Other Earths

[Sirius]

I'm thinking this thread could serve as a compilation for the various exoplanet discoveries that may classify as "Other Earths".

NASA has confirmed the existence of Kepler-22b, a planet 2.4 times the size of Earth lying some 600 light years away. Kepler-22b lies within the habitable zone of its parent star, that is, the region where it is neither too hot nor cold for life to thrive, where liquid water may be expected to exist on the surface.

Kepler 22-b is one of 48 candidate planets found thus far to lie in their parent stars' habitable zones, but the first whose existence has been confirmed. The Kepler space telescope follows an Earth-trailing orbit around the sun and for all its recent discoveries, monitors only a small fraction of our Milky Way galaxy. It was launched in 2009 for a 3.5 year long mission but has sufficient fuel on board for about a 7 year mission provided there is available funding.

NASA link: http://www.nasa.gov/mission_pages/ke...-briefing.html

[kayt]

Yes, I've heard about this. I do have questions though. When they say earth like do they mean a place supporting a large variety of organisms and connected eco systems or do they mean exactly like earth with a dominant inteligent species populated throughout? It can be considered to be less earth like because it is larger than our earth and if it is a solid planet that may mean a stronger gravity force in play so if it were possible for humans to live there in a colony they'd end up shorter, stockier/more compact and more muscular than humans living on earth. If it is as gas planet then that's not all that earth like Floating clods of bits of earth and water isn't what we're familiar with.

[edyle]

Yes, I've heard about this. I do have questions though. When they say earth like do they mean a place supporting a large variety of organisms and connected eco systems or do they mean exactly like earth with a dominant inteligent species populated throughout? It can be considered to be less earth like because it is larger than our earth and if it is a solid planet that may mean a stronger gravity force in play so if it were possible for humans to live there in a colony they'd end up shorter, stockier/more compact and more muscular than humans living on earth. If it is as gas planet then that's not all that earth like Floating clods of bits of earth and water isn't what we're familiar with.

When they say earth-like they mean *as far as they can see* it MIGHT have land and sea.

[Sirius]

Yes, I've heard about this. I do have questions though. When they say earth like do they mean a place supporting a large variety of organisms and connected eco systems or do they mean exactly like earth with a dominant inteligent species populated throughout? It can be considered to be less earth like because it is larger than our earth and if it is a solid planet that may mean a stronger gravity force in play so if it were possible for humans to live there in a colony they'd end up shorter, stockier/more compact and more muscular than humans living on earth. If it is as gas planet then that's not all that earth like Floating clods of bits of earth and water isn't what we're familiar with.

When we say it may be Earth-like we really just mean a rocky, water bearing world that has surface temperatures conducive to life. Whether it bears life or not is another matter, and whether it can support life in the form we know is yet another.

So far we know the planet is too small to be a gas giant, but we don't know if it is rocky or a water world (i.e. 100% covered in oceans). We know its average surface temperature, but not its atmospheric composition - though that can be determined by examining the spectrum of light that passes through its atmosphere. Such readings can also be an indicator of biological activity.

Either way, we are a very long way off from being able to visit this planet; 600 light years is an incredibly long way away. That this planet was discovered so early in the game though suggests there may be many more like it, perhaps much closer to home.

I would like to hope that if we find more planets like this closer to home it provides the incentive to begin planning our first interstellar probes. We know how to do it using present day to near future technologies; think tanks drafted up such plans back in the 1970's. We just need a reason to do it...a real target to aim for.

[edyle]

When we say it may be Earth-like we really just mean a rocky, water bearing world that has surface temperatures conducive to life. Whether it bears life or not is another matter, and whether it can support life in the form we know is yet another.

So far we know the planet is too small to be a gas giant, but we don't know if it is rocky or a water world (i.e. 100% covered in oceans). We know its average surface temperature, but not its atmospheric composition - though that can be determined by examining the spectrum of light that passes through its atmosphere. Such readings can also be an indicator of biological activity.

