

Well, if you were on the actual planet it would take less than 88 years as far as you were concerned.  It would take 88 years for the people observing you but far less for you.  (I.e time is relative)

[27vet]

The recent Nat Geo article poses the question on what one would observe if one was on such a planet. No sun, rapidly changing cosmos etc
More here....

[Taun]

PsiSeeker, on 24 March 2012 - 09:17 AM, said:

Well, if you were on the actual planet it would take less than 88 years as far as you were concerned.  It would take 88 years for the people observing you but far less for you.  (I.e time is relative)

True, but I'm way too lazy to try and calculate that...

[pallidin]

No, it would be not be too much more than 88 years. 30 million miles per hour is a fraction of the speed of light. 1/22th to be exact( if I have my math right )

[PsiSeeker]

pallidin, on 27 March 2012 - 05:16 PM, said:

No, it would be not be too much more than 88 years. 30 million miles per hour is a fraction of the speed of light. 1/22th to be exact( if I have my math right )

I don't think you understand how relative time works.  Assume you hopped on a space ship that can travel at the speed of light.  You shoot off and travel at the speed of light.  You decide to slow down and stop travelling at the speed of light after 1 second because you forgot something.  In that 1 second of time you experienced a presumably infinite amount of time would have past where you left off.

Edit1:  The faster you travel towards an object the less time you experience subjectively relative to your 0 speed.  (The time you experience won't feel different though)  The distance you travel towards the object doesn't change though because the speed of light doesn't change in relation to time.

Edit2:  
This may help:


And:


The key here being that objects in time distance are closer than they appear.  They're just super hard to get to.  (Require enormous amounts of energy)

Edited by PsiSeeker, 28 March 2012 - 05:53 AM.

[pallidin]

So, how much time dilation would there be with an object traveling only 1/22th light speed?

[Waspie_Dwarf]

From 27 March 2012 - 05:16 PM:

No, it would be not be too much more than 88 years.

At 1/22 the speed of light it would take 88 years to cover 4 light years. The Alpha Centauri system is a little further than that, 4.24 ly for Proxima and 4.37 ly for Alpha Centauri A & B. This gives use journey times at 1/22 c of 93 and 96 years respectively. I give these figures not to show off, but to justify a step in the calculation I will do below.

pallidin, on 29 March 2012 - 02:56 AM, said:

So, how much time dilation would there be with an object traveling only 1/22th light speed?

The short answer is not a lot. Time dilation is an exponential function and really only becomes significant above about 10% of the speed of light.

For fun (because I had nothing else to do) I decided to do the calculation.

The formula for time dilation is:

t = t₀/√(1-v²/c²)

Where:
t = time observed in the other reference frame

t₀ = time in observers own frame of reference (rest time)

v = the speed of the moving object

c = the speed of light in a vacuum

I am going to round up the journey time to 100 years to make the maths easier (that is why I give the figures to Alpha Centauri above).

We do not need to use the absolute value of c. If we say c=1 then we can use 1/22 (or 0.04545 as a decimal) as the value for v.

This gives us:

t = 100/√(1-0.4545²/1²)

= 100/√(1-2.060x10^-3/1)

= 100.1 years

In other words, from the point of view of an observer on Earth, a traveller on our hypothetical planet would only be a little bitt over one month younger than he would have been.

[PsiSeeker]

Hmm, if you're travelling at 1/x speed of light (where 'x' is any positive integer) the amount of energy you consume will be exponential increasing as x approaches 1.  What actually happens to the energy consumption in terms of distance traveled as time dilation starts taking effect?

I.e you objectively experience less time per unit of distance the closer x gets to 1.  Does this mean the energy being consumed also experiences less objective time per unit of distance and as a result travels more distance per unit of energy subjectively relative to 0 velocity?

[Waspie_Dwarf]

My understanding is that as any object with mass approachs the speed of light the energy required to accelerate it further approaches infinite.

This is one of the reasons that no object  with mass can reach the speed of light.

[PsiSeeker]

Edit2:  Does it makes sense to say that the closer and closer an object gets to the speed of light the more physical distance is traveled per unit of energy (subjectively and relative to the 0 velocity state) and as a result after the object reaches the speed of light the moment an infinitesimal amount of energy is spent the object will have traveled infinite distance in that moment? (relative to the 0 velocity state)

Edited by PsiSeeker, 29 March 2012 - 01:45 PM.