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New Planet Like Earth Found in Space?





heridlia
From : http://news.bbc.co.uk/2/hi/science/nature/6589157.stm

Quote:
New 'super-Earth' found in space

The new planet is not much bigger than the Earth

Astronomers have found the most Earth-like planet outside our Solar System to date, a world which could have water running on its surface.

The planet orbits the faint star Gliese 581, which is 20.5 light-years away in the constellation Libra.

Scientists made the discovery using the Eso 3.6m Telescope in Chile.

etc. ....


----------------------------

Maybe in the future, we can go to this planet.

But I'm pessimist that we will life over there.

How about you?

Thanks.
The Conspirator
We don't know the planet is earth like, they found it by measuring the stars wobble caused by the gravity of a the planet but they don't know what it looks like.
fbcompany
sounds like a bid to get some more research money.

Prolly just crack pot news.
The Conspirator
No, its real, they found a planet, they did it the same way they found all the other extra soler planets (by measuring the wobble of the star caused by the gravity of the planet). The star they looked at is a small red dwarf (which is why they where able to find a planet that small when they where all th planets found before where gas giants and super-giants).

I doubt the planets anything like earth, its very close to its star and though it is in the stars "Goldilocks zone" the gravitational tidal forces could cause the planet to be tidal locked (one side always faces the star) and the tidel forces could have the same effect as Jupiter has on Io.
Soltair
It is very interesting to see that we are now able to discover planets lightyears away from us and to make surprising analyses of these. I do not think, though, that we have what it takes right now to be sure, from this far, of what a planet is or not. We will get a quite precise idea, but we will never be sure.

Finding life is utopic. Even if there was life there, we couldn't know for sure. We would have to get there, and that's certainly not for tomorrow Wink . Still, finding planets that might look a bit like earth (regarding compounds or such) is a great step forward in the theory of extra-earth life somewhere, which was mostly a statistical bid up to now.
Bikerman
Soltair wrote:
It is very interesting to see that we are now able to discover planets lightyears away from us and to make surprising analyses of these. I do not think, though, that we have what it takes right now to be sure, from this far, of what a planet is or not. We will get a quite precise idea, but we will never be sure.
It depends on what level of certainty you are looking for. It is unlikely, I think, that we will be able to visit Earth Like Planets in the foreseeable future as the distances are extreme, in some cases even light-speed travel would not be fast enough. It follows, then, that we are going to have to make do with observation and educated guestimates.
Quote:
Finding life is utopic. Even if there was life there, we couldn't know for sure. We would have to get there, and that's certainly not for tomorrow Wink . Still, finding planets that might look a bit like earth (regarding compounds or such) is a great step forward in the theory of extra-earth life somewhere, which was mostly a statistical bid up to now.

Utopic? I think that is too pessimistic. I would not be too surprised, for example, if we discover life within our own solar system within a few decades. Europa seems like a good bet for some form of life, even if only microbial. Experience on Earth seems to indicate that wherever there is liquid water you find life and Europa may well possess liquid water in abundance...
Ennex
Yeah i heard about this, its ment to be in the zone like Earth is, not to close to be too hot, but not too cold to be too warm...it's just right, and it has some features like Earth...but even if it was capable...it would take millions of years for life to develop even if it could.
Bikerman
Ennex wrote:
Yeah i heard about this, its ment to be in the zone like Earth is, not to close to be too hot, but not too cold to be too warm...it's just right, and it has some features like Earth...but even if it was capable...it would take millions of years for life to develop even if it could.


