Seeking life on Europa...

As NASA develops its next "flagship" mission to the outer solar system, Jupiter's enigmatic moon Europa should be the target, says Arizona State University professor Ronald Greeley. Although Europa lies five times farther from the Sun than Earth, he notes it may offer a home for life.Greeley, a Regents' Professor, heads the Planetary Geology Group in ASU's School of Earth and Space Exploration. He presented the Europa proposal on Feb. 18 at the annual meeting of the American Association for the Advancement of Science in San Francisco."Europa is unique in our solar system," says Greeley. "It's a rocky object a little smaller than our Moon, and it's covered with a layer of water 100 miles deep." This holds more water than all the oceans on Earth, he explains. Greeley adds that Europa also has the two other basic ingredients of life -- organic chemistry and a source of energy. Scientists have identified four candidate worlds beyond Earth that might contain life, either now or in the past, Greeley says. These four are Mars, Saturn's moons Titan and Enceladus, and Jupiter's moon Europa. Mars is the target of numerous ongoing missions, and NASA's Cassini spacecraft is studying both Titan and Enceladus at present. Cassini's results, however, show that Titan and Enceladus have temperatures hundreds of degrees Fahrenheit below zero and may not hold any liquid water.

NASA's Galileo mission surveyed Europa in the late 1990s. Greeley notes the mission found that Europa's surface ice was mixed with organic minerals that came up from the solid rocky part of the moon or were deposited by meteorite and comet impacts at the surface. Yet Galileo's results raised more questions than answers."We know Europa's surface is frozen," Greeley says. "But we don't know if it's frozen all the way down, or if there's an ocean under an ice shell."The ice thickness is a key question, notes Greeley."Ultimately, we want to get down through that ice shell and into the ocean where any action is," he says. "So it matters whether the ice is 10 yards thick, or 10 miles or more. The data we have today will never answer that question."

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Can We Colonize Titan in the Future?

Scientists from all over the world are trying to find another Earth in the endless universe.

Researchers like Robert Zubrin have developed plans to make other planets like Mars inhabitable.

About Titan

Titan is the largest moon of Saturn and the second largest moon in the solar system after Jupiter’s Ganymede. Titan is about 50% larger than our own moon and is also larger than planet Mercury. Titan is also the only moon in the soar system with a dense atmosphere that is even denser than that at Earth. Considering 0.376g Gravity on Mars we can say that in this case Titan doesn’t have much for us as it is having a gravity of 0.14g. Though it is much less than that on Earth yet it is enough to keep humans on the ground.

With so much to offer for the humans still the question remains that can Titan support life…?

Studies have demonstrated that the most important and advantageous target in the solar system for colonization is Titan.

Why Titan?

Titan has an abundant supply of raw materials that are necessary for life. Robert Zubrin has also stated that Titan is the most hospitable extraterrestrial world within our solar system for colonization.

Titan’s atmosphere contains plenty of nitrogen and methane. There is also strong evidence that the liquid methane and liquid water are present under the surface of Titan which are often delivered to the surface by a volcanic activity.

This water can easily be used to generate oxygen. Water and Methane can also be easily converted into rocket fuel which can be used for a power supply. All these gases that are Methane, Nitrogen and ammonia can also be used as a fertilizer for growing food.

Moreover the atmospheric pressure of Titan is the same as five meters underwater. This will reduce the difficulty and complexity of engineering that is required for landing a craft when compared to that in case of almost zero pressure planet like Mars.

This thick atmosphere will also act as a protective shield for solar radiation which can have serious medical problems in humans.

Now let us consider the average surface temperature of Titan. Here is where we start to have some problems. Since Titan is about 1.4 billion km from sun its surface temperature is about -179-degrees Celsius. This means that we should be having effective heat generation and insulation techniques available before we try and land on Titan.

Why is Titan a much better choice than Mars?

Both Titan and Mars are thought to be the places that can be made inhabitable. But still Titan is a much better choice. The reasons for this are:

• Titan has a dense atmosphere that is about 1.5 times thicker than that on Earth. On the other hand Mars is having no atmosphere and will require extensive Teraforming processes before we get an atmosphere on it.

• Titan has abundance of life supporting materials that includes water, methane and Nitrogen. Water can be converted into oxygen and Methane can be used as a fuel for all power needs. On the other hand if we consider Mars, we are not even sure that the planet has some water, forget about all other gases.

• Since Titan has a thick atmosphere so the humans that live there will remain protected from all cosmic radiations. On the other hand the major problem on Mars is that it is not having any such atmosphere to protect life.

• Titan has an induced magnetosphere which can deflect all the harmful solar winds. But we don’t find any of it in Mars.


What are the problem areas?

Despite of the positives of the approach there are also a few problem areas that are to be dealt with, these include:

• Titan is about 1.4 billion Km from the sun. So far that the solar heat cannot reach there. This makes Titan a very cold world where the surface temperature is -179 degrees Celsius. We need to have massive heat generation and insulation systems else all humans will immediately freeze to death.

• Titan has an induced magnetosphere but is not having any of its own which can deflect all the harmful solar winds.

• Though we will remain protected from cosmic and other harmful rays on Titan still humans will be exposed to all these radiations when they are on the way to Titan which will be a pretty long journey.

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