Earth-Like planet 20 light years away

[Charles Pegge]

http://uk.news.yahoo.com/38/20100930/tsc-earth-like-planet-found-outside-our-98fda55.html

[Petr Schreiber]

I am packing my skis,

this seems like nice place for winter holidays!



Chances for life on this planet are 100 percent

That is quite bold statement, quickly, we need to send probe there, I will pick one of our older robots and put it aboard! :)


Petr

[JosephE]

20 lightyears isn't too terribly far away. If there is intelligent life there, they must hate living on only 10% of their planet that won't spin. I mean I would hate that.

[zlatkoAB]

Quickly build space ship with warp engine.... :D

[danbaron]

[font=courier new][size=8pt]I did a quick calculation (it might be correct).

Say, we have a 150 pound (68 kg) man. And he is going to travel to that planet, at 1/5th the speed of light, so that he will get there in 100 years.

How much energy would it take to accelerate him to 1/5th the speed of light?

I did the calculation in terms of gasoline.

The answer was approximately, the energy equivalent to burning 30,700,000 barrels of gasoline.

According to the following link, in 2007, North America consumed approximately 25,000,000 barrels of gasoline per day.

http://tonto.eia.doe.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=5&pid=54&aid=2

If, instead, he travels at 1/2 the speed of light, so that he gets there in 40 years, it would require the energy equivalent to burning approximately 230,300,000 barrels of gasoline.

According to the same link, the entire world consumed approximately 86,000,000 barrels of gasoline per day in 2007.

(Remember, that the calculation assumes that only the mass of the man is being accelerated. In the real case, that would not be true. He also has to take along the mass of his spaceship and fuel. I would not be surprised if no spaceship from Earth reaches even the closest star, Proxima Centauri (4.24 light years), during the 21st century. But, that's just my opinion.)

:oops: :x :twisted:
Dan

[LanceGary]

[font=courier new][size=8pt]I did a quick calculation (it might be correct).

Say, we have a 150 pound (68 kg) man. And he is going to travel to that planet, at 1/5th the speed of light, so that he will get there in 100 years.

How much energy would it take to accelerate him to 1/5th the speed of light?

I did the calculation in terms of gasoline.

The answer was approximately, the energy equivalent to burning 30,700,000 barrels of gasoline.

According to the following link, in 2007, North America consumed approximately 25,000,000 barrels of gasoline per day.

http://tonto.eia.doe.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=5&pid=54&aid=2

If, instead, he travels at 1/2 the speed of light, so that he gets there in 40 years, it would require the energy equivalent to burning approximately 230,300,000 barrels of gasoline.

According to the same link, the entire world consumed approximately 86,000,000 barrels of gasoline per day in 2007.

(Remember, that the calculation assumes that only the mass of the man is being accelerated. In the real case, that would not be true. He also has to take along the mass of his spaceship and fuel. I would not be surprised if no spaceship from Earth reaches even the closest star, Proxima Centauri (4.24 light years), during the 21st century. But, that's just my opinion.)

:oops: :x :twisted:
Dan



Isn't this - the massive amount of fuel required - the reason for space agencies to develop solar sails? I know the Japanese have recently successfully tested one. And I personally know someone working on them in America.

Lance

[Charles Pegge]

Some interesting energy fields at the edge of the Splar system (heliopause).

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

The Solar wind goes up to 1 million KPH but to approach the speed of light you would need to go 10 thousand times faster than this. You need photonic sails to go really fast.

Charles

[danbaron]

[font=courier new][size=8pt]It seems to me that the sails would solve two problems.

1)
You don't have to carry the fuel. The energy-weight ratio for gasoline is relatively terrible. But, I think that even if you used the most efficient nuclear drive, almost all of the mass you are accelerating, would be fuel. Presumably, the farther you went, the more fuel you would use, and the less your vehicle would weigh. On the other hand, if you are making a round trip, then you would still have half of your fuel when you reached your destination.

2)
If the sail is pushed by starlight, then you get the energy for free. (But, apparently, interstellar light is too weak (and it comes from all directions!). Most designs rely on lasers or masers, aimed at the sails from Earth. In that case, you still have to find the energy somewhere - but the energy required would be much much less, since you would not be carrying the fuel, so the mass of the vehicle you would be accelerating, would be much much less.)