Either way, we are a very long way off from being able to visit this planet; 600 light years is an incredibly long way away. That this planet was discovered so early in the game though suggests there may be many more like it, perhaps much closer to home.

I would like to hope that if we find more planets like this closer to home it provides the incentive to begin planning our first interstellar probes. We know how to do it using present day to near future technologies; think tanks drafted up such plans back in the 1970's. We just need a reason to do it...a real target to aim for.

Which is why we should be spending more effort on antigravity and ultimately teleportation research. For all we common people really know, some private entities with Government ties are literally already light years ahead, and using advanced technology for private PROFIT and POWER.

[Sirius]

Which is why we should be spending more effort on antigravity and ultimately teleportation research. For all we common people really know, some private entities with Government ties are literally already light years ahead, and using advanced technology for private PROFIT and POWER.

Sound a bit heavy on the conspiracy to me. Governments are likely concealing higher technology than is commercially available, but realistically, how much further ahead are they? Decade or two at most I think.

Personally, I think human colonization of the stars will take the form of relativistic starships with crew in cryosleep for star systems relatively close to Earth. More distant ones will likely be robotic spacecraft carrying either embryos or raw DNA. Perhaps, somewhere along the way we might have a generation ship or two thrown in.

I don't think teleportation if we manage it for living beings will be the answer for interstellar travel. The only real means of instantaneous interstellar travel as far as I am concerned is a wormhole.

[edyle]

Sound a bit heavy on the conspiracy to me. Governments are likely concealing higher technology than is commercially available, but realistically, how much further ahead are they? Decade or two at most I think.

Personally, I think human colonization of the stars will take the form of relativistic starships with crew in cryosleep for star systems relatively close to Earth. More distant ones will likely be robotic spacecraft carrying either embryos or raw DNA. Perhaps, somewhere along the way we might have a generation ship or two thrown in.

I don't think teleportation if we manage it for living beings will be the answer for interstellar travel. The only real means of instantaneous interstellar travel as far as I am concerned is a wormhole.

Yes I understand.
I thought so too.

Since you mentioned cryosleep, and since I so happened to have a similar discussion with a long time friend of mind today reminicent of the same topic; here is a question for you.

Question:
=============
If a habitable planet is, say, 100 light years away from us, would they need to use cryosleep?
=============

[Sirius]

Yes I understand.
I thought so too.

Since you mentioned cryosleep, and since I so happened to have a similar discussion with a long time friend of mind today reminicent of the same topic; here is a question for you.

Question:
=============
If a habitable planet is, say, 100 light years away from us, would they need to use cryosleep?
=============

I certainly think they would. Assuming we could even get to 99.9% of light speed it's still roughly 100 years. I think any interstellar journey would be most realistic under cryosleep if only because of the sheer amount of supplies and living space required otherwise - at some point, the journey becomes long enough that the ship becomes a generation ship with the descendants arriving. Doable for a one way trip perhaps, but still inefficient.

I'm looking forward to the possibility of a habitable world being found near to us. There are some stars that can potentially hold habitable worlds close to us - I'm thinking Epsilon Eridani and Tau Ceti for starters. I'm thinking both of the Alpha Centauri stars can possibly maintain habitable worlds, but we don't really understand the dynamics of a binary system yet. That would be ideal though - right next door!

[letric]

I certainly think they would. Assuming we could even get to 99.9% of light speed it's still roughly 100 years. I think any interstellar journey would be most realistic under cryosleep if only because of the sheer amount of supplies and living space required otherwise - at some point, the journey becomes long enough that the ship becomes a generation ship with the descendants arriving. Doable for a one way trip perhaps, but still inefficient.