What is the evidence for that? It depends, of course, on what you define as 'life'. The classical biological definition is something which can reproduce, grow and respond to stimulii. In physics terms life could be defined as a system which can decrease it's own entropy (disorder) by utilising external energy sources. This latter definition is broader in scope and could include man-made 'systems' or systems which are not made-up of normal matter.
LeeM
I think that it would be fascinating if we found intelligent life forms such as ourselves in Space. If we're in Space, I don't see why there can't be anymore intelligent lifeforms.
squirrelmaster
what about Alpha Centari, or was that just a fiction in some movie/game?

also, its cool how they just now found the kuiper belt, its funny how its been there all along we just couldn't see it, and now pluto isn't classified as a full-blown planet anymore Rolling Eyes
Gagnar The Unruly
Alpha Centauri is the closest star system to Earth, so it is a natural candidate for first exploration efforts, in the event that we acquire the necessary technology to reach it in the first place. It's remarkable because two of the three stars in the system are very much like the sun, so they seem like good candidates for hospitable planet formation. Most of our other stellar neighbors are not much like the sun. I'm sad that I probably won't live to see an expedition to Alpha Centauri. As far as I know, nothing is known about what, if any, planets exist in that system.
EanofAthenasPrime
If there was a spacecraft that could travel almost 100%c, because of time dilation it would only take a few minutes.
dickyzin
Whatever it is, nothing can reach that planet from earth in our lifetime. Even if there's a craft that can travel at the speed of light, it wouldn't get there for more than 20 years. Unless someone finds a way to bend space time and create worm holes, let's just try to sustain life on earth and protect it.
m-productions
Yes I heard about this as well, its rather sad that we will never get to see it in our lifetime, makes you wish you could live forever.
ocalhoun
The Conspirator wrote:
We don't know the planet is earth like, they found it by measuring the stars wobble caused by the gravity of a the planet but they don't know what it looks like.

Ah, but they could tell its size and distance from that star, and from that you could at least discern that it is a solid planet with an atmosphere, and has teperatures similar to Earth. If nothing else, it gives us somewhere interesting to go to, should we suddenly come across the capability to cross 20 light years of distance easily.
dac_nip
highly unlikely, you need the precise stability of a mass of a proton and all those delicate things to create a planet like earth - at least able to hold life. you would need another universe that is perfect.
Gagnar The Unruly
The mass of the proton is (presumably) the same throughout the universe. There's no reason to believe another Earth-like planet can't have formed elsewhere in the universe. It is a big place, after all. As far as what it takes to create a planet capable of supporting complex life -- we simply don't know. It'll take exploration to find out what is really necessary. If we can find organized life elsewhere in our solar system, it's a good sign that life is fairly abundant throughout the universe, and that life can either form in a variety of conditions or that the specific combination of necessary factors occurs fairly frequently.
Bikerman
EanofAthenasPrime wrote:
If there was a spacecraft that could travel almost 100%c, because of time dilation it would only take a few minutes.

That depends what you mean by 'almost' and where you are measuring time of course. OK - let's play.....

At 0.9c (90% of the speed of light) the time dilation ratio is around 2.3 (ie the traveller would experience 1 year passing for each 2.3 years passing on Earth). You have to get *very* close to c before you start to see really big dilation effects. The planet in question here is around 20.5 light years away, so, at c, that would take 20.5 years from Earth's FOR (frame of reference).
It would take no time at all for the traveller of course, since anything travelling at c does not experience time.

For reference here is a quick table I've knocked-up to show the relativistic dilation effect with increasing velocity (v) as v approaches c. The proportion is of c (=1), and shows that relativistic time dilation only becomes really significant when we push very very close to c.

Prop. of c.....Dilation ratio........Time@Earth (yrs)......Time for traveller (yrs)

  • 0.95.....................................3.2..................................21.6...........................................6.75
  • 0.98.....................................5.0..................................20.1...........................................4.02
  • 0.99.....................................7.1..................................20.7...........................................2.92
  • 0.995..................................10.0.................................20.6...........................................2.06
  • 0.999..................................22.4.................................20.52..........................................0.92
  • 0.9995................................31.6.................................20.51..........................................0.65
  • 0.9999................................70.7.................................20.5...........................................0.299
(I have rounded to 2 significant figs for most of the calc so the answers are approx to that degree of accuracy).