(Similar to gravity, the force (attractive for gravity, repulsive for light) is proportional to the inverse of the distance squared. So, if for instance, the power source is a laser or maser, and, at distance 1 light year from Earth the force on the sail is, "F", then at distance 2 light years, the force on the sail would be F/4, at distance 3 light years, the force on the sail would be F/9, etc. (Maybe light sails will be useful, but I don't think anyone will mistake them for warp drives.))

So, say that a craft from Earth lands on the Earth-like planet which is 20 light years away. Then, it would take 20 more years before any transmission from the craft reaches us. I think that the only way humans will survive, is if they fix this planet. I think imagining that we will escape to a better place, is a form of escapism. (On the other hand, who wouldn't want to wave goodbye forever to this place? Wouldn't it be great to see Earth growing smaller and smaller, and then disappear? It's become like a tree covered with insects, only, we're the insects.)

:twisted:

[LanceGary]

[font=courier new][size=8pt]It seems to me that the sails would solve two problems.

1)
You don't have to carry the fuel. The energy-weight ratio for gasoline is relatively terrible. But, I think that even if you used the most efficient nuclear drive, almost all of the mass you are accelerating, would be fuel. Presumably, the farther you went, the more fuel you would use, and the less your vehicle would weigh. On the other hand, if you are making a round trip, then you would still have half of your fuel when you reached your destination.

2)
If the sail is pushed by starlight, then you get the energy for free. (But, apparently, interstellar light is too weak (and it comes from all directions!). Most designs rely on lasers or masers, aimed at the sails from Earth. In that case, you still have to find the energy somewhere - but the energy required would be much much less, since you would not be carrying the fuel, so the mass of the vehicle you would be accelerating, would be much much less.)

(Similar to gravity, the force (attractive for gravity, repulsive for light) is proportional to the inverse of the distance squared. So, if for instance, the power source is a laser or maser, and, at distance 1 light year from Earth the force on the sail is, "F", then at distance 2 light years, the force on the sail would be F/4, at distance 3 light years, the force on the sail would be F/9, etc. (Maybe light sails will be useful, but I don't think anyone will mistake them for warp drives.))

So, say that a craft from Earth lands on the Earth-like planet which is 20 light years away. Then, it would take 20 more years before any transmission from the craft reaches us. I think that the only way humans will survive, is if they fix this planet. I think imagining that we will escape to a better place, is a form of escapism. (On the other hand, who wouldn't want to wave goodbye forever to this place? Wouldn't it be great to see Earth growing smaller and smaller, and then disappear? It's become like a tree covered with insects, only, we're the insects.)

:twisted:


I gather that the sails are incredibly large and so have to be made from extremely thin material that is also extremely strong. I also gather that the idea is that the craft powered by the sail would gradually accelerate to until it reached (say) half the speed of light). The idea would be to use the solar wind (which is not so weak) to help with the initial acceleration to a very high speed.

The Japanese have just tested such a sail - apparently successfully. And I know that America has been researching it too. So these people can't believe that they are just wasting their time.

Lance

[danbaron]

[font=courier new][size=8pt]Probably they are not wasting their time. But, I think their research shows that reality and science fiction can be completely different. I've never seen a spaceship in a movie that looked like a giant umbrella. Attached below is a picture of how a real spaceship may look.

I think we can agree that the main roadblock preventing spaceships from approaching light speed is the huge amount of energy required to accelerate them to those speeds. But, there are other problems too. For instance, say that hypothetically, the energy problem has somehow been solved. In that case, will man ever travel at, say, 99% of light speed? I think the answer is, "no". And, in my opinion, the reason is, the increase in mass. If you substitute 0.99 into the equation at this link, http://scienceworld.wolfram.com/physics/MassIncrease.html , for beta (v/c), you find that at 99% of light speed, a person's mass is approximately 7 times what it is at rest (but his strength would not have increased at all). In that circumstance, the person could barely move, if at all. And effectively, his heart would be pumping 7 times the blood that it normally pumps, because his blood would have 7 times the inertia (7 times the resistance to being accelerated). Most likely, he would asphyxiate.

