The landing on comet 67P was triumphant, but for scientists, the adventure is just beginning. This jagged and icy world is now located out past the orbit of Mars Mars but by summer will swing close to the sun. Comets are fascinating to space buffs and biologists alike for many reasons. For one thing, they are full of water and some of the organic molecules that make up the building blocks of life. Could they have delivered these ingredients to our planet?

To investigate this and other questions, the European Space Agency launched a craft the Rosetta Mission a decade ago. It reached its goal last August. Yesterday it sent a lander called Philae to the surface. Scientists dont know how long this refrigerator-sized lander will survive. It may be knocked down by high winds or comet-quakes, so it has been set up to do a host of experiments during its first days. Among its assignments drilling into the surface, grabbing some of the comets material and analyzing its composition. Here are three big questions that data from the mission could help scientists answer.

Image credit: European Space Agency

1. What are solar systems made of and how do they form?

Scientists have a pretty good general picture of our solar systems birth, which started some 4.6 billion years ago as the sun started to come together from a cloud of gases. In a swirling skirt of matter surrounding the infant sun, little particles of solid matter slammed together and grew bigger, in a process called accretion. That led to the eventual formation of planets, moons, asteroids and comets. As Villanova University astronomer Ed Guinan explains, comets are chunks that got flung out away from the sun, into the cold fringes of the solar system. Out there, they can hold frozen remnants of the original stuff from which our planet formed. The material that makes up earth and the moon, on the other hand, has been thoroughly cooked.

Scientists can learn a lot about comets through remote sensing, but never before have they been able to get a direct look at a piece of comet ice.

2. How did Earth end up with so much water when our understanding of its formation suggests it was once a hot, molten hell?

The accretion process that led to the birth of our planet would have made the surface hot perhaps even molten, explains astronomer Alan Stern of the Southwest Research Institute in Texas. Its not clear how all that water that makes up our oceans would have survived. One possible explanation comes out of the fact that after the Earth formed, things were still pretty chaotic. Our Earth continued to get bombarded with both asteroids and comets. Evidence for this heavy bombardment can be seen in all those pockmarks on our moon.

So the thinking goes that during this period of pummeling, comets brought at least some of our water to us. But how would we know? One clue, said Stern, comes from the proportion of so-called heavy water. Our ocean water is a mix of ordinary H20 and water in which one of the hydrogen atoms carries extra baggage in the form of a neutron. Tests done by Philae will be able to tell us how much of 67Ps water is of the extra baggage carrying type, and whether or not the proportion of heavy water matches that in our oceans.

3. How did life originate here and is there life elsewhere in the universe? Up until the later part of the 20th century, scientists thought those complicated carbon-containing organic molecules that make up living matter were a special product of our planet Earth, said Stern. It came as a surprise when they started turning up in meteorites (some of which actually stink when broken open), in comets (detected through remote sensing techniques) and even in interstellar space. Comets and asteroids both contain amino acids which are the component parts of the proteins that make up our bodies.

Excerpt from:

Three Mind-Blowing Things The Comet Lander Will Investigate Regarding Life In The Universe