Jim Peebles Quotes

The original project began because we know the universe is expanding. Everybody had assumed that gravity would slow down the expansion of the universe and everything would come to a halt and collapse. The big surprise was it was actually speeding up.

Up until the 1920s, everyone thought the universe was essentially static and unchanging in time.

The Big Bang theory is the idea that if we go back early enough in the history of the universe - and we can do this, of course, by looking at starlight coming to us from billions of years ago - we will see a very hot and dense period where the universe was much smaller, denser, and hotter.

For years, my early work with Roger Penrose seemed to be a disaster for science. It showed that the universe must have begun with a singularity, if Einstein's general theory of relativity is correct. That appeared to indicate that science could not predict how the universe would begin.

It now appears that the way the universe began can indeed be determined, using imaginary time.

You might expect gravity would slow it down, but it's just expanding faster and faster.

According to the standard model billions of years ago some little quantum fluctuation, perhaps a slightly lower density of matter, maybe right where we're sitting right now, caused our galaxy to start collapsing around here.

I am deeply impressed with the way dark matter has explained cosmological observations.

We know that the expansion of our universe is accelerating, which means a number called the cosmological constant must be positive.

Because there is a law such as gravity, the universe can and will create itself from nothing.

It's everywhere, really. It's between the galaxies. It is in this room. We believe that everywhere that you have space, empty space, that you cannot avoid having some of this dark energy.

The success of ordinary cosmology speaks against the idea that the universe was created in a random fluctuation.

We have never observed infinity in nature. Whenever you have infinities in a theory, that's where the theory fails as a description of nature. And if space was born in the Big Bang, yet is infinite now, we are forced to believe that it's instantaneously, infinitely big. It seems absurd.

'Eternal inflation,' as it's called - the endless generation of new universes - may be a hyper-cosmic imperative. It seems that it must happen.

They've discovered that, where all the other galaxies are moving in one direction, ours is going in another. Now, the Big Bang theory says that we're all moving outward.

The Planck satellite may detect the imprint of the gravitational waves predicted by inflation. This would be quantum gravity written across the sky.

We'll have four different gravitational wave windows open within the next 20 years, and each of them will see something different. We'll be probing the birth of the universe with this. The so-called 'inflationary era' of the universe. We'll be probing the birth of the fundamental forces and how they came into being.

The predominant theory of the origin of the universe is the Big Bang.

I'm baffled all the time. We don't know what's driving 96% of the universe. Everybody you know and love and heard of and think about and see in the night sky through a telescope: four percent of the universe.

And what we know, or think we know, about the universe of space and time is changing very quickly.

We get the exciting result that the total energy of the universe is zero. Why this should be so is one of the great mysteries - and therefore one of the important questions of physics. After all, what would be the use of studying physics if the mysteries were not the most important things to investigate?

Einstein wrestled with a problem back before we even knew the universe was expanding, and he was looking for a way to keep the universe from collapsing. And so he discovered, in his theory of gravity, something like this dark energy - he called it a cosmological constant - could play this role, pushing things away.

Every string theory that's been written down says the speed of light is universal. But other ideas about quantum gravity predict the speed of light has actually increased.

It was only about sixty years ago that the expansion of the universe was first observed.

We know there must be new physics. For example, we cannot explain what dark matter is.