:twisted:

[LanceGary]

[font=courier new][size=8pt]Probably they are not wasting their time. But, I think their research shows that reality and science fiction can be completely different. I've never seen a spaceship in a movie that looked like a giant umbrella. Attached below is a picture of how a real spaceship may look.

I think we can agree that the main roadblock preventing spaceships from approaching light speed is the huge amount of energy required to accelerate them to those speeds. But, there are other problems too. For instance, say that hypothetically, the energy problem has somehow been solved. In that case, will man ever travel at, say, 99% of light speed? I think the answer is, "no". And, in my opinion, the reason is, the increase in mass. If you substitute 0.99 into the equation at this link, http://scienceworld.wolfram.com/physics/MassIncrease.html , for beta (v/c), you find that at 99% of light speed, a person's mass is approximately 7 times what it is at rest (but his strength would not have increased at all). In that circumstance, the person could barely move, if at all. And effectively, his heart would be pumping 7 times the blood that it normally pumps, because his blood would have 7 times the inertia (7 times the resistance to being accelerated). Most likely, he would asphyxiate.

:twisted:




I think there are books by Larry Niven and possibly jerry Pournelle describing sail powered space ships in a science fiction setting.

I am not sure that I think the maximum speed I have heard mentioned is about half the speed of light. Apparently the rate of acceleration to get to that speed would also have to be low to avoid crushing mere humans. This point is made in Lawrence Krauss's book "The physics of Star Trek".

Lance

[Charles Pegge]

If your spaceship accelerated up to the speed of light at the rate of 10 metres/sec^2 then it would take 30 million seconds. This would take less than one year Since there are 31,557,600 seconds in a year. It would also provide an accelerating force equivalent to terrestial gravity.

If the spaceship sustained its acceleration then relativistic time dilation would reduce the journey time for the occupants to a fraction of the 20 years. But the risk of hitting obstacles at with that level of momentum is a serious hazard.

Charles

[zlatkoAB]

As i said before ....
only for me posibile way is build warp engine which can do this
properly and if you dont belive that is posibile Gooogle on
warp drive and you will find many intersting things.

[danbaron]

[font=courier new][size=8pt]Now I'm talking about things which I am basically ignorant of, so I might be totally wrong. Charles mentioned time dilation. I attached a graph below from this link, http://en.wikipedia.org/wiki/Time_dilation . If I am interpreting the graph correctly, then, you have got to be going really close to light speed (c), for time dilation to be significant. For instance, at v = c/2, it looks like gamma is only about 1.2.

And, like Charles said, if you are traveling at c/2, then if there is something solid in front of you, you had better detect it far in advance. At c/2, you won't be making any sharp turns!

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

I agree with Aurel. Even if you can travel at c/2, I think the trip to the Earth-like planet would still take 40/1.2, = 33.3 years (for the travelers).
(Probably, they would need to reproduce during the trip.)

Assuming they did not die of old age or disease, still, how likely is it that they would be alive after 33 years confined together in a biosphere?

Here is a link for Biosphere 2, http://en.wikipedia.org/wiki/Biosphere_2 , the experiment which tried to implement a completely closed environment.

I can foresee sending unmanned probes to the nearest stars before long. But, to me, sending people is a different story. (On the other hand, as we see from the success of "reality" TV shows, some people will do absolutely anything for glory and to be famous - probably including taking a 33 year one-way trip to an unknown planet.) The article only states that it has been determined that the planet has gravity and temperature similar to ours. I don't know how that guarantees any life at all. What about water, and oxygen in the atmosphere? To me, claiming that it has, "the potential to support human life", goes far far beyond what is reasonable to suppose from the data that the article cites. Remember the old saying, "Any publicity is good publicity.". And, remember the other old saying, "A sucker is born every minute.". The author of the article seems to have extrapolated from gravity and temperature, to, the Hawaiian Islands. Probably in 10 years we'll all be vacationing on the beaches there - make your reservations today!

(If I was in charge of space exploration, before we sent people anywhere else, we would attempt to colonize our own moon. (If you want to learn to do motorcycle jumps, you don't start with the Grand Canyon, yes or no?))

