Monday 29 August 2011

Will humans ever live on another planet?

Traveling to another planet has been a dream of human beings for quite a long time but can it really happen? There are two factors that will always be pertinent in making that dream possible. They are distance and speed.

We now know that there are many planets in space circling stars and is quite conceivable that some of them are the same size as our planet and the same distance from their stars as is our planet is from our sun. Unfortunately, those planets and their stars are a great distance from us. Let me give you some idea as just how far the closest star is from us.

Alpha Centauri A is only 4.3 light years from our Sun. When I use the word ‘only’ I am not diminishing the actual distance we are from that star. For example, light travels 299,792,458 metres per second. That comes to 186,282 miles per second or 700 million miles an hour. Traveling at that speed, it takes eight minutes and thirty seconds for the light from our sun to reach Earth.

Now if you multiply that distance times all the eight minute segments there are in 4.3 years, you will get some idea of just how far away Alpha Centauri A is from us and that is if we are traveling at the speed of light.

Will we ever travel at the speed of light? Never! There is a very good reason for this. There is a very strange quirk in nature that the faster you travel in space; the slower will the molecules move in your body and everything else that is going that same speed such as the rocket that would be taking you to our nearest star. If the rocket carrying you were to reach the speed of light, its engine would come to a complete stop because the molecules in the fuel would also stop moving and as we all know, the faster the molecules in a heated object move, the hotter it becomes. It follows that if the engine’s molecules would cease to be moving, it would reach the temperature of absolute zero in the Kelvin scale which is −273.15 °C on the Celsius scale. This equates to −459.67 °F on the Fahrenheit.

I once had an opportunity to talk with that famous rocket scientist, Werner Von Braun who was the leading scientist in Germany that created the V2 rockets that bombarded London during the Second World War and later headed the NASA space program in the United States. I asked him how much we would age if we traveled to our nearest star while traveling at the speed of light. He said that if we began our journey at that speed, we would end up as mush. He said that humans would gradually increased its speed to the speed of light and then slow down to a much slower speed when they got to the star and then do they same thing coming back to Earth. He said that it would seem to those who were in the rocket that they were only aging about 28 years but when they got back to earth, they would discover to their horror that as many as 5,000 Earth-years would have passed.

That may seem ludicrous but it isn’t because you have to remember that humans wouldn’t be traveling at the speed of light all the time they were moving towards our nearest star and later returning back to Earth. In fact, if it were possible to reach the speed of light, we would never be able to slow down because the engine of the rocket along with its controls would remain permanently fixed at zero Kelvin and thusly, they wouldn't be able to heat up again in order for the humans on board to to operate again. This means that if humans do travel to other stars in our galaxy, they must never travel at the speed of light at least from what we currently know about traveling at the speed of light.

We already have a rocket that can travel 61,000 kilometres (37,903 miles) an hour. That means that it would circle Earth in about 45 minutes. It would take 68 hours to reach the moon and 102 days to reach the surface of the sun. Now here is the real shocker for you. If astronauts flew from Earth to Alpha Centauri A at that speed, it would take (get ready for it) 70,000 years.

Now let us presume that sometime in the next century, humans will have built rockets that can travel ten times that speed. That would be 379 thousand miles an hour. It would then take almost twenty and a half days to reach the surface of the sun. To get to our next nearest star (Alpha Centauri A) it would take 7,000 years.

Now let’s imagine if you will that humans will be able to build rockets that can travel twice that speed. That would be 758 thousand miles an hour. It would take 10 days to reach the surface of our sun and 3,500 years to reach our next nearest star.

Now let’s imagine that the rockets in the future will be able to travel ten times that speed. They would be moving through space at a speed of 7,580,000 miles an hour. Thus, it would take around 8 hours to reach our sun and 35 years to reach our nearest star.

Now what? Well, here is the bad news. There are no planets that are livable that are circling that particular star. The trip would have been for nothing. Think about it. If you were returning to Earth to report your findings, who would you be reporting to? Many years would have passed on Earth while you were traveling through space during the previous 70 years. At least a hundred if not more years would have gone by. Your families and friends would be deceased, as would the people you were to report your findings to.

The planet astronomers discover last year a potential site for life, called Gliese 581c, which is about 20.5 light years away. Its habitability has since come under question, but some astronomers say another planet orbiting the same star might be livable.

Gliese 581c is a planet orbiting the red dwarf star Gliese 581. It is the second planet discovered in the system and the third in order from the star. With a mass at least 5.6 times that of the Earth, it is classified as a super-Earth. That means that humans would weigh 5.6 times what they currently weigh on our own planet and quite frankly, I hardly think their bones could support them very long carrying that kind of weight on their bones as they walk about on the surface of that planet.

Now if our astronauts were traveling at the speed of 7,580,000 miles an hour, it would take their rocket 90 years before it reached it which would be 119 trillion miles from earth. It would probably be the second and third generation of humans in the rocket that would finally step onto the surface of that planet. And what would they be stepping into?

Its temperature would be between 700 K to 1000 K (430 to 730 °C), like Venus is today. On the other side of the planet that is facing away from its sun, the temperature would be too cold. Of course, the planet turns like our Earth so the astronauts would be in constant danger of being caught off guard from the star’s rays and subsequently be burned to a crisp. I am afraid that that planet is not suitable for habitation by humans. The oxygen, if there was any, would have been long gone. It is suspected that the air comprises of carbon dioxide. Humans cannot live on carbon oxide. They might be able to take oxygen from the ice but the process would be so time consuming, they would probably die long before they could succeed.

I am afraid that that planet is not for humans. While planets that are generally Earth-like may be plentiful, it is just as important that their larger system be agreeable to life. The habitable zone is a theoretical shell surrounding a star in which any planet present would have liquid water on its surface. After an energy source, liquid water is considered the most important ingredient for life, considering how integral it is to all life-systems on Earth.

The chief assumption about habitable planets is that they are terrestrial. Such planets, roughly within one order of magnitude of Earth mass, are primarily composed of silicate rocks and have not accreted the gaseous outer layers of hydrogen and helium found on gas giants.

It has been estimated that there are at least 50 billion planets in the Milky Way of which at least 500 million are of the habitable kind. However, they are so far away, and there is so little we know about them, it is highly unlikely that humans will ever venture that far out into space with a view of living on them. One thing that is for sure is that if humans did go on such a trek, they would not be returning back to earth. Who would be willing to make that trip into the unknown?

This is not to say that there are not extra terrestrial beings out there? On Earth, all life as we know it is based on DNA. Even plants have it. The existence of other beings in space with DNA is not in doubt. Their DNA could use a different genetic code than what is found on Earth. Their molecules could be based on some other complex molecule other than DNA or based on some other chemistry other than carbon, such as humans.

Alas, we will never know since it is highly unlikely that we will be visiting those beings and if they were vastly superior to us, they would have visited us which they haven’t—at least, not as of yet.

The good news is that humans will someday populate Mars because what we are learning is that that planet has potential for both water and oxygen. The bad news is that eventually, our sun will expand as a red giant and literally incinerate all the inner planets in our solar system. However, that won’t take place for many, many years.

Although folding space and its resulting wormholes have yet to be documented, there continues to be a healthy discussion in the scientific community about their existence. In theory, one would travel so quickly through a wormhole; that one would be moving faster than the speed of light. Professor Hawking puts it this way: “if you can travel from one side of the galaxy, to the other, in a week or two, you could go back through another wormhole, and arrive back before you set out.”

Is it far fetched? Maybe but then the idea of going to the moon was also far fetched at one time and if we have learned anything thus far, anything is possible.

No comments: