Arrow of Time Quotes

The asymmetry of time, the arrow that points from past to future, plays an unmistakable role in our everyday lives: it accounts for why we cannot turn an omelet into an egg, why ice cubes never spontaneously unmelt in a glass of water, and why we remember the past but not the future. And the origin of the asymmetry we experience can be traced all the way back to the orderliness of the universe near the big bang. Every time you break an egg, you are doing observational cosmology.

The arrow of time doesn't move forward forever. There's a phase in the history of the universe where you go from low entropy to high entropy. But then, once you reach the locally maximum entropy you can get to, there's no more arrow of time.

Time has two aspects. There is the arrow, the running river, without which there is no change, no progress, or direction, or creation. And there is the circle or the cycle, without which there is chaos, meaningless succession of instants, a world without clocks or seasons or promises.

Time never runs backward when I need it to. Not for me, and not for anyone else.

The story of the universe finally comes to an end. For the first time in its life, the universe will be permanent and unchanging. Entropy finally stops increasing because the cosmos cannot get any more disordered. Nothing happens, and it keeps not happening, forever. It's what's known as the heat-death of the universe. An era when the cosmos will remain vast and cold and desolate for the rest of time the arrow of time has simply ceased to exist. It's an inescapable fact of the universe written into the fundamental laws of physics, the entire cosmos will die.

So far as physics is concerned, time's arrow is a property of entropy alone.

I'm trying to understand cosmology, why the Big Bang had the properties it did. And it's interesting to think that connects directly to our kitchens and how we can make eggs, how we can remember one direction of time, why causes precede effects, why we are born young and grow older. It's all because of entropy increasing.

Or in other words, why does disorder increase in the same direction of time as that in which the universe expands?

The increase of disorder or entropy with time is one example of what is called an arrow of time, something that distinguishes the past from the future, giving a direction to time.

Disorder increases with time because we measure time in the direction in which disorder increases.

The laws of science do not distinguish between the past and the future.

It's not clear in physics why you can't see the future.

The particular aspect of time that I'm interested in is the arrow of time: the fact that the past is different from the future. We remember the past but we don't remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can't turn an omelet into an egg.

Thus is our treaty written; thus is agreement made. Thought is the arrow of time; memory never fades. What was asked is given; the price is paid.

The weird thing about the arrow of time is that it's not to be found in the underlying laws of physics. It's not there. So it's a feature of the universe we see, but not a feature of the laws of the individual particles. So the arrow of time is built on top of whatever local laws of physics apply.