I'm looking forward to the possibility of a habitable world being found near to us. There are some stars that can potentially hold habitable worlds close to us - I'm thinking Epsilon Eridani and Tau Ceti for starters. I'm thinking both of the Alpha Centauri stars can possibly maintain habitable worlds, but we don't really understand the dynamics of a binary system yet. That would be ideal though - right next door!

Interesting dialogue...

[Sirius]

A habitable world within a couple light years would make an interstellar mission doable. I think an unmanned probe on 10-20 year trip at about 50% light speed is acceptable and technologically feasible. After all, the voyager probes are decades old and still sending back invaluable data.

Who knows, maybe whatever we find might be attractive enough to take on the challenge of a manned voyage! Either way, if we want to survive as a species, we need to get our eggs out of one basket. A civilization spread across multiple star systems is safeguarding itself against extinction.

I don't see this as a flight of scifi fantasy; I am 100% positive that Kepler-22b is only the beginning.

[letric]

A habitable world within a couple light years would make an interstellar mission doable. I think an unmanned probe on 10-20 year trip at about 50% light speed is acceptable and technologically feasible. After all, the voyager probes are decades old and still sending back invaluable data.

Who knows, maybe whatever we find might be attractive enough to take on the challenge of a manned voyage! Either way, if we want to survive as a species, we need to get our eggs out of one basket. A civilization spread across multiple star systems is safeguarding itself against extinction.

I don't see this as a flight of scifi fantasy; I am 100% positive that Kepler-22b is only the beginning.

[edyle]

Question:
=============
If a habitable planet is, say, 100 light years away from us, would they need to use cryosleep?
=============
Answer:
I certainly think they would. Assuming we could even get to 99.9% of light speed it's still roughly 100 years.
================================================== ================================

When we say a planet is 100 light years away, we mean that if we transmitted light to the planet and waited for the reflection to come back, we would have to wait 200 years.

If a spaceship left Earth and somehow travelled at the speed of light to that same planet :
THE TRAVELLERS ON THE SPACESHIP WOULD REACH INSTANTANEOUSLY according to their clocks.

To check what I am talking about please refer to the "TWIN PARADOX".

Twin paradox

From Wikipedia, the free encyclopedia
In physics, the twin paradox is a thought experiment in special relativity, in which a twin makes a journey into space in a high-speed rocket and returns home to find he has aged less than his identical twin who stayed on Earth.

[edyle]

A habitable world within a couple light years would make an interstellar mission doable. I think an unmanned probe on 10-20 year trip at about 50% light speed is acceptable and technologically feasible. After all, the voyager probes are decades old and still sending back invaluable data.

Who knows, maybe whatever we find might be attractive enough to take on the challenge of a manned voyage! Either way, if we want to survive as a species, we need to get our eggs out of one basket. A civilization spread across multiple star systems is safeguarding itself against extinction.

I don't see this as a flight of scifi fantasy; I am 100% positive that Kepler-22b is only the beginning.

I agree.
However, I do believe that antigravity drives can be developed within this century.

[lexbarker]

The way how things are going now, I wonder if the earth will outlive this 10 thousand year clock.

http://longnow.org/clock/

[Sirius]

Question:
=============
If a habitable planet is, say, 100 light years away from us, would they need to use cryosleep?
=============
Answer:
I certainly think they would. Assuming we could even get to 99.9% of light speed it's still roughly 100 years.
================================================== ================================

When we say a planet is 100 light years away, we mean that if we transmitted light to the planet and waited for the reflection to come back, we would have to wait 200 years.

If a spaceship left Earth and somehow travelled at the speed of light to that same planet :
THE TRAVELLERS ON THE SPACESHIP WOULD REACH INSTANTANEOUSLY according to their clocks.

To check what I am talking about please refer to the "TWIN PARADOX".

Understood -- but while a good thought experiment, relativity prevents us from achieving actual light speed. At light speed, time as we understand it would stop. Now the closer we get to light speed is the slower time is perceived for the traveler, but it's still a pretty long distance to go. A trip to Alpha Centauri 4.3ly distant would take 4-5 years to reach if we were to achieve a shade under the speed of light. That's a long time to spend on a starship if you're not frozen.