There is a problem, though. This simple model does not take account of acceleration/deceleration. It is inconceivable that our traveller could accelerate immediately to a high proportion of c and, likewise, decelerate at the other end back to 0. We need to complicate our model a bit more then. Let's talk about acceleration.......

The human body can stand an accelerative force of many tens of g (g being the accelerative force of gravity on Earth = 9.81 metres per second per second) but only for short periods.
A head-on car crash, for example, at about 50km/s, would generate about 60g for the driver (with an air-bag), which is generally survivable. (For reference, Princess Diana would have experienced around 75-100g in her fatal crash).

The body cannot stand these forces for long, though, and a more realistic figure for long-term exposure would be less than 4g (an F1 driver experiences up to around 3g in a typical race, a fighter pilot may experience around 6g for short periods).
(Even this small g would be medically catastrophic over a long period, I have no doubt, but we are talking about limiting cases here, not actual proposals).

Let's say, then, that our astronaut is a super-fit man/woman able to stand 4g for prolonged periods. So, starting from 0 km/s relative to Earth, we will assume a constant acceleration of 4g for 10.25 light years, at which time we turn the ship about and decelerate at the same 4g until the planet is reached and our velocity is again 0. We need to know how long this will take, allowing for relativity.

The sums are not trivial because we have to get 'relativistic' and we cannot simply use Newtonian laws of motion - which would be trivial here.
(For example the Newtonian term v=ut+1/2at^2 would let us solve this immediately with no bother, but it would be wrong, since we are now in the realms of Relativity, and so we need to use relativistic math).

The world-line for a point with acceleration a relative to a FOR at co-ordinates (t,x) is given by (t,x) = (1/a) (sinh(a tau), cosh(a tau)-1) where tau is the proper time along the world-line. We only want x in terms of t so we can eliminate tau to give the hyperbolic quadratic : a*(t^2-x^2)-2x=0

I won't detail all the workings because it will probably confuse most readers too much (btw - if anyone wants to take me up on this, challenge my logic, math, assumptions, or correct any errors I might have made, then please feel free - this is off the top of my head and so may be wrong)....

I've scribbled down the workings on a piece of paper here and I get something around :

10.72 years elapsed on Earth
1.84 years elapsed for the traveller
final velocity 0.99898c


This is for half the journey - ie the first 10.25 light years, so we have to double this for the entire trip (the second half of the voyage will be simply the reverse of the first in terms of acceleration and therefore time will be exactly the same).

So, finally we get a figure for the journey based on the several non-real-world assumptions, amongst which are:
a) the astronaut is superhuman and can endure 4g for prolonged periods (not possible in the real world)
b) the ship has unlimited fuel/power and can maintain a 4g acceleration (no technology we currently have, or are planning, can do this).
c) the ship can instantly swing around, travelling at nearly c and reverse the direction of thrust (this would not be possible in reality).

Still, this exercise gives us a limiting case, based on our current understanding of physics and, I hope, based in sound math. It is, therefore, useful to give at least a ball-park indication of the sort of figures involved.

Solution - the trip would take 21.44 years as measured on Earth during which time the astronaut would experience 3.68 years locally.

References and further reading for those so inclined:
http://cr4.globalspec.com/blogentry/310/Acceleration-by-Constant-Force
http://cr4.globalspec.com/blogentry/312/Relativistic-Acceleration-Part-2
http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html
http://bikerman.info/resources/mywork/relativistic-mass-and-dynamics.pdf

POSTSCRIPT - I made a dumb error in the calculation above due to scribbling the calc on a scrap of paper. Essentially I halved the total journey at the start and then (on the second scrap of paper) forgot I had done so and halved it again. Duh!! Anyway - I've recalculated and the results are below (I've stuck the calculations into Excel so I don't make any more dumb mistakes)

Time of flight (measured from Earth) - 20.98 yrs
TOF (measured on Spaceship) - 2.16 yrs
Max Velocity - 0.9997c
Gagnar The Unruly
Bikerman, would the travelers be experiencing 4g of acceleration for that entire period of time?
Bikerman
Gagnar The Unruly wrote:
Bikerman, would the travelers be experiencing 4g of acceleration for that entire period of time?

