Physics A–Z: I

Topic
If photons have no mass, how can they have momentum?

Discover how photons, despite having no mass, can still carry momentum and affect the world around us.,

If you view the Earth from far enough away can you observe its past?

Imagine seeing Earth as it was thousands of years ago — is this possible if you look far enough into space?

Is nuclear fusion power really close to becoming a reality?

Could the energy of the sun be harnessed on Earth in our lifetime? Discover what's holding fusion power back — and why it might finally work soon.

Is temperature a Lorentz invariant in relativity?

Temperature may seem simple, but relativity adds a twist—does it stay the same for all observers?,

Is time continuous or discrete?

Does time flow smoothly like a river, or does it tick like a clock? Explore the debate between continuous and discrete time.

Is time not absolute?

Discover how time might not be the same for everyone, depending on where you are or how fast you're moving.