Are we alone in the universe?

After reading about the 20 big questions in science, I have chosen the question: Are we alone in the universe? I am interested in this question because it is a very interesting concept. If many planets in the universe can sustain life, then is there alien life out there?

1) How many of the stars we see in the sky actually still exist?
2) Can mars sustain micro-organisms because of the recent finding of streams?
3) Is it possible for a break in the time-space continuum?
4) Could a person safely travel through a wormhole if one existed?
5) Is the process of aging stoppable or reversible?
6) Are humans still evolving even though we have created adaptations around us?
7) Are the polar ice caps the world's air conditioning?
8) Can space travel at "warp" speed be possible?
9) If you shine a light into space, will the light keep going when you turn the source off like stars?
10) Is the aging process caused by your body fighting off bacteria?
11) How can chemicals known to the state of California to cause cancer mutate cells?
12) Is it possible to use the earth's magnetic field to cause things to levitate?
13) What type of damage could the emissions of Volkswagen cars have done to the environment?
14) Why do objects create their own gravitation field with enough mass?
15) Why does the sun keep planets in an elliptical orbit, and not a circular orbit?
16) Why does coke dissolve a nail within 2 weeks?
17) When you pour acid on an object, how does it dissolve the object?
18) How do chemical reactions get affected by temperature?
19) Can we change the properties of a material? Example ( Make egg rubbery/bouncy)
20) How does cornstarch + water maintain a liquid and solid form at the same time?