Yep.
Gagnar The Unruly
(I'm no mathematician, so, if you don't mind humoring me...) what would their final velocity and TOF be with a constant 1 g of acceleration?
Bikerman
Gagnar The Unruly wrote:
(I'm no mathematician, so, if you don't mind humoring me...) what would their final velocity and TOF be with a constant 1 g of acceleration?


Firstly I must come clean - I made an error in the last posting - an error of schoolboy simplicity which is embarrasing Smile.
Having halved the journey to calculate the two legs, I then forgot I had done it and halved it again over the page. My scribble was so spidery that I missed the error completely....
I've recalculated the data (I hope correctly this time) to give the amended figures as follows (for 4g)...

TOF (Earth FOR) - 20.98 yrs
TOF (Spaceship FOR) - 2.16 yrs
Max Velocity - 0.9997c

For 1g I get the following:
TOF (Earth FOR) - 22.35 yrs
TOF (Spaceship FOR) - 6.09 yrs
Max Velocity - 0.9963c

(I've set it up on a spreadsheet so it's relatively simple to run it with different data)

Postscript
Further to this I had a dig around a few sites I know and managed to come up with a JavaScript routine that does the calculation. (The author is happy to make the code freely available).

I've compiled-it into a web-page which does the calculation and explains a bit more of the math used. You can now try the calculations yourself by simple entering the distance (in either Light Years or AUs) and the acceleration (in either g or m/s/s).
The application is HERE
Manuel
That planet is really far from the Earth. It is really similar thought. It orbits a star thatmay be in the end of its life. The new planet is about the size of jupiter so the gravity would be the double of Earths gravity!! It has conditons in which humans can live in, that means, similar to the Earth, and to be honest, this is amazing
Bikerman
Manuel wrote:
That planet is really far from the Earth. It is really similar thought. It orbits a star thatmay be in the end of its life. The new planet is about the size of jupiter so the gravity would be the double of Earths gravity!! It has conditons in which humans can live in, that means, similar to the Earth, and to be honest, this is amazing

'Similar' is a subjective term. My understanding is that the planet is about 5 times the mass of Earth and about 1.5 times the diameter (nowhere near the size of Jupiter which is about 11 times the diameter of Earth). Surface gravity would be around 2.25g. The following information is taken from Wikki and summarises the main data we have.
Wikki wrote:

Parent star
Star...................Gliese 581
Constellation.......Libra
Right ascension...(α) 15h 19m 26s
Declination..........(δ) −07 43′ 20″
Spectral type.......M2.5V
Orbital elements
Semimajor axis...(a) 0.073 AU
Eccentricity.........(e) 0.160.07
Orbital period......(P) 12.93d
Inclination...........(i) ?
Angular distance..(θ) 11.661 mas
Physical characteristics
Mass...................(m) >5.03 ME
Radius.................(r) ~1.5 RE
Density...............(ρ) ~8000 kg/m3
Gravity................(κ) 2.24 g
Temperature........(T) ~290 K
Discovery information
Discovery date.....2007-04-04,
announced...........2007-04-24
Discoverer(s).......Udry et al.
Detection method..Radial Velocity
Discovery status...published
dickyzin
This might be a little unrelated to this topic but it's about space, planets and universe.. so I'll post it here.
There's going to be a spectacular night sky this coming Tuesday. There's going to be a lunar eclipse and the moon will appear red in the sky. The eclipse of the moon will start in the eastern hemisphere of the night sky apparently. This sort of eclipse won't be observed from Earth until 2011 as reported by scientists. The last one occurred in the year 2000.
EanofAthenasPrime
Ennex wrote:
Yeah i heard about this, its ment to be in the zone like Earth is, not to close to be too hot, but not too cold to be too warm...it's just right, and it has some features like Earth...but even if it was capable...it would take millions of years for life to develop even if it could.


