Over the last couple of years we've been running a project in which you've been voting for the questions from the frontiers of physics you'd most like to have answered. The last question you chose is "What is space?" and we're talking to the experts now to bring you the answers. Previous questions were

• What is space?
• Are there parallel universes?
• Does infinity exist?
• Is there free will?
• What is time?
• How many dimensions are there?

Thanks for taking part in the project and happy reading and listening!

---

This project is a collaboration between Plus and FQXi, an organisation that supports and disseminates research on questions at the foundations of physics and cosmology. The FQXi community website does for physics and cosmology what Plus does for maths: provide the public with a deeper understanding of known and future discoveries in these areas, and their potential implications for our worldview.

Here are some of the questions we put to you which didn't win — post a comment on a blog if you'd like us to look at them again!

How did the Universe start?

What does modern physics say about the origin (or non-origin) of the Universe? And how can we test these theories? Vote for the start of the Universe or read these taster articles:

• On Plus: What happened before the Big Bang? — the answer will make your mind bubble.
• On FQXi: The holographic Universe — turning the Universe into a hologram to understand the birth of the cosmos.

What's the role of chance in the Universe?

Did chance have a hand in the early stages of the Universe? What does this mean for physics and how can we calculate the probabilities of different outcomes? To find out, vote for chance or read these articles:

• On Plus: Lambda marks the spot — is the biggest mystery of theoretical physics, the cosmological constant, a result of chance?
• On FQXi: Phantasms of infinity — can you define probabilities in the face of infinity?

What is information?

What does information really look like? Are there fundamental laws of information processing? And can they lead us to a physical theory of everything? Vote for information and read these articles:

• On Plus: The illusory Universe — what happens to information when it falls down a black hole?
• On FQXi: DoubleThink — storing information using quantum physics.

Will there be a theory of everything?

Finding a theory of everything is the biggest challenge for modern physics. Will we ever find it? And what will it look like? Vote for the theory of everything and read these articles:

• On Plus: String theory: from Newton to Einstein and beyond — on the currently hottest contender for a theory of everything.
• On FQXi: The quantum PlayStation — how the PS3 is helping physicists develop a theory of quantum gravity.

What is quantum cosmology?

We've all heard of quantum mechanics, the physical theory that describes the microscopic world so well. But what happens when you apply quantum mechanics to the whole Universe? If you'd like to find out, then vote for quantum cosmology or read our taster article:

• On FQXi: The holographic Universe — Take one universe, turn it into a hologram, find its quantum wavefunction and understand the birth of the cosmos.