I agree.
However, I do believe that antigravity drives can be developed within this century.

I would certainly look forward to that!

[edyle]

Understood -- but while a good thought experiment, relativity prevents us from achieving actual light speed. At light speed, time as we understand it would stop. Now the closer we get to light speed is the slower time is perceived for the traveler, but it's still a pretty long distance to go. A trip to Alpha Centauri 4.3ly distant would take 4-5 years to reach if we were to achieve a shade under the speed of light. That's a long time to spend on a starship if you're not frozen.

"relativity prevents us from achieving actual light speed"
Big deal; so it takes an hour instead of instantaneous travel .

"the closer we get to light speed is the slower time is perceived for the traveler"
Yes; but I wouldn't be dubious with the "percieved" part;
the closer we get to light speed is the less time it takes for the traveller to reach destination.

If we were only able to achieve a shade under the speed of light, what would be the point?

You are starting with the premise that current technology does not allow us to accelerate fast enough to make the trip in a short enough time.

That's true.

I'm starting on the premise that it wouldn't be worth the investment right now with current technology and we're better off improving the technology.

Here's a question:

Current technology wouldn't allow us to reach Alpha Centauri in a few months.
WHEN WILL TECHNOLOGY GET TO THAT POINT that we can reach Alpha Centauri in a few months.

Or are you still misunderstanding that a trip to Alpha Centauri will always take more than 4.3 years to reach.

[Sirius]

I think I was misunderstanding.

With time dilation, the the journey would take less than 4.3 years shipboard time, provided we were going really fast. A few months shipboard time yes, maybe. To create the most comfortable living conditions on board the ship, we are talking constant 1g acceleration followed by constant 1g deceleration.

Now I'm not too familiar with the calculations but how long would the trip take assuming we could build an engine that provides that constant 1g of thrust? The next question of course would be, how far away are we from building such an engine?

[edyle]

I think I was misunderstanding.

With time dilation, the the journey would take less than 4.3 years shipboard time, provided we were going really fast. A few months shipboard time yes, maybe. To create the most comfortable living conditions on board the ship, we are talking constant 1g acceleration followed by constant 1g deceleration.

Now I'm not too familiar with the calculations but how long would the trip take assuming we could build an engine that provides that constant 1g of thrust? The next question of course would be, how far away are we from building such an engine?

Excellent. Now we're on the same page and you're talking exactly about what it's all about.

Now the relativistic calculation is more complicated and it's literally decades since I've looked at those equations but the simplistic calculation which is an overestimate of the travel time would look like this:

Light speed : 3 x 10E9 m/s2: Lets just approx that to 10E9
Assume we accelerate at 1 g which is 10 m/s2
Time to reach light speed = 10E9 / 10 = 10E8
3600 sec in an hour; 24 hours in a day: ballpark: 100,000 secs in a day;
10E8 secs / 10E5 secs per day gives you a thousand days.

So basically it might take something like 3 years using newtonian estimate based on an acceleration of only 1g.

And THAT is the real reason one would need to do something like cryogenics for moving humans.

Of course everything changes if you're sending an unmanned drone ship; now maybe you can use 10g.

But the big thing I'm interested in is what if you develop an electrogravitic system; essentially an antigravity drive; that puts you now in the possibility of extreme high accelarations without the contents of the ship experiencing acceleration.

One reason I take seriously the question of antigravity, is the numerous videos of so-called UFO's; quite a few of these, assuming that they are not all hoaxes, suggest that what the origin of these things, they are capable of sudden extreme high acceletions; which means either drones with everything absolutely bolted down and extremely rigid electonics; OR anti-gravity propulsion.


===
And to be clear on my central point:
It is not relativity that limits us to long interstellar travel times; as discussed, if you could accelerate fast enough you could reach as fast as you want.
The limit is the current state of technology.