So you think the planet was created magically right before it was discovered?
EanofAthenasPrime
Bikerman wrote:
Manuel wrote:
That planet is really far from the Earth. It is really similar thought. It orbits a star thatmay be in the end of its life. The new planet is about the size of jupiter so the gravity would be the double of Earths gravity!! It has conditons in which humans can live in, that means, similar to the Earth, and to be honest, this is amazing

'Similar' is a subjective term. My understanding is that the planet is about 5 times the mass of Earth and about 1.5 times the diameter (nowhere near the size of Jupiter which is about 11 times the diameter of Earth). Surface gravity would be around 2.25g. The following information is taken from Wikki and summarises the main data we have.
Wikki wrote:

Parent star
Star...................Gliese 581
Constellation.......Libra
Right ascension...(α) 15h 19m 26s
Declination..........(δ) −07 43′ 20″
Spectral type.......M2.5V
Orbital elements
Semimajor axis...(a) 0.073 AU
Eccentricity.........(e) 0.160.07
Orbital period......(P) 12.93d
Inclination...........(i) ?
Angular distance..(θ) 11.661 mas
Physical characteristics
Mass...................(m) >5.03 ME
Radius.................(r) ~1.5 RE
Density...............(ρ) ~8000 kg/m3
Gravity................(κ) 2.24 g
Temperature........(T) ~290 K
Discovery information
Discovery date.....2007-04-04,
announced...........2007-04-24
Discoverer(s).......Udry et al.
Detection method..Radial Velocity
Discovery status...published


Well the creatures (if any) on the planet, if similar in morphology to Earth Creatures, would be expected to be very strong/resilient (because of the high amounts of gravity.)
Bikerman
EanofAthenasPrime wrote:
Well the creatures (if any) on the planet, if similar in morphology to Earth Creatures, would be expected to be very strong/resilient (because of the high amounts of gravity.)

What does that mean? Strong? In what sense? Physical size? Morphology only considers the possible biologies without considering functionality. High gravity certainly has implications if we postulate similar biology to Earth - it would impose limits on mass, for example, and perhaps favour exoskeleton biology to the extent of developing an ecology with insect-like lifeforms being dominant. It would certainly reduce the likelihood of any dinosaur-type epoch and have profound implications for the potential development of mammalian lifeforms such as ourselves - I'm not enough of a biologist to know exactly what those implications are....
EanofAthenasPrime
Bikerman wrote:
EanofAthenasPrime wrote:
Well the creatures (if any) on the planet, if similar in morphology to Earth Creatures, would be expected to be very strong/resilient (because of the high amounts of gravity.)

What does that mean? Strong? In what sense? Physical size? Morphology only considers the possible biologies without considering functionality. High gravity certainly has implications if we postulate similar biology to Earth - it would impose limits on mass, for example, and perhaps favour exoskeleton biology to the extent of developing an ecology with insect-like lifeforms being dominant. It would certainly reduce the likelihood of any dinosaur-type epoch and have profound implications for the potential development of mammalian lifeforms such as ourselves - I'm not enough of a biologist to know exactly what those implications are....


Yes that is a good hypothesis. Insects tend to have mechanisms of flight and can withstand virtually no damage from high falls at velocities relatively to their size (although air resistance and and distance acceleration play a huge key.) Basically, creatures on that planet would have to be stronger to withstand the higher gravity (they become stronger because of the gravity.) In your opinion, what would the dominant species look like? (If there is one.)
ThreeRight
Know something funny? If we ever able to find that we are not alone in space, then it would also prove that the universe is abundant in life.

Think about it, lets say... we find life at 1 billion light years away. that could also mean that for every 1 billion light years across in space, there can be life. 1 billion light years to us is NOTHING compared to the size of the universe which is "infinitely expanding".

if we find universe is 1 trillion light years away, then it could also mean taht for every trillion light years, theres life.