:twisted:

[Charles Pegge]

Here is a useful reference for relativity physics:

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/ltrans.html#c2

In the scenario I'm considering, the rocket propulsion gives a steady thrust of about 1g. The engineers working at the back end of the rocket are convinced they are travelling faster than light after one year's constant acceleration. In relativity momentum is always conserved, whether you observe from the outside or the inside. To the outside observer the rocket is travelling around 0.87C but the mass of the rocket has doubled and the rocket's chronometers appear to be running a half speed. As the years go by the observed mass of the rocket steadily increases (ignoring fuel consumption) though the speed hardly increases at all. But inside the rocket the astronauts as they see it, are speeding along nicely at up to 4C before decelerating at the mid point of the journey and arriving at their destination within 10 years.

My Lorentzian mental arithmetic is not very accurate. Anyone care to write a program? :)

Charles

[danbaron]

[font=courier new][size=8pt]Charles may be right. I haven't the patience to go through all of the calculations at his link. Probably, the reason is, that I anticipate the return on my investment of time and energy will not be much. For most people, even a complete understanding of relativity theory has little or no practical benefit. Most of us do not get paid to do physics. And, probably none of us will ever move at relativistic speeds. But, I think it would be worth learning if you were going to write science articles, or, science fiction books. Or, just if you are interested enough.

One thing I thought about. I could be wrong, but this is my idea. No natural objects (which have mass) in the universe move at relativistic speeds - clusters, galaxies, stars, planets, moons, asteroids, comets, rocks, etc. As far as I know none of them move relative to another of them anywhere near the speed of light. The distance between objects which are very far apart can grow at relativistic speeds, but, that is only because of the expansion of space itself. I think if you subtract the speed due to space expansion, then you don't find relativistic speeds in our universe. So, my hypothesis is that relativistic speeds do not naturally occur. If, for instance, we ever detect an object in our solar system moving anywhere near the speed of light relative to Earth, then, we should expect that an advanced intelligence is the cause.

Incidentally, the speed of light is approximately, 670,615,200 mph.

:twisted:

[danbaron]

[font=courier new][size=8pt]More.

http://www.space.com/scienceastronomy/habitable-alien-planet-gliese-581g-facts-101001.html

http://www.space.com/scienceastronomy/doubt-cast-habitable-alien-planet-gliese-581g-101012.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+C2C-InTheNews+%28Feed+-+Coast+to+Coast+-+In+the+News%29

http://www.space.com/scienceastronomy/gliese-581g-discoverer-responds-101013.html

[danbaron]

[font=courier new][size=8pt]I thought about clocks a little bit.

There was a guy, T. Lee Baumann (http://www.baumannbooks.com/), on Coast-To-Coast-AM (radio) a couple of nights ago. He is an MD who has written a lot of books.
On the show he made the connection between light, and the existence of God.

He said one thing which I think is absolutely wrong (but, I may be absolutely wrong). He said that if you are traveling at the speed of light, your clock stops,
it never moves even the tiniest fraction of a second.

My understanding is that if I am stationary and you are moving, then, your clock will advance slower than mine. The faster you go, the slower your clock will
advance relative to mine. If you reach the speed of light, then, relative to my clock, your clock will stop. But, from your perspective, no matter what your
speed is, your clock will advance at the same rate.

So, if, for instance, you are moving at 99% of light speed (c), your clock will be moving significantly slower than mine. If you are traveling to a star that
is 20 light years away, then, from my perspective, it will take you, 20 / 0.99 = 20.202.. years to get there.

But, from your perspective (see the link below), it will take you,

20.202 * sqrt(1 - 0.99^2) = 2.85 years.

(I think this is approximately what Charles said.)

On the other hand, I think you still will have a problem.

20.202 / 2.85 = 7.09.

If I am correct, at 0.99c, your mass will have been multiplied by the same factor, approximately, 7.09.

(But, I realize that I have not been absolutely clear in what I have written here. I don't know enough about relativity theory, to be. I think I do know that for
an object with mass, there is no such thing as absolute velocity. The velocity of Object A, can only be measured relative to Object B. Velocity is undefined for
an object in isolation. So, intuitively, I cannot say that I am stationary, and you are moving; because, from your perspective the situation would be reversed.
In that case, whose clock runs slower? I think the answer has something to do with symmetry, but, I am mostly ignorant.)

:oops: :x :twisted:
Dan

http://en.wikipedia.org/wiki/Time_dilation#Time_dilation_due_to_relative_velocity