[Sirius]

UFOs do seem to operate using antigravity propulsion systems. Now if it is we can build such a propulsion system in this century it means we are much closer to becoming a space faring, and even interstellar, civilization than expected.

I agree with your central point but I would also note that it is more applicable to an eventual manned voyage. Imagine how long we will have to wait on the results from a trip to Kepler-22b. Even with the effects of relativity, at 600ly away it's still a long trip and it is an exponentially longer time for us back on Earth to wait for the results. I think our best bet is to find worlds closer to home.

For example, apart from hopes of finding something at Alpha Centauri, there is the Gliese 581 system which is 20ly away. This system contains two rocky worlds on the edges of the habitable zone with an unconfirmed third lying right smack in the middle of it. This I think is a fascinating target.

One has to wonder: What would our civilization look like in the years after we begin using such futuristic propulsion systems as the antigravity engine? I picture a local core stellar neighbourhood but with eventual expeditions to such far flung locales that they end up as civilizations of humans in their own right, developing completely independent of the Earth. For all we know, that could be exactly how we got here to start with.

[edyle]

UFOs do seem to operate using antigravity propulsion systems. Now if it is we can build such a propulsion system in this century it means we are much closer to becoming a space faring, and even interstellar, civilization than expected.

I agree with your central point but I would also note that it is more applicable to an eventual manned voyage. Imagine how long we will have to wait on the results from a trip to Kepler-22b. Even with the effects of relativity, at 600ly away it's still a long trip and it is an exponentially longer time for us back on Earth to wait for the results. I think our best bet is to find worlds closer to home.

For example, apart from hopes of finding something at Alpha Centauri, there is the Gliese 581 system which is 20ly away. This system contains two rocky worlds on the edges of the habitable zone with an unconfirmed third lying right smack in the middle of it. This I think is a fascinating target.

One has to wonder: What would our civilization look like in the years after we begin using such futuristic propulsion systems as the antigravity engine? I picture a local core stellar neighbourhood but with eventual expeditions to such far flung locales that they end up as civilizations of humans in their own right, developing completely independent of the Earth. For all we know, that could be exactly how we got here to start with.

In terms of systems closer to us I think we should be looking at the moons of Jupiter and Saturn; that distance is much more practical with our current state of technology, and some of these objects may actually have liquid water!


http://science.nasa.gov/science-news.../ast22oct98_2/

Callisto makes a big splash

Callisto makes a big splash

Scientists may have discovered a salty ocean and some ingredients for life on Jupiter's moon

October 23, 1998: Until now most scientists thought Jupiter's moon Callisto was a dead and boring moon, an unchanging piece of rock and ice. Data reported in today's issue of Nature could change all that. It appears that Callisto, like another of Jupiter's moons Europa, may have an underground liquid ocean and at least some of the basic ingredients for life.

[Sirius]

The Jovian moons are most important targets in the search for extraterrestrial life, as is Mars - for past life at least. Space exploration for habitable worlds ought to take two forms:

1) Seeking out signs of extraterrestrial life, to put the question of whether or not we are alone to rest and to better understand the evolution of life in the Universe

2) Seeking out worlds upon which we can establish colonies of humanity, spreading our presence beyond our home world and, among other goals, ensuring the continuity of the species

I suspect the motive and subsequent funding for such endeavours will not happen until we have discovered Earth-like worlds close to home. Once we do we will see a plethora of research taking place with the ultimate goal of setting foot there, one output of which will be such propulsion systems as an antigravity engine. In the interim what we can hope for is to see next generation propulsion systems used in local solar system transit. At least then we can send frequent manned and unmanned missions to such targets as Mars and the Jovian moons. It is high time we retire the chemical rocket.

For near future in-system transit I am of course thinking ion and plasma propulsion. One possible solution is the VASIMIR rocket.