If life is supposed to be rare in space, then it would be PRACTICALLY IMPOSSIBLE to find it, because by "infinitely expanding size of the universe" the chances of finding life close enough to see, would be very close to nil.

Trying to find something rare in space is like getting a blank piece of paper and putting random dots on it and saying every centimeters apart from each dot represents 50 trillion miles, and even that seemingly daunting 50 trillion mile, would seem like nothing compared to the "infinitely expanding universe"
Bikerman
ThreeRight wrote:
Know something funny? If we ever able to find that we are not alone in space, then it would also prove that the universe is abundant in life.

It wouldn't you know....
Quote:
Think about it, lets say... we find life at 1 billion light years away. that could also mean that for every 1 billion light years across in space, there can be life. 1 billion light years to us is NOTHING compared to the size of the universe which is "infinitely expanding".
'*Could* mean' is not the same as does mean. We might be incredibly lucky and discover the only life within a trillion-trillion light year radius...
Quote:

if we find universe is 1 trillion light years away, then it could also mean taht for every trillion light years, theres life.
Same problem. Statistics with a sample size of 1 is impossible. With a sample size of 2 it is possible but very unreliable....
Quote:
If life is supposed to be rare in space, then it would be PRACTICALLY IMPOSSIBLE to find it, because by "infinitely expanding size of the universe" the chances of finding life close enough to see, would be very close to nil.

It depends on what you mean by the universe and what you mean by 'practically impossible'. If you mean the 'observable universe' which stretches to the Cosmic Light Horizon then you have a theoretical radius of about 13 billion light years which is a big distance, for sure, but not infinite by any stretch....
Quote:

Trying to find something rare in space is like getting a blank piece of paper and putting random dots on it and saying every centimeters apart from each dot represents 50 trillion miles, and even that seemingly daunting 50 trillion mile, would seem like nothing compared to the "infinitely expanding universe"
Is it really? How big would the paper be? How many dots would you need to make?
EanofAthenasPrime
Bikerman wrote:
ThreeRight wrote:
Know something funny? If we ever able to find that we are not alone in space, then it would also prove that the universe is abundant in life.

It wouldn't you know....
Quote:
Think about it, lets say... we find life at 1 billion light years away. that could also mean that for every 1 billion light years across in space, there can be life. 1 billion light years to us is NOTHING compared to the size of the universe which is "infinitely expanding".
'*Could* mean' is not the same as does mean. We might be incredibly lucky and discover the only life within a trillion-trillion light year radius...
Quote:

if we find universe is 1 trillion light years away, then it could also mean taht for every trillion light years, theres life.
Same problem. Statistics with a sample size of 1 is impossible. With a sample size of 2 it is possible but very unreliable....
Quote:
If life is supposed to be rare in space, then it would be PRACTICALLY IMPOSSIBLE to find it, because by "infinitely expanding size of the universe" the chances of finding life close enough to see, would be very close to nil.

It depends on what you mean by the universe and what you mean by 'practically impossible'. If you mean the 'observable universe' which stretches to the Cosmic Light Horizon then you have a theoretical radius of about 13 billion light years which is a big distance, for sure, but not infinite by any stretch....
Quote:

Trying to find something rare in space is like getting a blank piece of paper and putting random dots on it and saying every centimeters apart from each dot represents 50 trillion miles, and even that seemingly daunting 50 trillion mile, would seem like nothing compared to the "infinitely expanding universe"
Is it really? How big would the paper be? How many dots would you need to make?


What Cosmic Light Horizon? And how would that mean behind this "horizon" would lie a different Universe? For their to be a different Universe, the laws of physics would have to be so different that they couldn't really be called "physics", and most (if not all) of our senses would not be applicable in that Universe...
Bikerman
EanofAthenasPrime wrote:
What Cosmic Light Horizon? And how would that mean behind this "horizon" would lie a different Universe? For their to be a different Universe, the laws of physics would have to be so different that they couldn't really be called "physics", and most (if not all) of our senses would not be applicable in that Universe...

