Host of popular science show Cosmos and a renowned astrophysicist, Neil DeGrasse Tyson, has a list of five science questions of which he would like to know answers before he dies.

Lately, he shared these questions with MSNBC host Chris Hayes. Tyson said he hasn't got the answers of these problems till now. Therefore, he has asked scientists across the world to find out satisfactory answers for these questions.

Read on the following intriguing questions he wants to be answered till he is alive.

1. Why is the universe expanding faster?
After the Big Bang, the universe has expanded quite swiftly and is expected to continue expanding, but at a slower rate due to gravity. However, studies would unveil that the universe is expanding faster than ever irrespective of gravity.

2. From where most of the universe's gravity comes?
Dr. Tyson claims scientists can claim for one-sixth of the total gravity in the universe that comes from black holes, stars and planetary objects. Rest 85% of the gravity observed in the cosmos comes from unknown origins.

3. What was the situation before Big Bang?
Researchers have no idea on what was before the Big Bang. Neither time nor space would have existed during that time. For this reason, Neil DeGrasse Tyson describes it a negative time.

4. How life began?
There is no denying that theory of evolution very much explains about life and our existence as a species. But then also, scientists have not been able to know how life really began.

5. Are we alone in the universe?
Neil DeGrasse Tyson said liquid water is the basis for life. Therefore, he wonders if there are life forms outside earth's atmosphere.