The CLH is a sphere in space centred on an observer which is drawn so that anything which could be visible to the observer is contained within it (the BB was over 13 billion years ago and so any particle within a sphere around 13 billion light years radius would qualify whereas anything outside that distance is beyond any possibility of observation or interaction with the observer. In reality it is more complex than this because of expansion and the geometries involved.
In fact the edge of the observable universe (another way of expressing the CLG) is currently thought to lie at a distance of 46.5 billion light-years in any direction to the observer. This equated to a volume of 3.56^1080 cubic metres.

http://en.wikipedia.org/wiki/Observable_universe

What lies beyond the CLH is unknowable. Anything beyond the observable universe is, as you might guess, unobservable and will always be so. It is 'causally disconnected' from us since even light cannot travel between us and such points and therefore nothing else can - so there is no possibility of interaction.
The laws of physics need not change and anything outside the observable universe is still part of the whole universe, it is just that we will never be able to interact with it. Imagine looking West using a huge telescope and observing a distant Galaxy over 10 billion light years distant. You then look East and see another galaxy at about the same distance.
You can interact with both galaxies because the universe is around 13.7 billion years old and that is sufficient time for light to reach us. They cannot, however, see each other since their 20 billion light year separation means that light could not have travelled between them and they are causally disconnected.
There is no extra problem or constraints imposed on physical law by this phenomenon, it is simply a matter of distances.
EanofAthenasPrime
Bikerman wrote:
EanofAthenasPrime wrote:
What Cosmic Light Horizon? And how would that mean behind this "horizon" would lie a different Universe? For their to be a different Universe, the laws of physics would have to be so different that they couldn't really be called "physics", and most (if not all) of our senses would not be applicable in that Universe...

The CLH is a sphere in space centred on an observer which is drawn so that anything which could be visible to the observer is contained within it (the BB was over 13 billion years ago and so any particle within a sphere around 13 billion light years radius would qualify whereas anything outside that distance is beyond any possibility of observation or interaction with the observer. In reality it is more complex than this because of expansion and the geometries involved.
In fact the edge of the observable universe (another way of expressing the CLG) is currently thought to lie at a distance of 46.5 billion light-years in any direction to the observer. This equated to a volume of 3.56^1080 cubic metres.

http://en.wikipedia.org/wiki/Observable_universe

What lies beyond the CLH is unknowable. Anything beyond the observable universe is, as you might guess, unobservable and will always be so. It is 'causally disconnected' from us since even light cannot travel between us and such points and therefore nothing else can - so there is no possibility of interaction.
The laws of physics need not change and anything outside the observable universe is still part of the whole universe, it is just that we will never be able to interact with it. Imagine looking West using a huge telescope and observing a distant Galaxy over 10 billion light years distant. You then look East and see another galaxy at about the same distance.
You can interact with both galaxies because the universe is around 13.7 billion years old and that is sufficient time for light to reach us. They cannot, however, see each other since their 20 billion light year separation means that light could not have travelled between them and they are causally disconnected.
There is no extra problem or constraints imposed on physical law by this phenomenon, it is simply a matter of distances.

Thanks for explaining that to me, it makes a lot more sense now. Except for that 2nd to last paragraph. So, we send a beacon of light to communicate to the galaxy 10 billion light years. After 10 billion years, they get the beacon. Then they send a beacon to the galaxy 20 billion light years away. After 20 billion light years, the other galaxy will receive the beacon. I see no limitations here. The universe would dynamically expand, so the limit would be 20+13.7 lightyears. Also, this is irrelevant because the BB originated in one location. It isn't relative. The big bang didn't start in the location of 3 different galaxies at once.
Bikerman
EanofAthenasPrime wrote:

Thanks for explaining that to me, it makes a lot more sense now. Except for that 2nd to last paragraph. So, we send a beacon of light to communicate to the galaxy 10 billion light years. After 10 billion years, they get the beacon. Then they send a beacon to the galaxy 20 billion light years away. After 20 billion light years, the other galaxy will receive the beacon. I see no limitations here. The universe would dynamically expand, so the limit would be 20+13.7 lightyears. Also, this is irrelevant because the BB originated in one location. It isn't relative. The big bang didn't start in the location of 3 different galaxies at once.

Ahh, you are using common-sense again, I'm sure I warned about that. When thinking about deep matters of Cosmology and astronomical matters then you will usually find that 'Common sense' is not really common and often not sense either. This is one such case.
You have said that the BB must have occurred in one place...hmm...no. This is quite challenging, of course, and the immediate instinct is to think I'm babbling or nitpicking, but no, I'm saying in a non-tricksie manner that No, the Big Bang is not thought by most cosmologists to have occurred at a particular spot at all.
We are used to spacetime as our ever-present reference system. Even when space is 'empty', spacetime still acts as a framework for the universe and allows us to talk about the position of entities in the universe by referring to their 4 spacetime co-ordinates.
Now consider, at the moment of the BB spacetime was compressed into a much smaller 'space' than now but consider a bit more and you will realise that this is a meaningless sentence. How could it be smaller? The concepts of small and large loose their meaning - the whole of the universe was still present but it was compressed into a smaller volume and back until it compresses into a singularity. Of course the temptation is then to assume that this singularity must have been somewhere - a point in space. But hold on....what space? How could it have been somewhere when it contained everything within itself?
Are you with me? Do you see what I'm getting at? In one sense the BB happened everywhere at the same time.

It's probably best to get a beer and settle down in a comfy chair to think about this for a while at this point Smile
EanofAthenasPrime
Woa I understand this now!

But on a side note, those galaxies 20 billion light years away from each other could still communicate...
Bikerman
EanofAthenasPrime wrote:
Woa I understand this now!

But on a side note, those galaxies 20 billion light years away from each other could still communicate...


Possible, but not certainly. We know that the universe is expanding and we also know from recent work that this expansion is accelerating. Finally we know that expansion is not limited in 'speed' to c because it is not a movement through spacetime, it is spacetime itself 'growing'.
Actually that use of language will just not do - it is sloppy and misleading. Here's a more precise statement of what I'm trying to express:
Quote:
For a "galaxy" towards or beyond the horizon, its "velocity", defined as comoving distance from the observer divided by the present cosmological time, can be greater than the speed of light.

Still with me?
cornga56
Stuff like this should be widely celebrated, people who don't support space travel don't understand what they're not supporting. This is great news if in fact it is totally true. Congrats space exploration supporters.
EanofAthenasPrime
Bikerman wrote:
EanofAthenasPrime wrote:
Woa I understand this now!

But on a side note, those galaxies 20 billion light years away from each other could still communicate...


Possible, but not certainly. We know that the universe is expanding and we also know from recent work that this expansion is accelerating. Finally we know that expansion is not limited in 'speed' to c because it is not a movement through spacetime, it is spacetime itself 'growing'.
Actually that use of language will just not do - it is sloppy and misleading. Here's a more precise statement of what I'm trying to express:
Quote:
For a "galaxy" towards or beyond the horizon, its "velocity", defined as comoving distance from the observer divided by the present cosmological time, can be greater than the speed of light.

Still with me?


Yes I understand. Tryin to think of ways to accelerate/decelerate space time. And create a matter/photonic converter.
Lord Klorel
It would be very important that we need to create an entire new system of propulsion technology. The main technology is unefficient. Like someone sayed about wormholes, we need something like hyperdrive engines so jump in space.
But i don't think that this technology will not be researched in a short time.
I hope that there will be one day on a smart guy that can tell us that he found an efficient way to travel quicker through the universe.
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